ecoLincNZ

10000 maniacs?

2012-01-19T15:42:00.005+13:00

Over the holiday break Ecolincnz reached a significant milestone with our 10000th visitor. When the blog was launched on April 4th 2009 we hoped to provide information about ecology research being done in and around Lincoln University, particularly at the Department of Ecology. We weren't sure what to expect but we did hope that Kiwis, especially high school kids and their teachers, might like to see what was being done in their own backyard. We also hoped that a few overseas visitors might drop by. Since 5th April 2010 we have collected information on where visitors come from. Although Canterbury is the biggest source of visitors in New Zealand (1084) there are more visitors from the North Island overall.

What is surprising is that 59% of our traffic is from overseas. one in four visitors are from the US with most of them from Califonia, Texas and New York - we have someone from every state except South Dakota! There is a large gap back to the next countries: United Kingdom (5%), Australia (4%) and Canada (3%). It's hard to know what to make of some of these numbers. Germany with 125 visitors seems low given the close links that Lincoln has with Gottingen University whereas 71 from the Philippines seems more than we might expect. For the single visitors from Iceland, Angola, Cambodia, Uruguay and the 20 other countries with one visitor we say welcome, come back soon, and bring a friend. At this stage we are still happy with how things are going, and we even use the blog as an assessment tool for our masters students, so we will continue to bring you details about ecology in our region.

Along came a SPIDER

2012-01-17T13:31:00.011+13:00

As Rowan Atkinson said "There is a certain level of uncertainty about, of which we can be quite .... quite sure". The problem with living in the information age is trying to deal with all of the information as well as the uncertainty. We need to have good filters to remove the noise and retain the signal. This is a real problem in biology where, with the advent of technology to collect DNA, there is far more data than we can often sensibly deal with. Another problem is that although there are often useful tools for making sense of the data they are usually scattered around the internet and can be difficult to find. A group of Lincoln molecular ecologists, including Rob Cruickshank and Stephane Boyer, have put time an effort into creating a tool to help identify species and to understand speciation. The package is called SPIDER and the details of what it can do are found in a paper from Molecular Ecology Resources.

The SPIDER package (SPecies IDentity and Evolution in R)uses the the statistics package R (which is free to use) to develop tools to aid researchers in handling barcoding data. Genetic barcodes are regions of DNA (often the CO1 gene) that are unique to each species. Taking DNA from an unknown specimen, examining its barcode gene region and comparing with a DNA library allows that specimen to be positiviely identified. The SPIDER package provides summary measures of genetic distances between samples, assessments of variation and test of how accurate each match is are part of the statistics provided. SPIDER also implements a sliding window analysis that explores signal conflict within the gene region (not all data say the same thing) and allows the uncertainty to be shown in the evolutionary tree obtained from the data.

The package is in constant development and there are tutorials and a manual available from the SPIDER webpage. If you are in the business of DNA barcodes then this will be a useful tool to add to your work. Of that we can be quite sure.

The rules of attraction

2011-12-19T12:58:00.006+13:00

It's the end of the year and, as such, I get to combine two things that I like and dislike the most. It's cricket season with representative tournaments all over the place. I am fortunate to have three boys with good cricket ability and I have a real passion for coaching the game. One thing about cricket is that it needs a lot of gear. And it ain't cheap! It is also Christmas time and that means shopping. I do not have a real passion for this. However, my sons' and my interest in cricket does make it easier to think of presents... (And, no, they don't read this blog so they are not getting a hint before the big day). But where to go to get the gear? Actually, it's an easy decision for us as one shop with a good name in cricket gives a discount for players in my district. Why would they want to get paid less for their products by me? Well they want to attract me into their shop so that I buy stuff (and hopefully more than I enteded). They reward my behaviour by giving me a bargin. As it turned out we did spend considerably more than we planned... So this store uses an 'attract and reward' system so that they will gain benefits of their own. Seems like a good idea for humans but also something that might be useful in nature. Afterall, there are many opportunities to attract species of some benefit to you.

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A group of researchers, including Steve Wratten and Sophie Orre-Gordon from the Bioprotection Centre at Lincoln University, looked at the role of 'attract and reward' systems in crops, such as wine-grapes, broccoli and sweetcorn. These researchers provided artificial attractants modelled on herbivore-induced plant volatiles (HIPV). When plants are damaged by herbivores they produce HIPVs to let natural enemies of the herbivores know that their next meal is available on that particular plant. It saves these predators from having to spend so much time searching. The researchers, who published in Journal of Applied Ecology, used artificial HIPVs to bring natural enemies into a crop (attract) and planted buckwheat as a food source (reward). Insect numbers were monitored using yellow sticky traps over several weeks. Were these attempts to get more predators into crops successful? Certainly,there were more beneficial insects found in the crops. The 'attract and reward' system seemed to work for this. Of course, this system is only useful to the plants if these beneficial predator and parasitoid insects species actually reduce pest herbivore numbers. Significantly fewer pest larvae were found in the crops which had higher number of beneficial insects and this translated to significantly less damage on the fruit. So this seems like a win-win-win situation where the plants, growers and beneficial insects are all working together and getting good results. Now I'd better head off and finish my gift buying, there's a loyalty card deal going on at the mall.

Dirty needs non dirt heap

2011-11-23T14:23:00.007+13:00

As I mow my relatively small lawn I am always faced with what I should do with the lawn clippings. I could put them in a green waste bin or put them back into my garden soils. I usually go for the latter - it's easier and I feel like it's a better option for my garden. Nutrients go back into the soil, carbon is contained in my property, I don't get a sore back from carrying the catcher to the bin. The same decision making probably happens all over the world in people's yards. Given the sheer area of urban soils around the world this is probably an instance of where lots of small decisions add up to a major impact on the world around us. Just how useful is putting greenwaste back into the soil?
Nick Dickinson moved to New Zealand last year to take up a position as the Head of the Department of Ecology at Lincoln University. In between earthquake aftershocks he has found time to publish on this issue of urban soils with Luke Beesley. In a study published in Soil Biology and Biochemistry, Nick looks at what happens to dissolved organic carbon and heavy metals under different soil treatments.

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Nick set up experimental containers of soil and added greenwaste to some, biochar (a coal-like product) and noncomposted woody material in others. He also looked at the affect of adding earthworms as they churn the soil. The experiments were left for two months before water was collected from each and analysed for dissolved organic carbon and heavy metals. Addition of the various materials all contributed to increased mobility of dissolved organic carbon and heavy metals (rather than staying 'locked' into the soil they were moving around in water). Greenwaste seemed to increase this mobility compared to the biochar and woody materials. Earthworms also contributed to this mobility.
What does this mean for urban soils? While these additions increase the health of the soil, often urban soils are high in heavy metals. Ideally we do not want these metals to move out of the soils where they could contaminate ground water. Urban soils are also a useful place to lock up carbon and, again, we don't want it to move out of the system. So Nick and Luke conclude that non-composted additions are probably better to add to soils. However, they are quick to point out that doing these experiments at larger scales (like a backyard) are important before we read too much into the results. So I'll go on adding the lawn clippings to my garden soil in the meantime while knowing that acting locally really may be affecting globally!

Darwin down on the farm

2011-11-15T14:16:00.005+13:00

To Darwin, agriculture was a vital source of evidence for evolution and for natural selection. One area where Wallace disagreed with Darwin was in how useful agriculture was in explaining evolution. Wallace thought that the comparison was not very close nor was it very effective whereas Darwin devoted much space to it in the Origin. In many ways Wallace was proven correct as evolution has been only a bit player in agriculture over the last 150 years. Until now. A new book, Pragmatic Evolution: Applications of Evolutionary Theory edited by Also Poiani, is due out in December and looks at where evolution is helping to understand the world around us in a practical sense. One of those areas in in agriculture. One of the chapters, Evolution in agriculture, is written by Steve Wratten (Lincoln University) with a former student Mark Gillespie and colleague Aldo Poiani. In this chapter they review how understanding evolution is transforming what we know in the area of agroecology. Steve points out that most agricultural activities attempt to halt evolutionary processes, trapping ecosystems in a state which produces consistent crops and so on. Much evolutionary conflict comes from this including resistence to insecticides, reducing diversity in communities,and removing natural predators and competitors. Taking an evolutionary approach allows us to build more natural and sustainable agricultural ecosystems. In the chapter Steve explains how an evolutonary approach is vital for agriculture to move forward. Hopefully this is the start of evolution regaining its natural place in this most human of endeavours and that Darwin is welcomed down on the farm.

What they will be doing this summer

2011-11-14T16:01:00.004+13:00

Every summer the Department of Ecology offers summer scholarships to undergraduates to get a taste of research (and to be paid for 10 weeks doing it). It's a great way to figure out if this research lark is for you, to make contacts and to meet staff and postgraduates. This year we welcome a number of students who will be calling the department home for the summer.

Gerrit Roux is working on Using morphological and molecular approaches to determine the diet of ground beetle candidates for translocation to Quail Island with Stephane Boyer and Mike Bowie.

Maree Henderson-Fitzgerald is working on the Styx Living Laboratory with Kelly Walker.

Also at the Styx is Chris McClure examining the Effectiveness of a predator-proof fence for conserving lizard fauna in the Styx Catchment with Kelly Walker.

Cathy Mountier will work on the establishment of a monitoring programme for the Punakaiki Coastal Ecological Restoration Project with Mike Bowie.

Ben Wiseman will work with Kelly Walker to enhance and update the Entomological teaching collection.

Marie MacDonald will balance on cliff edges with abundance, behaviour and distribution of the Mt Somers bluff weta – Life on a precipice working with Mike Bowie.

Denise Ford will test a range of rodent traps and baits for species selectivity, bycatch, and animal ethics with Mike Bowie.

Finally, Ceridwin Benn will examine microbrial species compistion in possum bites as a means of identifying individuals with James Ross, Adrian Paterson and Rob Cruickshank.

Good luck and happy researching to these students! We'll find out how it all went next March.

Of questionable character

2011-11-01T16:14:00.004+13:00

It is almost election time here in New Zealand. This year we have been spared much of the usual hoo hah because of the recent (and spectacularly successful) Rugby World Cup dominating the news as well as the Canterbury earthquakes before that. One of the tasks that we will have on Election Day is to find out what New Zealanders think of our voting system. We moved away from a winner takes all 'first past the post' system 15 years ago but there is a move to bring this back. The problem with 'first past the post' is that you can become the government despite winning less than half the overall vote, and once you are in you can act as if you won 100%. Other systems encourage representation in proportion to the amount of votes you won. What has this to do with ecology? Well it turns out that there are similar issues when it comes to analysing large molecular data sets. Such data sets can tell us about the evolutionary history of a group of species; who is related to who and when their last common ancestor lived. The problem is that most of the methods for finding these patterns tend towards the first past the post ideal. The evolutionary tree is built from the strongest signal and other signals are ignored.
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Rob Cruickshank has explored the issue of character conflict within molecular data sets in a recent issue of Zootaxa. Ideally, your data set would contain one signal, that of the evolutionary history of a group. Unfortunately there are a number of factors that can introduce other signals, such as convergence, parallel evolution, human error, high rates of change and so on. So within your data set there are usually competing signals, much as within society there are competing political parties. Most analyses simply find the signal with the most votes and this is proclaimed the winner. However, Rob points out that there are several ways to find smaller strength signals to further analyse, after all one of these might be the true answer of how species are related. For example, the fantastically named spectral analysis looks at each signal in the data and shows how much support there is (how many characters agree with this signal) and what conflict they have (how many characters disagree with this signal). Sometimes the signal with the greatest support has a lot of conflict whereas the next largest signal has none. Given that we might expect the correct phylogentic signal to have little conflict then this might encourage us to look further than the loudest signal. This would be like being given two votes: one for the person/party that you wanted to support and one for the person/party that you especially didn't want. If the leading candidate is also the one with the largest conflict then maybe they are not as good for consensus politics as the next candidate with a much lower conflict score. Certainly, in the world of species relationships determined by molecular characters, this might be something worth considering.

Lantana: a fuel's paradise?

2011-10-13T11:12:00.007+13:00

Given the sheer number of invasive species in New Zealand and the difficulties that we have with them it often feels like things couldn't get much worse for our native ecosystems. Of course things can always get worse and there are some prominent invasive pest species in other parts of the world that we don't have, thankfully, here in New Zealand. One of these is the weed shrub lantana (Lantana camara). Although this South and Central American species is a major problem in various parts of the world, all I knew about it was that it was good at invading bush edges and regularly disturbed environments, hard to get rid of and was the title of a very good movie featuring Geoffrey Rush. Thanks to our new plant ecology lecturer, Tim Curran, I now know a great deal more.

Tim recently moved to our Department of Ecology from a field station in northern Queensland where he was part of the School for Field Studies at the Centre for Rainforest Studies. Lantana is a problem species in this part of Australia and Tim and colleagues have just published a paper in Weed Research on a potentially insidious aspect of this species. Lantana often invades dry rainforest (yes a strange combination but an important habitat nevertheless!) where it dominates the understory. One of the suggested problems that this invasion causes is in changing the fire regime, such that these habitats become more prone to fire. This change could be the result of chemicals in lantana that make it more ignitable (and therefore fires are more likely to start) or, by changing the structure of the understory, more fuel may accumulate that would aid in the spread and duration of fires (making them more damaging).

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Tim and his undergraduate students went to field sites in Forty Mile Scrub National Park and measured fuel bed depths, leaf litter depths, % cover of fuels in areas with and without lantana. They also took lantana specimens back into the lab and measured how much dry matter the leaves and twigs had as well as burn durations.

The results were reasonably clear-cut. Lantana was not found to be particularly ignitable. In fact, lantana burnt faster than many native plants, which would usually decrease the damage from a fire moving through a forest. However, measurements of fuel loads in dry rainforest found that fuel cover was significantly greater in areas with lantana and fuel bed depth changed from 9 cm without lantana to 66 cm with lantana. So, lantana added significantly more fuel to burn in the habitat (so fires would burn longer and more intensely in an area) and also allowed greater access to the canopy layer of the forest (so that parts of the habitat not normally at risk were affected).

This research helps to show why lantana is such a successful weed species. It is a species that is very good at colonising disturbed habitats and this study shows that lantana can cause further disruption of the habitat, allowing itself to become even more competitive. This study suggests that removing lantana from forest edges near frequently burned savannas should be a high conservation process. All in all, this is certainly one species we can do without here in New Zealand!

The web stays in the pitcher

2011-10-03T17:21:00.009+13:00

Some of my earliest biology memories are as a 9 year old at Balclutha Primary School working through food web diagrams. The idea of the interconnectedness and interdependence of life was an extremely powerful idea and I recall the first afternoon we worked on food webs more vividly than most in my primary years (although the day Rolf Harris came, sang and painted a picture was pretty cool; and then there was the great pea-shooter battle one afternoon – but I digress).
Of course at the time it was comprehending that the big things eat the little things who eat the planty things that really sank in. Suddenly the natural world around me started to make sense in a cool and interesting way. From what I see from my own sons’ passages through primary school, the whole food web activity still seems to exist, hopefully influencing future biologists. Which is great, as there is still much to be done on understanding how food webs work. Hannah Buckley (Lincoln University) and colleagues from around the USA have worked on a very simple food web that can be found all around North America, the fluid filled pitcher plant, Sarracenia purpurea. The long-lived (> 50 years) carnivorous plant grows in bogs, sand plains and pine savannahs across much of North America Within this carnivorous plant lives a small community that typically contains 6 arthropod species, 9 protozoans and 17 bacterial species. The beauty of the pitcher system is that the food web is about as simple as you can find, the links between the different species is reasonably well understood and, more importantly, the system is replicated in thousands of sites at a continental scale. That makes for a great natural experiment which they investigated earlier by looking at the variation between populations. In the present study they wanted to see what effect temperature, rainfall, atmospheric nitrogen availability as well as the abundance of the keystone species (the pitcher plant mosquito, Wyeomyia smithii) had on food webs.

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The team collected data from all over North America. At the level of individual pitcher plants, food web complexity was proportional to the volume of liquid in the plant – the more liquid, the more complexity (meaning the pitchers act just like little islands). At the scale of sites over North America there was a less clear cut picture of the pitchers. The further north the site was (moving to higher latitudes) the less variation there was is the various traits of the pitcher food web but, overall, food web structure was not driven very much by climate variables like rainfall and temperature and it seemed that food webs at sites were often built simply by which species historically happen to have arrived in the site in which particular order. This finding is a bit unexpected as it suggests that random processes play an important role at the larger scales. So there’s plenty more work to do on this great little model system. There is something quite satisfying in finding that food webs are still as cool and interesting as that day long ago in South Otago.

It's thieves, not killers, that you should worry about!

2011-09-12T17:00:00.000+12:00

You know, just once I would love to see some ecological research that found a really simple answer that explained the phenomenon under study. Alas, we live in a complicated world where it is difficult to make robust predictions. I guess it keeps us ecologists in jobs. For example, possums are the biggest pest species in New Zealand wild areas, controlling their numbers must be a good idea. Introduced stoats are a devastating predator in most of our ecosystems, again controlling them must be the best thing to do? Turns out that (surprise, surprise) it's just not that simple. There is the cliche that 'nature abhors a vacuum' and that applies to ecosystems as well. Remove a species from a local area and suddenly a different species has a new opportunity. The remaining species might benefit because you have removed its main predator and so numbers will boom (called mesopredator release) or because you have removed a competitor for resources and so numbers will boom (mesocompetitor release).

Wendy Ruscoe from Landcare Research and a host of authors, including Richard Duncan from Lincoln University have examined the issue of meso-release in New Zealand ecosystems where there is a complex interplay of introduced pest species that degrade the natural ecosystems. There work has just been published in Ecology Letters.

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The group worked in forests of the North Island of New Zealand where they looked at interactions between a top predator (the stoat), two mesopredators (rats and mice) and an omnivore (possum). These are all species that are often controlled to reduce population numbers. (Note that in New Zealand the word 'control' generally means 'kill'). The team set up areas of stoat removal, possum removal, possum and rat removal and a control with no removal. Populations in the areas were assessed before and after control operations. The results were convincing. The removal of stoats (a top predator) caused no response in the two mesopredators (mice and rats). The removal of the omnivore (possum) released rats and their populations grew. The removal of rats led to a growth in mice numbers. The net result for the ecosystems was that removing possums and rats (while useful in the short term) probably had little long term benefits as other competitive species filled the void and continued to cause problems for the native biota. The lack of an impact from the removal of the predator was of great interest and suggests that competition, not predation, is the important process that shapes communities. So wildlife managers need to think in terms of multi-species control if they want to effectively manage ecosystems in the long term. Which is a reasonably non-complex answer for a complex process!

Buoyant moas and overweight explorers

2011-09-02T15:16:00.006+12:00

The Third Combined meeting of the Australian and New Zealand Entomological Societies Conference has just concluded here at Lincoln University. Four days of good talks and plenaries. About 200 participants, of whom about a third were postgraduate students, made for much excellent discussion. I was involved in the opening symposium on New Zealand biogeography and whether we should consider Australia to be the mothership or sistership of our biota. I talked through a rough overview of the geological history of Zealandia and the implications for our biota. I strongly urged that we need to start thinking in terms of a Zealandia biota in addition to a Gondwanan biota. I also reiterated the geological evidence for the Oligocene drowning of Zealandia that saw almost all of New Zealand underwater about 23 million years ago (for previous blogs on these issues see here , here , here , here and here). I'm pleased to report that the concept of Zealandia and of a dramatic drowning seem to be gaining traction as measured by the content of other talks at the conference. There is one aspect, though, that I would like to address: the curious case of the buoyant moa.

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Pete Cranston delivered the opening keynote address to the conference just prior to our symposium. He spoke about austral chironomids (freshwater insects) and what they tell us about the ecological and biogeographical history of our part of the globe. All very interesting and delivered in his usual witty manner. At one point Pete thought to make a point about the likelihood of the Oligocene Drowning having occurred. One common response that I get to the idea is "yeah but what about the moa?". Moa were gigantic birds once common in New Zealand until driven to extinction by humans and are related to other large birds around the southern hemisphere. People find it hard to comprehend how big flightless birds could colonise an area across a big water gap. Pete illustrated this problem with the moa buoyancy hypothesis that was put forward by Rich Leschen in 2008 (you can find it here - scroll down to page 5). Although meant in a humorous sense, moa have natural floatation abilities to get across water gaps (and are spacious enough to bring other passengers), it is really saying "what a silly idea the drowning is to even contemplate that moa could colonise New Zealand". Of course I beg to differ.

I could come up with several comebacks. Kiwi, another ratite, clearly arrived well after the Zealandia broke away from Gondwanaland (as determined by molecular dates) and are more closely related to emu than to moa! So they got across the water OK. We now know that South American tinamou (small and flighted birds) are part of the ratite group and that the ancestors of each ratite regional group were able to fly and colonise these regions. Island species also often share a common evolution trajectory which results in gigantism and flightlessness in birds. So there is a method for moa to get across the water OK and one that explains why the are so large. Finally, we should not fall into the trap of assuming that modern traits were always the same. I think I'll call this the 'Fat explorer hypothesis'. New Zealand is fast catching the USA as the most obese country in the world. If I was looking at modern New Zealand and thinking about how humans arrived in our shaky islands, I might think that clearly, based on what we know about early waka and the sailing ships of Cook and the size of present day New Zealanders, that we would have been much too large to have fitted into these vessels and so there is no way we could have got here in that manner. Perhaps our ancestors lived in Gondwanaland and walked (waddled?) into Zealandia before it split apart? Of course this is a silly arguement, present morphology (large and round) is not a full-proof predictor about previous morphology (small and wiry). Clearly, our ancestors were much smaller and quite happily fitted their ships. In recent times, their descendants have have burgeoned until we see the size of our present populations. A good analogy for the moa perhaps. All good fun!

Blue hotels: nestsite location in Little Penguins

2011-08-23T15:25:00.001+12:00

Little Penguins (or Blue Penguins, Korora, Eudyptula minor or even, in Australia, Fairy Penguins) are the most common penguin to be found in New Zealand. They have numerous colonies ranging from a few nest to several thousands and they are found all around our shorelines.Despite being the most numerous penguin species in the New Zealand region there are concerns about population decline throughout the range. Some areas of New Zealand are of greater concern than others. Little penguins are restricted to colony sites that have easy access to the sea, where there is good soil to build burrows (or small caves) and where the right food is found in inshore waters.
One area of New Zealand that has been little studied for Little penguins is along the west coast of the South Island. Many colonies along this coastline are threatened with encroaching development by humans as well as a increasingly busy coastal highway. A recent study by Lincoln University researchers Jasmine Braidwood and Kerry-Jayne Wilson along with Janine Kunz (Georg-August University)examined which features of the habitat were important for burrow use and breeding success along the West Coast.

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Braidwood, as part of her Master of International Nature Conservation, collected data from 167 burrows and artificial nest boxes spread through five colonies in the Buller region as well as 110 burrows across three colonies in South Westland, over three years. Information on numbers of eggs, chicks and adults seen was recorded as well as distance from the high-tide line, track/road and edge of scrub, vegetation type, and terrain.

Over the two years, Little penguins were found in 1/3 to 1/4 of all burrows available, and breeding success increased over the period and was broadly similar to other parts of New Zealand. Most colonies were found in regenerating coastal forests and most burrows were with 25m of the sea. Of most interest was the lack of obvious impact of human activity on breeding success which gives some optimism for the future. The authors worked closely with the West Coast Blue Penguin Trust and hope that this study will provide information for improving the placement of nest boxes in Little penguin colonies in the future to best ensure good breeding success.

Strewth! Australasian insect conference at Lincoln

2011-08-12T11:25:00.003+12:00

The third combined Australian and New Zealand Entomological Societies conference will be held at Lincoln University from 28th August to 1st September. The theme of the conference is "The Status of Australasian Entomology: Where the bloody hell are we?". Currently, about 200 lovers of all things insecty (and honorary insects like spiders) are set to swarm on Lincoln. Participants will hear from keynote speakers Peter Cranston (What can insects, especially Chironomidae, tell us about austral ecological and biogeographical history?), Georgina Langdale (The economics of nature- findings from the TEEB study), Mark Burgman (Making the most of intelligence information and expert judgements for biosecurity), and Andy Suarez (The biogeography of ant invasions and its implications for biosecurity). Plenary speakers feature Steve Goldson, Steven Chown and Robert Hoare.

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There are several themed sessions including:
Australia: Mothership or sistership th the New Zealand invertebrate fauna
Strategic trans-Tasman collaborations enhance arable and vegetable IPM in Australia and New Zealand
Biological control of athropods
Biodiversity and ecosystem services
Communication in a digital age
Climate change and insects
Community ecology
Conference organiser John Marris (Lincoln University Research Museum) promises an informative and fun time with lashings of 3 Boys beer and Wither Hills wine!

A fine pine: Kakapo not picky about their diet

2011-08-10T04:43:00.001+12:00

This article was prepared by postgraduate student Ana Baral as part of the ECOL 608 Research Methods in Ecology course. This marks the last of this year's cohort. Thanks to the class!

Kakapo are found only in New Zealand where these magnificent green parrots struggle for their survival. Only a few of these large birds survive in their natural habitats and are listed as a critically endangered species. Kakapo are unusual parrots in that they become active at night, cannot fly and forage on plants. These birds are ‘treasures’ of New Zealand.

Kakapo are vulnerable to introduced mammalian predators. By the mid 20th century, only a few Kakapo were fighting for existence in Fiordland and Stewart Island. Between 1970 and 1990, all known Kakapo were moved to predator free islands. One such island was Maud Island, in the Marlborough Sounds, because it was free from feral sheep and goats as well as mammalian predators of the Kakapo. The natural forest of Maud Island, now a scientific reserve of 309 ha, was highly modified to pasture and farmlands in the late 1800s. The island was brought back into the conservation estate in 1972 and restoration began. Nine birds were taken to Maud Island between 1974 and 1981.

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Fruiting species, including gooseberries, blackcurrants, guava and apple, were planted in 1975 to provide additional food for Kakapo. Since 1990, Kakapo have been provided with protein rich supplementary food , which includes apple, kumara (sweet potato), and the kernels of almonds, brazil nuts, sunflower seeds and walnuts, to induce breeding artificially.

In an effort to better understand Kakapo, Julie Walsh and Kerry-Jayne Wilson of Lincoln University and Graeme Elliott of Department of Conservation, New Zealand carried out research about home range size and habitat selection of Kakapo on Maud Island. At the time, there were 18 Kakapo on the island; four adult males, nine adult females and five juveniles.
All kakapo were fitted with small backpack radio-transmitters and the positions of birds were obtained at night for almost a year. They estimated seasonal home range size which varied from 1.8 to 145 ha. The home range was smallest in winter and the size varied individually in the use of habitats and plant species.
As a result of conservation initiatives, previously cleared and converted natural forest to pasture was changed to regenerating scrub of eight vegetation types. Nearly all Kakapo used the pine plantation in summer because they fed on pine needles, barks and young cones. Kakapo rarely roosted in the pines because pine has relatively open forest floor of the plantation, and the straight, often branchless, tree trunks. The Kakapo used the treeland scrub in the autumn because they were feeding on five-finger berries. The Kakapo avoided lowland scrub in all seasons and other vegetation types seasonally.

The researchers concluded that Kakapo were more that capable of surviving on highly modified Maud Island. However, despite supplementary feeding, the Kakapo have only bred on the island once. The lack of successful reproduction suggests that Maud Island’s vegetation does not provide sufficient high quality food to trigger or support breeding, though it is more than adequate to support non-breeding birds.

Fly my pretties

2011-08-07T14:55:00.001+12:00

This article was prepared by postgraduate student Nick MacDonald as part of the ECOL 608 Research Methods in Ecology course.
For those of you who have ever ventured beyond the boundaries of buildings and urban assemblages you would at some stage be greeted by one of Mother Nature’s miracles of aviation. I am referring to the New Zealand Hover fly (Melanostoma fasciatum) which can often be seen hovering, acrobating and nectaring at flowers around New Zealand’s natural environments. So what are these busy little creatures? What are they doing and where do they go?

Hoverflies are members of the insect family Syrphidae. They can vary in appearance depending on species and despite their black and yellow striped mimicry of wasps, are harmless and share a unique relationship with humans. Gardeners consider themselves lucky when they are blessed with the presence of hoverflies. This is because at a larval stage, they are predators and prey upon pest insects such as caterpillars, aphids and other small insects. When larvae get close to prey they strike grabbing hold of them with their mouths and suck them dry. Adult hoverflies are herbivorous feeding on the nectar from grass species and Dandelions. They are also expert fliers hovering, manoeuvring and in some cases walking from flower to flower collecting pollen. They are considered to be, along with bees, an important pollinator of New Zealand’s flowers.

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Field boundaries such as hedgerows and fence lines can impede hoverflies ability to pollinate. In a 2003 study, Field Boundaries as Barriers to Movement of Hover Flies(Diptra: Syphidae) in Cultivated Land by Wratten et al, the extent to which field barriers impeded hoverfly movements was analysed. The study used four types of field boundary with varying permeability in each replicate. The boundary types were: post and wire fences, poplars with gaps and dense poplars. Lacy Phacelia or Phacelia tanacetifolia, a plant with nectar rich flowers, was planted on one side of the four boundary types. Five yellow traps were placed on either side of the Phacelia, this provided a trap line on either side of each boundary. Hoverflies found in traps with Phacelia pollen in their guts were collected and counted. This enabled scientists to see if the permeability of a boundary would impede hoverfly flight movements between the Phacelia in each replicate.

Results showed that the type of boundary does have an effect. Less permeable boundaries, for example, the dense poplars had the lowest proportion of hoverflies in traps, post and fence boundaries had the highest proportion and poplars with gaps were in between. The ability of hoverflies to fly through boundaries and pollinate flower is directly influenced by the permeability of boundaries. Other studies such as: Interacting effects of landscape context and habitat quality on flower visiting insects in agricultural landscapes by David Kleijn and Frank van Langevelde, 2006, point to the importance of landscape context for hoverflies; the abundance and richness of hoverflies depends upon the quality of the habitat patches.
So, what does this mean for hoverflies and for us if we continue to erect impermeable boundaries? It would not be a stretch of the imagination to conclude, that there could be environmental implications for New Zealand. If we reduce hoverflies ability to gather food this could reduce their population numbers and lead to a decline in the pollination of New Zealand’s flowers. It could also, diminish larvae numbers and dilute their role as a bio-control mechanism. This could increase the need and use of pesticides and insecticides on our foods. Plants have evolved in conjunction with hoverflies and are dependent on this complex relationship. I suggest that we adopt a mindset that takes permeability of field boundaries into consideration. We could erect boundaries that work with hoverflies, not against them. After all they are here to help.

Butterflies and wine: friends or foes?

2011-08-03T11:13:00.010+12:00

This article was prepared by postgraduate student Hannah Lewis as part of the ECOL 608 Research Methods in Ecology course.
Most of us enjoy the sight of a butterfly flitting around our backyard, however many of us will not be aware of the importance of native butterflies in agricultural ecosystems and the plight that they are facing. Could you name even 3 types of native New Zealand butterflies? The monarch butterfly which is native to North America seems to be the most well known representative of butterfly species within New Zealand.

The intensification of modern agriculture has resulted in an increase in food production to meet the requirements of a growing worldwide population. The amount of cereals (wheat, barley, oats etc) coming off an area of land has increased from 3800 kg/ha in 1968 to 8000 kg/ha 2008. A major issue with intensification has been the reduction of suitable habitat for butterflies and other insect species and the development of plant monocultures. Monoculture (photo 1) is the continuous planting of the same crop over a large area. Doing this greatly decreases the amount of places that are suitable for insects and butterflies to nest/lay eggs and live in. Insects are our main plant pollinators, without this essential function that they provide us for free, there would be no food to feed the world.

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Mark Gillespie of Lincoln University studied his PhD on the prevalence of butterflies in vineyards in the Waipara region, North Canterbury. The intensification of agriculture is one of the main drivers behind biodiversity loss. The introduction of agrochemicals and the creation of homogenous fields (monocultures) without hedgerows or shelter belts have modified natural habitats which have become unproductive for no other use than intensive agriculture and food production.

The analysis of six different vineyards partaking in the Greening Waipara project (see link 2 for more detail) showed that the endemic common copper (Lycaena salustius) (photo 2) and endemic southern blue (Zizina oxleyi) (photo 3) were the most prevalent native butterfly species. Mark measured butterfly density by doing The results show that it is important to maintain remnant vegetation sites for butterflies to inhabit near cropping areas as these are not influenced by farm machinery and agrochemicals.

Mark’s thesis results showed that the Greening Waipara plantings were of least importance to butterflies although this could be because they are so young. Having only been planted within the past 7 years, the plantings are also fairly isolated from other bigger patches of favourable living conditions. Basically, butterflies require a very diverse conservation area to sustain a population including differences in vegetation and the landscape.
To increase the population of butterflies in their vineyard, landowners need to see economic benefits to them being there. Aside from their general conservation value, native butterflies have aesthetic and economic effects on tourism and marketing. Making them good money earners for the landowner, particularly in wineries where tourists will stop and visit and spend some time outdoors. Currently, the vineyards in the Waipara Region are poor habitats for native New Zealand butterflies. Butterflies are commonly used as an indicator species of a particular environment, that is the presence or absence of butterflies native or otherwise can indicate the state of the environment that is being searched. Hence an increase in native butterflies can indicate a healthier environment which is better for the sustainability of monocultures in New Zealand.

Names at light speed

2011-07-27T17:40:00.002+12:00

A major staple of science fiction (especially tv and movies) is a device that can tell you what species of seaweed, stick insect, sun bird or slavering alien monster you are looking at. The tricorder of Star Trek is the most famous of these device. Just point and click and you get the identification of what the beastie is, lots of information about its ecology and the likelihood that it will suck your brain out. For the last decade ecologists have been working towards a machine with this ability but we may have been sidetracked by our DNA dependence. Much of the activity in this area has been around being able to diagnose species in the field by quickly analysing DNA samples. Which is fair enough because we have been spectacularly successful in using DNA to do all sorts of things (including quickly identifying species).
However, there may be a more elegant way of doing this: getting the answer, quite literally, at light speed (and what could be more scifi than that?). Rob Cruickshank (Lincoln University - pictured, appropriately in a red shirt) and Lars Munck (Copenhagen University) have summarised a new approach to identifying species that does not use DNA and gets us closer to 'point and click' technology. The most promising new method involves beaming near infra-red light onto the surface of the individual you wish to identify (say a beetle). You then calculate the amount of absorption/reflection of light coming off the surface. It turns out that different species of closely related species will absorb different amounts of light and have distinct 'fingerprints'. So without even collecting a sample you could identify individual species. At the moment this can only be done in a controlled lab environment and we are not sure if it will work on all sorts of different species with precision but the future is looking bright for the first 'real tricorder'! Make it so.

The Citizens of Mushroom City

2011-07-27T13:14:00.002+12:00

Sky Blue Mushroom (Entoloma hochstetteri) – one of many fungi found within New Zealand

This article was prepared by postgraduate student Olga Petko as part of the ECOL 608 Research Methods in Ecology course.

When we hear the word “biodiversity” magnificent tigers and cute koalas, beautiful coral fish and bright parrots first come to mind. But biological diversity or, to be more precise, species richness, is not about appearance or popularity but is simply about numbers. And no other group can claim to be richer in species than the insects.

Insects can be found almost anywhere: running on sand in hot deserts or making tunnels inside icebergs, flying over tropical forest canopy or hiding behind curtains in your room. Any habitat is a home to countless six-legged dwellers, one just need to look. Little wonder that mushrooms are not an exception. To look at fungi of New Zealand to find out who exactly finds them irresistible is an adventure on its own for such a dedicated entomologist as John Marris from Lincoln University.

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The woodland insects associated with the fruiting bodies of macrofungi, i.e. mushrooms, include specialist fungi-eaters, generalist detritus feeders and all their associated predators and parasitoids. Marris and his colleagues used rotted commercial mushrooms (Agaricus spp) as a bait to collect insects from native beech forest (Nothofagus spp), native mixed forest, exotic conifers (Pinus radiate or Cupressus macrocarpa) and urban restoration areas. Overal 2 429 invertabrates were collected, which mainly consisted of beetles (Coleoptera), flies and midges (Diptera), also parasitic wasps (Hymenoptera). To name just a few interesting species: a parasitoid wasp of spider eggs Idris spp (Baeini), round fungus beetles Leiodidae, Saphobius spp (Scarabaidae) and moth flies Psychoda spp (Psyhodidae). Of course, as it always happens with these tiny creatures, among collected specimens were several newly-described genera and new species.

The list of insect species that are associated with mushrooms increases our knowledge of the nature of New Zealand. Worldwide habitat-specific insect assemblages are used as indicators of site quality and conservation value, as well as measurement of anthropogenic disturbance. The survey of Marris and his colleagues showed that two conspicuous native beetles Zeanecrophilus prolongatus and Saphobius can be used as good indicators of site quality. A handy method in assessing the remnant patches of New Zealand woodland. It also became clear that monoculture plantations of exotic conifers are not a wood equivalent of a desert and can compare favorably to native forests in terms of richness and diversity of insect faunas. What is most important these plantations can provide suitable habitat for indigenous insects too.

There are many restoration projects in cities and around them. And here is the good news. The research brought new evidence that despite the fact that urban nature reserves are small in comparison to remaining native forest and low in total species richness, they still play a valuable role in conservation of invertebrates, providing a refuge at a local level.

This study was first of its kind in New Zealand. The “mushroom bait” method is not ideal, not all insects are attracted by the smell of commercial Agaricus. The researchers are sure that the use of any native New Zealand fungi as bait or alternative collection techniques will widen the species list of the citizens of Mushroom City.

Photo sources: mushroom, moth fly, round fungus beetle

Tangled webs in braided rivers

2011-07-22T14:37:00.000+12:00

Humans like to put things in boxes, name them, groups similar things together, impose order on chaos and generally make the world a tidier place. This is very much the case in biology where we seek to put names to species so that we can then make sense of a complex, living world. Unfortunately, the living world is not always so black and white. For example, there are times when groups look different to one another, and are called different species, but they still can successfully mate (or hybridise).
Such a situation may occur in the last stages of speciation, as it takes numerous generations for new species to fully diverge. Repeated crossing of hybrids with parent species is termed 'introgression' and this can often have negative impacts on the parent species, such as removing local adaptational traits. Because of these impacts, organisms usually have traits for avoiding mating with hybrids or members of closely related species. Luckily, introgression does leave its mark on an organism's DNA and can be readily detected. One group of organisms with a history of introgression is the spiders.

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Within New Zealand there are four species of Dolomedes, a genus of large spiders spread around the world. Dolomedes aquaticus is found among the stones of braided riverbeds and D. minor in grass and scrub areas as well as swamps and other wet areas. Although individuals from these two species often come into contact and have the potential for interbreeding to occur, a study by Vink and Duperre found that this did not happen throughout New Zealand. Everywhere, that is, except the southern end of the range that they sampled where there was the suggestion of introgression occurring. Following up this study was the task for honours student Vanessa Lattimore with here supervisors Adrian Paterson, Rob Cruickshank (both Department of Ecology, Lincoln University) and Cor Vink (LU Entomology Research Museum and AgResearch). Vanessa sampled from braided rivers throughout the southern South Island of New Zealand and obtained Dolomedes specimens from 13 locations. She then examined a nuclear gene (actin 5C) and a mitochondrial gene (COI) for evidence of introgression.
Evidence for introgression was found with three haplotypes (versions of a gene region) from D. aquaticus being present in D. minor and this was recently published in Invertebrate Systematics, where it made the front cover! (Although I didn't buy 5 copies for my mother) Interestingly, there was no evidence for movement of genes from D. minor to D. aquaticus.
Why is the introgression only occurring in one direction? Because of the way that mitochondrial DNA is inherited, the most likely reason is that males from D. minor are willing to mate with females of D. aquaticus whereas D.aquaticus males are either too big (they are much larger than D. minor males) or more picky than D. minor males. The geographical pattern of the three haplotypes are also different which suggests that these introgression events have happened at different places and probably at different times. A major question to arise out of this research is explaining why the introgressions occur in southern braided rivers and not elsewhere in New Zealand. The authors suggest that as braided rivers are prone to variable flows (from no flow to floods in short time periods) that D. aquaticus may be forced into the surrounding vegetation where D. minor are found from time to time.

Archaea vs bacteria: who is doing most of the work?

2011-07-21T16:07:00.008+12:00

This article was prepared by postgraduate student Aimee Robinson as part of the ECOL 608 Research Methods in Ecology course.

Nitrification is an important process in the nitrogen cycle and has the most obvious environmental implications. The end-product of nitrification is nitrate (NO3-) which can be leached into groundwater (see diagram below). High concentrations of nitrate can cause algal blooms and contamination of lakes and rivers. In drinking water, high concentrations can cause the potentially fatal blue baby syndrome in young children. This occurs when nitrate is converted to nitrite in the baby’s digestive system. This then reacts with the body’s oxygen carrying molecule, haemoglobin, forming a non-oxygen carrying molecule called methaemoglobin which decreases the infant’s ability to utilise oxygen. Nitrate from nitrification can also lead to the production of nitrous oxide (see diagram), a greenhouse gas, which has further implications for the environment through global warming and climate change. It is therefore important to understand the biological process of nitrification for the application of mitigation strategies to reduce these environmental hazards.

It has long been thought that ammonia oxidising archaea (AOA) (single celled micro-organisms which have no nucleus or any other bound organelles) only drive the nitrogen cycle in harsh environments. However, in a paper published in Nature, Linginer and colleagues discovered that AOA may be the most abundant ammonia oxidising organisms in soil ecosystems. This questions the traditional assumption that nitrification is dominantly the role of ammonia oxidizing bacteria (AOB) and begs to question what really is driving the nitrogen cycle in the soil?

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Although it has been shown that AOB dominate the nitrification process in some agricultural soils, it is interesting to see how AOA may react to nutrient changes in the soil and in the presence of an inhibitory substance.
In a recently published study in the Federation of European Microbiological Societies Microbiology from Hong Di and his team at the Centre for Soil and Environmental Research, Lincoln University, they investigated the role of AOA and AOB in differing layers of soil and determined the effects of animal urine and a nitrification inhibitor (DCD) application on the two organisms. Samples from Waikato, Canterbury and Southland were collected to gain a holistic view of New Zealand soils. They found that AOA was more abundant in the soil than AOB in both soil layers with the bacteria decreasing in the lower layer. With the addition of urine AOB greatly increased whereas AOA seemed to be inhibited. This demonstrates that AOA and AOB prefer different soil nutrient conditions with AOA favouring low-nutrient environments.

Adding nitrification inhibitor sufficiently reduced the AOB nitrification rates and hence lowered nitrate leaching and nitrous oxide production. The AOA were inhibited by the urine addition but this could have been due to the urine or DCD which were both present in the treatment. It would be useful to determine the AOA reaction to the DCD alone. However, because nitrification inhibitors work by preventing the enzyme produced from the organism rather than targeting the actual producer, Archaea would most likely react in a similar way to the bacteria and be inhibited.
This study demonstrates that AOB are the hardest workers in the soil nitrogen cycle, although AOA should not be underestimated. AOA’s abundance in the soil suggests their importance, but the processes they undertake are yet to be understood. Continued research from Lincoln University will continue to decipher the roles of AOA and their potential presence in agricultural soils as well as their value in lower nutrient environments.

Newly discovered interaction has farmers buzzing

2011-07-19T16:46:00.005+12:00

This article was prepared by postgraduate student Sam Read as part of the ECOL 608 Research Methods in Ecology course.
Nature is full of wonderful and surprising phenomena. Organisms can often be linked directly or indirectly in amazing and unpredictable ways. It came as somewhat of a surprise when honeybees were discovered to have an impact on caterpillars. Common sense would suggest honeybees (Apis mellifera) and caterpillars would have little to do with one another, as honeybees increase plant fitness by pollination and caterpillars decrease plant fitness by herbivory.
Other relatives of the bees are not so benign. Wasps (Vespula spp.) are generalist predators and are natural enemies of many caterpillar species worldwide. Rapid wing movement while flying creates vibrations in the air, heard as a buzz. Previous research indicated that these vibrations stimulate special sensory hairs on caterpillars and pre-warn them that predators are present. The caterpillar will then stop moving and damage to the plant will cease, until the predator has gone. Occasionally, the caterpillars may even drop off the plant, if the predator gets too close.
Wasps could therefore be effective biological control agents to reduce pests. However wasps themselves are considered pests by many. Wasps are one of the most invasive insect pests in the world. They cause problems to agriculture, horticulture, wildlife and are a nuisance in urban environments due to their nesting and aggressive behaviour. Instead, a similar alternative buzzing insect is required. As honeybees are of high economic value and also create a buzz, they were thought to be a potential candidate. A new study was published in Current Biology by Jürgen Tautz and Michael Rostas (Lincoln UNiversity), in which they carried out an experiment to test whether particular herbivores would show the same behavioural reaction with honeybees, as occurs with wasps.

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A field cage experiment was carried out using the beet armyworm caterpillars (Spodoptera exigua), as they are a generalist pest that feeds on at least 50 plant species. The caterpillars were applied to either bell pepper (Capsicum annuum), with or without fruit, or soybean (Glycine max). Honeybee hives were applied to half of the treatments, with the remaining half with no hives as controls.
When the honeybees were present, there was a significant reduction in leaf damage (60.6-69.3%). The caterpillars’ behavioural reaction to the honeybee buzz was similar to the reaction triggered by a wasp buzz. Honeybees created very similar air vibrations, at an almost identical frequency (Hz) to the wasps, which the caterpillars could not distinguish between.
These findings indicate that other caterpillar species with sensory hairs may also react to the presence of honeybees. Some smaller experiments were then carried out by Michael Rostás. The cabbage moth (Mamestra brassicae), a common European moth was then tested and did behave in a similar way in the presence of honeybees. The large white butterfly (Pieris brassicae) is another species which may potentially respond in a similar manner, as it responds to the air particle movement of hand clapping. Numerous other species worldwide could also be candidates, but future success may depend on honeybee densities in the area.
Honeybees can therefore not only perform pollination by transporting pollen from flower to flower, but also they may contribute to the reduction of plant damage by some herbivores. This unexpected interaction may prove to be a useful tool in the development of future integrated pest management programs.

It’s about time – wildlife managers rejoice over new stoat toxin

2011-07-07T12:40:00.005+12:00

This article was prepared by postgraduate student Tim Sjoberg as part of the ECOL 608 Research Methods in Ecology course.

New toxins that are effective, humane and sociably accepted are desperately needed in New Zealand for predator control. Wildlife managers have relied upon too few toxins for broad control of many predator species. The development of a safer, humane, and predator specific toxin is highly desirable and long overdue for New Zealand predator control.
New Zealand wildlife evolved in the absence of mammalian predators. Birds (such as Kiwi, Mohua and Kokako to name a few) have particularly been impacted by the introduction of non-native predators, and this is reflected by the extinction of over 40% (Eason et al. 2010) of the pre-human land bird species.
Stoats (Mustela erminea) were introduced into New Zealand in 1884 for the control of rabbits which were reducing pasture production. Stoats moved from farmlands and into the native forests where they have become the most significant factor in New Zealand’s historic fauna decline. Their large home ranges (up to 100 hectares), excellent swimming ability, and furious appetite for any animal that moves, has made the stoat, one of the Department of Conservation’s (DoC) main targeted animals.

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Control methods for stoats currently rely on labour intensive trapping and poisoning. However, the use of 1080 (sodium fluoroacetate) is becoming increasing unpopular in New Zealand, as public fears relating to the contamination of water supplies, possible sub-lethal effects on humans, welfare impacts on targeted species, and the potential of 1080 to kill native birds and other non-target species is still embroiled in controversy. At the present time there is no stoat specific toxin available.
Para-aminopropiophenone (PAPP) was investigated in the 1980’s as an alternative to 1080 for coyote (Canis latrans) control in North America. PAPP is a red blood cell toxin. This toxin works by reducing the oxygen supply to the brain, making animals lethargic, sleepy and unconscious prior to death, which is within 1 to 2 hours. This rapid time till death gives PAPP a high humane rating when compared with other toxins used worldwide.
PAPP was trialled by Connovation in conjunction with DoC at Lincoln University facilities, under the guidance of Professor Charlie Eason. Captured wild animals were given a PAPP paste within meat baits, which caused 95-100% mortality. There were no signs of discomfort, stress or vomiting associated with poisoning, and animals became unconscious quickly following ingesting the bait.
From this study , PAPP looks extremely useful for stoat control, with no toxins currently registered for use against stoats and few effective techniques are available to control them. PAPP has relative specificity for mammals, and is lethal to stoats at low doses. PAPP would therefore be a significant advance for wildlife protection in New Zealand. With stoats continuing to have significant impacts on a wide range of threatened birds, lizards and invertebrates, PAPP is a welcome relief for wildlife managers and long overdue.

Further reading:
Eason C., Wickstrom M.and Gregory. 1997. Product stewardship, animal welfare, and regulatory toxicology constraints on vertebrate pesticides. Proceedings of 50th New Zealand Plant Protection Conference. Pg 206-213
Gregory N., Milne L., Rhodes A., Littin K., Wickstrom M. And Eason C. 1998. Effect of potassium cyanide on behaviour and time to death in possums. New Zealand Veterinary Journal 46 pg 60-64
Littin K., O’Connor C., Gregory N., Mellor D and Eason C. 2002. Behaviour, coagulopathy and pathology of brushtail possums (Trichosurus vulpecula) poisoned with brodifacoum. Wildlife Research 29 pg 259-267
Littin K., Gregory N., O’Connor C., Eason C. and Mellor D. 2009. Behaviour and time to unconsciousness of brushtail possums ((Trichosurus vulpecula) after a lethal or sublethal dose of 1080 and implication for animal welfare. Wildlife Research 36 pg 709-720.

Mothbusters! The importance of forest fragments in nature conservation

2011-07-07T10:24:00.002+12:00

This article was prepared by postgraduate student Elise Arnst as part of the ECOL 608 Research Methods in Ecology course.

New Zealand has vast areas of highly modified and fragmented, disconnected landscapes. It is important for the conservation of biodiversity to understand the ecology in these modified, human-dominated landscapes. Urbanised areas and farmland both tend to be on low-lying land that is high in nutrients and resources and previously supported biodiversity hotspots. Remnants of native forest are rare pockets of once widespread species and are important in conserving biodiversity. Both remnants and restored native vegetation are important in the conservation of other native species, such as invertebrates. To maintain and increase biodiversity we must build on such remnants by restoring native plant species in altered habitats.
Landscape-scale patterns in fragmented areas provide an important understanding of the ecological processes driving invertebrate distribution and abundance. In New Zealand there are many small patches of native trees, which are not joined to a larger patch of forest making it difficult for invertebrates to move between areas to find food or a new habitat. These patterns have been explained by Ruth Guthrie and two other Lincoln University scientists, Hannah Buckley and Jon Sullivan, in their study of cabbage tree (Cordyline australis) damage by the larvae of the endemic moth Epiphryne verriculata Feld (Lepidoptera: Geometridae) in Christchurch, New Zealand.

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Studying cabbage tree herbivory has helped to explain the abundance and distribution of E. verriculata. The larvae eat only cabbage tree leaves (i.e. they are monophagous), which means its ability to survive is dependent on the presence of the cabbage tree. This also means that the clearly identifiable damage on cabbage trees is a straight-forward way to determine the abundance of the moth larvae. Herbivory was measured by Guthrie et al. (2008) as the percentage of damaged leaves on a cabbage tree crown. Herbivory was seen on almost all trees across all sites, indicating a widespread presence of the moth in both natural and modified areas. Damage was higher in adult trees, this is likely to be because they provide a larger food source. Herbivory was also higher when few other cabbage trees were in close vicinity, which is a likely to be result of the moth larvae being monophagous – fewer cabbage trees means they will do more damage to less trees. The skirt of dead leaves on the cabbage tree was thought to be a refuge for adult moths but the presence or absence of a skirt appeared to have no impact on the level of damage. This may indicate that larval abundance is more dependent on the availability of food rather than suitable habitat for adults. The abundance and distribution of E. verriculata can help to explain more complex landscape-scale patterns.
There appears to be a pattern across the Canterbury Plains where endemic herbivorous invertebrates are present on their host plant regardless of landscape fragmentation. In the study by Guthrie et al. (2008) this was confirmed as larvae were found on cabbage trees in all landscape types. The widespread presence of larvae indicates that the availability of suitable host tress is the determining factor for the E. verriculata moth to be able to survive in an area. Native trees in both restored and urban areas provide potential habitat and food sources for invertebrates. This emphasises the significance of native flora in modified landscapes for maintaining invertebrate diversity, providing strong motivation to ensure we continue to promote native biodiversity through restoration in modified areas.
Guthrie, R.J., Sullivan, J.J. and Buckley, H.L. 2008. Patterns of host damage by the cabbage tree monophage Epiphryne verriculata Feld (Lepidoptera: Geometridae) across urban, rural and native forest habitats. New Zealand Entomologist 31: 77-87.

Bacteria, friend not foe in stream ecology

2011-07-04T13:18:00.003+12:00

This article was prepared by postgraduate student Julia Bellemy as part of the ECOL 608 Research Methods in Ecology course.

Determining the ecology of freshwater streams is important because it contributes to our understanding of the effects of human activities on the stream and lets us monitor remediation strategies. The health of freshwater streams is typically determined by examining the diversity and abundance of fish and invertebrates. But there may be another way of determining the health of freshwater streams, in the form of tiny, microscopic bacteria. These bacteria may be useful as highly responsive indicators of changing environmental conditions.

Freshwater streams display both temporal (time) and spatial (space) differences. Time variation is a result of seasonal influences and space variation is due to flow regime, substrate type, water solutes, suspended materials and incident light exposure. It is believed that bacterial communities are good indicators due to their rapid life cycle. However, if we can’t see them, how do we know that they are present and observe changes? Bacteria can be detected using Automated Ribosomal Intergenic Spacer Analysis (ARISA) which creates ‘fingerprints’ of microbial communities. The ‘fingerprint’ produced is just like a human fingerprint, because it is unique to a bacteria species just like a fingerprint is unique to a person.

So how is ARISA used to construct a ‘fingerprint’? Unfortunately, it isn’t as easy as dipping bacteria into ink and pressing them against paper. First, the DNA has to be extracted from the cells and then DNA sequences are identified for each species. The length of the gene region varies between different species and this difference in length allows a unique ‘fingerprint’ to be constructed for each species.

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In the study “Spatial and temporal heterogeneity of the bacterial communities in stream epilithic biofilms” conducted by Gavin Lear from Lincoln University, the time variation in biofilm communities was analysed over a range of spatial scales. It was expected that the main study site, Cascade Stream, located within the Waitakere Ranges, west of Auckland, New Zealand, would have uniform water chemistry characteristics. Interstream variability was also assessed using samples from a second stream. It was hypothesised that there would be no significant bacterial variation on a spatial scale and that the temporal variation in the two streams would be similar.

The study found that the differences in bacterial communities were greater between streams than within the same stream. Significant spatial variation observed in the principle study site suggests that the hypothesis stating that there would be no significant bacterial variation on a spatial scale must be rejected. Greater variation was observed on the same rock than between sections of rocks and this indicates that reduced community similarity with increased physical distance was not observed.

So spatial variation was observed, but what about temporal variation? It was found that temporal variation was greater than spatial variation. The microbial communities not only changed over time, they never returned to their original composition over the duration of the study.

Now that we know that both spatial and temporal variation were observed we need to know why. The study concluded that water temperature and irradiance had the greatest influence on the bacterial communities. The most significant variation occurred when the warmest air and water temperatures were recorded.

In conclusion, ARISA was successfully used to determine spatial and temporal variation in bacterial communities in a freshwater stream with temporal variation having the most significant effect. Water temperature was identified as causing the greatest variation. Overall, the use of bacteria as indicators of freshwater ecology looks promising and should prove to be a sensitive technique of understanding the effects of human activities on freshwater systems and monitoring remediation strategies.

Further readings:
Lear, G., Anderson, M. J., Smith, J. P., Boxen, K. & Lewis, G. D. (2008). Spatial and temporal heterogeneity of the
bacterial communities in stream epilithic biofilms. FEMS Microbiology Ecology, 65. 463-473. Retrieved from
http://onlinelibrary.wiley.com/doi/10.1111/j. 1574-6941.2008.00548.x/pdf

Morgan, J. (2009). May the stream be with you. Retrieved May 22, 2011, from
http://www.jmorganmarketing.com/may-the-stream-be-with-you/

Sharing knowledge with the community – the Styx Living Laboratory Trust

2011-07-01T15:27:00.001+12:00

This article was prepared by postgraduate student Megan Oliver as part of the ECOL 608 Research Methods in Ecology course.

Communities around New Zealand are becoming more aware of the state of natural areas in their community and how they are becoming degraded from pollution. This awareness has resulted in restoration projects that begin with good intentions and enthusiasm but come to a halt because of a lack of understanding of ecological knowledge about the ecosystem that is being restored.

The Styx River originates in the suburb of Harewood, Christchurch. Springs feed the river as it moves north-eastwards through residential, horticultural, agricultural, and lifestyle developments as well as conservation reserves before it empties into the Brookland Lagon. The Styx River has two main tributaries, Smacks Creek and Kaputone Stream. The Styx Living Laboratory is a community restoration project that has a mixed board of scientists that help the community to keep going in their restoration project. Kelly Walker, senior tutor in biology at Lincoln University, is one of the scientists working on the Styx Living Laboratory Trust restoration project by contributing her knowledge of fresh water invertebrates to the community and is on the board of management.

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The aim of the trust is to restore the Styx river catchment in 40 years to an urban nature reserve by creating a living green corridor from the top of the Styx river catchment to where the river empties into the Brookland lagoon. Restoring the Styx river catchment includes both riparian plantings and in-stream restoration. A living green corridor is the area surrounding a focal feature, e.g. river, track etc; that is planted in native plant species which allows wildlife to either live in or pass through it.

The Styx River is a spring feed water system that is suffering from a sedimentation issue. The springs are drying up due to urban development which is increasing the amount of sedimentation in the river and then causes problems for fresh water invertebrate’s living in the river. There has been no indication that the recent earthquakes have caused the springs to dry up, as the springs had started drying up before the earthquakes occurred. There are six monthly samplings in the Styx River and its tributary waterways, collecting data on water quality, invertebrate species and spring status.

Kelly helps the community members when they survey the Styx River and its tributary waterways in identifying the invertebrates that have been collected. This work keeps the community involved in the restoration project by up-skilling the community group, which keeps them interested and makes them feel that their work is valuable to the restoration project. This enables there to be a closer relationship between the scientists and the community members which helps everyone keep the restoration project going.

Kelly also looks after the summer studies conducted by Lincoln University students on different topics in the catchment area. Previous studies have been on fresh water invertebrates, assessing the restoration of Radcliffe Drain which was a box drain, terrestrial arthropod abundance and diversity, lizard abundance and diversity of algae in the Styx River. These studies have produced interesting and useful results, including a new species of algae. The work done by the Styx Living Laboratory trust, community and the summer students has produced data that can be used as an indicator of how healthy the Styx River catchment is and shows how communities working with scientists can increase their knowledge and skills to take on a major urban restoration project.

Life is a Garden, Dig it- and plant some green manure while you’re at it!

2011-06-28T10:13:00.002+12:00

This article was prepared by postgraduate student Scott Sharp-Heward as part of the ECOL 608 Research Methods in Ecology course.

New Zealand: land of the long brown dairy farm. Or at least it sometimes feels like that, what with the proliferation of dairy farming over the last 10-15 years. This typically intensive farming method is often associated with loss of biodiversity due to removal of natural habitat and food sources for endemic species. However, one of the largest and most varied reservoirs of life, the soil, is often not taken into account when examining the effects of farming practices. This seems like a huge oversight when the pesticides and fertilisers being applied in conventional agriculture are likely to directly affect soil-borne life. In contrast to this, organic farming often concentrates on soil microbial health to a great extent, something which can be seen in such international organisations as Soil Foodweb. It is often thought that organic farms have a much wider diversity and larger amount of microbial life in soil than conventional farms, but is this truly the case?

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Christine Stark, Leo Condron and their team at Lincoln University sought to address this question by carrying out a study on the links between soil microbial properties and agricultural production systems. In particular, the effects of long term land use management and short term land use practices on soil microbiology were studied.

So why care about microbial diversity and abundance in soil? Well, as any keen So why care about microbial diversity and abundance in soil? Well, as any keen gardener will tell you, earthworms are indicators and facilitators of fertility in soil; they are present in healthy conditions and help turnover nutrients in soil so they can be used by plants. Soil micro-organisms are the same; even though they may be invisible to the unaided human eye. Micro-organisms are working constantly by breaking down and consuming nutrients that aren’t available to plants and excreting nutrients which are. If there were no micro-organisms in soil there would be no break-down of dead material and hence no new nutrients for plant growth! These micro-organisms include filamentous fungi, bustling bacteria, predatory protozoa, and ancient archaeans (some of which are seen in the picture on the right). It is good to have a diverse bunch of these different micro-organisms as they all occupy their own unique position in the soil food-web and will be adept at breaking down different things.

In this study performed at Lincoln University, soil taken from two farms of different long-term management types (one conventional farming, one organic farming) had different nitrogen fertiliser treatments applied to examine the effect on soil life. These fertiliser treatments included use of an organic form of nitrogen (green manure lupin) and use of an inorganic form of nitrogen (urea fertiliser). It was found by Dr. Stark and her colleagues that while there was slightly greater microbial life to begin with in the organically farmed soil, it was not statistically greater, so it was concluded that there was no major difference in soil life between the long-term farm management types. However, when it came to getting a response from the soil micro-organisms from the different types of nitrogen fertiliser that were applied, the green manure lupins stimulated not only a massive increase in both soil microbe population but also in diversity- even in conventionally farmed soil! This was in stark contrast to the Urea fertiliser which didn’t elicit any response in the soil microbial community when applied.

So the results are clear- if you want soil with a bustling microbial population, make sure you till plant matter back into the soil and grow a green manure crop whenever you can!

Stark, C., Condron, L.M., Stewart, A., Di, H.J., O’Callaghan, M. (2007). Influence of organic and mineral amendments on microbial soil properties and processes. Journal of Applied Soil Ecology Vol. 35 Iss. 1, pgs 79-93.

Kiwi vision: the blind side

2011-06-24T11:43:00.019+12:00

This article was prepared by postgraduate student Mortiz Schmid as part of the ECOL 608 Research Methods in Ecology course.

Photo by Kerry-Jayne Wilson, Lincoln University.

One of the basic principles of vision is that an eye which is supposed to maximize information gained at low light levels needs to be large. Information is gained through two cell types in the eye (cone cells for colour vision and rod cells for contrast) that detect and convert light into electro-chemical signals that can be processed by the brain structure. This poses a particular problem for nocturnal (active at night) flying birds since they need huge eyes in order to compensate for the low intensity of natural light and unfortunately large eyes are heavy. To be able to fly, there is always selective pressure (traits that are favoured by evolution) among birds to reduce their overall body mass.

What about kiwi?
We would think that as a nocturnal bird that is not subject to the mass constraints of flying, Kiwi would develop huge eyes. But they didn’t. This brings into question: Why?

Graham Martin, Professor of Avian Sensory Science, at the University of Birmingham and Kerry-Jayne Wilson, who has recently retired from Lincoln University in conjunction with J. Martin Wild, Stuart Parsons, M. Fabiana Kubke, Jeremy Corfield, investigated this paradox.

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The researchers looked at the eye, brain and bill structure and measured the visual field (the part of the sphere around the head the bird is able to see, Fig. 1) in two species of Kiwi. They discovered that Kiwi rely minimally on their visual sense, instead relying more on their olfactory (what they smell) and tactile (what they touch) senses. This situation is similar to some nocturnal mammals, but Kiwi and nocturnal mammals evolved these features independently. The researchers propose that the visual system of Kiwi has undergone an adaptive regressive evolution, meaning that through evolution, they have lost a highly developed visual system in favour of the other senses which became more developed. This regressive evolution may have been driven by the trade-off between the low amount of visual information that can be gained at low light levels and the energy costs of the processes involved.

Each structure that was investigated pointed clearly towards a bird that relies mostly on its olfactory and tactile senses, but not so much on its visual sense. On the one hand, the overall eye shape of Kiwi was similar to birds which are active during daylight. The visual field of Kiwi are the smallest yet reported, with a very small binocular area (where both eyes can see something), a relatively small monocular area (visible with one eye) and a very large area in which there is no vision, the blind sector. Comparison with three different species (Barn Owl, Emu and Pigeon) showed that Kiwi have by far the smallest optic nerve diameter (which transmits information from the eye to the brain) and the area of the brain devoted to visual information is virtually absent in Kiwi while they are very large in the other species. On the other hand, the nostrils of Kiwis are right at the tip of the bill. Here, there is also a high concentration of mechanoreceptors which detect mechanical cues that are produced when the bill touches something. In addition, brain centers representing tactile and olfactory processing are well developed. This information supports the idea that the bill is the focus for gathering olfactory and tactile information. Regarding the close relationship between Moa (with large eyes) and Kiwi (with small eyes), it seems plausible that the evolutionary step that led to a reliance on olfactory and tactile cues, which happened in Kiwi, was caused by the low light level on the forest floor. Where the costs of maintaining a visual system adapted to low light intensity was higher than the benefits which were gained by relying on olfactory and tactile cues. Here, the scientists were able to reveal this very important principle regarding kiwi vision which now can be included in all kinds of kiwi recovery projects and makes for a new perspective in kiwi habitat management.

Bringing nature (back) into cities...

2011-06-17T11:42:00.007+12:00

This article was prepared by postgraduate student Cynthia Resendiz as part of the ECOL 608 Research Methods in Ecology course.

“Canterbury plains are one of the worst examples of the loss of native plants in New Zealand...less than 0.5% of native vegetation remains on our plains”, New Zealand’s Spellerberg, a Lincoln University scientist, said in a blog interview in 2010. Trees that live in cities come from different parts of the world; however, not all trees are suitable for all environments. Each species has special requirements to grow successfully, but native trees are already adapted, and they are a good choice for urban spaces.

We need trees in cities. Trees, especially native species, have many functions and values, producing economic, social and environmental benefits. They can provide us with goods and services such as: improving air quality, recreation, saving energy, and ornamentation.

The kind of trees found in a city depends on public preferences, planning decisions and even historical reasons. There are many areas in cities reforested with new trees, but mainly using non-native trees. Particularly in New Zealand, due to the historical influence of the United Kingdom, urban trees are chiefly non-native, and often from the northern hemisphere.

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The use of exotic trees is becoming old-fashioned. There is a global tendency to plant native trees. For example cities such as Adelaide in Australia or Warrington New Town in United Kingdom are implementing programs to redress the loss of native vegetation.

Many scientific studies suggest that native trees are the best option for cities. One of these studies was published in Landscape Review by Ian Spellerberg in 2008. He highly recommends planting native trees and gives the following criteria for choosing trees:
• Besides an aesthetic and functional tree, we need to think carefully about why we need a tree and where it will be planted. We must have in mind that this is a long-term decision.
• The genetic origin of the plant is important, particularly when it is a indigenous tree. We should ask for native species grown from seeds from the local area (eco-sourcing).
• Try new species, especially trees indigenous to your area. These kinds of trees have low maintenance requirements. This is important because life in cities is busy and you should not have to worry about your tree. If you are living in Canterbury, the organizations Trees for Canterbury or Motukarara Conservation Nursery may help you to make your choice.
• Learn about possible nuisance factors. This involves safety and structural problems. Sometimes trees can cause health problems (i.e. allergies). Also the anatomy of the tree can bring problems to houses and people (e.g. root spread can damage pipes).
The diversity of species and ages of trees are important. It is recommended to have patches that include a mixture of them.

We should be proud of New Zealand’s natural heritage. Planting native trees contribute to conserve genetic resources that are exclusive from New Zealand. This will attract native wildlife, such as native birds, providing sources of food and habitat.

“I think New Zealand’s more precious natural heritage are native plants. Therefore, we should celebrate native plants by having a native only policy for urban areas” – Ian Spellerberg said in May 2011.

Given these points, the decision around planting a tree is very important and must be taken carefully, because it is an investment for the long term, which can bring us invaluable benefits. Your tree must be adaptable to urban conditions, otherwise we can get the opposite result, and the tree can bring us problems. Buying a tree seems simple, but it is an important decision that can contribute to nature conservation. Next time, look at the trees growing around you, and think about what kind of tree you would like to plant.

Kind regards John Maillard for the photo of Ian Spellerberg

Quake

2011-06-15T11:03:00.001+12:00

Two large aftershocks hit the Canterbury region yesterday (a 5.6 at 1pm and a 6.3 at 2.20pm). They were extremely unpleasant to be in on the 5th floor of Ecology! The building got a real sway on. The university was evacuated as a precaution and was shut today while buildings were inspected. Apart from liquefaction in areas close to Lincoln, there was no obvious problems with the university and township. We are up and running again today (15th June).

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A Burning Issue for Magpies

2011-06-09T15:33:00.019+12:00

This article was prepared by postgraduate student Laura Hollerbach as part of the ECOL 608 Research Methods in Ecology course.

The Azure-Winged Magpie (Cyanopica cyanus) occurs over wide parts of Asia and Iberia. The species, unhesitatingly described by Haojin Tan (Jin) as “pretty loud and noisy” has been studied throughout its range but most recently a population in Northern Mongolia has been researched. Jin has spent two summers following these birds around watching how they adapted to the aftermath of a fire in 2009. The fire was human-induced and devastated 70,000 ha of wood- and grassland.
Jin recently completed her Lincoln University thesis on habitat use and population dynamics of the Azure-Winged Magpie and their response to fire in Northern Mongolia.

The Azure-Winged Magpie is a cooperative breeder, meaning that mainly non-breeding individuals help the breeding pair rear their chicks. Both sexes are similar in plumage and size - they have a black hood and pale blue wings and tails. The magpies mainly feed on invertebrates, seeds and fruits and live in social flocks. They lay five to nine eggs between April and July which are incubated by the females.

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Jin conducted her fieldwork in Khonin Nuga, which is a valley in the West-Khentey region of Northern Mongolia. She was based in the research station of Georg-August University Göttingen (Germany) that was established in cooperation with the National University of Mongolia in 1997. The Khentey Mountains where the Siberian forest (also referred to as Taiga) meets the steppe are still widely untouched by humans.

Jin located a 1.2 km2 home range for “her” colony with six areas utilised by the birds, one of which was particularly preferred. The preferred area was least affected by the fire and was characterised by having the densest, protective Padus asiatica shrub and the highest diversity in other plant species utilized by the magpies. The birds seem to have expanded their home range after the fire, which can possibly be explained by food availability being affected by the catastrophe.

In order to analyse population dynamics, Jin obtained data collected over a four-year period (2006-2009) from previous studies on the same colony. She found that over the years the colony size at the beginning of each breeding season was constant. However, the number of chicks that hatched and fledged declined significantly, and the adult survival rate decreased. This might be explained by the harsh winter and the fire during the study period. A constant juvenile survival rate is possibly associated with intensified helping behaviour after the fire. Jin found that the colony was an open population, meaning breeding with other populations occurs. The proportion of breeding adults was 26-67%, and one quarter of the females abandoned the partners they bred successfully with and approached a new male between breeding seasons.

Jin is about to finish her Master’s degree in “International Nature Conservation”. This degree is jointly offered by Lincoln University and Georg-August University and includes one semester at each university and a compulsory internship semester that provides an opportunity to work in a practical project anywhere in the world. The last section of the degree involves writing the master thesis.
“It was very hard work”, Jin admits, yet with a smile on her face. For Jin, working in Mongolia was a precious experience that provided her with a unique insight into the Mongolian culture. “It was interesting to learn about the Mongolians’ perspective on life. They are not hurried and solve problems on a day-to-day basis. You don’t find that any more in the developed world.” She also enjoyed the transportation which was riding the horse to work every day: “That’s something most people will never get to do in their lives.”

“After having finished my thesis I have more questions about the topic than before”, Jin laughs. Further research is required to identify long-term effects of fire on the colony.

This article was prepared by postgraduate student Laura Hollerbach as part of the ECOL 608 Research Methods in Ecology course.

Voice Hears His Calling – An Interview with David Voice, Graduate of Lincoln University

2011-06-02T16:31:00.003+12:00

David Voice is an entomological scientist at the Ministry of Agriculture and Forestry in Christchurch, New Zealand; he completed a Master of Applied Science under the supervision of Bruce Chapman at Lincoln University in 2000. His thesis was done through the entomology department on insecticide resistance in offspring of crossed diamond backed moths. Juliane Diamond, ECOL 608 student, interviewed him to get his opinion on the program and the relevance it had to his career.
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Why did you decide to pursue the degree?
Before beginning the degree, while working for the Ministry of Agriculture and Forestry in quarantine, on the border, I would find something suspicious and have to send it to the lab. That is where I took an interest in what I was finding. I began to be able to do some basic identification and save the trip to the lab. It is from that initial interest that I decided to pursue a science degree program.

David Voice and Tommy
Photo by Juli Diamond

What does your job now entail?
My title is Scientist, in the Entomology department of the Plant Health and Environment Laboratory at the Ministry of Agriculture and Forestry.

Primarily I work as a lab coordinator. I do diagnostics and project work on high impact species that would cause harm to the environment in New Zealand if they arrived.

I practice diagnostic entomology, which is the study and identification of insects, and that requires me to spend some time behind a microscope. I also do surveillance of fruit fly trends and eradication procedures. I recognize research opportunities and design experiments.

How do you feel Lincoln University did at preparing you for this career and what courses were most useful to you?
I feel Lincoln prepared me well because in this field you have to learn the basics about taxonomy, and you need to understand where the creature lies in the greater animal kingdom, as well as the relationship between species and how to ensure accuracy in identification.

Therefore, the courses I took in taxonomy, systematics and pest management were most beneficial to what I was doing. The program itself allowed me to customise my studies towards my career, and courses were available that strengthened my knowledge of the field. I feel Lincoln had excellent lecturers and staff.

What is your impression of your time at Lincoln University and the entomology department?
I thought Lincoln was great, I really enjoyed it. I felt a bit awkward at first - being a senior student, but they were great and treated me like a peer. At that time there was a full entomology department and there were a lot of people working on different insect-related research. I felt the work being done was really comprehensive. I also was very motivated because I could see how I could apply what I was learning directly to my job.

What advice do you have for current or prospective students regarding how to make the most of their study at Lincoln University?
I’d like to say that biosecurity is a highly significant field that New Zealand needs to take great heed of, because we still haven’t seen the worst invasive species. I think there are a lot of opportunities in the biosecurity sector, including policy and laboratory work. There is a lot at stake and we need more individuals to come out of university knowing about these issues who can make good policy and protect New Zealand from exotic pests and disease.

Any other comments?
I’d like to close saying that studying entomology gives you a wonderful understanding of how nature operates. There is a lot going on in the environment and there should be a balance, and when that gets disturbed things can go wrong. That is often how pests emerge and by knowing and understanding the system we will be able to prevent that from happening.

David Voice felt very positive about his experience studying entomology at Lincoln University, are you interested in learning more about the program? Contact John Marris, Curator of the Entomology Research Museum for more information.

This article was prepared by postgraduate student Juliane Diamond as part of the ECOL 608 Research Methods in Ecology course.

Birds dislike tannin in vineyards

2011-05-20T09:35:00.010+12:00

It is not just humans that enjoy the fruit of the vine. Birds also like the subtle flavours, the delicate nose and varying sweetness of the grape. Unfortunately, this has lead to conflict between grape-growers and birds. Small songbirds, like blackbirds, starling and silvereyes, are pest species in the vineyard and cause millions of dollars of damage each growing season and force growers to spend millions more on protecting their crop. A long-term series of studies at Lincoln University by Val Saxton has the aim of understanding what it is about grapes that birds like and dislike which will in turn provide possible strategies for reducing bird damage. Val has already looked at the influence of sugar, aroma and organic acids on the decision of blackbirds and silvereyes to eat grapes. In a study just published at Austral Ecology she turns her gaze to important compounds within the grape: tannins (used in plant defence and UV protection) and anthocyanins (used in forming pigments or colour). Tannins are in high concentration in ripening grapes and are known to cause digestive stress in some birds when eaten. Anthocyanins signal the stage of ripening that a grape has reached.

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Val made use of an experimental technique that she has developed where she creates artificial grapes out of gelatine, filled with sugar water. Shecan then alter the levels of tannins precisely and, in a second experiment, change the colour (green or purple) without there being any other differences between the test 'grapes'. Birds were offered the test grapes on racks set out in vineyards and their feeding decisions were videoed. Blackbirds and silvereyes are common vineyard pests in New Zealand and their behaviour was recorded and compared. Both species were found to dislike tannins, although silvereyes could tolerate higher levels than blackbirds. In summer, there was no preference by the birds for either colour. However, in autumn, the time of grape harvest, blackbirds took only purple grapes and silvereyes green. Wild grapes are purple and a vivid purple is a signal that the grapes are ripe. Unlike blackbirds, which swallow grapes whole, silvereyes peck at grapes and suck out the fluid. This allows silvereyes to avoid ingesting grape skin and seeds which contain the bulk of tannins in grapes and probably accounts for the greater tolerance to tannins by this species. Overall, this research continues to build a picture about the difference between bird species and a greater understanding of how birds make decisions within the vineyard.

So long and thanks for all the birds

2011-04-14T21:25:00.015+12:00

Hoki, a female kākāpō on Whenua Hou.
Photo by Laura Molles

One of the giants of New Zealand conservation, Don Merton, passed away this week. Don was instrumental in saving from extinction the South Island saddleback (Philesturnus carunculatus carunculatus), the black robin (Petroica traversi), and the kākāpō (Strigops habroptilus), surmounting often considerable obstacles. There are very few conservationists worldwide with such an impressive legacy.

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Some of us had the pleasure of hearing Don's keynote address at the 2005 Australasian Ornithological Conference in Blenheim. He talked at length on his career to date and the challenges ahead. He started his address by relating a story from his childhood. As a prank when a boy, together with his brother, Don stole a goldfinch nest with eggs and had his Grandmother's male canary incubate the eggs and raise the young. Don attributed this childhood experience with cross-fostering as the gem of his idea later in life to cross-foster black robins with grey warblers (on same island, unsuccessfully) then tomtits (only present on a different island but successfully). This ingenious stunt famously saved the black robin.

Don's career had its bittersweet moments. When ship rats reached Big South Cape Island, Don and colleagues from the Wildlife Service mounted a rescue operation, despite a lack of support from some in Wellington. (It is hard to comprehend in hindsight but at that time there was widespread skepticism amongst ecologists internationally that predators could drive prey to extinction in large areas.) All South Island saddleback now descend from the birds Don and colleagues saved from Big South Cape Island in 1964. However, the six Stead's bush wrens they rescued failed to survive and that was the last of the species, as it was for the Stewart Island snipe and the greater short-tailed bat.

Don looked back with regret that his team were not allowed to take all the kākāpō they found from Fiordland because of the risks of mortality during translocation. All of the Fiordland birds they left died, lost to mammalian predators. He revisited Fiordland several times in the hope of finding more birds, without success. Richard Henry, the famous Fiordland bird rescued by Don and his team, passed away in December last year, around 80 years old, after passing his genes into the surviving kākāpō. All other kākāpō genes are now from Stewart Island Birds.

Don and the plight of the kākāpō featured prominently in Douglas Adams and Mark Carwardine's book, "Last Chance to See..." (1990). They recount visiting the last kākāpō track and bowl systems in Fiordland, still there but no longer visited by kākāpō. Don kept a potato in the bowl they visited, hoping that one more bird would visit and tidy it up. When they left the site, Don carefully put the potato back on the edge of the bowl. No kākāpō returned.

Mark ended their book as follows.

"There is one last reason for caring, and I believe that no other is necessary. It is certainly the reason why so many people have devoted their lives to protecting the likes of rhinos, parakeets, kakapos and dolphins. And it is simply this: the world would be a poorer, darker, lonelier place without them."

Thanks, Don, for leaving us a world less lonely.

Local flasher ignored

2011-03-30T11:04:00.003+13:00

Figuring out which animals are present in an area can be a difficult task. We often need to count local populations of endangered or pest species or check to see if certain individuals are present. Sometimes we can simply go out and count but often the terrain makes this impossible or the presence of a human can affect the behaviour of the animals of interest, by scaring them away. There are several methods that can record the presence of mammals. In New Zealand, for example, we use tracking tunnels where small mammals leave their inky footprints, waxtags where curious individuals leave bite-marks and various kinds of traps where the animals leave themselves. A method rapidly gaining in popularity is the camera trap, where animals leave their image. Basically cameras are left in the field and are activated by either an animal breaking a light beam or by entering an area where a motion detector alerts the digital camera. Images of the animals are then saved to memory and can be downloaded for further analysis. A difficulty with camera traps is that they often are placed in dim environments, forests for instance, and of course, mammals are often very active at night. So camera traps need some kind of flash in order to capture a useful image. For many years infra-red flashes have been used. Most mammals do not see into the infra-red spectrum well and therefore should not notice that a flash has gone off. Of course there are downsides to infra-red, the images are in greyscale and are not particularly clear. It would be useful if an image could be taken in white-flash as greater detail would be recorded as well as colour. However, it is assumed that the sudden bright light would influence mammal behaviour, probably by scaring individuals off. More... In New Zealand, most of the mammals of interest, usually from a pest management point of view, are active at night. It would be very helpful if white-flash images could be used to help observe behaviour of species like possums where age, sex and individuals could be identified. With this in mind, Shona Sam, a PhD student in the Ecology Department at Lincoln University and her advisor team (Shaun Ogilvie, Adrian Paterson, John McIlroy and Charlie Eason) have looked at the effect of different flashes on possum behaviour around bait stations. The brushtail possum (Trichosurus vulpecula) is a major pest species in New Zealand and a huge effort goes into controlling this furry plague. Common methods of control include delivering toxins in cereal biscuits at bait stations in areas with high possum densities. Understanding possum behaviour at bait stations is crucial to designing the best way to deliver these toxins. Do the possums fight each other at stations with the dominant possum restricting access to others? How long do they spend at the station? Do they visit several times a night? Camera traps are an ideal way to collect these data, particularly if white flash can be used. Shona set up her trial in a pine plantation in the foothills of the Southern Alps. 30 camera traps and bait stations were placed throughout the 700 ha study area with equal numbers of infra-red and white flashes. Each test was for 6 days at each site with cameras and baits being checked every second day. Shona found that there was no significant difference between the number of possums 'captured' by the different flash techniques. Likewise, the amount of time spent by possums at bait stations and the amount of bait taken did not differ significantly either. The results from this experiment, published in the Proceedings of the 24th Vertebrate Pest Conference, clearly show that using a white-flash will not affect the behaviours of interest in possum research at least. Shona is now using camera traps to further examine the nocturnal life of several of our mammalian pest species.

Another quake

2011-03-02T11:48:00.003+13:00

Last Tuesday (22nd February) Lincoln suffered a second powerful earthquake in 5 months. This was centered further from Lincoln although it has caused Lincoln University to be closed for the last week. Unfortunately, this quake devastated large areas of Christchurch and resulted in over 200 deaths in the central city and there will be many short to long term implications for the city. Lincoln University reopened today and we will start our teaching semester two weeks late. The university is in good condition. The Ecology Department suffered no new damage and the Entomology Research Museum is in good shape. As far as we are aware, all ecology staff and students are safe (although many are still without running water and sewerage. Our thoughts go out to all those that have suffered during the quake and the many aftershocks (of which there have been about 5000 since September 4th).

New tools for weta (DNA) workshop

2011-02-11T14:07:00.011+13:00

Banks Peninsula is home to an endangered tree weta rather imaginatively called the Banks Peninsula tree weta (or Hemideina ricta to its friends). This species is only found on the eastern edges of the peninsula and there is a concern that its range is still shrinking. Lincoln University scientists have an active role in conserving this species. Aside from the usual cuplrits, like habitat modification and introduced predators, a major reason for the decline of this species is another tree weta species, the Canterbury tree weta (Hemideina femorata). It is thought that the two species are able to mate and produce hybrids. Why is this such a problem? Hybrids are obviously not 'pure' individuals of either species. If too much hybridisation occurs then there may be few pure Hemideina ricta left (and certainly it will be hard for these individuals to find pure mates). Conversely, the Canterbury tree weta is found throughout.... well Canterbury and has a large population. Only a small proportion of the Hemideina femorata population will become hybrids and most matings within the region will be between pure members of the species. Obviously it would be useful to be able to identify which tree weta are hybrids but it is not always easy. However, you can't fool DNA.

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Roddy Hale and Gregoire Alabergere from Lincoln University have worked with Marie Hale (University of Canterbury) to identify useful sections of DNA that will identify which species parents of weta found in Banks Peninsula belong to. The idea is that some parts of the genome (the entire DNA found in an individual) change at such a fast rate that some versions are only found in one species and some in the other. In a study recently published in the journal of Conservation Genetics Resources, they showed how they had looked at 20 microsatellites (fast changing regions) from the weta species and found that 12 of them were useful for identifying which species the DNA came from. With these new tools scientists will be able to survey tree weta populations and get a better feel for the scale of the problem facing Hemideina ricta.

Watch me wallabies feed, mate, watch me wallabies feed

2011-01-26T09:20:00.007+13:00

New Zealand is home to numerous introduced species that do so well in the wild that they have become pest species. Probably the largest and least known (outside of South Canterbury and Rotorua) are Australian wallabies. Dama wallabies (Macropus eugenii) were released around Rotorua in 1912. I'm sure it seemed like a good idea at the time. Since then the population has increased and spread and is now a pest species that damages native plants, reduces plant diversity and alters local ecosystems. As such, Dama wallabies have been controlled using poison baits and hunting for several decades. As with any situation where you have long-term control, the wallaby population has built up a resistance to the main toxin, 1080. There is also a growing concern from the public about the use of this compound and so alternative toxins are being investigated.

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A recent study by James Ross and Charlie Eason (Lincoln University) as well as several colleagues from Connovation Ltd, Department of Conservation, and University of Auckland was published in New Zealand Journal of Ecology. In this study the team looked at the effect of the toxin Ferratox (a cyanide based compound with low secondary poisoning risks an high humaneness). Their study site was a 32 ha block of degraded forest south-east of Rotorua. Surveys were done to estimate the local wallaby population and 24 wallabies were captured and fitted with radio collars so that they could be followed. The toxin was loaded into a baits and laid out throughout the study area. Half of the collared wallabies were found 3-8 km from the study site a week later showing how much the population moves around. Eleven of the twelve that remained in the area were killed by the ferratox baits as well as at least 20 other uncollared wallabies. These results are extremely promising and a viable alternative to 1080 seems to have been found.

Hyraxes invade Ulva Island!

2011-01-10T21:15:00.004+13:00

Beware the hyraxes! According to a photo on TVNZ's website, they have invaded Ulva Island. Errors like this turn up regularly in the media.....

tvnz.co.nz//national-news/rodents-invade-rat-free-island-3995671

I've written to suggest they replace the photo with one of an actual rat, or, at the very least, an actual rodent.

Kokako successfully anchored in ‘safe’ forest

2010-12-17T18:34:00.005+13:00

This blog post was written by postgraduate student Anna Reuleaux as part of the course, Research Methods in Ecology (Ecol608).

North Island kokako are an endangered New Zealand forest species known for their beautiful song. In the past conservationists have translocated these birds from mainland areas to managed islands and succeeded in establishing new populations. These safe kokako havens were predominantly literal islands surrounded by water but also used have been islands of suitable forest in a ‘sea’ of grassland or farmland. The advantage of these islands is the guarantee that the birds will stay in the area that has been prepared for them by predator control. But how do you get birds to stay in a managed area if it is situated in continuous forest without any boundaries to stop dispersal?

Laura Molles and her colleagues attempted such a translocation to a managed area surrounded by continuous forest: Ngapukeriki is located in the Bay of Plenty on the North Island of New Zealand. The conservationists decided to use social attraction in order to encourage the kokakos to stay in the target area after release. For the kokako the presence of resident individuals indicates that they are likely to find the right habitat conditions, food resources and potential mates in the vicinity.

But what if there are no resident kokako yet in the target area? One answer is to trick the birds, giving them the impression that there are plenty of other kokako around. In this case three social attractants were used simultaneously: 1. releasing many birds at the same time; 2. keeping a pair of kokako in an aviary at the release site and 3. using playback of kokako song as ‘acoustic anchor’.

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Acoustic anchoring is the most exciting one of these tactics as it had never before been used in translocations of terrestrial birds. Recordings for the playback were made in the source population so that the translocated birds could be exposed to the song of their former neighbours, singing and calling in their familiar ‘dialect’. Three kokako held in the aviary at the release site responded positively to a trial playback.

Eighteen kokako were released in July and August 2005. After the release the playback was broadcasted for one and a half hours every morning from speakers near the release site. Most of the released birds visited the area of the playback at least once, some of them repeatedly. On several occasions kokako approached and counter-sang with the playback speakers.

All this is good evidence that acoustic anchoring is likely to have contributed significantly to the success of this translocation. On the other hand this study was not designed to prove the effectiveness of acoustic anchoring on its own but to find out if the combination of the three social attractants would lead to a successful establishment of a population. The re-introduction of kokako to Ngapukeriki can definitely be regarded as a success as the first young already fledged in 2006. “And every year since, the kokako of Ngapukeriki have bred successfully and the population continues to grow” says Laura.

The researchers also pointed out that acoustic anchoring is also worth investigating for the translocation of other terrestrial species. Laura Molles and her team have already put that into practice in a translocation of Tui to Banks Peninsula in 2009. The acoustic anchoring technique has also been trialled on robins, whiteheads and in two further kokako translocation projects.

This article is based on:

Molles, L.E., Calcott, A., Peters, D., Delamare, G., Hudson, J.D., Innes, J., Flux, I., Waas, J. 2009. 'Acoustic anchoring' and the successful translocation of North Island kokako (Callaeas cinerea wilsoni) to a mainland management site within continuous forest. Notornis 55(2): 57–68.

Photos from kokakorecovery.org.nz with kind permission from Laura Molles.

It's time to take a step forward

2010-12-10T14:39:00.002+13:00

This blog post was written by postgraduate student Lauren Maciaszek as part of the course, Research Methods in Ecology (Ecol608).

Penguin road sign in Westland.
Photo by Mollivan Jon

Kaka, kotuku, kea, kakariki, kokako, kereru, and kiwi. What do all of these have in common? Apart from providing some interesting alliteration and perhaps a bit of a tongue twister, they are all native New Zealand birds which are considered nationally vulnerable, threatened, or endangered. The Department of Conservation’s (DOC) 2005 Threat Classification System showed that 153 bird species were considered at risk, chronically threatened, or acutely threatened. Another 50 bird species might be at risk or threatened, but there was not enough information known to be able to classify them.

Conservation is a necessity in New Zealand, unless we want our surviving bird species to follow the moa, Haast’s eagle, and huia to extinction. The biggest challenge for conservation, both in the past and looking into the future, begins right in the middle of our capital city at Parliament – it’s getting funding. DOC’s already strained budget is being tightened again, and every cent for conservation needs to be spent as wisely as possible.

This is where more studies like the one done by Jonah Busch and Lincoln University’s Ross Cullen would be useful. Busch and Cullen used a panel data set of yellow-eyed penguin nest counts to analyse different recovery treatments and their effectiveness and cost-effectiveness (the study was published in the journal Ecological Economics in 2009).

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Three recovery treatments were assessed. The first was trapping, in which traps were laid out to kill predators. The second treatment was revegetation, in which appropriate plants were planted to provide shelter for the penguin and provide better breeding conditions. The third treatment was intensive management, which involved an on-site manager who cared for sick or injured penguins and managed nest boxes. The site manager also used trapping and revegetation, so this method is essentially a combination and enhancement of the other two methods.

Using the data from the different sites, Busch and Cullen then used econometric techniques to analyse how effective the treatments were, by focussing on the population growth rate over time. They also allowed for other factors which might impact their results, such as time lag between the treatment being implemented and beginning to have an effect, and the presence of the Hooker’s sea lion.

The results of the econometric analysis showed that only one of the treatment methods, the intensive management, was responsible for a significant increase (about 9%) in yellow-eyed penguin nests over the period of time (13–15 years) that the data covered. This shows that both the trapping and revegetation treatments are not particularly effective on their own, and that money spent on these treatments alone could be money unwisely spent. The cost of each additional nest gained through intensive management was also calculated, with the final cost shown as about NZ$68,600. The study also concluded that the intensive management was the only cost-effective method, because it was the only method that was effective.

Ross Cullen stated that he “would warmly support similar studies being completed on other New Zealand threatened species”. These studies would better inform conservation managers in New Zealand about how to spend their budget, and provide them with an idea of the outcomes that are likely to be reached with the money spent. However, Cullen also points out that similar studies would require time series data collected from a number of sites, and that this might only be available for a few species.

Perhaps, then, it is time to start collecting more data. Information is power, and when monetary power is restricted by budgets and forced into trade-offs between conservation efforts, it seems to me that it’s best to have all the information we can get. The way I see it, the study runs an analysis on a set of already collected data – that means no extra cost, time, or disturbance to the animals, and the data is also being used by others (such as DOC). This could be the beginning of a large step forward in conservation management. After all, what have we got to lose?

Source:

Buscha, J., and Cullen, R. 2009. Effectiveness and cost-effectiveness of yellow-eyed penguin recovery. Ecological Economics, 68(3):762–776

Not so different

2010-11-15T16:30:00.002+13:00

This blog post was written by postgraduate student Rohith C. Yalamanchali as part of the course, Research Methods in Ecology (Ecol608).

Australia and New Zealand: different environments, similar weeds.
Sourced from Google Earth.

Invasion biologists use the term “naturalisation” to describe when introduced species form self-sustaining wild populations. A subset of naturalised species become so widespread and have such large impacts that they are regarded as pests and weeds. An important step in predicting new pests and weeds is predicting which introduced species will naturalise.

The success of naturalisation of the introduced species depends on factors such as the geological, climatic, and biological conditions of the habitats it is introduced into. The native species present in the habitat also play role in this success (competition for resources).

Australia and New Zealand are closely neighbouring countries separated by 1600 km of sea. The significant differences between two countries include Australia having 29 times more land area, 5 times greater population and very different types of wildlife than New Zealand. Also, the indigenous people of Australia are Melanesian in orgin while New Zealand Maori are Polynesian (see Yahoo! Answers for a wide ranging discussion about the many differences between New Zealand and Australia).

Along with these differences there are similarities which will aid the understanding of this article. Similarities, include the recent European colonisation history and the presence of temperate climate zones (although much of Australia is warmer and drier than any of New Zealand). Surprisingly, naturalisation of introduced plant species turns out to be another similarity between these two countries, despite their many environmental differences.

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Jeff Diez, Phil Hulme, Richard Duncan and Jon Sullivan from Lincoln University, and colleagues, have analysed the naturalisation patterns of introduced plants in New Zealand and Australia (Diez et al (2009)).

The results of the study showed that out of the 12927 species that were introduced in both countries the number of them naturalised in both countries are surprisingly similar (Australia 1713 species (13%) and New Zealand 1617 species (13%)). Similar patterns are seen in genera naturalised; out of 2663 genera introduced to both countries, 807 (30%) naturalised in Australia compared 746 (28%) in New Zealand. Of the 155 families introduced to both countries, 152 (98%) naturalised in Australia compared to 155 (100%) in New Zealand.

The analysis of the plant families successfully naturalised in both countries showed that the top four families are the same in both countries: Juncaceae (76% of introduced species in this family naturalised in NZ and 61% in Australia), Poaceae (46%-NZ and 30% Australia), Cyperaceae (42% NZ and 39% Australia), and Amaranthaceae (36% NZ and 43% Australia).

Note that ranking of these families within the top four differs between the countries. Juncaceae and Cyperaceae are the two families which hold the same positions (first and third respectively) in both countries. The other two families Poaceae (second in NZ, fourth in Australia) and Amaranthaceae (fourth in NZ, second in Australia) switch between second and fourth positions depending on the country they are in. A similar pattern is shown with the other families in two countries with some exceptions.

We can conclude that naturalisation patterns of introduced species in both the countries are not so different, most likely due to similarities in colonization history and overlapping temperate climate zones. The study by Diez and colleagues can be used as a guideline for future studies with regards to naturalisation patterns of introduced plant species in these two countries. It also suggests that environmental differences between invaded countries are less important for predicting new naturalisations than differences in the country’s cultures of plant introduction and cultivation.

Source:

Diez, J. M., Williams, P. A., Randall, R. P., Sullivan, J. J., Hulme, P. E., and Duncan, R. P. 2009. Learning from failures: testing broad taxonomic hypotheses about plant naturalization. Ecology Letters, 12:1174–1183.

Urban Realities: the contribution of residential gardens to the conservation of urban forest remnants

2010-11-08T12:50:00.003+13:00

This blog post was written by postgraduate student Elisabeth Christensen as part of the course, Research Methods in Ecology (Ecol608).

Urbanization has destroyed and fragmented natural areas, resulting in decreasing native biodiversity. Fragmented natural areas can only sustain small populations of plants and animals, and these are often vulnerable to extinction. Minor fluctuations in climate or resources, which would be unremarkable in large populations, can be catastrophic in small, isolated populations. Furthermore small populations have higher risks of inbreeding and a decrease in genetic diversity.

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In Christchurch City, the urban remnant Riccarton Bush is an example of such an isolated fragment of natural habitat. In Riccarton Bush, the number of native vascular plant species has declined by a third, from 106 to 67, over the last 125 years. In order to achieve sustainable wild plant populations, the management of urban remnants needs to find a way to expand the plant populations into the surrounding urban areas and thereby increasing their effective population size and genetic diversity. A recent study shows that residential gardens have the potential to play an important role in the conservation of native plant species.

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Brendan Doody, Jon Sullivan, Glenn Stewart, Harvey C. Perkins, all from Lincoln University, together with Colin Meurk from Landcare Research, recently published the first results from an ecological and sociological study in the journal Biodiversity and Conservation where they answered the three following questions:

Are native woody species naturally dispersing from the urban forest remnant and establishing in surrounding urban residential gardens?

How are garden management practices influencing the establishment of native woody species in urban residential gardens?

What is the awareness of and support for the use of native plants among local residents?

Kahikatea tree
Photo by Alan Liefting

As an example of an urban remnant they specifically looked at Riccarton Bush, which is the only remnant in Christchurch dominated by the native tree species kahikatea (Dacrycarous dacrydioides, shown in picture and also known as white pine). Jon Sullivan says about the significance and rarity of Riccarton Bush: "It is the only old growth lowland forest in Christchurch to have survived the creation of the city. It is also one of only two lowland old-growth forest fragments left in mid-Canterbury that are not associated with the Southern Alps or Banks Peninsula." Nationwide, only 2% of pre-settlement kahikatea forest remain.

The study revealed that some of the native woody species, especially kahikatea, are dispersed by birds into the surrounding gardens, mostly within a radius of 250 meters. However it also showed that the juvenile trees never reach maturity as most gardeners tend to remove all non-planted woody species.

These results suggest that there exists a natural potential for regeneration but that it is insufficient without human intervention. This is where the last part of the study becomes interesting. What is the attitude towards native plants among garden-owners?
A carefully designed questionnaire was developed to answer this.

The results from their questionnaire revealed that attitudes towards New Zealand's native flora were overall positive. 84% agreed or strongly agreed that ‘species unique to New Zealand are important to our identity’ and 81% that ‘native plants are attractive’. When it came to having native plants in their own gardens the answers were a bit more reluctant yet still positive - 54% agreed or strongly agreed ‘they would be prepared to plant Riccarton Bush species in their garden’.

Kahikatea seedlings.
Photo by Mollivan Jon

The study also found that people in general lack knowledge of native species, for example only 2% were able to correctly identify a seedling of the kahikatea tree. This suggests that information and education is an important step towards engaging people in conserving native plants. Another important factor is for the garden-owners to have control over the location of plantings as many are concerned about too much shade in the garden.

If this article has encouraged you to get out there and help preserve New Zealand's native plants, you can get in contact with an organization such as Trees for Canterbury which does community projects and environmental education and has a native plant nursery. The majority of their trees in the nursery are grown from seed collected in the Canterbury Plains and Banks Peninsula in order to ensure genetic integrity of the native plant populations. This is an important fact to remember, as the genes of native plant populations in the urban remnants are adapted to make them fit for the local environment. However this may be threatened by gene flow from non-local or modified plants in the surrounding gardens.

Source:

Doody, B. J., Sullivan, J. J., Meurk, C. D., Stewart, G. H., and Perkins, H. C. 2010. Urban realities: the contribution of residential gardens to the conservation of urban forest remnants. Biodiversity and Conservation, 19:1385–1400.

The long invasion

2010-10-14T16:48:00.011+13:00

New Zealand has worried about invasion for the last 200 years. Dotted around our major harbours are gun emplacements built to repel Russian and Japanese imperial designs in the late nineteenth and mid twentieth century’s, respectively. Of course neither of these invasions eventuated but there have actually been enormous numbers of successful invasions into our proud island nation. Thousands of plants, hundreds of insects and multitudes more have colonised New Zealand since Europeans themselves arrived. Species continue to arrive and New Zealand spends a lot of time and effort in preventing them from doing this or in trying to reduce the impact of these invasive species when they do get here. Much of the ecological research at Lincoln University and the Lincoln Crown Research Institutes is centred around these issues. One strand of this research is to understand the rules that describe the spread of non-native species through the landscape and over time. Many aspects complicate our understanding of these rules especially the fact that rules may differ at the level of local habitat, region or island. Also, factors that are important in the early phases of an invasion, like human modifications of habitat that suit the invading species, may be less so after several decades when the invading species becomes more widespread.

A carpet of Hieracium pilosella hawkweed in the Canterbury high country. Photo by Mollivan Jon

In a new study published in Austral Ecology, Nicola Day and Hannah Buckley of Lincoln University have looked at the fate of three closely related invasive species over three decades. The plant species Hieracium (Hawkweed, Asteraceae) are native to Europe but are invasive in many parts of the world where they often degrade native and pastoral grasslands. In New Zealand, three species in particular, H. lepidulum, H. pilosella, and H. praealtum, were introduced accidentally in grass-seed mixtures and cause major problems in high country areas. Day and Buckley wanted to know which ecological and environmental traits explained the spread of these species, whether these traits were important at all scales and whether they were the same for all three species. To test these ideas they were able to make use of a fantastic long term study. In the mid 1980s, 124 study sites were set up in high altitude tussock grasslands in Otago and southern Canterbury. Information about the plant species found at these sites and characteristics of the site, like levels of calcium and phosphorus and climate data, were collected. The sites were resampled in the mid 90s and again between 2005 and 2007. So Day and Buckley had the luxury of looking at the changes that had occurred over three decades.

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Overall, all three species increased at all scales during the study. All three species had complex relationships with the various traits measured. However, it appeared that there were some predictable patterns to be detected. For example, all three species were better able to invade areas of short-tussock than tall-tussock. It also appeared that each species shared a similar invasion trajectory for their population spread but that they were at different phases in their invasions. H. praealtum is widespread but its increase is slowing and is probably towards the end of its invasive phase. H. pilosella is in an earlier stage of its invasion and continues to spread at a high rate. H. lepidulum is only a minor component in the grasslands and seems to be in the earliest lag phase of its invasion (H. lepidulum was the last of the three species to naturalise). This study shows the benefit of sampling over decades and over large distances. In some ways this is a little worrying for ecological research which typically does studies over small scales and one or two years. Day and Buckley show that to understand the small scale you sometimes have to think at the larger scale.

Darwin & the Sandwalk 3

2010-10-14T15:58:00.003+13:00

Here is one that is just as topical as it was in the 90s. The Marsden Fund is the major fund for 'blue skies' (i.e. no immediately applied purpose) science in New Zealand. This year 91% of those that applied failed to get funding! I'm not sure that Charles would have recieved much funding in this environment! "Oh yes I'd like to breed a few pigions and see what happens".

Life above our heads – the invertebrate fauna of West Coast rata canopy

2010-10-01T16:32:00.006+13:00

This blog post was written by postgraduate student Andrea Honig as part of the course, Research Methods in Ecology (Ecol608).

Kathrin Affeld did not choose an ordinary topic for her PhD thesis at Lincoln University. She and her team of scientists carried out a research project on the invertebrate fauna high up in the canopy of northern rata trees on the West Coast of the South Island of New Zealand. Northern rata, or Metrosideros robusta, in the family Myrtaceae, are tall emergent trees in New Zealand's temperate rain forests and before Kathrin's work their canopies were unchartered territory for science. Her project would be a real pleasure for all the outdoor climbing fans among us.

To collect data, Kathrin climbed 15–25 m up each tree before she could set up her experiments. Photo by Mollivan Jon

As Kathrin stated in 2004, “I’m looking at invertebrate communities that live in epiphytes and their response to climate change.” The study gave a significant insight into the high level of invertebrate diversity present in the canopy of northern rata trees at the two sites studied and uncovered several species new to science including one genus of species

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Kathrin and her colleagues decided to sample epiphyte mats directly, because conventional methods, such as insecticide fogging, would not be appropriate for capturing all invertebrates, as any individuals in funnel shaped plants or thick humus layers would be missed. Each sample had to be detached from the bark and transported carefully in plastic bags to the lab. Invertebrates were extracted using Berlese funnels over several days.

Berlese funnels are a common method to extract invertebrates from soil or litter samples. Heat produced by a light bulb dries the sample. Invertebrates will move away from the light and heat and fall down the funnel through a mesh into a preservative fluid (for example, ethanol).

Berlese funnel.
Illustration by
Andrea Höing, Lincoln University.

To make sure all invertebrates were extracted the researchers washed all remaining organic material over three stacked sieves with their mesh size decreasing from 1.7 mm to 75 μm.

Berlese funnels in action extracting invertebrates from Kathrin Affeld's canopy samples. Photo by Mollivan Jon

Identification could be conducted by expert taxonomists for most species to family level, but it was a great challenge to go further and just 16.2% were assigned to species level. There were at least 10 new species found and one new genus, although there is likely to be many more species new to science amongst the many specimens that could not be identified to species. All of the species collected in this study can be viewed at the Entomology Museum at Lincoln University, Canterbury, New Zealand.

Data analysis showed that the study reflected only a portion of the real biodiversity in the podocarp-broadleaf forests canopy. This portion already indicated a highly diverse invertebrate fauna, both functionally and taxonomically (more than 242,000 invertebrates were collected). Results were presented in a 17 page long table giving important baseline information to each species, site where they were found, sampling time, feeding guild and their status, if they are endemic, introduced, cosmopolitan or native.

The most interesting discoveries included the following.

Several undescribed and new species in epiphyte mat habitats (>10 new species).

Extended geographical ranges for various species.

Large arboreal ant colonies; until this study they had been known as solely ground nesting species.

Relatively small numbers of exotic insect species (7 species, all in relatively small numbers); this information is very important for assessing invasion risk.

All this information is important in terms of national biodiversity inventories and global species estimates. Kathrin further recapitulated the importance of investigating invertebrates and epiphytes of New Zealand: “Understanding their distributions and interactions is fundamental for predicting and dealing with the threats posed by habitat loss and climate change. Data from my study could further be incorporated in climate change models and used to identify conservation priorities.”

This study was the first invertebrate inventory of New Zealand forest epiphyte habitats. It provides important baseline data for conservation of biodiversity in New Zealand's forests. However, it also highlights how much we have yet to learn about the amazing bio-diverse canopies above our heads. For detailed information on this study see Affeld et al. 2009.

Affeld, K., Worner, S., Didham, R.K., Sullivan, J. Henderson, R., Malumbres Olarte, J., Thorpe, S, Clunie, L, Early, J, Emberson, R., Johns, P., Dugdale, J., Mound, L., Smithers, C, Pollard, S., and Ward, J. 2009. The invertebrate fauna of epiphyte mats in the canopy of northern rata (Myrtaceae: Metrosideros robusta A. Cunn.) on the West Coast of the South Island, New Zealand. New Zealand Journal of Zoology 36,177–202.

Darwin & the Sandwalk 2

2010-09-27T10:29:00.003+13:00

Another SYSTANZ cartoon from the 90s.

Coast-to-coast, biodiversity style

2010-09-21T20:15:00.018+12:00

This past weekend, staff and students of Lincoln University's Ecol202 course, Biological Diversity, ventured west for their annual three day field trip of field biology and weather. This year held a bit more weather than usual, on account of a large storm slamming into the western side of New Zealand. It was reportedly one of the largest storms on the planet at the time, about the size of Australia.

Still, West Coast weather is never predictable so off we went. Things worked out surprisingly well. Rather than the usual New Zealand weather of "four seasons in one day", we instead got "four seasons in one hour". Each hour. We got a snowed on, rained on, blown about, and, surprisingly often, shined on.

David Pontin discusses kelp ecology at Truman's Track. Photo by mollivan_jon

Beech-licking good. Sampling Ultracoelostoma honeydew in Lord's Bush. Photo by mollivan_jon

Highlights of our trip this year were seeing a New Zealand falcon (at Kelly's Creek in Arthur's Pass), plenty of weka around Moana, glow-worms in Punakaiki Cavern, a northern rata mid-way through strangling a large matai tree along Truman's Track, Lord's Bush (one of the last forests of the Canterbury Plains), and, as always, the Westland petrels flying in from the ocean to their colony at dusk.

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Some ill-timed horizontal rain squalls curtailed our annual fish'n'chips evening on the beach. We usually have dinner on a beach just south of Punakaiki watching Westland petrels (Procellaria westlandica) approach land. The rain dampened our chips forcing us to retreat to our bus. The huge stormy seas also prevented us from seeing to the horizon over the breaking waves where the Westland petrels would have been gathering. Gathering they were, though.

After dinner in the bus, we headed down to the roadside beside Nikau Scenic Reserve and watched the dark petrels slip through the sky to their colony in the forested hillside behind us. Student Tim Gale and I counted 89 birds arriving in 25 minutes between 6:47 pm (when the first bird arrived) and 7:07 (when we had not seen another bird for several minutes). That is down from the 150 birds we counted on last year's trip but is still an impressive turn-out for such a weather-filled evening.

It is quite something to see Westland petrels as they represent a glimpse into what much of coastal mainland New Zealand would have been like before people and their mammals arrived. The species is also remarkable in that it only nests in this area of the West Coast of the South Island and yet the birds regularly range at sea as far as the Chatham Islands to the east and are thought to go as far east as South America.

For the first time, we also did plant plots along our coast-to-coast transect where we recorded the diversity of shrubs and trees and measured features of the leaves of each species. Our trip spans over a 1,000 m of elevation and 5,000 mm (yes, five metres!) of annual rainfall so we hope to see some strong signals in the leaf morphology of the vegetation along the way. If it works out, we will tell you all about it on this blog.

You can see photos of our trip on our Ecology@Lincoln Flickr group.

Are two heads better than one? Kokakos and playback responses

2010-09-20T13:51:00.013+12:00

This blog post was written by postgraduate student Jetzabel Gross as part of the course, Research Methods in Ecology (Ecol608).

A Kōkako (Callaeas cinereus). Taken at Mt Bruce
Wildlife Centre, New Zealand.
Photo by Doug Mak

The perception of reality is different for each animal species and communication can be a very helpful resource. Yet animal communication skills are a complex topic to understand, for example, what is the function of bird songs? How are they perceived? Do only birds of the same species react to songs or do others as well? And more importantly are song emitters perceived differently by single or paired receivers?

These are some of the questions specialists working on bird behavior ask themselves and the research by Lincoln University's Laura Molles and Waikato University's Joseph Waas , whose results were published in the journal Animal Behavior in 2006, try to answer. Moreover with this study they wanted to generate knowledge of the advantages of both birds singing the same song at different times, or only the male singing, or the pair singing.

Hence, two variables were tested: one where the song of a single bird was broadcasted from one speaker and another where the song was split up between two speakers, simulating a duet. The perception of threat to a territory was measured by how fast nearby birds approached the playback speakers and by how long male and female birds of a pair spend next to each other.

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Photo by Guy Vickers
(Used with permission of Laura Molles,
kokakorecovery.org.nz )

To test these predictions in 2003 they conducted research in specially selected and marked areas of the Pongakawa Ecological Reserve, North Island, New Zealand. In these playback arenas, 11 territorial pairs of endemic and endangered, New Zealand kokako birds (Callaeas cinereus wilsoni) were tested and two playback stimuli were performed and each repeated four times. Observations were recorded visually and by audio indicating location of each bird and distance between pairs. The treatment consisted of three phases: a lure phase to attract the bird until it reached a specific position; a main playback, which lasted around three minutes and was the focal period where behaviours for the main findings of this research were extracted; and a post-playback period where observers kept monitoring birds for 30 minutes.

The main findings are as follows.

Perceiving Danger: Pairs (female and male birds) feel more danger to their bond if the song is broadcasted by a pair rather than by a single bird. This was suggested after observing that speakers broadcasting this simulated duet were approached faster by the bird pair. Some possible explanations for this faster approach are: 1) that birds find it easier to locate the two speakers, 2) confusing source of sound, 3) two speakers perceived as a moving opponent, thus more danger and 4) two speakers were perceived as very close opponents.

Proximity: Bird pairs did not stay close together during playback periods. It appears that the perceived danger in both broadcast situations is to the territory rather than to the bond. A remarkable observation is that cooperation for territory defense may be argued since observations indicated that male and female birds approached the speakers together.

Answering playbacks: Birds did match and anticipate the playback song very quickly suggesting that the birds pairs are quick in recognizing and react accordingly to familiar external audio stimuli.

Vandercamp, Naugib and colleagues suggest that matching and anticipating are aggressive signals in kokako, which has been observed in a number of other species.

The relevance of this kind of study is to generate expanding knowledge of the different functions singing brings to birds, and how essential it is for the maintenance of the complex interactions between them. Finally, a solid understanding of the behaviour of any relevant species is essential for conservation efforts on them.

Source:

Molles, L & Waas, J. 2006. Are two heads better than one? Responses of the duetting kokako to one and two speaker playback. Animal Behaviour, 2006, 72: 131–138.

Darwin and the Sandwalk

2010-09-17T12:20:00.007+12:00

During the 1990s the Systematics Association of New Zealand was a very active science group with regular conferences and a membership of around 100. SYSTANZ was based around scientists who were interested in systematics (the science of working out evolutionary relationships. There is an old site for SYSTANZ which has a good definition of what systematics is. Earlier this decade, for various reasons, the association went into abeyance. During the 1990s I was lucky enough to be the secretary for the association and produced regular newsletters. One of the things that Cor Vink and I added to newsletters were a series of cartoons. One was themed around Darwin walking along the Sandwalk (the route he built at Down House to take some exercise and ponder). Many of them were based on finding reasons for Darwin's delay of many years in publishing the Origin. The other series was on a phylogenetic superhero called Unrootedtreeman. Rather than consign these to the bottom of filing cabinets throughout New Zealand forever, I will occasionally show them off here at EcoLincNZ. This is the first one that wonders what would have happened if pay for view TV was around in Victorian times....

Shaken but not stirred

2010-09-10T13:55:00.003+12:00

The ecology staff are back at work today. Offices have been tidied, labs set right and we will be open for lectures on Monday. Ecology at Lincoln seems to have gotten off lightly after the big quake and aftershocks. The Entomology Research Museum is largely intact with some damage to one of the rows of cabinets (but it did the job in protecting the specimens). The wet collection is also intact. John Marris, the curator, took the accompanying photo. His office was in much worse condition!

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Interestingly, ecology staff at Lincoln have done research over the last couple of decades on the impact of earthquakes on forests in New Zealand. Richard Duncan and Glenn Stewart have looked at the periodicity of when trees were knocked over by earthquakes to get a picture of when future big quakes were dues. As they have reminded us for a decade, we are well overdue for a large alpine fault quake. Unfortunately, the one earlier this week was from a fault on the Canterbury Plains and we still await the other!

A whole lot of shaking going on

2010-09-09T13:17:00.004+12:00

What a long time a week is since the last blog! A 7.1 earthquake hit the Canterbury region at 4.35am on Saturday morning. The epicenter was just over 20 km away from Lincoln University. Despite a lot of damage there was, incredibly, no loss of life. This was due to the time of day it hit, luck and the preparedness of NZ for such quakes. We're not known as the shaky isles for nothing. However, this was the biggest land centered quake since the 1930s. And what a ride it was. The quake went for over 40 seconds which was long enough to think about exactly how big it was. A terrifying experience. Since Saturday there have been over 300 aftershocks, many over 5.0. Lincoln University has sustained a reasonable amount of damage which has closed the university for at least this week. The Ecology Department is in reasonably good shape.

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A couple of staff went into the department a few hours after the initial quake to get generators onto incubators and -80 freezers as there was a loss of power for most of the day. Most labs were surprisingly well off, having tight regulations for earthquakes seems to have worked. Most offices were a mess, monitors down, books all over, windows broken, filing cabinets toppled. I'm pleased we weren't working on the 4th and 5th floors at the time. We were concerned about the Entomology Research Museum and the priceless collection of insects but the new cabinets (upgraded just over a year ago) did their job. There was some damage to some of the collection not yet put away. The biggest remaining worry is for the wet collection which wasn't checked. Still overall, ecology seems to have survived and we should be back to work by Monday.

The spirit of wine shall be green

2010-09-02T16:40:00.005+12:00

This blog post was written by postgraduate student Juan F. Dueñas Serrano as part of the course, Research Methods in Ecology (Ecol608).

“I know the cost in pain, in sweat,
And in burning sunlight on the blazing hillside,
Of creating my life, of giving me a soul:
I shall not be ungrateful or malevolent”

Charles Baudelaire (1821-1867), The Spirit of Wine.

Set aside your work for a moment. Look for your favourite spot at home and allow yourself a moment of pleasant rest. Take a bottle of your preferred New Zealand wine and enjoy a sip while you read the label on the bottle. Does the description match your expectations? Hopefully, it will be a brief summary of the characteristics that help to define this delightful drink. Sometimes, labels will describe a picturesque bucolic scenery or use the notion of profound human values to remark on the quality of the product. Virtues such as honesty, character and, why not, spirit, are all often associated with wine. So let's think about where all these images and language come from.

Leafroller moth's caterpillar (Epiphyas
postvittana) on a grape leaf.
Photo by Jean Tompkins, Lincoln
University (used with permission).

Winemaking starts at the vineyard. It requires many years of study, experience and sometimes intuition to yield a grapevine that will satisfy the demands of discriminating consumers. But more than that, it requires a gifted land. Remember that the wine industry is a multi-million dollar business, so grapes are to be carefully selected and cultivated yet they also have to come in great volume. Accordingly, vineyards generally tend to become extensive mono-cultures, and like any other intensive resource use, this practice radically changes the landscape and carries with it a series of associated problems, such as increased vulnerability to pests. In the case of New Zealand vineyards, the introduced Australian leafroller moth Epiphyas postvittana is the unwanted guest and it must be controlled.

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Up until now, the conventional approach has been to apply pesticides over the precious vineyards to get rid of the inopportune 'bug'. But this presumably affects the environment, increases the cost of the final product, and potentially, will have a negative impact on the very glass of wine you are enjoying. The solution might come from nature. Regulation of insect populations by predation occurs naturally in an ecosystem, thus, if handled carefully, this capacity might potentially provide the agricultural landscape with a service, an 'ecosystem service'. This concept provides the basis for an alternative approach that tries to encompass the demands of a complex industry and the need of a truly sustainable landscape. After all, land is where the spirit of wine begins its journey.

This alternative to pesticides involves the manipulation of the habitat to enhance biological control, and it offers a great potential. A recent study published in the Journal of Applied Ecology by Mahumuda Begum and colleagues, including Lincoln University's Steve Wratten of the Bio-Protection Research Centre, features a series of greenhouse and field experiments that test the ability of selected flower's nectar and pollen to enhance the function of the omnivorous parasitoid wasp Thichogramma carverae. This was is a natural enemy of the light brown apple moth. Flowers potentially supplement the wasp diet by providing important resources such as sugar from the nectar and protein from pollen.

The main idea behind this approach is to incorporate selected flowering plants into the agroecological scheme of vineyards, hence naturally increasing the density and longevity of the wasp. This approach benefits the vineyards in different ways. First, by avoiding the costs associated with breeding up and releasing large numbers of the parasitoid. Second, by reducing occurrence of weeds and cover crops that can potentially host different stages of the pest by planting instead the selected plants; and third, by reducing both the cost and the amount of pesticides that need to be applied to vineyards.

Allysum (Lobularia maritima) strips in an organic lettuce crop.
Photo from Lincoln University (used with permission).

But the process is not straightforward. Experiments were needed to determine the best plants to provide the required 'ecosystem service', in this case biological control. The selected plants should not interfere with the wasp's ability to parasitise the moth. Additionally, the plants have to be a below-vine, shallow-rooted crop to avoid resource competition with grapevines. After conducting greenhouse experiments with combinations of several plant candidates in the presence of the parasite wasp and the moth, a trial in the field was performed to test greenhouse findings in a realistic situation. From the five plants originally selected, Begum and colleagues concluded that sweet alyssum (Lobularia maritima), a common garden plant, is the most effective candidate for the purpose described above.

This study demonstrates how the careful and informed manipulation of natural resources can improve the provision of ecosystem services. By integrating research on the functions that ecosystems naturally provide with reasonable economic revenue, we are taking a step forward towards the sustainability of our land. These alternatives to conventional practices are promising and will enable us to work with nature instead of against it. We will be assuming our role in providing environmental stewardship, or kaitiakitanga as Maori people beautifully put it, while giving wine a rightful 'green spirit'.

The big pitcher

2010-08-31T12:02:00.008+12:00

Ecologists spend a lot of time thinking about how species in communities are linked together. While we have made progress in understanding this at small scales (like your backyard) we have seldom tried to understand this at large scales (like across continents). One of the reasons for this is that there are huge numbers of species in communities and the problem of dealing with them all is too difficult. However, some communities are not so complex. Hannah Buckley (Lincoln University) and her colleagues, Thomas Miller (Florida State), Aaron Ellison (Harvard) & Nicholas Gotelli (Vermont), realised that there are some communities that are easier to study. In a paper published in Global Ecology and Biogeography, the team looked at communities that live with pitcher plants over much of North America. Pitcher plants collect rainwater in their leaves and these pools are colonised by species of bacteria, insects and so on. The pitcher plants create a simple community that can be investigated at a several scales: different pitchers (or cups) within a plant, different plants within a local population, and across the plant’s entire distribution (continental scale).
The pitcher plant Sarracenia purpurea was the subject for their study and is a long-lived (> 50 years) carnivorous plant that grows in bogs, sand plains and pine savannahs across much of North America. The pitcher-shaped leaves are open to the sky and collect rain and snow as well as various species of animals and bacteria that happen to arrive in the cups. Many of the species, finding themselves trapped in the pitcher, drown and form the basis of a food chain on which other species feed who, in turn, provide food for predators. The plants are thought to absorb some nutrients, particularly nitrogen and phosphorus, from the decaying bodies.

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Buckley collected the contents of pitchers from 39 sites across North America. When examined, across all sites, the researchers found 13 arthropod & rotifer species, 48 protozoan species and 29 bacterial morphotypes. Pitcher plants typically hosted 6 arthropod species, 9 protozoans and 17 bacterial species. Nearly half of the species found were only from one site, whereas 4 species that specialise in living in pitchers (three fly and one mite species), were found at almost all sites. Overall, and very surprisingly, pitchers at the same site were less similar to each other in species make-up than comparing pitchers at different sites across North America! That is food webs, and therefore communities, were more variable at the smallest scale that at the larger scale. This is probably not as surprising as you would first think. For example, the streets in your home town can be highly variable as to the businesses that you might find there but if you compare between towns they will generally all have a pharmacy, a supermarket, a fish’n’chip shop, hairdressers, a joinery and so on. It’s all about the scale you ask your questions at. And that is the key finding of this study.
This study emphasises the benefits of examining how communities change at a variety of scales and should serve as a model for others. Buckley and her co-authors intend to use this idea of simple natural communities in future studies to examine the effects of local and continental scales on how biotic and abiotic challenges affect species richness and community membership.

Not-so incy wincy spider

2010-08-26T17:11:00.003+12:00

Cor Vink, adjunct curator of spiders at the Entomology Research Museum, Lincoln University and research scientist at AgResearch, has recently published a taxonomic revision of the New Zealand Pisauridae (nurseryweb spiders) with his colleague Nadine Dupérré (American Museum of Natural History) – Vink CJ, Dupérré N (2010) Pisauridae (Arachnida: Araneae). Fauna of New Zealand 64: 1-60. A taxonomic revision takes a good look at what we know about species in a particular group as well as any new species that have been discovered since the last major look. The Fauna of New Zealand series will eventually aim to cover all of the species found there. Cor is New Zealand's leading arachnologist and has discovered many new species of spider. Nadine is a talented drawer of spiders and you can see some of her work in the latest Angelina Jolie movie Salt (one of the characters is an arachnologist).

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Nurseryweb spiders are easily recognised in New Zealand by the nurseryweb that the female builds around the eggsac, which serves to protect the newly emerged spiderlings. New Zealand nurseryweb spiders do not build a web for prey capture and are sit-and-wait predators. Four closely related species of nurseryweb spiders are found in New Zealand; three on the mainland and one on the Chatham Islands. All species are endemic to New Zealand and are likely to be related to Australian species. The most common species is Dolomedes minor, which is found throughout New Zealand in scrubland, grassland, swamps, and marshes. Dolomedes aquaticus is found in open riverbeds and stony lakeshores throughout the South Island and in the southern half of the North Island. Another species, Dolomedes dondalei is found in shaded riverbeds throughout mainland New Zealand. The Chatham Islands species, Dolomedes schauinslandi, is known from only three islands (South East, Mangere, and Houruakopara Islands) and is nationally endangered due to its restricted range. Molecular evidence of interbreeding between two common mainland species, D. minor and D. aquaticus, was also discovered and this is being investigated further by B.Sc. honours student Vanessa Lattimore.

Success for Nina Valley Restoration Group

2010-08-23T12:46:00.011+12:00

Hurunui College established the "Nina Valley Restoration Group" at the start of 2009. Nina Valley is located near Lewis Pass and is a region of beech forest. The valley has a good level of accessibility with tracks running from the road to the head. A major goal of the group is to establish a breeding kiwi population. The group has successfully gained funding from BNZ Save the Kiwi and the Air New Zealand Environmental Trust.

The funding has been used to purchase 150 DOC200 and 40 Henry (resetting) traps to control mustelids, particularly stoats. Stoats have a large impact on bird breeding paopulations. In November 2009 about 20 volunteers - students, parents, and a couple of NZ Deerstalkers Association members - spread these out over 15 km of river valley in the Nina valley. The traps were checked and reset fortnightly by groups of 5-6 students and parents over the summer season.

The 2010 Youth Leadership for Sustainability Awards are a joint initiative between Environment Canterbury and Ngai Tahu recognising awareness of environmental and social issues among Canterbury’s youth. The individual award was open to students in Years 12-13 and recognised their work in sustainability, either through their own initiative or by supporting or leading a wider project. The group award celebrates the contributions of a youth organisation, marae or school. Nina Valley Restoration were placed as group category prize-winners, along with Lincoln Enviro Organisation and Youth River Action, in recognition of their excellent work.

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The "Restoration Group" consists of around 20 students, ranging from 12-15 years old. It was set up at the beginning of 2009 by Hurunui College science teacher, Tim Kelly, and DOC ranger, Malcolm Wylie. Since then, the group has done kiwi-listening, and trapping and tracking-tunnel training. They have had hands-on opportunities to view kiwi eggs and chicks raised through the BNZ Operation Nest Egg at Willowbank.

Since the Group was formed staff and students from the Department of Ecology at Lincoln University has helped with installing and monitoring tracking tunnel (purpose built wooden tunnels containing inkpads and paper that record when stoats move through them). Also, the department has hosted a group of Hurunui student while they investigated stomach contents of stoats caught in traps at Nina Valley.

Tim Kelly has recently applied to the Royal Society of New Zealand for a 6-month teaching fellowship. If successful he will be hosted at Lincoln University while working with Drs James Ross and Adrian Paterson and his study will investigate new self-setting traps for stoats and possums.

How to have a lousy time in Durham

2010-08-23T10:32:00.010+12:00

Durham, England, famous for its grand old city and cathedral, where bus loads of senior citizens spend their day dragging their Zimmer frames over the cobbled streets to admire ye olde England. More recently and probably more famous in New Zealand, Durham's castle and cathedral might be better known as Hogwarts School of Witchcraft and Wizardry, as seen in the Harry Potter films. So, what have Lincoln University and Harry Potter got in common? Not a lot, but it sets the scene for where my current fieldwork is based.

I am in northern England to sample birds for feather lice. As you sit and scratch, feeling small legs walking through your hair, you might ask why I would travel half way around the world to do this. The source of almost all of New Zealand's introduced song birds is the UK. Sparrows, blackbirds, skylarks and finches, amongst others, were brought to New Zealand by settlers to help create a sense of home. Along with the birds came their feather parasites, although not all of the species. It is the pattern of what made it and what didn't that is of interest to us and will allow us to better think about invasive species (see this previous blog). We know how the lice are distributed around New Zealand but have only minimal knowledge about their ancestral home, especially the northern areas of England where many settler-ships left from. To model UK distributions of chewing-lice, I have been catching selected bird species and processing them for chewing lice.

While you suffer winter in NZ, I am enjoying the UK summer. I arrived in the UK in early July and quickly made arrangements to join British Trust for Ornithology (BTO) bird ringers in the field. Bird ringing (or banding) is heavily regulated in the UK and takes at least two years to gain a licence to ring birds without supervision. Naturally, this is well beyond the scope of a Masters project. This means that I am at the mercy of suitably qualified people to complete my research. All of the ringers that I work with volunteer their time and they also pay for the rings and all other costs associated with ringing birds.

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Apart from their natural love of birds, there are other reasons why these people ring birds: the BTO run various ringing programmes, such as The Constant Effort Sites Scheme (CES) and Retrapping Adults for Survival (RAS) that rely on data collected by these volunteers. The CES sampling protocol dictates that each site is visited once every 10 days during the breeding season (this means 11 visits). The effort at each site remains constant, i.e., the same number of nets in the same positions for the same amount of time. For example, at the Foxglove Covert CES they erect 30, 18 metre mist-nets, begin ringing at sunrise (4am in mid-summer) and remain ringing for 10 hours; whereas, at the Rainton Meadows CES they erect 8 mist-nets (a mixture of 12 and 18 metre nets) and catch birds between 7am and 1pm.

The benefit of CES for my fieldwork is that I can plan on mist-netting at least once every 10 days, weather permitting. Birds loose body heat rapidly when they get wet, so to avoid bird mortality, nets must be collapsed when it rains. Wind also affects sample effort; birds are less active in high wind and the nets become highly visible flapping about. More importantly, birds can also be injured in a moving net (e.g., broken wings and strangulation). CES sites are usually visited in the weekend, so I must decide on which to visit. Lately, I have gone where I catch the greatest number of birds, but soon, to increase the number of records for more rare species, I will have to concentrate on locations where specific bird species are caught.

This is a convenient segueway to the RAS (Retrapping Adults for Survival) scheme. Sites are selected where many individuals of targeted species will be caught for monitoring species survival rates. So far, as part of my study I have processed birds at yellowhammer, house sparrow and blackbird RAS sites. There are some species that I have few records for, so I need to find redpoll, songthrush and starling RAS sites to sample at. Which should fill the last five weeks that I am here.

While I am not delousing birds in the field, I process my samples in the lab (thanks to Biological sciences at Durham University). This entails sifting through my field samples under a dissection microscope. I have become quite tuned into finding lice floating about in a mixture of ethanol and flea powder, but it still takes about one day to process 10 samples. I have processed 135 birds (about 10% of all the birds caught at these sites) and blackbirds are by far the most lousy bird, both for prevalence and intensity.
Ok, gloves on and back to work....

Banks Peninsula Biodiversity Workshop: Proceedings

2010-08-11T11:04:00.006+12:00

The Biodiversity Workshop that was held at Akaroa in October 2009 is now available as a proceedings. The proceedings compile information from the various presentations given on the day and were put together by Mike Bowie, Rachel Barker and Tina Troup.

Over the course of a very successful day, scientists, conservation organisations and landowners came together to talk about conserving Banks Peninsula’s special plants, birds, lizards, fish and invertebrates. The proceedings run to 49 pages and are packed with information on on trapping various predators threatening the native species, how to conserve and/or restore habitats of native species present on Banks Peninsula as well as updates on the management of various endangered species, such as tui or little penguins.

You can read the proceedings here.

Vegetarian zombie weevils rise from down under

2010-07-19T10:08:00.009+12:00

A Canterbury Knobbled Weevil on Aciphylla.
Photo by Mike Bowie, Lincoln University
(used with permission).

In 2004, in an unsuspecting sleepy town in South Canterbury, zombies rose from the dead. Headlines were dedicated to spreading the news, zoologists world-wide were excited, all due to the rediscovery of a species thought to be extinct for 82 years! Wow, like the takahe? Well, maybe: a weevil. It may be smaller than the charismatic species we are used to hearing about, but no less important.

Despite the fact that specimens are located in history museums around the world, the endemic Canterbury knobbled weevil (Hadramphus tuberculatus) had not been seen alive for 82 years. To everyone’s great surprise, it was rediscovered in Burkes Pass in 2004 by Laura Young while she was studying for her Masters degree. It is currently one of New Zealand’s most endangered invertebrate species. The news at that time exclaimed how four specimens were found (and consequently pinned and archived). But what happened after that? Were there any survivors? Lincoln University researchers and students were quickly hot on the trail of this elusive large, flightless knobbled critter to find out.

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Following the rediscovery, conservation efforts to save this species have been impressive, especially when we know so little about the species. Sampling measures have mainly included the use of pitfall traps and visual searches of the speargrass species that the weevil is known to primarily feed on (speargrass, or Spaniards, are species of Aciphylla, a famously spiky New Zealand plant in the carrot family). These efforts located more weevils within a second site on farmland across the road from the location of the initial rediscovery. However, until this last summer, all past efforts found very few additional weevils in either area. The summer of 2007–2008 recorded just six specimens; five located on Aciphylla, one in a pitfall, and the 2008–2009 summer returned no weevils at all. Thankfully, the past season (summer 2009–2010) found 49 weevils, the majority of which were recorded in the original area and all bar one were caught in pitfall traps.

Emily Fountain, a Lincoln PhD student currently studying the weevil, has hypothesised that the reasoning for these vast differences in weevil numbers between years is due to the ecology of the speargrass. Many threatened New Zealand birds put much more effort into breeding during the years their food plants flower heavily (“mast-seeding”). In contrast, Emily thinks that knobbled weevils are easiest to catch in years of poor flowering. Last summer very few plants flowered. Emily proposes that this caused a weevil mass movement, interplant dispersal, to locate more food resources that resulted in a very successful pitfall trap count. The previous two summers were good flowering years so the weevils are thought to not have needed to move around so much. This may be why the few specimens that were found were mainly located on the speargrass plants rather than between them.

Environment Canterbury and Department of Conservation staff in Twizel have both been frantically trying to protect the weevil and its habitat with the use of rat, stoat and hedgehog predator control since its rediscovery in 2004. Lupin spraying and the decapitation of wilding pine seedlings has also been a priority to stop competition with speargrass. The future conservation efforts for this species may include translocations, but this will only be once Emily’s research into the genetic health of the current population is completed. This research will allow us to see if the species is genetically stable enough to survive in additional populations. Until this time, a booklet has been released by Mike Bowie (Lincoln University) to inform farmers, and the general public, on what they can do to help locate more weevils and how they can aid in the species conservation. If you find a large knobbled weevil on a speargrass in Canterbury or Otago, please contact Mike.

Although the Canterbury knobbled weevil is, well, a weevil, its rediscovery was a significant event in New Zealand’s history. It reignited the awareness in the general public about the importance of the lesser known species. It also provides hope for other ‘extinct’ species that may be out there somewhere, still managing to survive under the radar of human detection, waiting for their chance to walk, or crawl, among the living again.

More information:

Bowie, M. 2009. The Canterbury Knobbled Weevil, Hadramphus tuberculatus, Conservation Guide. Lincoln University. (1.7 MB PDF)

Young, L. M., Marris, J. W. M., and Pawson, S. M. 2008. Back from extinction: rediscovery of the Canterbury knobbled weevil Hadramphus tuberculatus (Pascoe 1877) (Coleoptera: Curculionidae), with a review of its historical distribution. New Zealand Journal of Zoology, 35:323–330.

This blog post was written by postgraduate student Vanessa Lattimore as part of the course, Research Methods in Ecology (Ecol608).

The origin of the Chatham Islands’ flora

2010-07-07T16:00:00.005+12:00

The Chatham Island archipelago lies over 800 km to the east of mainland New Zealand. There are two major islands, Chatham and Pitt, and several smaller islands. Humans have lived on the islands for a few hundred years. There is a good level of diversity of species in the archipelago. For example, there are about 410 plant species, subspecies and varieties present although the vast majority are the same as mainland New Zealand species. There are 36 endemic plant species (species only found on the Chathams), including 17 trees and shrubs and 11 herb species. A recent study led by Peter Heenan (Landcare Research), with Anthony Mitchell (University of Otago), Peter de Lange (Department of Conservation), Jeanette Keeling (University of Auckland) and Adrian Paterson (Lincoln University) has used molecular methods to look at the evolutionary history of these endemic plant groups. Their work has now been published in the NZ Journal of Botany. In this study the group analysed 35 endemic species and their separate closest relatives using information from several gene regions to estimate evolutionary relationships and time since last common ancestor for each group.

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Not surprisingly, the vast majority of species had their closest relatives on the New Zealand mainland. It had been argued that most species colonising the Chathams would have originally come from northern New Zealand but this was not supported. Rather, closely related species were often those that were widespread around the mainland, perhaps indicating their ability to colonise successfully. Most of the speciation of Chatham species has occurred as allopatric speciation where the colonising population has since become isolated from mainland populations. Only six species pairs appear to have arisen within the Chathams themselves (from the genera Aciphylla, Coprosma, Hebe, and Olearia) and this speciation may be driven by niche differentiation into wet and dry habitats. These results are all consistent with the isolation of the Chatham Islands and the predominant winds and currents moving from the west (New Zealand) to east (Chathams) making it easy to colonise the Chathams but difficult to get back to the mainland.

The age of the endemic Chatham flora was investigated using molecular clocks. First, 14 species showed virtually no DNA divergence when compared to their mainland closest relative. This suggests that these Chatham species are recent arrivals. Second, 19 species showed low levels of divergence (less that 1%) which indicated a relatively recent colonisation of the Chathams over the last 3 million years. Finally, four species had much higher levels of divergence that implied 4-7 million years since the last common ancestor.

These results fit well with what we know about the geology of the Chatham Islands. The Chathams have a long history. They were part of Gondwanaland and then Zealandia (as seen by terrestrial dinosaur bones found on the islands). However, most of the last 60 million years have been spent underwater with short periods of volcanic island building. In recent times, the Mangere volcano produced land about 6 million years ago which had largely sunk again by 4 mya. The Rangitihi volcanics raised land about 2-3 mya and land has persisted since then. The plant evidence certainly supports this idea of most plant species arriving in a newly emergent land over the last two million years. Coupled with the fact that about 350 plant taxa are identical to mainland species, these findings support the idea of a young flora and the hint at the tremendous power of long distance dispersal and colonisation to establish diverse biotas on isolated oceanic islands.

How many? Where-abouts?

2010-05-13T15:09:00.004+12:00

In order to estimate the total population of a species you need to know the mean size of local populations and where the populations are. Numbers and amount of sites where species are present are usually linked and this is referred to as the abundance-occupancy relationship. However, there are many exceptions to this rule and it appears that many organism traits may affect either local numbers or distribution. Much of the research in this area, both showing the link between abundance and occupancy and where life history traits impact on this link, has been done on birds and insects. Plants, major drivers in ecosystems, have seldom been examined. Until now. Hannah Buckley (Lincoln University) and Robert Freckleton (University of Sheffield) have used data from sites that have been monitored for 25 years. The 52 high country tussock grassland sites are scattered throughout Otago and southern Canterbury of the South Island of New Zealand. The number of species and the number of individuals at each site were measured in the mid 1980s, mid 1990s and 2005-2007. The length of time that the plant populations have been monitored make for an unique opportunity to examine long term changes in species abundance and distribution. A paper in the Journal of Ecology has just been published on what they found.More...Occupancy and abundance of species at each site was highly correlated through all sample periods. Within each site, there was movement of species with 76% of species colonising and about 20% of species being lost from the sample transects. Traits that might impact on relationship between species abundance and distribution were measured. If a plant was ‘weedy’ (fast growing in most habitats) enabled the species to be more widely distributed than expected. If a plant was clonal (not sexually reproducing) this enabled the species to be more abundant at a site than expected. Surprisingly, dispersal ability and size did not affect a plant species’ distribution and abundance. Overall, this study is a positive step forward. It confirms that plants respond in similar ways to other organisms and increases our understanding on how plants species persist and move around the landscape.

Parasites lost

2010-03-23T14:08:00.005+13:00

One aspect that is often overlooked when thinking about biological invasions is that in addition to the invading species, be it a bird, beetle or banana, there are usually associated parasite species that come along for the ride. More intriguingly, sometimes one of the reasons why invasive species are so successful is because the parasite species that come with them cause greater problems for native species allowing the newcomer to out-compete the locals. At other times invasive species succeed because they left a nasty parasite at home and escaped their influence. Studying the absence of parasite species is a challenging task! There are several reasons why a parasite species might be missing from the host species new home. And here things get a little nautical...
In the late 90s Adrian Paterson, studying feather lice on birds in New Zealand, speculated that many parasite species of introduce birds species would not be present because they had 'missed the boat'. When birds, like sparrows and blackbirds, had been collected in Great Britain to be brought out with colonists to release in New Zealand, there was always a chance that a particular louse species might not be present on the individual birds collected and therefore never even had a chance to establish. Paterson had some limited data to support this idea.

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A new study by Paterson and Richard Duncan (both Lincoln University) and Catriona MacLeod and Dan Tompkins (Landcare Research) has examined this idea in a more sophisticated manner and is just published in Ecology Letters. The team realised that New Zealand is in a unique situation to test this idea. Bird species introduced into New Zealand were reasonably well recorded. We know roughly how many individuals were brought to New Zealand, how often attempts were made to establish populations and how successful they were. We also know a great deal about the louse species present in the UK and NZ. Using newly collected data where birds were collected in the UK and their lice recorded, as well as similar records from early in the 20th century, MacLeod and colleagues were able to work out the louse population distribution over a number of bird species. They then asked the question 'if, say, 33, individual greenfinches were used to establish a successful colony in NZ, how likely is it that these 33 individuals would have all or some of the louse species present in the UK for this particular sample?'. Complicated statistical methods ensued
The results were interesting. About 38% of UK louse species actually have colonised New Zealand successfully. Of those that failed, only 5% are predicted to have missed the boat. That is, it is likely, given the numbers of individual birds brought to NZ, that almost all louse species should have at least got onto the ships. Another third failed to establish because their host species also did not establish (which we term 'sinking with the boat'). Finally, 27% are 'lost overboard' where their hosts are successful but for some reason the louse species did not survive the colonisation event (perhaps because of low numbers). This is a rather surprising result as it tells us that a successful host colonisation is simply not enough to ensure a successive parasite invasion. This is promising in our efforts to stop the spread of pest species.
There are lots of ways in which this research may progress. For example, we currently have a postgraduate looking at louse distributions in populations in more detail. In particular, he is focussing on sampling error, that is that there may be stowaway species that are in low numbers and have avoided detection thus far. And there are many more nautical terms left to explore...

Turning up the volume on nature

2010-03-22T13:31:00.016+13:00

Whitewash head, awash with weeds
Originally uploaded by Mollivan Jon

Most environmental problems of today are caused by people super-sizing nature. Too much CO₂. Too much nitrate in lakes and streams. Too many fires. Too many invasions. These things are all part of nature's music but we've turned up the volume on some instruments. Way up. The music's not sounding so good any more.

I made some calculations in a recent paper in the New Zealand Journal of Ecology showing just how far New Zealanders have turned up the volume on species invasions. Not surprisingly, it's a lot.

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This is usually tricky to do because it's hard to know the rates with which new species have naturally invaded isolated places like New Zealand. Many, probably most, some suggest even all, of New Zealand's plants and animals are descendants of dispersal events from Australia and beyond long after New Zealand left Gondwana. Invasions have always been part of New Zealand nature. But how much?

The Chatham Islands, off the eastern coast of mainland New Zealand, offers a useful opportunity to figure out just how much people have turned up the volume on invasions in the New Zealand region. The Chathams archipelago has most recently been above the ocean for about 3.5 million years (the precise age is still being debated by geologists, but it's likely between 2–4 million years). All of the terrestrial species currently on the Chathams therefore had to invade since then. The nearest land is >650 km away on the New Zealand mainland, which is a very long way to swim, fly, or drift. Still, 3.5 million years is a long time to play Lotto and so prior to human arrival the Chatham Islands had accumulated a lot of lottery winners: 392 plant taxa, 64 breeding bird species (including recent extinctions), and 283 beetle species (references for these numbers are in the paper).

The first people arrived in the Chathams about 500 years ago and changed the rules of the lottery. The Chathams have since accumulated a further 396 wild plants, 16 breeding birds, and 39 beetles, and more keep arriving. Since the great bulk of the new species arrived after European settlement 218 years ago, this represents an increase in the successful invasion rate of >16,000 times for plants, >4,000 times for birds, and >2,000 times for beetles. Note that these estimates exclude unsuccessful invasions, both before and after human arrival. Note here that I am comparing the rates at which species arrive and establish.

My pre-human estimate of natural invasion is complicated by several factors. Three million years is a long time and spans some substantial climatic changes in the region, including the Ice Age Pleistocene epoch. The current known list of Chathams species most likely misses some species that arrived, established, and went extinct. This will mean that I am underestimating the natural invasion rate. Any species that arrived, went extinct, then re-invaded from mainland New Zealand again, perhaps many times through the cycles of glacial maxima and minima, are counted as one invasion. This will also mean I am underestimating the natural invasion rate. In contrast, any species that have arrived, established, then speciated into several species will result in my overestimating the natural invasion rate. While important details, none of these uncertainties are likely to alter my estimate of natural invasion by anything close to a thousand-fold.

A common justification I often hear from people who don't want to alter their lifestyles to benefit their environment and future generations is that it's all natural anyway. Why should we remove known weeds from our gardens or stop releasing exotic fish into rivers? All these new species are just nature running its course. Let them be.

That argument is clearly not valid. An increase in plant invasions of 16,000 times is simply not natural and neither are the disruptions they are causing to the invaded ecosystems.

Questioning the drowning

2010-03-11T13:59:00.014+13:00

One of the contentious debates in New Zealand biogeography (the science of explaining the geographical distribution of species) is about what happened at the end of the Oligocene period (24-21 million years ago). We have known for a long time that most of New Zealand's current land area was underwater during this period. However, a recent paper in The Geological Magazine reviewed the geological and biological data for any sign of land during this time and decided that there was no convincing evidence. The authors, including Adrian Paterson from Lincoln, suggested that the possibility of complete submergence of New Zealand during this period was something that had to be seriously considered. This has been a controversial idea because it means that all of the species native/endemic to New Zealand had to have arrived here from somewhere else over the last 20 million years. All of them. Kiwi, tuatara, kauri. Our blog has commented on this issue here, here, here and here. The Geological Magazine has now published a response to the earlier paper by Mike Pole and a reply from the original authors.

Pole has raised a number of issues with the original paper and concludes that the New Zealand flora does not support the idea of total submergence. Landis and company have responded in several ways. First, they are surprised at Pole's comment because in a landmark paper in 1994, which inspired the current research, Pole said ‘it is probable that the entire forest flora of New Zealand arrived by long-distance dispersal.’ Second, Pole states that there are coal deposits in Southland that may have accumulated through the Oligocene which means there were continuous forests growing (on land) through this period. Landis and company point out that it is difficult to show continuous deposition of organic material (it could be interrupted for considerable periods) and that the dating of this lignite seam is fairly broad (and could easily be from the late Miocene - after the drowning and when New Zealand had begun to emerge).

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Third, Pole points out that there are fossil pollens for lineages, like the southern beeches (Nothofagus), that are found before and after the drowning period, arguing for a continuous presence through this period. Landis and company point out that pollen for many plant lineages, including Nothofagus, is very generic, that is it is hard to tell the difference between species. So the pollen fossils tell us that Nothofagus species were present in New Zealand before and after the drowning but not that they are the same species. Molecular analyses suggest that modern southern beech tree species colonised after the Oligocene. Finally, Pole points out that previous pollen fossil researchers have not previously highlighted a sudden change in the plant species present in the fossil record at the end of the Oligocene period that you might expect if there had been a large 'turnover' in species due to extinction and then recolonisation. Landis and company concede that this is largely correct, although a few authors do indicate something was changing in the flora during this period. However, they go on to say that this is not too surprising given that pollen, as mentioned above, usually does not confirm the identity of species. If a species of a genus or family of plants went extinct in the drowning there is a good chance that another species of that group will colonise after re-emergence and we wouldn't be able to tell from the fossil if they were different. Landis and colleagues conclude with the comment ‘Although we cannot disprove the contention that land existed continuously in the New Zealand region throughout the Cenozoic, neither can we find evidence to support that hypothesis’. The debate will continue...

More 'What did you do in your summer holidays'

2010-03-09T10:21:00.008+13:00

Hamish Patrick, an undergraduate at Lincoln University, was awarded a summer scholarship to survey the Lepidoptera fauna of Otamahua from November 2009 to February 2010 with his supervisor Mike Bowie. Light-trapping on Otamahua involved using a powerful mercury-vapour lamp powered by a portable generator. During his nocturnal forays Hamish collected, curated and identified many species over his summer scholarship and has increased the known Lepidoptera taxa on Otamahua to 149 species. Some of the species collected were thought to be rare including an undescribed Eudonia species that feeds on moss of coastal rocks.
Otamahua an island in Lyttelton Harbour, Banks Peninsula is being ecologically restored by the Quail Island Ecological Restoration Trust. The Trust has planted 80,000 trees over the last ten years and introduced mammals have been eradicated. The ecology of the island is changing and with the flourishing vegetation some native bird species are increasing in abundance. Flying insects, like birds, can recolonise the island once habitat requirements are met.
Larvae of or Lepidoptera (moths and butterflies) are herbivores that feed on a large variety of plant, moss, lichen and other vegetative matter. New Zealand has about 2,000 species of Lepidoptera of which 92% are endemic (not found anywhere else), the highest in the world. Monitoring Lepidoptera in an area can provide a measure diversity that can be compared to other sites of similar habitat. Recommendations from his report suggest supplementary planting of larval host plants to enhance habitat for the rarer moth species.

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The Canterbury Knobbled Weevil (Hadramphus tuberculatus) was thought to be extinct since 1922 but was recently rediscovered in 2004 in Burkes Pass Scenic Reserve. H. tuberculatus is a large, flightless weevil that lives on a specific host plant known as speargrass/Spaniard (Aciphylla aurea and possibly other species). The Department of Conservation gives this weevil its highestconservation status and it is perhaps New Zealand’s rarest invertebrate.
Sam Rowland spent her summer searching for this weevil with her supervisor Mike Bowie in some exciting places such as Burkes Pass, Mackenzie Pass, Hakataramea Pass, Mt Somers and Lake Coleridge. During her scholarship she collected many invertebrate species on Aciphylla. Peter Johns and Sam Brown were kind enough to identify some of the specimens she gathered, and it was found that some interesting species were collected.
There are numerous threats thought to decrease the population of H. tuberculatus. These include fire, weed invasion, predators, possum and rabbit grazing and loss of Aciphylla habitat.
Since this summer the species was only thought to be found in Burkes Pass Scenic Reserve. Many years of sampling in areas where the Canterbury Knobbled Weevil was known to be present in the past or where Aciphylla is distributed has turned up negative for the species. This year Emily Fountain, Ben Wiseman and Sam Rowland found a new population adjacent to the Burkes Pass Scenic Reserve on private farmland.

What did you do in your summer holidays?

2010-02-12T15:22:00.008+13:00

This summer we had 15 students take advantage of our summer scholarships. These scholarships give students the opportunity to be paid to do research for 10 weeks. This is a great chance for them to look at whether this is something that gets them excited and maybe think about postgraduate research and a career. Various ecology staff at Lincoln mentored these students in a wide range of projects. The projects are drawing to a close now and we have been hearing what the students have been up to in a series of short talks.

For example, Warwick Allen and Natasha Wilson both worked on “The ecology of New Zealand sand dunes project” with Hannah Buckley. In collaboration with researchers at Victoria University they sampled plant and invertebrate communities all around NZ, including Stewart Island. At each location they sampled a site where sand dune restoration plantings have taken place and an adjacent site dominated by exotic plants. Their preliminary findings show that exotic-dominated sites host greater plant and invertebrate diversity than the native-dominated restoration sites.

Andrew Goodger has been working with Charlie Eason and Connovation Ltd. Because of the huge problems with many introduced mammalian pests in New Zealand, there is a major effort in looking at better and more effective methods for limiting their numbers. One way forward is to find more efficient poisons that target the pests and have few problems for the rest of teh ecosystem. Andrew helped to assess the potential of sodium nitrate as a fast-acting, humane and low-residue toxin for pig, possum & rat control. This has involved field and lab experiments and looks to be a very promising compound.

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Ian Phillipps has spent most of his time looking for mite-infested beetles in the few remaining lowland native forest fragments on the Canterbury Plains in order to get a better idea of the factors that effect their distribution. Although Ian is still collecting data, it's starting to look like these beetles and their mites may be useful indicators of habitat quality. The beetles only seem to be found where there are reasonably large patches of remnant bush, or at well established regenerating sites with mature trees and good canopy cover. Where beetles are present, mites tend to be found only in the larger, less disturbed patches. If this pattern holds up then this will be of interest to conservation managers as it may help them to prioritise sites for protection or evaluate the success of ecological restoration projects. Overall, the students had a lot of fun, the researchers got some good field work done and everyone was happy! We look forward to what next summer will bring.

New poisons for rat control

2010-01-28T12:23:00.009+13:00

New Zealand has many problems with introduced mammalian pest species like rats. Rats are present in such vast numbers that the most common means of control is in poisoning wild populations. There has been a great deal of work put in to finding more effective and humane ways to poison pest species. Anticoagulant poisons, particularly 2nd-generation anticoagulants such as brodifacoum, are very persistent and have been detected in a range of non-targets including game species (i.e. pigs, deer etc.) and native birds. In the face of increasing anticoagulant contamination of wildlife in NZ and overseas, the present study was conducted to provide further information on Feracol® paste; a potential tool for control of rodents as well as possums in native forest ecosystems.

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Feracol is a paste bait containing 0.8% cholecalciferol (vitamin D3). Cholcalciferol toxicity to birds is low (i.e. the LD50 for mallard ducks is 2000 mg/kg) and the risk of secondary poisoning for non-target species is low. In 1999, cholecalciferol was registered in NZ as paste bait for possums. This registration application was based on research in the early 1990’s, which demonstrated the high susceptibility of possums to cholecalciferol cereal bait.

The effectiveness of Feracol as a rodenticide was assessed in both cage and field trials. This work has recently been published in the New Zealand Journal of Ecology by James Ross of Lincoln University and other researchers based at Connovation. In the cage trials a total of 35 wild-caught and laboratory rats, including both ship and Norway rats, were presented with between 30-60 g of Feracol over 48 hours. Thirty four rats (97%) died in an average of 4.0 days following ingestion of the paste.

Field trials were then initiated with the paste delivered in either Philproof® or Striker® bait stations. Monitoring of rat numbers (using tracking tunnels) before-and-after the application of toxic bait was undertaken at three sites (Lions Hut, Mangaone and Pakoakoa) in the Te Urewera National Park. At Lions Hut, rat-tracking indices decreased from 78% to 3%; at Mangaone the reduction was 51% to 0%; and at Pakoakoa from 36% to 0%.

These trials demonstrate that Feracol is effective at reducing both moderate and high concentrations of ship rats. This is a promising result and providers users with an effective "non-anticoagulant" tool that can be used to effectively target both possum and rodents.

After several decades, tui are again breeding on Banks Peninsula

2010-01-21T14:16:00.025+13:00

Young tui. Flickr photo by Mollivan Jon

Last April, we blogged about the release of 30 tui (Prosthemadera novaeseelandiae, an endemic New Zealand song bird) onto Banks Peninsula to attempt to re-establish a self-sustaining wild population. Lincoln University lecturer Laura Molles has been leading the population monitoring. Laura and Karen Middlemiss, a Lincoln University summer scholar and Conservation and Ecology B.Sc. student, together with many keen local residents, have been spending their summer in south-eastern Banks Peninsula keeping a close eye on the tui as the birds explore what everyone hopes will be their new home.

Good news is that the released birds have chosen to stick around, rather than fly off back towards their original home in Maud Island. After massive historical deforestation, the south-eastern corner of Banks Peninsula is proving once again to be suitable tui habitat, thanks to increasingly large and mature areas of regenerating native forest and ongoing predator control. The second piece of good news is that the released tui have been breeding (!) and at least one nest has already fledged chicks. This amazing success less than 12 months into the project was reported in The Press newspaper on 18 Jan. 2010.

Despite the excellent start, the young tui population is certainly not safely into the woods yet. Several nests have already been hit by stoats and rats, despite intensive trapping around known nests. Stoats, especially, seem to be having a good year this year on Banks Peninsula. Also, thirty birds is inadequate to create a population with healthy levels of genetic diversity (see Lincoln postgraduate student Phil Cochrane's ecoLincNZ blog post on inbreeding depression in small populations of New Zealand birds). Because of this, a second release of Maud Island birds onto Banks Peninsula is planned for later this year and the Banks Peninsula Conservation Trust is fund-raising to pay for this translocation.

Laura Molles talking at the launch of artist Clare Reilly's exhibition "Return of the Tui - a celebration" Photo by Jon Sullivan, Lincoln University.

The tui project has been fortunate to join forces with local artist Clare Reilly of the Primitive Bird Group. Her spectacular tui paintings are currently on display at Gallery O in the Christchurch Arts Centre and proceeds from some of Clare's sales are helping to raise funds for ongoing predator control and the translocation of more tui. Laura Molles gave a talk and slide show about the tui release at the launch of Clare's exhibition on Tuesday 19 January and will repeat her talk in the gallery on Sunday 24 January at 2 pm.

If you're travelling on Banks Peninsula and see tui, Laura Molles and her team are keen to get your observations (where, when, what bird(s) (all released birds have colour bands on their legs), and what they were doing). Even if you don't get a close enough look to see the colour bands, Laura would still like to know where tui are on Banks Peninsula. You can send your observations to Laura or you can enter them online on the New Zealand Biodiversity Recording Network website (www.nzbrn.org.nz, the subject of a recent ecoLincNZ blog post).

I spy road-kill

2010-01-03T21:30:00.027+13:00

the outcome of stoat versus car
Originally uploaded by Mollivan Jon

Nature doesn't operate at the speed of Twitter. Well, maybe it does for microbes. It takes more patience to see changes in populations of big things like birds and trees. It typically requires stitching together lots of observations over many years or over large areas. That's a very important thing to do. Biologists expect a lot of New Zealand's species to be responding to the many physical and biological changes to environments caused by people doing what people do.

Surprisingly, New Zealand ecologists are largely in the dark about most of these changes because big datasets of observations of wild species in and around rural and urban landscapes don't exist. These are where environmental changes are most pronounced. Or, when these datasets do exist, they're typically scattered about unconnected, usually only in hardcopy and in a whole mix of formats (one shining exception to this is the NZ Ornithological Society's wonderful bird atlas).

The New Zealand Biodiversity Recording Network (www.NZBRN.org.nz) seeks to change this. It provides an online place where everyone from school children to professional biologists can enter in what they see. You can either enter observations straight onto the website or download spreadsheet templates that you can use to enter offline on your laptop or iPod Touch. With everyone's eyes open to the natural world around them, we can see how nature is changing.

NZBRN was covered by TVNZ's TV One News recently, featuring Landcare Research's Colin Meurk and Lincoln University's Jon Sullivan. Click the image below to check it out (and note that the NZBRN web address is www.nzbrn.org.nz and not www.nzbrn.com as they mention in the story).

This summer, NZBRN is challenging people to record road-kill hedgehogs and other flattened fauna that they see on roads. Counting road-kill while driving or biking about New Zealand over summer is a convenient way to collect lots of observations.

One man who has already been doing this in the North Island for several decades is biologist Bob Brockie. In a recent article in the New Zealand Journal of Zoology, Bob and colleagues describe how hedgehog numbers in the North Island have declined by 82% between 1995 and 2005. And nobody knows why. Equally mysteriously, the decline doesn't seem to have happened in the eastern South Island, although we need many more recent observations to compare with past data to be sure of this. That's where you can help.

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You can read more about counting road-kill and other projects involving NZBRN in the latest NZBRN newsletter, available here. At its simplest, NZBRN is great for creating species lists for locations and mapping species distributions. There are also all sorts of potential uses for NZBRN, including describing the spread of new pest and weeds, watching native birds reinvade New Zealand cities after pest control and the maturation of native plantings (hopefully), determining which species are most sensitive to climate change, or describing how species respond to large-scale conversion of farmland from sheep to dairying. The list of uses is only limited by the depth and breath of observations in NZBRN.

Ecologists in places like Europe and America have access to many big long-term datasets from urban and rural landscapes, often collected by keen amateur naturalists. These data have revealed all manner of changes, including shifts in species' seasonal activities and distributions and alarming declines in common birds and butterflies. Plants, birds, and insects are all responding to climate and landscape changes in different ways, disrupting the interconnections that make the natural world what it is today.

These are important things to know about New Zealand nature. For example, there has been concern raised here that many of our butterflies may be in decline (for example, watch this TVNZ Breakfast news item), but there's little hard data to back up that perception or to inform ecologists about the causes of any such declines. The observations needed to describe such changes in nature are not complicated or difficult. All we need is "What?", "Where?", and "When?", repeated over and over at lots of times and places and for lots of species. Also, recording when you looked for something and didn't find it is just as important (and there's an article on that in the latest NZBRN newsletter). If lots of people do this, together we'll know a lot more about the nature around us.

The best way to really get into NZBRN is to pick a few favourite species and places and start recording whether they're there or not each time you visit. A favourite place could be a summer holiday spot or your back garden or your drive to work. Favourite species could be fantails or all butterflies or, yes, even squashed road-kill hedgehogs.

Recording species certainly takes the monotony out of a long summer drive. When you get into the swing of it, it can be good fun. You'll find yourself noticing all sorts of things around you that you would otherwise have passed by.

Quail Island Biology Trip

2009-12-11T15:22:00.003+13:00

Over the last decade the ecologists at Lincoln University have been very involved with the ongoing restoration work on Quail Island in Lyttelton Harbour. Mike Bowie, in particular, has been a major force in keeping the connection going. During this time there have been numerous trips out to the island with dfferent groups of postgraduate and undergraduate students. Over the last week Sue Unsworth. in her role as science outreach co-ordinator, has organised four days of activities on the island involving Year 12 biology high school pupils from the Christchurch and Timaru areas. The students helped in ongoing restoration and conservation projects on the island. They checked tracking tunnels (containing inkpads that leave behind footprints)that monitoring for predators like mice and rats (and luckily found none as there has been a major control operation this year). There were also gull and gull chick counts and lizard lodge (corrugated squares that lizards love to live under) checks for monitoring lizard numbers and species. Despite variable weather and long tiring days, fun was had by all.

Town cats visit the wet rats

2009-11-05T10:16:00.003+13:00

Cats are common pets all around the world. Nowhere is this so pronounced as in New Zealand where we have the highest rate of cats/households in the world. One of things that we like about cats is their independence but this comes with a downside - what does your cat do when it is not in the home? Cats are natural predators and we know that they will catch almost any sort of prey. Concerns have been raised that cats may have many negative impacts on local wildlife, especially where their homes are near wild areas. In a study recently published by researchers from Lincoln University (postgraduate students Shelley Morgan, Cara Hansen, and their supervisors James Ross, Shaun Ogilvie and Adrian Paterson) and University of Tennessee (Graham Hickling) in Wildlife Research, this issue was directly addressed. Travis Wetland is entirely surrounded by suburbs in north eastern Christchurch. It is about 120 ha and is the largest freshwater remnant of its type left in Canterbury. As such it has many important natural values and, conveniently, lots of cats live around the periphery. This study surveyed owners around the wetland to find out how many cats were present, what the cats ate, how many were kept indoors for part of the day, and what prey they brought back home. Twenty-one cats were given radio transmitters to examine just where the moggies were going to over a 12 month period. So what did we find out about the secret lives of felines?.

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First, there were a lot of cats - about 600 in the study area or 6.4/ha. Second, the cats didn't mind getting their fur wet. Most cats spent about 10% of their time inside the wetland, moving up to 200 m from the boundary. Of course, being cats, they spent nearly 2/3 of their time at home. Cats moved up to 270 m away from home but usually stayed within 100 m. Male cats had ranges three times larger than females. Almost 1000 prey items were collected during the study with 38% being rodents (mostly mice), 20% birds (almost all introduced birds, like sparrows), 18% reptiles and 22% insects (mainly moths). The bulk of hunting was done by cats from 1 to 6 years of age. Interestingly, cats with bells took more prey (probably because their owners correctly identified them as good hunters). So what does this all mean? Well it is clear that domestic cats do move into nearby 'wild' areas (even those that are quite wet). While there they do kill a great range of species. From a conservation point of view they certainly have an impact on species like native lizards. But of course nothing is that simple. The cats' main prey species are either direct predators (e.g. rodents) or competitors for food (e.g. sparrows) of native species found in the wetland. The question then becomes do the positive outcomes of having cats around, removing problems for native species, outweigh the negative outcomes, killing native species. At this point we can't answer that question. We are currently doing a similar study on cats living around a bush reserve on Banks Peninsula which may tell us more. So overall cats are not the villains they are made out be by some but neither are they as harmless as championed by others.

A successful Banks Peninsula biodiversity workshop

2009-10-19T16:16:00.003+13:00

The Banks Peninsula Biodiversity Workshop held at Akaroa on October 8th was a chance for local landowners to learn about the special biodiversity found on their Peninsula properties and what they can do to enhance the habitats for local native species. It was a long and successful day which was attended by over 170 people. Lincoln University and the Banks Peninsula Conservation Trust chose a range of experts to give quality talks on local native fish, invertebrates, birds, lizards, plants and integrating farming with conservation. All of the talks, questions and answers, workshop sessions are being compiled to create a proceedings of the event so that people who attended, and those who couldn’t make it, can read more on the subject. If you did not attend the workshop and would like an electronic copy of the proceedings, contact Mike Bowie.

The Lincoln University/Lincoln Envirotown biodiversity calendar was also launched at the workshop. The calendar suggests ways in which landowners can create or enhance habitats for native species and of course has a lot of spectacular pictures. The calendar is available for only $10. Contact Mike if you would like to buy a copy.

Modelling the invasion

2009-10-05T17:07:00.005+13:00

Although the Argentine ant (Linepithema humile) is not the fourth best novelty folk group in New Zealand it is impressively ranked in the top 6 most invasive ant species in the world. In a country like New Zealand this species poses a threat to the local biodiversity by removing native ant species and other prey species and thereby disrupting local ecosystems. Although the ant has established in New Zealand in the Auckland area there is a lot effort spent in trying to stop its spread. In the war against the invasion, knowledge of the future plans of the enemy is valuable in turning the tide. One way of obtaining this information is to create a model which can give us a good idea of where the ant is likely to spread to next so that we can stop this from happening.

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In research just published in Ecological Applications, researchers Joel Pitt and Sue Worner, members of the Lincoln University’s Bio-Protection Research Centre, and their colleague Andrew Suarez from University of Illinois, Urbana, have created models that allow greater accuracy in examining how Argentine ants spread around the landscape. The researchers were frustrated that most existing models only dealt with an abstract environment that was all of one type which helped with the mathematics of the model but was very unrealistic. The team decided to use a GIS approach to include realistic landscape information, such as land cover and local temperature, in their models. A simulation was run for each year from 1990-2005 to look at where the ants would move to and likely survive. What they found was that the simple model assuming a similar landscape was actually quite accurate for the first few years of the invasion. The more complicated model started to perform better after a few years and was reasonably accurate with its predictions when we look at actual spread in 2005 (predicting hotspots of activity in Auckland, Hamilton, Whangerei, Great Barrier Island and Tiri Matangi Island). The figure above shows the areas potentially able to be colonised by 2005 predicted by the simple model (circular lines), the complicated model (colours) and what actually happened (red dots - look closely, they are hard to spot away from Auckland!). The success of this approach will allow managers to better target their resources into monitoring areas that are most likely to be invaded.

Banks Peninsula Biodiversity Workshop

2009-09-17T10:40:00.006+12:00

On the 8th October from 9am till 7pm there will be a free workshop held in the Gaiety Theatre in Akaroa about enhancing biodiversity around the Banks Peninsula area. The Banks Peninsula Conservation Trust and Lincoln University have assembled a great line up of contributors for farmers and landowners who want to increase the native biodiversity on their properties. The programme features many speakers which much experience in various aspects of monitoring and enhancing biodiversity. Please contact Rachel Barker (rachel.barker@bpct.org.nz or 03 3296340) to register by the 2nd October.

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Click the picture for a detailed programme of events.

Change under our toes

2009-09-12T16:16:00.000+12:00

Grazed tussockland
Originally uploaded by pluckytree

Tussock dominated grasslands are an integral part of New Zealand’s native vegetation. Ecologically, they do not only harbor a large diversity of grasses, shrubs, small woody and herbaceous plants, but also give home to insects, reptiles and birds. Influenced by climatic conditions and land management practices, the spatial distribution of tussock grasslands has varied over time. It is assumed that in the early 1800’s, after Maori fires had cleared much of the forest and before European settlers arrived, they covered about one third of mainland. As of 2002, agricultural land conversion and spreading human settlement have left us with only about 3%.

Today, we are more concerned about “range restoration” and that the preservation of New Zealand’s native landscapes is implemented by adequate land management policies. However, not only has the spatial extent of tussock grasslands declined, but research over the past four decades has revealed ongoing changes in plant diversity and abundance of remaining tussock grasslands, towards an increased dominance of exotic weeds. The reasons for this have never been satisfactorily identified. The degradation has often been blamed on continuous pastoral use of grasslands, but research could never find unambiguous evidence for such a causal connection.

In order to find out more about what was happening in our native grasslands, Lincoln University researcher Richard Duncan and colleagues compared vegetation composition on fixed sample sites in Canterbury and Otago between the mid 1980's and 1990's (see the New Zealand Journal of Ecology, 25(2):35–47). They collected data on a variety of ecological and land management factors to test them for their influence on any observed vegetation changes. As expected, their results after the second measurement did fall in line with prior studies. Native plant species of all families had declined significantly, with the group of small herbs leading the sad trend. On average, one quarter of these plants had disappeared from all measured sites. One notable exception was native grasses of the genus Chionochloa, the snow tussocks, which had obviously benefited from a reduced impact of grazing. The only other significant increase, on the other hand, could be recorded for invasive weeds of the genus Hieracium.

So what had happened? Had the rise of invasive weeds and tall grasses driven out the native plants? Were people to blame, the old culprits, with their grazing livestock and fire management? Were site location and ecological conditions of any importance? To ruin all suspense and excitement right here and now: We don’t really know.

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All statistical analyses run throughout the study could not come up with a significant connection. Native plants did decline on sites with no Chionochloa and Hieracium at all, at the same rate as where these species dominated. Neither did moisture, aspect, increased vegetation cover nor human management play a significant role.

So what had happened? Had the rise of invasive weeds and tall grasses driven out the native plants? Were people to blame, the old culprits, with their grazing livestock and fire management? Were site location and ecological conditions of any importance? To ruin all suspense and excitement right here and now: We don’t really know.

I would like to leave you with a call for continued long-term research into the underlying patterns of our degrading tussock grasslands. Change could be going on independent of human management and so we might have to broaden our research scope and start looking into other factors. Also, the situation may have already changed by now. If towards the good or bad, we can only find out by continued monitoring.

Note that this was the motivation of a recent Lincoln University masters project by Nicola Day. Nicola led the re-surveying of the same plots. Her results will be published soon and we’ll be sure to blog about them here.

This blog post was written by postgraduate student Moritz Wenning as part of the course, Research Methods in Ecology (Ecol608).

Summer Scholarships

2009-08-26T16:48:00.004+12:00

The Agriculture and Life Sciences Faculty at Lincoln University, including the Department of Ecology, is offering summer research scholarships over the summer vacation, valued at $5,000 each (tax free). The scholarship will last for 10 weeks. Scholarships will be awarded based on academic merit. So if you want to work on sandy beaches or follow tui around or search for weta in exotic places then have a look at the projects on offer.

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We have run summer scholarships for the last few years and many students have had a lot of fun getting involved with research (and getting paid!). Note that it may say that the due date is the 7th September when it is actually the 14th September.

A really lousy day!

2009-08-18T11:42:00.006+12:00

You won't usually see us evolutionary and ecological researchers driving around in a Ferrari, holidaying at tropical resorts or dining at the best establishments. But, hey, there are some perks! I am now the proud namesake of a bird louse species. Out there at this very moment crawling over the Gray-headed Tanager (Eucometis penicillata) somewhere in Central America are little feather lice called Myrsidea patersoni. The authors, Roger Price and Kevin Johnson, have named five new species of Myrsidea after people who have worked on lice, in the most recent issue of Zootaxa, including my colleague from down the corridor, Rob Cruickshank. Myrsidea is a reasonably common genus with over 120 species of lice that are found on passerine (song or perching) birds. Rob's louse, Myrsidea cruickshanki, is found on Carniol's Tanager (Chlorothraupis carmioli). Bird lice are little ectoparasites that live in the feathers of birds where they live their whole life-cycle feeding on debris and feather pulp. All birds have louse species and most birds around you will have some lice on them. I once picked 200+ off one Royal Albatross and that's not unusual for these big birds.

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The good thing about having a louse named after you, relative to most invertebrates, is that you do at least have a nice bird host species to show people ("OK, OK so the louse doesn't look like much but just look at what it lives on"). You're probably thinking about why so many people work on lice given that one or two would surely be enough. It turns out that lice are usually passed from parents to offspring in much the same way as genes. This means that the coevolve very closely with their host and allows the opportunity for evolutionary biologists to look at recurring patterns. That's where Rob and I have done our work, mainly with seabird lice (the picture is actually of a seabird louse from the Halipeurus genus found on shearwaters). Still, there's plenty of work to be done and there is a good chance that I might be able to reciprocate the honour for the authors with some songbird louse species of my own one day.

On the beach: plant communities in dune systems

2009-08-12T15:07:00.010+12:00

Sand dune habitats are found all around the world. Sandy coasts are ever-changing with the interactions between climate, geology and vegetation. Dune habitats have to contend with storm surges, wind and rain and human impacts. Considering how important these areas are to human activities it is surprising that so little is known about the biology of these systems. Dune systems are generally divided into three regions: foredune, interdune and backdune. Also, three different plant groups are found in dunes: dune builders (fast growing plants whose stems and roots stabilise the dunes), burial tolerant stabilisers (plants with rhizomes that can tolerate overwash and flooding and stabilise flat areas) and burial intolerant stabilisers (longer-lived species found in older dunes).

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A study by Hannah Buckley (Lincoln University) with Thomas Miller and Elise Gornish, colleagues from Florida State University, has been published in Plant Ecology. This study is the first to survey plant communities of dune systems over a relatively long period. The research took place on St George Island in Apalachicola Bay in north Florida. 249 plots were followed from 1999-2007 with measurements of the plants found growing in each plot being recorded each northern Autumn. The three dune regions had very different communities of plant species. Community structure was determined by elevation, soil moisture and soil richness. Hurricanes appeared to have a major role in reducing the diversity present. Diversity was low at the beginning of the study as Hurricane George had affected the area the year before (1998). Diversity then increased over the following years until Hurricanes Ivan (2004) and Denis (2005) reduced the diversity again. These results highlight the dynamic nature of plant communities in dune systems. It appears that there is a clear form of succession occurring in these habitats but that storm events tend to push the communities off their trajectories. Buckley is continuing to look at the processes that shape dune plant communities and has set up plots around New Zealand to do this work.

A tough decision for mum

2009-07-19T16:08:00.005+12:00

NZ Fur seal
Photo by Kerry-Jayne Wilson, Lincoln University.

Pinnipeds are a widely distributed and highly diverse group of semi-aquatic marine mammals. These animals are unique in a sense that although they spend a lot of time in water, they have to come up on land to breed, moult and rest. Altogether, there are 3 families, the phocids, otariids and the odobenids. In New Zealand, we have 2 species from the Otariidae family, the New Zealand fur seal/ kekeno and the Hooker’s sea lion/ rapoko (Phocarctos hookeri).

New Zealand fur seals (Arctocephalus forsteri) were widely distributed before humans arrived. They could be found all throughout the coastlines of the North and South Island, as well as most offshore islands. However they were hunted for food by Maori, and Europeans further decimated their numbers for the pelt industry (as they did with pinnipeds throughout the world). Fortunately, due to full legal protection, their numbers are increasing and they are slowly re-colonising their former habitats.

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NZ fur seals live in a wide variety of coastal habitats, but breeding colonies (also called rookeries) occur usually on exposed, rocky, rugged shores. In 1976, M. C. Crawley and G. J. Wilson observed that nearly all rookeries have shelters from storms or big waves, and have broken and irregular terrain (see the journal Tuatara 22(1):1–28). There are also hauling grounds, where non-breeding adult males literally “hang out” in large numbers. These sites are similar to, and quite often near, established rookeries.

In 1993, Christine Ryan, Graham Hickling and Kerry-Jayne Wilson of Lincoln University investigated the breeding habitat preference of the NZ fur seals in Banks Peninsula (see Wildlife Research, 24(2): 225–235 (1997)). Their aim was to see if there were any significant differences between the breeding sites and non-breeding sites. They found out that NZ fur seals indeed chose steeper, rockier sites for breeding and suggested that these criterion be used for determining future breeding sites for conservation purposes.

Fur seals choose sites to assist in behavioural thermoregulation. This is because peak breeding season often occur during the hottest time of the year and the seals are reluctant to cool off in the sea—females have pups and males are defending territories. As fur seals are superbly adapted to the cold seas, they need crevices and rocky pools to help thermoregulate. This behavioural preference was also seen in other species of fur seals in other regions of the world.

In addition to thermoregulation, preference of steeper, rockier sites would favour pups and females in terms of safety and shelter, and also minimise harassments by humans and probably adult male fur seals.

It has been suggested that the present distribution of fur seals habitat in Banks Peninsula may also be a product from hunting in the bygone eras. Individuals that escaped sealers may have modified site preferences and, therefore, recolonisation patterns of subsequent generations. Furthermore, fur seals have natal site fidelity, which means that they return to the place where they were born to breed, and this could be a confounding factor in their preference of breeding sites.

Kerry-Jayne Wilson told me recently that there has been an increase in seal numbers and also breeding sites on Banks Peninsula since the survey was done. It would be interesting to find out if the habitat preferences observed previously are still significant for breeding animals when high densities are reached. Indeed, Christine Ryan and colleagues in their 1997 publication also pointed out that an increase in numbers may lead to breeding animals expanding into a broader range of habitat types, maybe even to those which they classified as “not suitable”.

The Department of Conservation website offers more general information about New Zealand fur seals and pinnipeds in New Zealand.

This blog post was written by postgraduate student Haojin (Jin) Tan as part of the course, Research Methods in Ecology (Ecol608).

Effluent bacteria lives and escapes..... sometimes

2009-07-10T15:00:00.002+12:00

Dairy Cows have been getting a hard time in the media with catch phrases of ‘dirty dairying’ and ‘green streams’. But are scientists testing the impacts of land based effluent application on the natural New Zealand environment? It is, after all a natural product. What harm can it really do to natural ecosystems?

Cows: "Don’t blame us! Just because you call it effluent, doesn’t mean it’s any less natural than sewage!"

Thankfully Lincoln researchers are churning out papers on the properties, uses, and effects of dairy effluent. One of the latest by Shuang Jiang, Graeme Buchan, Mike Noonan and Neil Smith of Lincoln University and Liping Pang and Murray Close of the Institute of Environmental Science & Research studied the less widely examined property of bacteria in the form of faecal coliforms. The paper “Bacterial leaching from dairy shed effluent applied to a fine sandy loam under irrigated pasture” can be read in full in the Australian Journal of Soil Research, 46(7):552–564 (2008).

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Field trials considered the influence of seasonal variation (time) and soil water content (irrigation application). Trials involved the use of Lincoln University’s 6 soil lysimeters. Lysimeters are monitoring vessels containing large cores of soil. They are used for studying hydrological cycles within soil such as infiltration, runoff, and evapo-transpiration. Researchers got down and dirty collecting effluent and pouring it over the lysimeter soil. Typical soil treatment was mimicked by spray and flood irrigation, the two methods of water irrigation commonly used in the Canterbury region, and, of course, any rain that happened to fall. Researchers then watched and waited to see what, if anything, would make its way through the 700 mm depth of soil into the collection chambers for analysis.

700 mm of soil did not prove to be a barrier to leaching. Analysis discovered that bacterial leachate could readily penetrate 700 mm when facilitated by water in the mock water irrigation treatments. Alarmingly, summer trials had leachates with similar concentrations to the original dairy effluent.

Unfortunately those green streams aren’t just a figment of the media’s imagination

However, researchers were able to draw some recommendations for effluent disposal without submitting to the pessimistic catch phrases I referred to earlier. With an understanding of the disposal area’s soil properties and consideration of water irrigation treatment and seasonal variations, the amount of bacteria transportation can be greatly altered. Specifically, flood irrigation resulted in higher bacterial leaching and effluent irrigated in dry summer conditions posed a greater threat of shallow groundwater contamination.

Beautiful green pastures under dairy effluent irrigation outperform the neighbouring sheep farm.

So, it seems that with some careful consideration of the natural environment and ecosystem, dairy farming can prevent green streams whilst recycling nutrients. With the right conditions and management, soil acts as a natural filter of bacteria from the applied effluent before leaching to groundwater. However, this is also a warning to those that have considered only the nutrient losses from their poor practice as a pathogenic bacteria may be leaching unnoticed to your water supply right now!

An example of not so careful effluent application management.

This blog post was written by postgraduate student Anastazia Raymond as part of the course, Research Methods in Ecology (Ecol608).

Kānuka vs. gorse, the battle is on!

2009-07-03T14:05:00.001+12:00

Ulex europaeus
Photo by Mollivan Jon

There is a struggle going on in the New Zealand forest, and it’s a battle for ultimate (plant) domination. Kānuka (Kunzea ericoides) and mānuka (Leptospermum scoparium) were the original plant species that colonised forest sites cleared by natural disturbances in New Zealand. This has changed since the introduction of many “shrubby weed species” to a situation where many cleared sites are now colonised by gorse (Ulex europaeus), broom (Cytisus scoparius), tree lupin (Lupinus arboreus) and many other adventive plant species. The nearest kānuka and mānuka are often some distance away and don’t get a chance to establish.

Jon Sullivan (Lincoln University), Peter Williams (Landcare Research) and Susan Timmins (Department of Conservation), researched three different hypotheses that they obtained from the New Zealand literature on the relationship between the naturalised shrub gorse and the native shrub kānuka.

1. Kānuka stands have a different plant species composition and greater plant species richness than gorse stands at comparable successional stages.
2. Differences between gorse and kānuka stands do not lessen over time.
3. Several native plant taxa are absent from or less common in gorse than in kānuka stands.

The research was conducted in environmentally similar sites throughout the Nelson and Wellington regions. They selected a mix of young and old gorse and kānuka sites. At these sites they recorded the presence of all native and naturalised woody species, Department of Conservation weeds, ferns, orchids and a selection of herbaceous plants; they also recorded environmental variables. The results were published in a 2007 issue of the New Zealand Journal of Ecology.

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kanuka skies
Photo by Mollivan Jon

They showed that there are many differences in the final vegetation composition of a site that establishes under gorse dominated vegetation compared to a site that establishes under kānuka dominated vegetation. For example, gorse sites tend to be absent of, or have fewer beech trees (Nothofagus spp.), orchids (e.g. Pterostylis spp.), small leaved shrubs (e.g. Coprosma, Leptecophylla, Leucopogon) and the shrub daisy Olearia rani than kānuka sites. The gorse sites also displayed lower species richness (number of species) and a higher incidence of naturalised species than the kānuka sites. These factors tended to be persistent at the older sites, suggesting that these effects are long term and therefore inferring that gorse is not a substitute for kānuka when the desire is to return the site to a “natural state.”

There are many explanations for the differences between gorse and kānuka sites. Some of the differences may be explained by biological factors such as the nitrogen fixing ability of gorse and the effect this may have on below ground micro-organisms and soil invertebrates, or this could be due to different physical site characteristics like light penetration, soil temperature or soil moisture levels. Other factors may be different bird feeding preferences and subsequent seed dispersal between gorse and kānuka sites, or the documented increase in naturalised plants invading gorse sites

This study has shown that there is a difference in plant composition between gorse and kānuka sites and therefore, as good as any forest regeneration is, there needs to be more protection for areas of kānuka in landscapes where it is scarce. Also, in such landscapes, there will be benefits for biodiversity of planting kānuka back into areas dominated by gorse if the aim is to initiate native forest regeneration. There is also a need for further research into the main effects driving the differences found in this research paper. There is still much to learn about the ecology of gorse vs. kānuka.

Glossary

Adventive a plant or animal found in an environment where that it is not native to.

DoC weeds List of weed species actively managed on Department of Conservation reserves.

Succession the series of changes that create a fully-fledged plant community, e.g. from the colonization of bare rock to the establishment of a forest

Taxa A taxonomic group i.e. a plant species, genus or family.

This blog post was written by postgraduate student Mark Parker as part of the course, Research Methods in Ecology (Ecol608).

Geraniums: New New Zealand diversity

2009-07-02T10:55:00.007+12:00

Geranium aff. microphyllum
Photo by Mollivan Jon

Geraniums are a common plant genus with more than 400 species worldwide. New Zealand has its own share of species with seven native species and nine introduced species. There is, however, a reasonable level of variation within some of the native species, including variants in the ultramafic Red Hills. Other species are found on the Chatham Islands (Geranium traversii) and through the Subantarctic (G. microphyllum). A DNA-based study was undertaken by Anthony Mitchell (University of Otago), Peter Heenan (Landcare Research) and Adrian Paterson (Lincoln University) of samples from all species and most variants in order to look at evolutionary relationships, time of divergence events and species status.

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In a paper published in the New Zealand Journal of Botany (47:21-31), the researchers conclude that there is low genetic variation within native New Zealand Geranium indicating that they are very closely related and the likely result of one colonising event to New Zealand. More sampling of Geranium species in South America and Australia would help to determine the likely source of these colonists. Morphological variation (like leaf shape and patterning) appeared to be a reasonable predictor of species status with plants that look different actually also being different at the molecular level. The level of differences between different populations also suggested that they may actually be at least five different species (although confirmation of this would require more detailed work). This work shows that even in reasonably well-studied groups that there are still many species to be found in New Zealand.