27 September 2010

Darwin & the Sandwalk 2

Another SYSTANZ cartoon from the 90s.

21 September 2010

Coast-to-coast, biodiversity style

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.

A nice place for a lecture
David Pontin discusses kelp ecology at Truman's Track. Photo by mollivan_jon

beech
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.

20 September 2010

Are two heads better than one? Kokakos and playback responses

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.


17 September 2010

Darwin and the Sandwalk


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....


10 September 2010

Shaken but not stirred


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!


09 September 2010

A whole lot of shaking going on


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.


02 September 2010

The spirit of wine shall be green

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'.