20 October 2014

Winning the battle for our birds (but losing the war?): 1080, rats, possums and the NZ bush

Sometimes common sense is not actually our friend. In our society common sense is usually seen as a virtue that those so-called experts could do with more of. But common sense can fall down on the common side of things. The All Blacks have gone into every rugby world cup as the favourites to win over all. They have won only two. This is a case where 'common' is a statistical concept in which there is a higher likelihood of something happening, but no guarantee that it will happen. Common sense can also fall down on the 'sense' side of things as well. Looking at our modern lifestyle it seems obvious that we are much less active than our ancestors would have been. It's no wonder we have issues with weight in our societies. However, data points to the fact that we are actually just as active as our hunter-gatherer ancestors and we need to look at other reasons for obesity. This is a case where 'sense' is a statement that needs data to confirm it. So although common sense is a useful concept, allowing us to make predictions based on experience, it can be misled through probability and through not having correct facts. Common sense is particularly a problem when we are faced with emotion-charged debates. In New Zealand one of the more emotionally charged debates is with the use of toxins to kill mammalian pest species, like rats, possums and stoats, at very large scales.
There's a whole lot of seeds up there!

The southern beech (Nothofagus) forests of New Zealand are prone to heavy seed crops every 4-6 years (known as a beech mast). Mast events provide a huge amount of food for rodents whose populations swell over the next few months. With the rise in rodent numbers we get a similar, though slower, response by their predators, particularly the stoats (a mustelid). The following year is almost never a mast event and so rodent numbers crash as there is not enough food around. The inflated predator population will continue to eat rodents where they can but, with the rodent population decline, they often switch to other prey. In New Zealand this other prey is mainly birds, and in beech forest these are usually native species. So a mast event will usually lead to a massive reduction in bird populations the following year, when the stoats get hungry. This year has been a mast year in our beech forests. What can we do to ensure that our threatened bird species are not decimated over the next year?

The Department of Conservation has launched the 'Battle for our birds' campaign. Common sense would suggest that if we could keep the rodent numbers down during the mast event, then their populations will not increase and, therefore, stoat numbers will not increase as a result. So, no  problems for birds next year. Department of Conservation are delivering the toxin 1080 to several hundred thousand hectares of key beech forest habitat throughout New Zealand this year. The toxin is dropped into the forest where is can be encountered by rodents (usually rats) who will store some of the cereal bait, eventually consuming a lethal dose. Stoats eating recently dead rats may also accumulate a lethal dose and their populations don't increase as their food supply does not increase. Happy birds in 2015. Problem solved.

Rats: In action on the forest floor

Maybe. There are a number of studies now that have looked at the long term effects of intense control of mammal pest populations. In a seminar at the Department of Ecology, Lincoln University, Dr James Ross talks through a couple of studies that he has been involved with which looks at what happens to populations that have had pest control done. Long-story short (but you should listen to that entertaining talk!), 1080 does a great job of knocking down rodent and possum populations (and stoats as a by-product). The forests habitats respond positively to the removal of the pests, particularly the small bird species. However, different species recover at different speeds. Mice are not particularly troubled by toxin drops (as rats are usually dominant and grab the baits) and their numbers begin to grow after control as they have no competition from rats. This is not such good news for forest invertebrates that are in the food size range of mice. After a few years, the rat populations start to bounce back (mostly by re-invasions from the edges of the control areas) and at a much faster rate than stoats. So there is a period of time where rat populations will not be checked by stoat predation. So will the battle for our birds work? It depends on the timeframe and what follow up work is done. Control will certainly put a break on rat (and then stoat) populations and preserve bird populations in the following year, that's just common sense. However, if follow up control of rats is not done after three or so years then rat populations may rebound ahead of their predators and we will have a problem similar to that of a mast season occurring, lots of rats that lead to a surge in stoats. So we might win the battle but lose the war if we are not careful. And that, perhaps, isn't such common sense.

13 October 2014

Tolkien made me an evolutionary biologist

I've been an evolutionary biologist for over two decades now and I have been reflecting recently on how I came to join this profession. I started re-reading Stephen Jay Gould's Ever since Darwin, Goulds first collection, and have to acknowledge that Gould's amazing essays played a role as an undergraduate. Darwin's On the origin of species was also influential around the same time. Dawkin's The Selfish Gene was one of the first science books I read, so that has to be part of it. But, really, I have to go back further as I arrived at university with the passion for zoology and evolution already forming. In fact I can go back to when I was about 9 years old and read The Hobbit, followed by The Lord of the Rings a couple of years later. That's where it started.

Tolkien and evolution. These are not things that normally go together. Tolkien has often been portrayed as a romantic, always looking at the good old days, anti-technology and progress (especially by sf author David Brin). And this is hard to argue against. However, and perhaps ironically, there are many themes in Tolkien that help to prepare one for a life in evolution.

Min: The journey is important.
Summarising The Lord of the Rings as "short tourist loses valuable heirloom at volcanic destination" loses the whole sense of the journey, which is actually what the story is about. All the characters change (or evolve) significantly during the story. Evolution is about the journey, exposing the history of lineages. Ecology is about the destination, looking at the interactions that are here now. Tolkien helped my young mind to understand that everything has a history and that this journey is important.

Tad: Lineages are important.
Tolkien loves his genealogies. Frequently in his writings we are told who is related to who. It matters that Elrond has links to certain elven and human lineages. There are lineages in his appendices. This was a revelation to a young me. Relationships are important. Closely related characters respond in different ways to distantly related characters. Tolkien helped my young mind to understand that everything has a history and that lineages are important.

Neledh: Spatial scale is important.
Tolkien loved maps. One of the cool things to a nine year old was the map in the front of The Hobbit (as well as the runes!). Even in an imaginary world it matters where things are. It matters that the Lonely Mountain is on the Long Lake or that the Misty Mountains need to be crossed to get to Mirkwood. It matters that Farmer Maggot's farm is next to the Buckleberry Ferry. Tolkien helped my young mind to understand that where things are located spatially is relevant to explaining the journey.

Canad: Species distributions are important (as is how they came about).
Part of Tolkien's fascination with maps is that he uses them to explain where races are located. You learn about the distribution of dwarves, hobbits, elves and so on. You also learn about how these distributions have changed over time. Tolkien had detailed notes on the dispersal of races. For example, the hobbits had colonised The Shire relatively late in the piece, dispersing from Bree and prior to that from the shores of the great river Anduin across the Misty Mountains. Tolkien helped my young mind to understand that species move around, that what you see today has not always been the case, and that dispersal is a powerful force.

Leben: Landscapes are not permenant.
Tolkien presented different eras. The Lord of the Rings is set at the end of the third age which had been going for 3000 years. Two long ages preceded this one, giving a perception of deep time. Moreover, even the continental landscapes had changed during this period. Large parts of western Middle-Earth had submerged beneath the seas, cataclysmic battles had raised mountain ranges. Tolkien helped my young mind to understand that there is no long term permanence in geological features.

Eneg: Diversity is important.
Tolkien valued diversity. It is no accident that the fellowship is successful because it is made up of different races, each with skills that help achieve the final goal. Or that it is the hobbit joining the dwarven company that makes the difference. Tolkien also invented languages (I have used elven numbering here!) to emphasise this diversity. Tolkien helped my young mind to understand that diversity creates useful outcomes.

Tolkien was an author that pushed the importance of lineages, history, spatial scale, species distributions and dispersal, landscape impermanence and diversity through all of his stories. If this is not the ideal preparation for a young evolutionary biologist (especially one who specialises in biogeography) then I'm not sure what is!

Namárië !



16 September 2014

A tangled story: the coevolution of lichen


I'm a sucker for multi-volume books. Whether it is GRR Martin's Game of Thrones, Robert Jordan's Wheel of Time, Tad William's Shadowmarch, Dennis McKiernan's Mithgar or JRR Tolkien's Middle-earth, I like nothing more than getting lost in the depth and sheer volume of story that these authors have created (all that history, setting, scale, and characters, all those interactions). Often these books are in the fantasy line but they can just as easily be science fiction, say David Brin's Uplift, or historical fiction, like Patrick O'Brian's brilliant Master and Commander. Friends often ask me to summarise these series, "What is the story about?". That's a tricky question because their scope defies a meaningful simplification. Most people are familiar with A Game of Thrones now. A simple description of this story (even more complex in the books than the TV series) is either too broad to be helpful (a fantasy version of the War of the Roses) or misses a lot (a bastard, who know nothing, talks to wolves and becomes a leader; a spoiled princess domesticates dragons and sits around in conquered cities; or a dwarf with father issues loses a nose and has a fairly miserable time).  The Wheel of Time series stretches to 13 large books with umpteen viewpoint characters and could be summarised as 'shepherd boy heals the world' but this only takes up a tenth of the story amid all of the braid tugging, gender politics and nonrandomness of events. O'Brian's series about the British navy in the Napoleonic wars stretches to 21 books and follows the career of Aubrey (as captain of larger and larger ships) and Maturin (ship's doctor, naturalist and spy) with little overarching story other than that of following the lives and careers of these fascinating characters. Even The Lord of the Rings, with a reasonably linear story, loses something when condenced to 'short tourist loses heirloom at volcanic destination'. Sometimes, then, stories are complicated and refuse to be simplified. Much the same happens in history and most definitely it happens in natural history, especially when we are dealing with evolution.

The lichen Usnea draps a beech tree
Evolutionary biologists are interested in the history of life, we want to recover the story of how life on Earth ended up as we see it. We use data from fossils and DNA, species distributions and unusual traits to recreate our best guess at summarising the evolutionary story. One area of evolutionary biology that I have been involved with since my PhD is that of coevolution - where we try to recover the story of interacting evolutionary lineages, such as parasites and hosts or pollinators and plants. Sometimes the story is fairly straightforward. The work that I did for my PhD and in various projects since has been with chewing louse species that live on seabird species (like petrels and albatrosses). Lice are insects that live in the feather forests of their hosts and are mostly passed from seabird parents to their offspring. The story of this interaction is reasonably simple, we have two lineages, one insect and the other bird, that codiverge together. When the birds speciate their lice will also become isolated and often cospeciate at the same time. Feather lice have been studied as a nice model of cospeciation for a couple of decades now. We can tell this story well. Sure there are a few quirks here and there but it is now a reasonably predictable story. Louse-host coevolution stories are like nature's little rom-coms. Not all coevolution stories are this simple.
Lichen and mistletoe colonise a beech.

Lichens, commonly seen growing on fences or trees, are composite individuals,  a symbiosis that results when a fungus cohabits with a green algae (or sometimes a cyanobacterium, or, even less commonly, with both an algae and a cyanobacterium). The fungus provides a safe habitat and food for the green algae who, in turn, use their photosynthesis ability to provide products for the fungus. Lichens are the result of this win-win coevolution relationship and would seem a prime candidate for coevolution. Hannah Buckley and her PhD student Arash Rafat joined forces with other Lincoln University ecology staff to recover the coevolution story of lichens which has now been published in the journal PeerJ. Arash collected lichens from around New Zealand. Much of the sampling was from southern beech forests and focused heavily on the lichens Usnea and Ramalina. Genes were analysed from the fungi and algae that made up the lichens. It turns out that when it comes to coevolution in lichens, it's complicated.

Lichen taxonomy is woefully understudied. There were many instances of samples that looked like the same species being genetically very different species, there were many instances of samples that looked like there were from different species being genetically similar. Certain strains of algae were found with lots of different fungal species. Geographical scale, how far sites were from one another, played a role - sites close to one another shared similar diversity. Sometimes. It seems that for lichens to function there only needed to be a fungus and alga paired and it didn't really matter which ones. All of these complications meant that the 'standard' method of analysing coevolution, by comparing phylogenetic trees for fungus and algae, was not going to be very useful, the trees were just too tangled. Hannah and Arash used a distance (principle coordinates) approach to analyse the data rather than a tree-building approach. Surprisingly, give all of the uncertainty of the lichen component species, there was  significant congruence between the genetic variation of the fungal and algal partners. The was particularly true at small spatial scales where fungi and algae species seem to co-disperse and co-adapt with each other. These patterns started to break down at larger scales and were different between lichen genera.
Lichen diversity.

So what is the story with lichens? Well, like a multi-volumed series, it's complicated. Focusing on some of the species provides a story of cospeciation. However, other species have no evidence of codivergence. Sometimes geographical scale is important, sometimes it is not. We can say that there is probably more codivergence occurring than we might have predicted. Overall, though, there is no simple summary, the evolutionary story of lichens are not very predicable. To know more we need to research more. Lichens are not rom-coms, they are art-house. Or a multi-volume series of books.

19 August 2014

Counting Katipo and the known unknowns


Former US Secretary of Defence Donald Rumsfeld made the following observation: "because as we know, there are known knowns; there are things that we know that we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns, the ones we don't know we don't know". Although this sounds a little torturous (and not in the washboarding sense!) it conveys a useful view of the world which is particularly relevant to ecology and evolution. When we do research we are usually in the business of moving 'unknown knowns' to 'known knowns'. In the process we sometimes discover some 'unknown unknowns' which then become 'known unknowns'.  Obviously, the big issues for science are the 'unknown unknowns', things that may impact on how we model the world which we currently do not take into account. In short, we can't fully explain a system if part of the explanation contains 'unknown unknowns'. Not torturous at all! 
Kaitorete Spit looking north to Banks Peninsula - Katipo country!


As an example, the history of the New Zealand biota was thought to be well known, that is there are 'known knowns'. A fragment of the supercontinent Gondwanaland broke away around 80 million years ago, gradually subsided until it was left with New Zealand and other islands. The present day biota was derived from this long isolation, one feature of which was the absence of terrestrial mammals (other than a handful of bat species). Some of the 'unknown knowns' were just how much land area remained above sea level by the period of maximum submergence around 23 million years ago, which lineages had survived in the New Zealand region versus those that had successfully colonised these islands and when these events had happened. A few years ago an 'unknown unknown' surfaced in the form of a mammal fossil from 16-20 million years ago. Fossils make for great 'unknown unknowns'. They are hard facts that are sitting out there in the crust waiting to be found. In this case the fossil became a new known and generated a bunch of known unknowns', such as how many other mammal lineages might have been around at that time, what happened to these mammal lineages as they were extinct when humans arrived in these shaky isles and how did they come to be in New Zealand?

Another area of ecology and evolution where we spend a lot of time thinking about unknowns both known and unknown is in population estimation and monitoring. For most species it is difficult or impossible to locate and count all members of a population.  We are left with trying to estimate how many individuals are out there. This could be a 'known unknown' if a species has been found to be present or an 'unknown unknown' if we are just surveying an area to see what is there (like in a biodiversity assessment). Having an accurate estimate of populations allows us to manage and conserve populations. 

Katipo (Latrodectus katipo) is New Zealand's representative of the widow family, a close relative of the the Australian red back. Katipo live in a fairly restricted and threatened habitat - the dunes of sandy beaches. Katipo are under multiple threats from land fragmentation from seashore developments, competition from an introduced spider species, and the introduction of exotic plants into dune areas. Counting katipo is a difficult enterprise. They are small and relatively cryptic. Although they build nests at the base of dune grasses, these can be obscured by storms. A recent method for counting has been developed using artificial cover objects (ACOs), in this case two small sheets of corrugated roof cladding, with wooden dowels placed between them, are placed in the field. The cladding becomes a warm and dry location that is ideal for katipo to live in. The ACOs can be placed in the dunes for weeks or months and local katipo may eventually move in, providing an estimate for local numbers. Using ACOs can help you to map put areas into dune areas of high and low densities as well as areas with no katipo.
Katipo in pingao nest, note the white egg sacs.

Lincoln University student Vikki Smith has used the ACOs to go a step further. Vikki was interested in the effect that the introduced marram grass (Ammophila arenaria) had on katipo populations (a 'known unknown'). Marram has replaced much of the native plant diversity around the dunes of New Zealand. A major casualty has been the pingao (Ficinia spirals) which is generally a smaller plant that forms less dense clumps compared to marram. Pingoa does not bind dunes together as much as marram, meaning that beaches are not as wide with marram in the dunes, as they are more resistant to wind and sea. Vikki wanted to see if katipo had a preference for the native species over the introduced. Vikki took her ACOs out to Kaitorete Spit, a thin strip of land separating Lake Ellesmere from the ocean. The spit has a good population of katipo and is one of the few places in New Zealand where you can find substantial pingao as well as marram. Vikki placed her ACOs in katipo areas with equal numbers beside marram and pingoa clumps. Vikki visited the ACOs over the next year recording katipo that she found there and reporting her findings in the Journal of Insect Conservation. Over the course of the year Vikki was 2-3 times more likely to find katipo under ACOs next to pingao compared to marram. This was most noticeable in summer and autumn. The inference is that katipo numbers are greater in pingoa and the they are more likely to colonise the ACOs through chance. So the preference of katipo for pingoa over marram has become a 'known known'. Although katipo were found in marram, the low density of katipo in this habitat may increase the chances of the local extinction of a population. How marram affects katipo populations is currently a 'known unknown' (long roots drying out the local habitat, reduction of local prey species densities, marram growth structure excluding many sites for nests). These 'known unknowns' provide a useful guide for future research. There may also be an unknown unknowns waiting for us to locate them, invisible for now until further research unearths it. that is the thrill of science!

12 August 2014

The Grand Bugapest Hotel

Your home and garden can be a very diverse place. Often when we talk about diversity we think of it as something 'out there' in the wild, away from urban areas. While urban environments might not be as diverse as many locations around New Zealand, they still contain a surprising amount of native and introduced flora and fauna, especially with arthropods. A couple of recent interviews on Radio NZ look at this idea.
First, Cor Vink takes us into his home to look at  what spiders species he can find. Cor is the inverebrate curator at Canterbury Museum and a former PhD student in the Ecology Department at Lincoln. He is acknowledged as the leading spider expert in New Zealand. Cor talks about the spider species he finds as well as what we know about white-tailed spiders (and their fearsome bite).

As well as finding what diversity is present in an urban environment, one can attempt to increase and attract more diversity. Rob Cruickshank, senior lectured here at Ecology, chats about the profusion of bug hotels that have turned up around Lincoln University campus. These hotels are a result of a collaboration between entomology and landscape architects. The hotels are built with materials that encourage invertebrates to colonise and will help with increasing the local populations. The ento students will monitor the hotels over the next year to see what happens.

25 July 2014

Biological Warfare! Organic Management of Pests 101

This blog post was written by postgraduate student Andrew Kirk in the course, Research Methods in Ecology (Ecol608). Andrew revisits a Lincoln University research area that looks at managing insect pests in organic crops from 2007.

 
Organic visions in Tuscany, Italy courtesy of Chavelli
on Flickr creative commons





Interested in organic agriculture? You're not alone. Many of us were drawn to agriculture somewhere along the line by visions of warm summer days, rolling hills, and pesticide-free produce. However, if it were that simple, everyone would grow crops organically. No 20th Century farmer would have ever abandoned the traditional practices for the forbidden fruit of the synthetic chemical. Alas, organic agriculture is tough and it most definitely is dirty.

While the challenges faced in an organic production system are numerous, we will focus here on the strategies available for the management of arthropod pests. A tremendous resource is available on this topic in the 2007 work of Zehnder, Gurr, Kuhne, Wade, Wratten, and Wyss. That review will serve as the foundation for my discussion.

The framework outlined by these authors is based on the idea of Integrated Pest Management (IPM). As the name indicates, this type of regime incorporates preventative measures, instead of simply relying on reactive measures such as the application of agrichemicals. Most conventional agriculture systems would fit the latter description, leaning heavily on agrichemicals to solve a problem after it has taken hold. However, most farmers are intelligent, practical people. Synthetic chemicals, pesticides in our context, are often very cheap in the short-term compared to the cost of integrating Ecosystem Services into every level of production. There is no doubt, on the other hand, that pesticide residue is everywhere in our world, even on organic produce that we would like to assume to be safe. For instance, have a quick look at the toxicity report for copper sulphate, one of the most widely applied organic pesticides. With that in mind, what steps can be taken to minimise the use of chemicals on our crops?

The first phase of organic pest management includes the cultural practices that can help regulate pest populations. Most basic among these is site selection. An interesting example here is the geographic distribution of fruit production in the United States. 65 per cent of this production can be found in Western states with an arid summer climate that is inhospitable to many of the devastating insect and fungi pests of horticulture. Anecdotally, much of the fruit grown in other highlighted areas of that map is native to its respective location and has internal mechanisms for dealing with pest problems. On a more local level, many "old-timers" in an agricultural community will often gladly impart some knowledge about the best site for a particular crop.

Isolation and rotation are also of particular importance in devising a strategy for cultural management of pests. Essentially, the idea is to disrupt the spread of a particular pest by limiting the area in which it thrives. One can achieve this by planting a diverse range of crops, or rotating them, to create a wider range of environments for a pest to deal with. One can easily see how this idea conflicts with the monoculture situation found in many developed countries. On the other hand, veering away from monoculture will increase the cost of management in many instances. Proponents of an IPM system will probably counter-argue that this investment will be returned through reduced input costs and spillover benefits. So maybe we'll keep moving!

Inter-row and under-vine cover crops are often used as a
substitute for crop rotation in Viticulture, for the purpose
of attracting beneficial insects to compete with harmful
insects. Photo by Bela Hausmann on Flickr creative
commons.
Next, we turn to the ecological engineering to initiate our second phase of pest management. At the centre of this idea is the encouragement of ecosystems that allow the natural enemies and competitors of a given pest to thrive. This practice, known as conservation bio-control, is a relatively new idea in the applied ecology field. It requires one to do more than introduce a natural enemy as a bio-control agent, but to also manipulate its surroundings to create the desired result. It's sort of like being the referee of the football match and giving one side water breaks while the other team runs laps around the field. This is somewhat of an indirect approach to ecological engineering, though.

A more direct route might be found in intercropping, which works similarly to crop rotation. The core of both strategies is to make it as difficult as possible for the pest to establish a large core population. A variation on these is what is known as trap cropping. As the name indicates, this entails the luring of a pest species to a more attractive plant than the commercial crop in question. Zehnder et al. mention a classic example in New Zealand sweetcorn production, where the southern green stink bug is cleverly lured to the black mustard plant, instead.

The southern green stink bug is exhibit A of
effective trap cropping. Apparently it is
very fond of black mustard. Photo from Marcello
Consolo on creative commons via Flickr.
As alluded to before, the introduction of bio-control agents can be an important part of an organic pest management system.There are two types of bio-control releases and it is important to understand the difference. Inundation bio-control relies upon the released organisms, themselves, to alleviate the pest situation. An inoculation bio-control release takes a long view, one where the progeny of the inoculation group are expected to provide relief from the pest well into the future. Of particular note among the bio-control agent success stories is the development of Bacillus thuringensis, a fungi that is pathogenic to many arthropod species of insects. If that seems like biological warfare, it's because it is. Nevertheless, the track record of bio-control is decidedly mixed. Biological systems are complex, after all, and trying to manipulate them can be very tricky. For that reason, most researchers do not recommend bio-control agents by themselves, but rather as part of an IPM system.


Photo by jetsandzeppelins on Flickr
creative commons
Last comes the part of organic pest management that everyone likes to forget. That, of course, is the fact that some pesticides are permitted in an organic management regime. These chemicals are required to be biological or minerally-based, a definition that can seem quite arbitrary to those on the outside looking in. Rememember our old friend foe, copper sulphate! With regard to insects, though, a number of organic insecticide and pheromone products are available, but individual countries have different laws regulating their use. One interesting case is an insecticidal agent formed by the bacterium Saccharopolyspora spinosa during fermentation. This insecticide is thought to be environmentally safe in the long run, but is only permissible in the EU when obtained directly through fermentation, as opposed to a purification process. According to Zehnder et al. Discrepancy over regulation of organic insecticides represents one of the major challenges to the international trade of organic goods.
Organic reality courtesy of Antony*** on Flickr
creative commons
In truth, the organic management of pests is a challenge that deserves a review much longer than this. However, with some key concepts emphasised, you can branch out into a more detailed study of these strategies. Perhaps the most important thing to remember is that pest management starts on day one, not the day after the rains and humidity come. By understanding the life-cycle and tendencies of the pest, a grower can (try to) stay one step ahead of the pest. While that goal sounds like hard work and means less time for the enjoyment of sunny days and rolling hills, it is probably a more accurate depiction of the organic dream.


References

Zehnder, G., Gurr, G. M., Kühne, S., Wade, M. R., Wratten, S. D., & Wyss, E. (2007). Arthropod pest management in organic crops. Annu. Rev. Entomol., 52, 57-80.

22 July 2014

Which wine to take home? Sensory analyses of wine regions provides a clue


This blog post was written by postgraduate student Yunxuan Qin in the course, Research Methods in Ecology (Ecol608). Yunxuan revisits a Lincoln University research area that looks at how the region of origin affects wine traits from 2013.

Walking through wine aisles in a supermarket, different brands of wines fill the shelves. Besides all the appealing labels, there must be some inherent differences hidden within the bottles. Unless opened and tasted, the characteristics of the wine remain a secret. However, there is always a clue on the label, indicating where the grapevines were planted and the wine region of origin. Indeed, the expression of regionality is an important part of the philosophy of winemakers in all parts of the world.

Wine shelves in a French supermarket. Photo by christine592, CC BY-ND 2.0. 
That philosophy about regionality is based on a concept, "terroir", which has long been recognized but is difficult to interpret. Terroir itself includes many factors, such as climate, soil type, and topography. The common understanding of terroir is "a sense of place" that wines from specific geographic locations can be perceived as different. According to Patrick Iland's, past Senior Lecturer at The University of Adelaide, book The Grapevine: from the science to the practice of growing vines for wine, terroir modifies the flavor shape of wines from different sites within a region, sub-region and even within a vineyard block. Sometimes, the soil characteristics became the predominant factor impacting on vine growth, berry composition and wine style and quality, as indicated in the figure below.
A "vine to wine" web showing vine, berry and wine characteristics from terra rossa and deep black cracking clay soils. Adopted from The Grapevine: from the science to the practice of growing vines for wine, page 287. 
If we knew the differences in wine characteristics between regions, we could easily make the purchase decision by personal wine tasting preferences, instead of standing in front of wine shelves making a hopeful selection.

Another question is how to measure wine characteristics between regions? Wine characteristics are measured by sensory attributes, which are difficult to measure. Indeed, everything related to human sensation is hard to interpret. Variables such as personal odor threshold, physiological status (with perceived astringency by saliva as an example), psychological status (with emotional attributes and wine perception as an example) and descriptive vocabulary are examples. Thus, these variables are the reason why human perception of wines will vary from person to person, which makes it difficult and impossible to establish a standardized wine tasting note for every individual wine.

A recent study from Elizabeth Tomasino and co-workers aimed at measuring the differences in Pinot noir wine according to their sensory attributes (e.g. aroma, in-mouth flavor, mouthfeel) from four regions in New Zealand. Pinot noir, one of the noblest red grape varieties, is now the most widely planted red grape variety in New Zealand with these wines frequently compared to those from Burgundy. Several degrees of latitude were covered, including Central Otago, Marlborough, Martinborough, and Waipara. These regions were studied as Pinot noir is a locally important wine variety in these places.

How did they determine wine characteristics according to different regions? Elizabeth and co-workers did a preliminary tasting by six panelists who afterwards, listed wine aroma and palate descriptors for each of the wines. Combined with previous sensory work, a final list came out, including twenty-five attributes (fifteen for aroma, four for in-mouth flavor, six for mouth-feel). The formal tasting then conducted by asking twenty-one panelists to rank the intensity of each of the twenty-five attribute.

As customers, which Pinot noir wine shall we choose from the four regions? According to the results from Elizabeth and co-workers, you can have following options. If you want something red and fruity, you'd better choose Marlborough Pinot noir wine. It was characterized by greater raspberry and red cherry aromas, a red fruit in-mouth flavor, and longer finish length with a more harmonious balance. If you prefer a note of dark fruits and oak, Martinborough Pinot noir wine should be your first choice. Greater black cherry, oak, and spice aromas and oak tannin mouthfeel describe this wine. If you desire a herbal note in your "glass of wine", then the Waipara Pinot noir will be recommended for greater barnyard with violet aromas and a decent in-mouth fruit density/concentration. If you want something neutral, choosing Central Otago Pinot noir wine would be wise. It was the intermediate one and had fuller body.

The sensory table, filled with many of the aromas wine may possess.
Photo by H. C., CC BY-NC 2.0CC BY-NC 2.0
Based on the knowledge of wine characteristics upon corresponding regions and your own preference, followed by checking the region on the label, it won't be hard to make a decision. Indeed, you already establish an expectation before opening the bottle. Another choice is doing a blind selection, and having fun to discovery the secret hidden in the bottle.

Nevertheless, nature plays a magical role on wine sensory profiles/styles according to different regions. We often address "terroir" to roughly explain the cause, but which factor of the terrior contributes the most to the differentiation remains to be discovered by scientists. Actually, one of my colleague is currently working on it (check the wine research topics in Lincoln University).

How reliable is Elizabeth research results? You have to find out by yourself. Enjoy your wine. Cheers!

Reference
Elizabeth Tomasino, Roland Harrison, Richard Sedcole, and Andy Frost,(2013) Regional differentiation of New Zealand Pinot noir wine by wine professionals using canonical variate analysis. American Journal of Enology and Viticulture.64, 357–363.

Iland, P. and Promotions, P.I.W., (2011) The grapevine: from the science to the practice of growing vines for wine. Patrick Iland Wine Promotions.