Michael Kearney, professor at the University of Melbourne, presents his latest work ‘Where do functional traits come from? The role of theory and models’. He discusses the importance of definitions in science, remembers the beginnings of our journal and shows his (not so) secret passion for lizards.
About the paper
- What’s your paper about?
Our paper is about the concept of a functional trait. This is a notion that goes way back to the origins of Functional Ecology as a journal, especially Peter Calow’s 1987 article ‘Towards a definition of functional ecology’ (really worth a read if you haven’t seen it). Calow pointed out that, to interpret the function of a trait, one needs “an implicit, if not explicit, link between the trait and its impact on survivorship, fecundity and developmental rates”. Our aim in this paper is to show how to make that link explicit and thereby objectively define functional traits.
- What is the background behind your paper?
My main research focus has been finding ways to quantify how environments constrain where organisms can or can’t occur, through a mechanistic understanding of their niche. By this I mean using physical and chemical theories about how organisms exchange heat, water and nutrients with their environment. The models derived from these theories demand knowledge of very specific traits of organisms. So, the next logical step after assembling the models was to start to collate all the traits that we need to parameterise the models. It then became obvious that such an endeavour leads to a really great set of clearly defined functional traits.
- How did you come up with the idea for it?
As I discussed the idea with my co-authors it became clear that, in general, we can define functional traits explicitly by having a theoretical dynamical systems model (DSM) of an organism. This could be a model of heat exchange or energy exchange, which are ecophysiological in nature. But it could also be a behavioural model relating to information exchange (the dynamic state models of Clark and Mangel). We realised that, if you think of an organism in this way, there are four distinct categories of functional trait that emerge (you can find them in the paper).
- What are the key messages of your article?
There is a lot of work being done to collate trait data into openly accessible databases and to use these trait data to model the consequences of changes in biodiversity. However, amongst countless potential traits, it can be difficult to decide what to include or prioritise, and what metadata need to be collected. The main message of our article is that a theoretical perspective, in the context of dynamical systems models, provides a very clear and rigorous way to interpret traits, to define them as ‘functional’, and to determine the measurement context required (i.e. the metadata, such as the body temperature, food level or life stage at which an observation was made).
- How is your paper new or different from other work in this area?
Much has been written about functional traits since Calow’s article, especially in the past 10 years. What is unique about our paper is the specific emphasis on ‘dynamical systems models’ and how this leads to the four subcategories of functional trait. We have also made a decision-tree that can be used to assign a given measurement about an organism as a functional trait or not, which we think clarifies the concepts in our article.
- Does this article raise any new research questions?
One important outcome of the approach to functional traits that we are presenting in our paper is that it makes clear where data deficiencies lie. This can help prioritise future phenotyping efforts and can also motivate the development of new techniques to measure required traits. For example, surface areas are often very important aspects of functional traits and new, computer-aided technologies are allowing more rapid and accurate measurements of such traits.
- Who should read your paper (people that work in a particular field, policy makers, etc.)?
Our paper should be of practical use to researchers developing trait databases or wanting to make mechanistic predictions about how species will respond to environmental change. But it should also be of conceptual relevance to any biologist. We certainly found that we had a clearer perspective on the link between traits, environment and performance after writing this article, so we hope that it helps others to similarly clarify their thinking on this topic.
About The Author
- How did you get involved in ecology?
When I found a lizard in my garden, circa 1980. I wanted to find more …
- What are you currently working on?
A study of a grasshopper from Australia’s arid zone that has ditched males and instead reproduces clonally (parthenogenesis). We’re working out what the costs are of this approach to life (it’s hard to find any!).
- What’s your current position?
Professor of Ecology and Evolution in the School of BioSciences, The University of Melbourne
- What project/article are you most proud of?
NicheMapR – a tool for mechanistically working out a species’ niche from functional traits.
- What is the best thing about being an ecologist?
Field work – especially road trips.
- What is the worst thing about being an ecologist?
Not enough time for road trips.
- What do you do in your spare time?
I still like looking for lizards.
- One piece of advice for someone in your field…
Don’t be shy to initiate a conversation about your research with the leaders of your field. They love talking about ecology just as much as you do.