24 January 2014

Finding your niche

In which we dwell on the problems of the niche

Most people tell me that they don't remember much about ecology from school. One thing that does remain, once you scratch the surface with some gentle probing, is the concept of the niche. The niche does have an advantage in that it has entered common usage, e.g. finding your niche, niche products and so on. In common language niche, when not being used to mean a useful recess in the wall, generally refers to something that is especially suited to a person's abilities. In ecology it has a somewhat similar meaning where it defines a way of living for a species. If pushed, people often will remember that different species will not share the same niche (otherwise they are in direct competition for the same resources and bad things will follow). The niche seems to a fundamental part of ecology. Surely there's nothing left to know about it? Well of course there's plenty left to know. In fact ecologists haven't even been able to settle on a preferred definition of the niche.
Being in the same niche can lead to conflict

We have a new ecologist here at Lincoln, Will Godsoe. Will comes to us after a short stint at University of Canterbury. Before that he was at the University of Tennessee (Knoxville) and University of Idaho (Moscow). Will has thought long and hard about why organisms are found where they are. When I look at the papers that Will has published I notice a certain similarity in interests with what I do. We both are interested in species distributions (where you find them, where you don't) and what shapes these distributions (abiotic factors like climate, biotic factors like disease or food). We both have an interest in coevolution, when organisms evolve together and in response to changes in the other. One could almost say that we share the same or a similar niche. So does that mean that Will and I are now locked in a battle to the finish, in conflict until one of us claims the niche? Luckily, a closer look at our interests reveals that we have complementary and only partially overlapping interests. Broadly speaking Will is an ecologist and I am an evolutionary biologist. Will is interested in the distribution of individuals, populations and sometimes species. He cares about what happened yesterday or last century or a few thousand years ago. I am more interested in the distribution of orders, species, and sometimes populations. I care about what happened a hundred thousand or a million or 50 million years ago. Will uses experiments, observations of organisms and statistical models to answer his questions. I mainly use DNA and evolutionary trees to answer mine. When Will publishes a paper on the niche ("I can't define the niche but I know when I see it" in Oikos) he is talking about statistical properties of determining a niche. When you publishes on species distributions (in Ecography) he is using models to show how much different species overlap. When he publishes on coevolution (in New Phytologist) he is looking at how much climate drives a close relationship between yucca plants and their pollinating moths. While there is overlap between us, where ecology meets evolution, we exist in different niches. That's a relief - we won't have to enter into alpha male conflicts to show who's boss! So welcome to Will.

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