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Janneke Hille Ris Landers - The response of plant communities to climate change

Talk #3 of the faculty mini-symposium was Janneke Hille Ris Lambers, on The response of plant communities to climate change. She talked about the prevailing theory of how climate change will affect the range of a given species, and work she has done using a highly detailed corpus of data from the Kansas prairie to test the theory.

First Lambers presented the 'climate envelope model' of climate change's effects on species distribution. This is the simple, intuitive approach of basically assuming that as the temperature contours on a map shift, a species' range will follow. Actually it's slightly more complicated than that, because there are variables other than temperature—such as rainfall quantity and pattern—but the principle is just to assume that species' ranges will continue to fill the same climate/environmental zone, even as the geographical extent of that zone moves.

There is at least some animal data to support the climate envelope model, one example of which is the documented change in the Sachem Skipper butterfly's range. 50 years ago this butterfly was found in Northern California, but not in Oregon or Washington. In recent years it's been reported extensively in Oregon and even in the warmer [inland low-lying] parts of Washington. However, there are also problems with the model; in particular it looks at individual species in isolation and ignores the relative abundance of species and any transient dynamics.

To consider the effect of climate change on whole communities of plants, Lamber used a corpus of data collected from 46 different shortgrass prairie sites around Hays, KS from 1937-1972. What impressed me most about this data was not the number of sites or years—though both are unusual in their extent—but the rigour and detail present. Researchers had surveyed each sample site for the number, species, location and extent of every single plant present, which even made it possible to distinguish survival from recruitment (i.e. whether there were the same number of individuals of a given species between years because none died or because as many new exemplars established themselves as old ones died off).

Over the period studied, the climate around Hays became progressively more like what had been found at points SE of it in 1937, so the climate envelope model would have predicted that species which were in the northwestern extent of their range in 1937 would increase in density, and vice versa. This was not borne out by examination of the data—patterns of change were much more complicated and disorderly—suggesting that the model is not adequate for plant species in general. Lamber pointed to a couple of specific issues that need to be taken account of in a better model: inter-species effects (competition and symbiosis), and transients such as how fast/far a species is able to spread and whether the conditions for a plant's survival may be different from those for its initial propagation and/or reproduction.

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Trackback URL for this entry is: http://blog.case.edu/exg39/mt-tb.cgi/10464 UW Biology - Faculty mini-symposium
Excerpt: The University of Washington Biology Department kicked off the new academic year's seminar series with a Faculty mini-symposium. This consisted of 4 departmental faculty taking 15 minutes each to present their current research; four talks for the price...
Weblog: Eldan Goldenberg's lab notebook
Tracked: October 19, 2006 07:15 PM UW Biology - Faculty mini-symposium
Excerpt: The University of Washington Biology Department kicked off the new academic year's seminar series with a Faculty mini-symposium. This consisted of 4 departmental faculty taking 15 minutes each to present their current research; four talks for the price...
Weblog: Eldan Goldenberg's lab notebook
Tracked: October 19, 2006 07:16 PM

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