Bioclimatic models attempt to draw correlations between species distributions and climate patterns. As ecologists and climatologists hone these models, they become a useful tool for predicting future species distributions based on projected climate patterns.
In the March issue of Ecology, Joshua Lawler of the University of Washington and his colleagues undertook a huge task: using a bioclimatic model, they estimated the effects of climate change on future species ranges of almost 3000 species of birds, mammals and amphibians in the Western hemisphere. Their comprehensive survey revealed that some areas could experience a 90 percent change in species representation. The authors conclude that “as a result of climate change, many areas in the western hemisphere will likely experience a significant reorganization of their vertebrate fauna over the coming century.”
Some of these largest shifts have also been found to be in areas of high conservation concern, such as rainforests in the Bahia region of Brazil. While this might initially seem fortuitous, since funding may already be in place to conserve these areas, the authors point out that under this climate change scenario, there may be little we can do to abate these drastic faunal changes.
Bioclimatic models are useful as a first step, but as the authors concede, they only correlate distributions with climate variables (e.g. temperature, air moisture, precipitation), and thus don’t take into account species interactions, habitat requirements and evolution of animals. Especially in the case of amphibians, which have specific hydrological and habitat needs, these factors play a huge role in distributions. Sadly, even without these ecological factors, the bioclimatic models predict that amphibians’ ranges will be the most affected of any group tested. Add in the ecological factors, and our frog and salamander friends have a very grim outlook.
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Joshua J. Lawler, Sarah L. Shafer, Denis White, Peter Kareiva, Edwin P. Maurer, Andrew R. Blaustein, Patrick J. Bartlein (2009). Projected climate-induced faunal change in the Western Hemisphere Ecology, 90 (3), 588-597 DOI: 10.1890/08-0823.1