Biodiversity left behind in climate change scenarios
Bálint Miklós, Domisch Sami, Engelhardt Christine, Peter Haase, Stephanie Lehrian, Jan Sauer, Kathrin Theissinger, Steffen U. Pauls, and Carsten Nowak, "Cryptic biodiversity loss linked to global climate change," Nature Climate Change, 1, no. 6 (2011), 313-318.
Climate change predictions show that the habitats of many species are likely to shrink, if not disappear, in the coming years. These predictions are based on species-distribution models, which are essentially computer simulations that analyze the environmental factors affecting the distribution of suitable habitats for plants and animals. These models, however, typically take the term "species" at face value without questioning whether the long-standing, Latin-named identity of a particular species is the best unit of analysis for measuring changes in biodiversity.
A team led by Bálint Miklós, based at the Biodiversity and Climate Research Center (BiK-F) in Germany, has published new research in Nature Climate Change addressing this assumption. They find that simply using the traditional classification of a species in climate change simulations can underestimate the true scale of biodiversity loss. This happens because the subtle genetic variations among similar-looking species – typically hidden from view – are overlooked. Such a misstep in the models could undermine future conservation efforts.
A species can nowadays be identified using the power of genetics. This is often more refined than using the Latin name, which is fundamentally based on the physical features of an animal or a plant. The authors combined genetic and geographic data for insects that live in the streams and mountains of central Europe to test which species definition gave the most useful information on biodiversity loss. One test used the traditional, physical definition of a species and the other used modern genetic definitions. The authors used well-known climate change scenarios to see how the distributions of the insects would change with global warming.
The models showed that changing the unit of interest in a simulation—from physically-derived species to genetic variants—would affect the relative level of biodiversity loss expected under a certain decline in suitable habitat due to predicted climate change; biodiversity loss was lower when the Latin definitions were used than when the units of interest were populations or genetically defined units under the same scenarios. The genetic definitions essentially gave populations more "units" for an area. The most dramatic losses occurred when region-specific genetic variants were assessed. The study revealed that hidden genetic diversity between similar-looking species was reduced much more with the Latin classifications. However, all of the models consistently showed that biodiversity would be lost if the climate gets hotter.
Conservation efforts should be prioritized differently in order to preserve the hidden genetic diversity of nature, often referred to as "cryptic" diversity. Preserving a spectrum of diversity within the same species is vital because only this level of diversity allows organisms to adapt in times of climate change. Predictive models should take this into account as they are improved in the future.