Climate Change Will Hit Genetic Diversity
By Virginia Gewin of Nature magazine
Climate change represents a threat not only to the existence of individual species, but also to the genetic diversity hidden within them, researchers say. The finding promises to complicate assessments of how climate change will affect biodiversity, as well as conservationists' task in preserving it. DNA studies have revealed that traditional species, as defined by taxonomists, contain a vast amount of 'cryptic' diversity -- such as different lineages, or even species within species. Carsten Nowak, a conservation biologist at the Senckenberg Research Institutes and Natural History Museum in Gelnhausen, Germany, and his colleagues have made a first attempt to understand how global warming might affect this form of diversity. Their findings are published in Nature Climate Change. The team looked at aquatic insects living in the mountain streams of central Europe -- seven species of caddis fly, a mayfly and a stonefly. The insects were chosen because they are likely to be especially vulnerable to rising temperatures -- they need coldwater, and have limited ability to travel large distances.
To measure genetic diversity, Nowak's team sequenced genes in the animals' mitochondria -- energy-generating cellular organelles that have their own small genome. This allowed the authors to divide each species into a number of evolutionary significant units (ESUs) -- the technical term for a population within a species that is genetically distinct from the rest of its kind. On the basis of where in Europe each ESU is found, the researchers then analyzed whether the associated insect would be able to tolerate higher temperatures or move to somewhere cooler, using two models developed by the Intergovernmental Panel on Climate Change (IPCC). Lost potential
Under the IPCC's business-as-usual climate scenario, 79% of ESUs...
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