Dermal disruption: Amphibian skin bacteria is more diverse in cold, variable environments

Amphibians are victims of lethal skin-disease epidemics. In the first global-scale study, researchers from 31 universities and research centers, including the Smithsonian Tropical Research Institute (STRI), collected skin bacteria from more than 2,300 healthy frogs and salamanders from 12 countries to describe microbes on a wide range of host animals to improve knowledge of the distribution of frog-skin bacteria, known to be important in maintaining amphibian health.

Based on samples of 205 different species of amphibians, the team concluded that an animal's environment, especially the temperature, plays a big role in which bacteria live on its skin. Their most striking result, published in Nature Ecology and Evolution, was that amphibian skin microbes are more diverse in areas with cold winters and variable temperatures. This was unexpected because most animals and plants are more diverse in the tropics.

"Finding higher overall diversity of these skin bacteria in temperate areas was a surprise, and then it became our task to explain why," said Jordan Kueneman, a STRI postdoctoral research fellow who led the study.