Identifying Environmental Refuges (“Coldspots”) from Infection by Batrachochytrium Dendrobatidis of Amphibians in Eastern Europe

Abstract

Amphibians are the most threatened group of vertebrates. While habitat loss poses the greatest threat to amphibians, a spreading fungal disease caused by Batrachochytrium dendrobatidis (Bd) is seriously affecting an increasing number of species. Although Bd is widely prevalent, there are identifiable heterogeneities in the pathogen's distribution that are linked to environmental parameters. Our objective was to identify conditions that affect the geographic distribution of this pathogen using species distribution models (SDMs), with a special focus on Eastern Europe. SDMs can help identify hotspots for future outbreaks of Bd, but perhaps more importantly identify locations that may be environmental refuges ("coldspots") from infection. In general, climate is considered a major factor driving amphibian disease dynamics, but in particular temperature has received increased attention. Here, 42 environmental raster layers containing data on climate, soil and human impact were used. Mean annual temperature range (or 'continentality') was found to have the strongest constrain on the geographic distribution of this pathogen. Using the partial dependence visualization module in the R package 'embarcadero', a number of corresponding coldspots were identified.

Geographically Isolated Wetlands as a Reserve for the Conservation of Amphibian Biodiversity at the Edge of Their Range

“…Nowadays, more amphibian species are in need of protection due to their sensitivity to environmental quality; population decline and range reduction are therefore observed globally [2,3]. There are many reasons for this: anthropogenic influence (fragmentation, destruction, and pollution of wetlands), climate change (which, for example, leads to the reduction of amphibian spawning grounds), biological invasions (especially impacts caused by predatory fish and reptiles), diseases (e.g., the devastating fungi species Batrachochytrium dendrobatidis), and other agents that can cause changes in the structure of populations and the appearance of anatomical and physiological anomalies amongst individuals [4][5][6][7][8][9][10].…”