Influence of landscape on the presence of Batrachochytrium dendrobatidis and Ranavirus in tadpoles in the southern Atlantic Forest of Brazil

Abstract

Habitat loss and infectious diseases have both been suggested as major causes for worldwide declines of amphibian populations. Searching for biotic indicators is a useful tool for mapping priority demands in disease management. The aim of this study was to analyze the prevalence of two pathogens, Batrachochytrium dendrobatidis (Bd) and Ranavirus (Rv), in anuran communities in southern Brazil. We explored the relationship between the prevalence of Bd and landscape class and used an indicator-species and indicator-community approach to identify which species and communities have the potential to indicate the presence of Bd.Based on 26 anuran communities, we found high Bd prevalence inthe region but absence of Rv. Three species were found to be Bd indicators, including endemic species from southern Brazil and Argentina. Additionally, the analysis with an indicator-community approach revealed that communities from larger forest areas are Bd indicators.Analyses at the community level, which relate landscape to pathogens, provide unprecedented and highly relevant information for fragmented Atlantic Forest landscapes. Based on our results, we argue that even communities in larger forest patches (apparently well-preserved) are susceptible to Bd and deserve attention regarding the possibility of incidence of chytridiomycosis. Implications. From our results, we consider that the use of Bd-indicator species and Bd-indicator communities is a useful approach for conservation and could be used to evaluate the threatened status of species and for proposals for landscape management.