EXTINCTION RISK AND POPULATION DECLINES IN AMPHIBIANS

Abstract

This thesis is about understanding the processes that explain the patterns of extinction risk and declines that we see in amphibians, how we can use that understanding to set conservation priorities, and how we can convert those priorities into practical, hands-on research and management. In particular, I focus on the threat posed by the emerging infectious disease, chytridiomycosis, which is caused by the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Amphibians display a non-random pattern of extinction risk, both taxonomically and geographically. In chapter two I investigate the mechanism behind the observed taxonomic selectivity and find that it is due to species biology rather than heterogeneity in either threat intensity or conservation knowledge. In chapter three I determine which biological and environmental traits are important in rendering a species susceptible to declines, focussing on susceptibility to Bd. I found that restricted range, high elevation species with an aquatic life-stage are more likely to have suffered a decline. Using these traits, I predict species and locations that may be susceptible in the future, and which should therefore be a high priority for amphibian research and conservation.