Global niche and range shifts of Batrachochytrium dendrobatidis, a highly virulent amphibian-killing fungus

Abstract

Batrachochytrium dendrobatidis (Bd) is one of the world's most invasive species, and is responsible for chytridiomycosis, an emerging infectious disease that has caused huge losses of global amphibian biodiversity. Few studies have investigated invasive Bd's niche and range relative to those of native Bd. In the present study, we applied niche and range dynamic models to investigate global niche and range dynamics between native and invasive Bd. Invasive Bd occupied wider and different niche positions than did native Bd. Additionally, invasive Bd was observed in hotter, colder, wetter, drier, and more labile climatic conditions. Contrast to most relevant studies presuming Bd's niche remaining stable, we found that invasive Bd rejected niche conservatism hypotheses, suggesting its high lability in niche, and huge invasion potential. Bd's niche non-conservatism may result in range lability, and small niche expansions could induce large increases in range. Niche shifts may therefore be a more sensitive indicator of invasion than are range shifts. Our findings indicate that Bd is a high-risk invasive fungus not only due to its high infection and mortality rates, but also due to its high niche and range lability, which enhance its ability to adapt to novel climatic conditions. Therefore, invasive Bd should be a high-priority focus species in strategizing against biological invasions.

Keywords: Amphibian-killing fungus; Batrachochytrium dendrobatidis; Biological invasions; Niche dynamics; Range dynamics.