Estimating critical habitat based on year-round movements of the endangered Jefferson Salamander (Ambystoma jeffersonianum) and their unisexual dependents

Abstract

Habitat protection is a key component of endangered species conservation, but critical habitat designations are often based on limited data or habitat use during only a portion of a species’ life cycle. Protected habitat around breeding pools for the endangered Jefferson Salamander (Ambystoma jeffersonianum (Green, 1827)) and their unisexual dependents (Ambystoma laterale – (2) jeffersonianum) is based upon limited movement data from primarily spring and summer seasons. Furthermore, despite their treatment as distinct species under Canada’s Species at Risk Act, differences in habitat use have not been directly compared in areas where they co-occur. We used radiotelemetry to track A. jeffersonianum (JJ) and A. laterale – jeffersonianum (LJJ and LJJJ) during fall migrations to overwintering sites. We used these data and summarized available movement data from past studies that tracked movements in other periods of the annual cycle to estimate year-round critical habitat. Ambystoma jeffersonianum travelled significantly longer distances to overwintering locations than unisexuals. Individuals were more likely to overwinter next to a similar genomotype individual than not. Critical habitat encompassing the entire annual cycle of A. jeffersonianum extends up to 400–450 m from breeding ponds indicating existing regulatory habitat protections in Canada do not currently protect sufficient habitat.