Environmental Characteristics Associated with Settlement of Reintroduced Chinese Giant Salamanders

Abstract

Captive breeding and reintroduction have been increasingly used to restore endangered amphibians worldwide. Knowing habitat requirements for targeted species will help to enhance post release settlement and contribute to the success of reintroduction projects. To collect critical information on habitat requirements of the poorly documented Chinese Giant Salamanders (Andrias davidianus), we reintroduced 31 juveniles at two streams in central China and monitored them through radio telemetry from May 2013 to September 2014. We recorded 14 environmental variables twice a month (except during winter) at salamander locations and random locations. We also conducted transects systematically along streams to collect data on environmental variables and prey species. Habitat selection by salamanders was examined at two spatial scales: home-range scale and stream-reach scale. At the home-range scale, water quality variables were not different between salamander locations and random locations, although salamanders were found in deeper water, used larger boulders, and were closer to boulders. Regression models confirmed that presence of salamanders was positively associated with boulder size, river depth, and canopy cover but negatively associated with distance to boulders. At the stream-reach level, only the average water velocity was lower within home ranges than out of home ranges; however, no difference was found between core home ranges and out of home ranges. These results showed that large boulders were the most important variable selected by salamanders. Plenty of large boulders in the streams, together with evidences of postrelease growth of salamanders, indicate the two streams likely are providing suitable habitat for salamanders.