The Western Pond Turtle Conservation Partnership is an exciting local collaboration in which this at-risk species is head-started and reintroduced to a restored lake ecosystem.
In 2008, the San Francisco Zoo, Oakland Zoo and Sonoma State University created a unique, local conservation partnership to work with the western pond turtle (Clemmys marmorata), a declining species of native turtle. The western pond turtle faces numerous challenges and has been listed as a Species of Special Concern by the California Department of Fish and Wildlife.
With funding from the AZA Conservation Endowment Fund, the Disney Worldwide Conservation Fund, the San Francisco Zoo and Oakland Zoo Conservation Committees, and various other supporters, the project has been extremely successful. For the past five years about 30-40 hatchling western pond turtles have been raised annually at each of the two zoos. The turtle eggs are collected from a natural population thriving in a protected pond in Lake County. After being hatched in the biology lab at Sonoma State University, hatchling turtles are sent to the zoos to be reared. Predation by small carnivores wipes out large numbers of the nests laid by the wild turtles and it is thought that the population in Lake County may not be sustaining itself. Nearly XX turtles have been returned to their natal pond through this unique partnership which helps to increase the number of juveniles recruited into the population.
Through these collaborative research and conservation program, the partner organizations developed protocols for locating western pond turtle nests, recovering eggs in the field, and establishing an infrastructure for incubating eggs at Sonoma State and head-starting hatchlings at the zoos. Turtle gender for most species is determined by the temperature of incubation in the nest but little research had been done on what the critical temperature was for sex determination in this species. Data is being collected to explore two major areas of study – how landscape conditions characterize optimal nesting habitat and how in situ nest temperature affects hatching success, growth, and sex determination in western pond turtles. Understanding the role of the thermal environment on embryonic development and phenotype is especially important in reptilian species, such as the western pond turtle, with temperature-dependent sex determination.
A small group of the turtles raised at the San Francisco Zoo are bound for San Francisco’s long-blighted Mountain Lake as part of the Presidio Trust’s phenomenal effort to restore one of the few remaining natural lakes left in the City and the only lake within the Golden Gate National Recreation Area. The Mountain Lake restoration is underway and will create a natural and healthy lake for reintroductions of extirpated native wildlife. The pond turtle is one of eight species planned to be reintroduced into the newly sustainable and functioning lake ecosystem. Zoo staff and Sonoma State University students and faculty have been part of an advisory group assisting with the restoration planning of the Lake. Pond turtles are currently scheduled to be introduced to the Lake in summer 2015.