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Actinemys marmorata
There is ample information on the ecology of the western pond turtle and many peer-reviewed research studies; however current sizes and densities of western pond turtle populations in California are not well known. Information on dispersal, population structure, population dynamics, and the nature and dynamics of environmental factors affecting populations (including edge effects) is needed to effectively design and implement conservation plans. In addition, the current genetic diversity of existing populations should be investigated to determine metapopulation status, gene flow between populations, and long-term population viability.
Western pond turtles occur in a variety of aquatic habitats from sea level to elevations of 1,980 meters (6,500 feet). They are found in rivers, streams, lakes, ponds, wetlands, reservoirs, and brackish estuarine waters. (Holland 1994; Jennings and Hayes 1994.) Western pond turtles use aquatic habitats primarily for foraging, thermoregulation, and avoidance of predators. They prefer habitats with large areas for cover (logs, algae, vegetation) and basking sites (boulders or other substrates) and have been observed to avoid areas of open water lacking these habitat features (Holland 1994). The turtles use basking sites for thermoregulation. Western pond turtles can be found in waters with temperatures as low as 1oC (34oF) or as high as 39–40oC (102–104oF) (Jennings and Hayes 1994). Western pond turtles overwinter in both aquatic and terrestrial habitats. Aquatic refugia consist of rocks, logs, mud, submerged vegetation, and undercut areas along banks. Terrestrial overwintering habitat consists of burrows in leaf litter or soil. The presence of a duff layer seems to be a general characteristic of overwintering habitat
This is a juvenile that was just released into the wild. A joint project between Sonoma State University, Oakland Zoo, and San Francisco Zoo allows for a head-start for this species of special concern in California. Sonoma State researchers track females and monitor nests, and the zoos raise them to a larger size. That way, they are less likely to be invasive bullfrog food, and might be able to compete with nonnative turtles, such as the red-eared slider
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