Publication Date

Spring 2019

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Studies

Advisor

Lynne Trulio

Subject Areas

Environmental studies

Abstract

The loss of natural habitat is one the primary drivers for species decline worldwide. Artificially, created habitat in human-altered landscapes can help supplement or enhance habitat for threatened wildlife populations. The western pond turtle (Emys pallida), a species declining in California, depends on aquatic habitats for its survival, but can use human-created livestock ponds in lieu of natural aquatic habits. This study examined the extent to which western pond turtle used livestock ponds in Santa Clara County, CA, and the importance of key habitat features in the turtle occupancy of livestock ponds. From March 2017 to September 2017, I conducted visual encounter surveys at 78 livestock ponds within the Diablo Range of eastern Santa Clara County. Habitat feature data were collected at 31 ponds. At each site, seven habitat features were evaluated: surface area, pond depth, elevation, number of basking structures, presence of bullfrogs, level of aquatic vegetation, and level of terrestrial tree and shrub cover. Evidence of turtles was found at 13 ponds. Habitat features did not statistically differ between occupied and non-occupied sites, but the number of basking structures and tree and shrub cover may be biologically important. Of 16 previously documented sites, western pond turtles were extant at 12 and likely extant at two. One new documented site was recorded. These results indicate that ponds previously occupied are likely to still contain western pond turtles. To protect western pond turtles, conservation efforts should be directed towards protecting known sites and restoring previously occupied sites.

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