Document Type

Capstone Project

Degree Name

Bachelor of Science (B.S.)


Science & Environmental Policy


alifornia provides habitat for many different species of wildlife. Throughout the years many of these species have decreased in numbers and have become threatened with extinction. The California red-legged frog (Rana aurora draytonii), the California tiger salamander (Ambystoma tigrinum californiense) and the Western pond turtle (Clemmys marmorata) are three species that have declined in numbers in recent years. Human activity is one suggested reason for this decline. In the summer of 2000, I worked for the East Bay Regional Park District doing biological surveying to assess populations of these three species in the stock ponds that exist on the park district's lands. The ponds were also surveyed in the summer of 1996. I was able to obtain 1996 and 2000 human visitation numbers for each park studied and analyzed these numbers with the survey data. The number of ponds with tiger salamanders increased from 1996 to 2000, but was not significantly correlated with changes in human visitation to the parks. There was also no significant change in the number of visitors to each park between 1996 and 2000. A significant difference was not found between 1996 and 2000 for the other two species in terms of the number of ponds with them and also changes related to the number of visitors in each park. Continued surveys and more consistent sampling techniques that can accurately assess population densities might be able to determine if human visitation influences amphibian and reptile populations. By studying populations of these three species and possible reasons for their declines, scientists may be able to prevent the complete extinction of them.


Capstone Project (B.S.) Earth Systems Science & Policy Institute

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