Monitoring of Terrestrial Reptiles & Amphibians by Pitfall Trapping in the Mediterranean Coast Network: Santa Monica Mountains National Recreation Area & Cabrillo National Monument: Version 1.0

Busteed, Gary; Cameron, J; Riley, Seth; Lee, Lena; Compton, Andrea; Berbeo, Eileen; Duffield, Tiffany

Reptiles and amphibians in the parks of the Mediterranean Coast Network (MEDN) are affected by numerous stressors and impacts to their environment and habitat. Global fluctuations in temperature, increased exposure to ultraviolet radiation, interaction with exotic species, and changes in air and water quality have all been linked to declines in amphibian populations (c.f. Blaustein & Wake 1990). In addition, urban development has significantly altered or destroyed critical habitat for many reptile and amphibian species. This is especially so in the Santa Monica Mountains National Recreation Area (SAMO) and Cabrillo National Monument (CABR, located on Point Loma peninsula and included in the Point Loma Ecological Conservation Area, PLECA, formerly known as the Point Loma Ecological Reserve). Thirteen of the 34 species of herpetofauna found in the Santa Monica Mountains are listed as rare, threatened or endangered by the California Department of Fish and Game and/or the U.S. Fish and Wildlife Service. Seven of the nineteen species of herpetofauna historically known to occur on Point Loma are now thought to have been extirpated (Atkinson et al. 2003, attached). Evaluation of historic data and some recent studies suggest that a number of reptile species in the mountains are in decline (NPS unpublished data; De Lisle et al. 1986; Gamradt & Kats 1996, 1997). Much of this information, however, is insufficient to determine the actual and/or potential impacts that have or might be occurring from expanding urbanization in southern California. Recent data suggests that certain reptile and amphibian species are sensitive to fragmentation of natural habitats by development and land use changes in the region of the Santa Monica Mountains (Busteed 2003). Additionally, studies from other areas of southern California have noted declines in reptile and amphibian species as a result of urban associated impacts (Robert Fisher, USGS, personal communication). These declines will likely continue as the human population of southern California continues to grow and urban development expands. Because of the broad diversity of reptiles, their habitat requirements, and diet specificity, species richness has been suggested as a good indicator of ecosystem quality and integrity for these animals. Additionally, information on the distribution and abundance of reptiles and amphibians supports efforts to design restoration strategies and land management programs to aid in their protection and/or recovery from decline. Repeated quantitative assessments of the distribution and abundance of reptiles in the Santa Monica Mountains and the PLECA will provide information on the status and trends in status of these animals, providing information critical to NPS resource managers in evaluating the ecological health of these important indicator species and the broader ecosystems of which they are a part. Monitoring of terrestrial reptile and amphibian species distribution and abundance has been ongoing in the PLECA since 1995 (Brown & Fisher 2002). This monitoring was initiated and conducted by staff from the United States Geological Survey (USGS), Western Ecological Research Center (WERC) following a generic protocol for monitoring herpetofauna using pitfall traps (Stokes et al. 2001). Because of the regional significance of reptiles and amphibians as indicators of ecosystem health similar monitoring was initiated in the broader Santa Monica Mountains ecosystem early in the monitoring planning process. This protocol captures the monitoring processes employed by Cabrillo NM in the PLECA and the Santa Monica Mountains as implemented by the MEDN, establishes a uniform process for administering these monitoring efforts within the network, and incorporates the sampling design optimization analysis completed for data collected in the PLECA (Atkinson et al. 2003).

Monitoring of Terrestrial Reptiles & Amphibians by Pitfall Trapping in the Mediterranean Coast Network: Santa Monica Mountains National Recreation Area & Cabrillo National Monument: Version 1.0

Series

Collections