Effects of urbanization, and habitat composition on site occupancy of two snake species using regional monitoring data from southern California
Detection data from a regional, reptile-monitoring program conducted by the U.S. Geological Survey were analyzed to understand the effects of urbanization and habitat composition on site occupancy of the coachwhip (Masticophis flagellum) and striped racer (M. lateralis) in coastal southern California. Likelihood-based occupancy models indicated striped racers responded to habitat composition, favoring scrub-dominated sites. Coachwhips also responded to habitat composition, favoring open habitats. However, unlike racers, coachwhip spatial population dynamics were strongly associated with the fragmentation and isolation of natural areas caused by urbanization. The odds of coachwhips occupying a site were 64 times greater in large connected areas than the most urbanized and fragmented sites. For coachwhips within urbanized and fragmented sites, the odds of extinction were 10 times greater and odds of colonization were five times lower than in large connected sites. Observed differences between both species in habitat use and specificity are supported by telemetry studies and corroborate existing knowledge of historical patterns of occurrence within the region. Movement data on the coachwhip and striped racer indicate the coachwhip is a wider-ranging species with a greater propensity to encounter roads and other edge environments. Collectively, the results suggest there is widespread loss of the coachwhip from the region, and that long-term persistence of remaining populations is dependent on metapopulation dynamics. The substantially different response of the two species to land-use change serves as a caution against the casual use of closely related species as surrogates in the development of species-specific conservation plans.
Citation Information
| Publication Year | 2018 |
|---|---|
| Title | Effects of urbanization, and habitat composition on site occupancy of two snake species using regional monitoring data from southern California |
| DOI | 10.1016/j.gecco.2018.e00427 |
| Authors | Milan J. Mitrovich, James E. Diffendorfer, Cheryl S. Brehme, Robert N. Fisher |
| Publication Type | Article |
| Publication Subtype | Journal Article |
| Series Title | Global Ecology and Conservation |
| Index ID | 70198922 |
| Record Source | USGS Publications Warehouse |
| USGS Organization | Western Ecological Research Center |
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Masticophis occupancy in southern California, 1995-2000
Jay Diffendorfer
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Robert N Fisher
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- Data
Masticophis occupancy in southern California, 1995-2000
These data are CSV files comprised of a heading and tables from Appendix 1 and Appendix 2 in the accompanying paper. The tables show the sampling dates and locations for the coachwhip (Masticophis flagellum) and striped racer (Masticophis lateralis) in pit-fall arrays (Fisher et al. 2008) monitored in southern California from 1995-2000. GPS data are shown in decimal degrees and were collected in t - Connect
Jay Diffendorfer
Research EcologistEmailPhoneRobert N Fisher
Supervisory Research BiologistEmailPhone