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Thesis Abstract – Perfors (2002)

Title:

Edge Effects in the Plant Community of a Coastal Sage Scrub Fragment in LA County, CA, USA

Author and college:

Tracy Perfors, Harvey Mudd College

Date:

May 1, 2002

Degree:

Bachelor of Science in Biology

Advisor:

Catherine McFadden, Harvey Mudd College

Abstract:

The biological integrity and stability of conservation areas can be threatened by impacts from activity outside the area encroaching into the conserved habitat, creating edge effects. It is important to find the penetration depth and magnitude of biotic and abiotic edge effects when managing a conservation area. I studied edge effects on the plant species richness, diversity, exotics and soil nitrate content in the coastal sage scrub habitat in a corner of the Bernard Field Station, Claremont CA, USA. Specifically, I counted the abundance of all inidividual plants of every species in 63 1-m x 1-m plots spaced regularly from 5 m to 273.5 m from the fencelines on the two edges. Significant (p<0.05) decreases in species richness and diversity were seen near the south and west edges, and soil nitrate content increased significantly (p<0.05) near the west edge. Plots with a higher percentage of exotic species were correlated with lower overall plant diversity, indicating diversity may help protect against exotic invasion.

For more information:

Contact Catherine McFadden – catherine_mcfadden@hmc.edu