Differences in morphospecies composition of ground-dwelling arthropods along an edge to interior gradient in a coastal sage scrub community in Orange County, California

Urban development has reduced coastal sage scrub habitat in California to less than 10% of its prehistoric range. This encroachment is modifying community structure and dynamics, causing changes in biodiversity and altering ecosystem functions. This study was designed to illuminate the influence that urbanization may have on biodiversity in coastal sage scrub. This habitat type was investigated in 1998 using morphospecies from arthropod pitfall traps on a gradient from edge to intermediate to interior sites in a coastal sage scrub community in southern California. Morphospecies richness was the same at all sites; however, there were compositional differences among sites. Perennial vegetation also exhibited composition differences. In addition, non-native arthropod species were detected at all sites, with higher densities at the edge. These results suggest that morphospecies composition may have stronger implications than diversity richness for evaluating ecosystem change. The fauna and flora at the coastal sage scrub-urban interface (edge) have been altered in relation to their interior counterparts, suggesting that an edge effect does exist. Morphospecies composition is a valuable measure in determining habitat structure and should be considered when making habitat management decisions.