VEGETATIVE STRUCTURE OF WOODLAND-GRASSLAND EDGES IN COASTAL CENTRAL CALIFORNIA

Most research on effects of edges to vertebrate wildlife comes from eastern-deciduous, boreal, and tropical forests where most edges are abrupt and have resulted from anthropogenic forest fragmentation. California oak (Quercus) woodland, by contrast, is naturally patchy and contains abundant edges, constituting a naturally fragmented vegetative complex. No published research has characterized the vegetative structure of these natural edges in California oak woodlands. To begin to fill this information gap, we measured 10 vegetative characteristics and the number of dusky-footed woodrat (Neotoma fuscipes) dwellings on 8 edges at 4 oak-grassland sites in San Luis Obispo County, California. Stem density and shrub cover were less at edges. Canopy cover and tree diameter were greater at edges, but other vegetative characteristics were similar between the edges of the woodland stands and their interiors. Woodrat dwellings were equally abundant between edges and interiors. Concepts of nest predation, nest parasitism, and other deleterious effects of induced edges previously identified in contiguous-canopy forests might not be applicable to California oak woodlands. Further research is needed to assess wildlife response to oak woodland edges and to further quantify vegetation characteristics of natural and induced oak woodland edges at stand and landscape scales.