PARENT SESSION
Oral Session 13: Rare, Threatened, and Endangered Species I: Management I.
Presiding: H Balbach
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room D 135.

Spatial structure of multispecies habitats and tolerance of habitat loss in the western Riverside County of California, USA.

Chen, Xiongwen ^{1, 2}, Li, Bai-Lian ^{1, 2}, Allen, Michael², ¹ Department of Botany and Plant Sciences, University of California, Riverside, Riverside, California, USA² Center for Conservation Biology, University of California, Riverside, Riverside, California, USA

ABSTRACT- Analysis of spatial characteristics of all concerned species and the tolerance of possible habitat loss is important for habitat management and strategies making in biodiversity conservation. In this study, we studied (1) the distributions of rare, special concerned, threatened and endangered species (herein multispecies) of plants, reptiles, mammals and birds at western Riverside County of California USA based on their spatial aggregation, associations and vegetation types; (2) the relationship between species richness and habitat quantity; and (3) tolerance of habitat network to habitat loss by computer simulation. The results indicate that the spatial pattern is clumped for plants, reptiles, mammals and birds when the scale is below14, 12, 2, and 10 km, respectively. There exists a high positive spatial association between distributions of any two different species groups. Santa Rosa Plateau is the most preferred location for habitats by most species in observations, and all lakes and their surroundings are also the preferred locations. Shrub (coast sage and chaparral) is the most preferred vegetation type for habitats of multispecies in this region. There exists good relationship of exponential decay between species richness and habitat quantity for plants, reptiles, mammals, birds and all species. The current habitat network of each species group has low tolerance for habitat loss, especially for habitats of mammals. A concept model with ecological safety in habitat network between habitat loss and tolerance of habitat network was proposed. Our results suggest that local land use planning, zoning and reserve design should consider the spatial structure of all these habitats. Maintaining high species richness and proper environmental conditions in current habitats is necessary for preserving other species. Increasing preserved areas properly would increase the ecological safety of the entire habitat network under risk of habitat loss at western Riverside County of California.

Key words: preferred locations, tolerance of habitat loss, spatial structure, preferred vegetation type