Tuesday, August 7, 2007

PS 22-13: Community level effects of vegetation architecture and prey availability: An experimental field study of ground-dwelling spiders in a shrub-steppe ecosystem

Mary E. Pendergast and James A. MacMahon. Utah State University

There are a great variety of factors, both biotic and abiotic, that work together to structure communities. With a myriad of possible influences, it is important to evaluate the relative importance of each factor if we are to understand the functioning of communities especially in the face of ever-changing environments and level of disturbance. Habitat structure is one factor known to influence community diversity and organization. Community-level effects of habitat structure and predator-prey interactions can be examined by including multiple spatial scales in experimental alterations of vegetation architecture. Guilds have been described in various ways for the spider fauna based on prey capture methods. In this study, we are examining the influence of vegetation architecture and prey abundance alterations on community-level organization in a natural system through spider guild assemblages. There are clear influences of vegetation architecture on spider community organization at the guild level of organization. It is unclear from the preliminary data whether it is a direct influence of architecture or an indirect influence with prey availability.