Habitat fragmentation is accelerating, especially in urban settings like Phoenix, Arizona, and is thought to greatly affect community diversity. Creosote bush (Larrea tridentata) is populated by a diverse and abundant arthropod community that is well characterized making it a model system with which to study concepts central to community ecology such as the impacts of habitat fragmentation and priority effects on arthropod community structure. My previous research found that, when compared to highly fragmented urban desert remnants, communities in less fragmented outlying desert areas are richer and composed of more individuals and exhibit an overall higher degree of recovery following defaunation. To extend this research, I conducted extensive field experiments at 8 study sites (4 urban desert remnants and 4 outlying desert areas) investigating the effect of two predatory pioneer colonists differing in movement rates on community recovery and to determine how long priority effects were detectable during community assembly. These experiments consisted of removing all arthropods from bushes and then seeding the bushes with the following pioneer colonists: 1) jumping spiders, 2) crab spiders, and 3) no pioneers. This research constitutes the first time that priority effects experiments, on the same study system, have been performed in two habitat types varying in degree of habitat fragmentation. Results from the proposed field experiments will help identify not only the importance of priority effects on community assembly in general, but also whether habitat fragmentation modifies the influence of priority effects on developing communities. Additionally, experiments conducted at multiple study sites within a habitat type will identify how well the influences of priority effects on community assembly can be generalized across locations or whether they are source pool dependent.
Keywords: priority effects, community assembly
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA