Document: JES-3-52-29

Patch isolation and priority effects and the structure of arthropod communities inhabiting creosote bush (Larrea tridentata) in central Arizona.

RANGO, J.J.*

Arizona State University, Tempe, AZ, 85287-1501, USA. ¹

Abstract:
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 making it a model system in which to study concepts central to community ecology such as the impacts of habitat patch isolation and priority effects on arthropod community structure. To quantify the impact of patch isolation on creosote bush arthropods I compared the composition of communities in two natural desert areas (located on the outskirts of Phoenix) to those in two isolated desert remnants (located within the Phoenix metropolitan area). Composition of communities was determined by sampling arthropods on creosote bush every two weeks from March - November 1999. Arthropod communities were richer on creosote bushes located in natural desert areas than in isolated desert remnants. Additionally, during some time periods greater numbers of individuals occurred on creosote bushes located in natural desert areas than in isolated desert remnants. I conducted a priority effects pilot to investigate the influence of pioneer colonists on the recovery of arthropod communities to previously defaunated creosote bushes. This experiment consisted of removing all arthropods from bushes and then seeding the bushes with the following pioneer colonists in natural densities: 1) Leaf hoppers, 2) jumping spiders, and 3) no pioneers. No differences in the relative recovery of arthropod communities were observed among treatments suggesting that priority effects may not be important in structuring creosote bush arthropod communities following disturbance.

Keywords: priority effects, arthropod communities, urban ecology

This abstract is being presented at: 10:30 AM in session:
Oral Session #4: Herbivore Responses to Plants.