Irrigation and Land Use Drive Ground Arthropod Community Patterns in an Urban Desert

Abstract

Urbanization has been observed to affect arthropod communities through mechanisms such as removal of habitat and creation of habitat remnants. However, very little research has been conducted that simultaneously analyzes the range of anthropogenic, remnant, and quasi-natural land uses in a city as potential habitat for arthropods. Here we report on >2 yr of a long-term study of ground arthropods of Phoenix, AZ, focusing on the communities assembled in agricultural fields, commercial sites, mesic and xeric residential yards, desert remnants surrounded by the city, and peripheral natural desert. Agricultural fields and mesic residential yards generally supported the greatest number of individuals and taxa, showed the best separation from other types in ordination analyses, and had the greatest number of significantly associated taxa in indicator species analysis. Thus, of the urban habitats, two heavily irrigated and highly productive land use types seem to stand apart from the others in most community measures. Outlying desert sites also supported significantly associated taxa, including those not found regularly in desert parks and members of higher trophic levels less common in the city. Despite this, outlying desert and desert parks supported similar taxon richness. Xeric residential yards and commercial sites did not support any taxa not found in other land use types. While our results may be dependent on the location of Phoenix in the water-limited Sonoran Desert, we urge broader consideration of highly modified urban landscapes as wildlife habitat.