Ant biodiversity in arid urban environments: effects of fragmentation and habitat modification

Urban environments are capable of sustaining considerable diversity of some animal taxa. Ants are an excellent example of this. They are important for city inhabitants due to their capacity to provide ecological services and their potential to become pests.  We characterized the diversity, abundance and composition of ant assemblages in contrasting urban environments in Tucson, AZ. We expect that our results will have implications for ant conservation in urban environments and the prevention of pest outbreaks. We sampled the ant communities in three contrasting environments around the city: municipal parks, small urban remnants of the native desert, and unfragmented natural desert. Sampling was carried out with pitfall traps during the fall of 2010 and the spring of 2011. The composition of ant assemblages was significantly different among the three kinds of environments considered. Ants were more abundant in parks than in the other environments, probably as a result of increased water availability due to irrigation. When individual sites were considered, natural desert sites included higher ant diversities than either parks or desert remnants. This pattern was maintained when diversity was compared at the landscape level. Our results suggest that parks have a low potential for ant conservation and are possibly sources for ant pests. Conversely, desert remnants seem to be able to maintain a significant portion of the native ant diversity of the region without generating pest outbreaks.