Urban biogeography of ants, global to the local scale

Background/Question/Methods

The consequences of urbanization on native faunas remains relatively unknown, despite the growing size of the urban habitats and the demographic reality that most humans interact with nature primarily through its urban manifestations. Urban ecosystems, to the extent they are considered, are typically viewed negatively. It has been widely speculated that these urban areas act as sinks for native species, sources for invasive species, and have relatively low levels of β–diversity between urban areas compared with natural sites. But, these predictions remain poorly tested, particularly for invertebrates. Here we consider the consequences of urbanization for ant species diversity at two spatial scales. First we use a global ant database to look at effects of urbanization on native and introduced ant diversity patterns. Second we compare the ant communities of native habitats in the North Carolina piedmont to stratified random samples in heavily urbanized Raleigh NC.

Results/Conclusions

Our results suggest that urbanization may have a larger effect on the relative abundance of species than on the local occurrence of species. In addition, the consequences of urbanization on ant faunas are scale dependent, with decreases in diversity confined primarily to small scales. Overall our results suggest that urban habitats with their complex mixes of natural and managed elements, may facilitate some introduced species, but also, given appropriate management, allow persistence of many native species, including rare species. A key next step is understanding how to facilitate the persistence of native species and reduce introduced species abundances in urban landscapes.