High diversity in an urban habitat: are some animal assemblages resilient to long-term anthropogenic change?

Urbanization is thought to lead to the loss of biodiversity both because of habitat disturbance and the increased abundance of invasive species. However, most studies of biodiversity in cities are conducted on a short time scale, usually less than 3 years, and so miss the long-term dynamics of communities inhabiting these ecosystems. Here we use a study performed in the early 70's on North Carolina State University (Raleigh, USA) as a baseline to evaluate the long term effects of disturbance and introduced species on native ant communities. Ant species were sampled almost 40 years later using a variety of sampling techniques in order to maximize species collection. Our results show that while the number of exotic species increased, including three major invasive ants, native ant species richness remained high. Furthermore, our survey was able to add several new records for the area considered, in comparison of the 70's study, for a total of 89 species known from NCSU campus. After comparison with other studies, our results represent one of the most species-rich urban environments monitored and thus open encouraging perspective on how urban ecosystems could contribute to the preservation of the biodiversity of small-bodies organisms such as ants.