Wooded areas promote species richness in urban parks

Abstract

Urban green spaces can have an important role in biodiversity conservation. However, they are not often a focus of biodiversity studies, although their global area is raising. We investigated the impact of habitat characteristics of urban green spaces on an ecologically important group of insects—ants (Hymenoptera: Formicidae). We tested three questions: 1) does ant species richness positively correlate with park size and the extent of wooded areas? 2) Is ground temperature the best predictor of ant activity? 3) Will communities be dominated by thermophilic, dry-tolerant, generalist species? Using pitfall traps, hand collecting, and baiting we sampled 7595 ants belonging to 30 species, across eight localities in urban protected areas of the city of Zagreb, Croatia. Parks with larger wooded areas had high species richness, but park size was not a good predictor of species richness. Ant activity was largely influenced by temperature. Five out of eight localities had similar ant community composition. The remaining three localities each had unique ant communities with no overlap with any other locality. Overall, in addition to typical urban species, we recorded species of conservation interest. Thus, small urban green spaces have the capacity to support and conserve diverse ant communities, but their habitat characteristics need to be considered in urban planning.