Abstract:
Globally, ant species (Hymenoptera: Formicidae) are a prominent part of terrestrial ecosystems, with high richness, abundance, and ecosystem function. The New Zealand ant fauna is characterised by poor species richness and is dominated by introduced species, however their ecology is poorly known. At the global as well as the local scale, a variety of abiotic and biotic variables are likely to influence species distribution patterns. This study investigates the role of habitat structure, temperature, and inter-specific competition on the assembly of ant communities within four different habitat types in the Auckland region. Two distinct ant communities were found in this study, one largely composed on endemic ant species occurring in forest habitat, the other largely composed of introduced species and occurring in non-forested areas. The local microclimate of these habitats was found to play a key role in the composition of these communities, with the cool environments of forest areas offering a refugia for endemic species, due to the apparent inability of introduced species to establish in these areas. New ant species continue to arrive at the New Zealand border. Competition appears to be of limited importance in New Zealand ant communities due to species not saturating the entire habitat that is available to them. The risk of invasive ants establishing in New Zealand is of serious economic and environmental concern, therefore the factors that determine species composition in current communities are of particular interest for predicting future invasions. The results of this study suggest that many future invaders will be unable to establish in forest habitats, however further research in these areas is required to better assess the risk of introduced ants to New Zealand ecosystems.