Relative risk of invasive ants (Hymenoptera: Formicidae) establishing in New Zealand

Abstract

Human‐assisted spread of species poses a major challenge to border security agencies. Ideally, limited resources need to be targeted at species posing the most risk. Climate matching is an important component of assessing risk but often little or no biological information is available to enable detailed modelling. To assess if distribution records alone provide useful establishment predictions we compare the climate in New Zealand and its outlying islands to that found in the current native and introduced ranges of 12 tramp ant species, three of which are already established in New Zealand, using the climate module of BIOSECURE, a risk assessment tool. Eleven species showed a similar general pattern, with mean annual temperature being the climatic variable with the least overlap between the estimated realised niche and the predicted New Zealand niche. The twelfth species, of temperate origin, is less restricted by temperature, but much of New Zealand may have too high a rainfall. The present and future threats posed by tramp ants are discussed in relation to climate limitations.