Assessment of protected area coverage of threatened ground beetles (Coleoptera: Carabidae): a new analysis for New Zealand

Abstract

Gap analysis is a tool that allows conservationists to quantify the effectiveness of protected areas at representing species diversity, but the lack of distribution maps for invertebrates has precluded its application to the world’s most diverse animal groups. Here, we overcome this limitation and conduct a gap analysis, using niche modelling, on the Pterostichini (Coleoptera: Carabidae) of New Zealand, one of the most diverse and most threatened tribes of ground beetles in the nation. Niche modelling uses data on abiotic parameters to model predicted species ranges based on records of their known distribution, and is a useful tool for conservation planning. This method is widely applicable where there is good taxonomical knowledge of the group in question and distribution records are available. We obtained sample localities from museum records for 67 species of Pterostichini, including 10 species listed as threatened, and modelled their spatial distributions based on climate, landforms and soil properties. Most species had small spatial distributions, with 48–75% of species having ranges of less than 100 000 ha. We found the areas with highest species richness fell largely outside of the protected area network, as did the distribution of most individual species, with just 20–25% of species having more than 30% of their range falling within a protected area. In terms of percent land area, New Zealand has one of the world’s largest protected area networks, but the spatial distribution of that network affords little protection to this group of invertebrates. This analysis provides support for the creation of new reserves to increase the value and efficacy of the protected areas network.