Using niche conservatism information to prioritize hotspots of invasion by non-native freshwater invertebrates in New Zealand

Abstract

Aim: Identifying suitable areas for invasive species establishment is of critical impor-tance for their early detection and rapid eradication. However, our ability to detect suitable areas is impeded by the tendency of species to shift their niche postinvasion. In this study, we (a) investigate the frequency of niche shift within invasive freshwa-ter invertebrates and (b) use niche conservatism information to prioritize potential hotspots of invasion for non- native freshwater invertebrates in New Zealand.

Location: Global occurrence data and predictions over New Zealand.

Methods: We characterized the native and invasive realized niche using occurrence data for 22 invasive freshwater invertebrates in relation to 27 derived climate variables. Using principal component analysis and species distribution models, we measured the degree of niche shift for each species and identified hotspots of invasion and niche conservatism described within biogeographic units in New Zealand.

Results: Niche shift was detected frequently among the invasive freshwater invertebrates studied here, where 90% showed a significant niche change. The characterization of the species niche enabled the identification of species whose management might be hampered because of their ability to colonize novel environments. Locations covering more than half of the land area of New Zealand were found to be climatically suitable for at least four and up to 11 species. Areas that were found to be climatically suitable for several species but were not identified as hotspots of niche conservatism could be considered less critical for surveillance and monitoring.

Main conclusions: Aquatic invertebrates show a high degree of niche shift. By combining climate suitability predictions and niche conservatism, we were able to prioritize invasion areas.