Potential for high-latitude marine invasions along western North America

Aim High-latitude regions host many fewer non-native species than temperate ones. The low invasion loads of these colder regions may change with increases in human-mediated propagule supply. We test the hypothesis that colonization by non-native species that have already invaded temperate shorelines would be precluded by environmental conditions if they were introduced to Alaska and other high-latitude regions by shipping or other vectors. Location Pacific coast of North America as well as coastal oceans world-wide. Methods Using 16 habitat descriptors in ecological niche models, we characterized the conditions throughout the native and introduced distributions of four marine species (Amphibalanus improvisus, Carcinus maenas, Littorina saxatilis and Styela clava) that have invaded multiple global regions to test the extent to which suitable conditions for these species exist in Alaska and other high-latitude regions under current and predicted future climate scenarios. Results Models projected environmental match for all four species in many areas beyond their present range limits, suggesting that Alaska and other high-latitude shorelines are currently vulnerable to invasion by non-native species that occur in lower latitudes. Main conclusions Given current and possibly increasing human-mediated species transfers and suitable environmental conditions that exist now and with projected warming, policy and management efforts are urgently needed to minimize invasion opportunities at high latitudes.