Displacement and Local Extinction of Native and Endemic Species

Abstract

The observational evidence on non-native plants, mammals, reptiles, fish, mollusks earthworms, and insects as drivers of population declines or extinctions of native taxa suggests that non-native predators are far more likely to cause the extinction of native species than non-native competitors. Notable examples of such taxa include non-native vertebrates and mollusks as mainly predators and plants and insects as mainly competitors. The most vulnerable species are insular endemics, presumably because of the lack of coevolution between introduced predator and native prey. Island-like situations contribute to severe impacts because the affected native taxa have nowhere to escape. The presence of dormant stages in plants makes it possible to escape unfavourable conditions over time and might contribute to the lack of clear evidence of native plant species driven to extinction by plant invaders. Overall, robust evidence has accumulated during the past few decades that non-native species are drivers of local and global extinctions of threatened, often endemic, native species.