Do native predators benefit from non-native prey?

Despite knowledge on invasive species' predatory effects, we know little of their influence as prey. Non-native prey should have a neutral to positive effect on native predators by supplementing the prey base. However, if non-native prey displace native prey, then an invader's net influence should depend on both its abundance and value relative to native prey. We conducted a meta-analysis to quantify the effect of non-native prey on native predator populations. Relative to native prey, non-native prey similarly or negatively affect native predators, but only when studies employed a substitutive design that examined the effects of each prey species in isolation from other prey. When native predators had access to non-native and native prey simultaneously, predator abundance increased significantly relative to pre-invasion abundance. Although non-native prey may have a lower per capita value than native prey, they seem to benefit native predators by serving as a supplemental prey resource.