Opinion The “Non-Native” Enigma

Non-native species have been introduced to ecosystems throughout the world, and in some instances, have degraded the invaded system. Consequently, the distinction between native and non-native species has become an integral component of conservation planning. Recently however, the conservation value of the distinction has been questioned. We examine how the native versus non-native dichotomy is intrinsically ambiguous, which therefore limits the conservation utility of the designation in and of itself. A large degree of uncertainty exists as to whether many species are or are not native. Measures outside the non-native dichotomy (e.g., impacts, evolutionary ecology, paleontology) could better inform conservation efforts, because species’ ranges are part of dynamic processes. We recommend that the eld of conservation should avoid arbitrary points in history as benchmarks and incorporate findings from multiple disciplines to better manage resources.