Wasp carrying pollen of Brazilian pepper tree, Schinus terebinthifolius WIKIMEDIA COMMONS, RAFAEL BARBIZAN SUHS
The argument that introduced species should not be judged on their geographic history ignores biological reasons why non-native organisms pose a particular threat. Unlike native species, non-natives arrive in their new homes with no shared evolutionary history with most other organisms already there. They leave their predators, parasites, and competitors behind, and they often attain huge population sizes, occupy large areas, and heavily impact native species and ecosystems.
Examples abound. Non-native Brazilian pepper changed south Florida’s landscape, shifting prairie to forest. The non-native fire tree altered nitrogen cycling in the Hawaiian Islands. Non-native cheatgrass modified fire regimes in the western United States by fueling more frequent and intense fires that increase its own populations while suppressing native grasses further. The non-native brown tree snake extirpated ...
