Many non-native species have set up residence in Great Smoky Mountains National Park. A non-native is any species that occurs outside its native range as a result of deliberate or accidental introduction by humans. Non-natives compete with native species for habitat and food and often take over specialized ecosystems that rare plants or animals need to survive. The non-native species are not natural components of the ecological system and, as a result, have not evolved in concert with the native species.