Nature has a very interesting piece up right now, Don't judge species on their origins, which addresses the periodic bouts of hysteria which are triggered by 'invasive species.' I've addressed before the issue of biological terminology of convenience being transformed into fundamental and principled Truths. The separation between 'artificial' and 'natural' selection, or more archaically the division between 'humankind' and the 'natural world.' There are important reasons why these terms emerged the way they did, but we shouldn't confuse the terminology for the truth. This seems definitely a problem when we humans talk about 'invasive' and 'non-native' species, as well as whether population X is worth being protected because it is a 'species' according to a genetic definition, or whether it is too 'genetically polluted.' We are after all an invasive species ourself! Since the piece is behind a paywall I'll extract the most relevant paragraphs:
Today's management approaches must recognize that the natural systems of the past are changing forever thanks to drivers such as climate change, nitrogen eutrophication, increased urbanization and other land-use changes. It is time for scientists, land managers and policy-makers to ditch this preoccupation with the native–alien dichotomy and embrace more dynamic and pragmatic approaches to the conservation and management of species — approaches better suited to our fast-changing planet. ... But many of the claims driving people's perception that introduced species pose an apocalyptic threat to biodiversity are not backed by data. Take the conclusion made in a 1998 paper that invaders are the second-greatest threat to the survival of threatened or endangered species after habitat destruction. Little of the information used to support this claim involved data, as the original authors were careful to point out. Indeed, recent analyses suggest that invaders do not represent a major extinction threat to most species in most environments — predators and pathogens on islands and in lakes being the main exception. In fact, the introduction of non-native species has almost always increased the number of species in a region. The effects of non-native species may vary with time, and species that are not causing harm now might do so in the future. But the same is true of natives, particularly in rapidly changing environments.