A group of prominent ecologists is calling on conservationists to stop bad-mouthing introduced species – and accept the fact that ecosystems will increasingly be a melting pot of “long-term residents and of new arrivals.”

“Over the past few decades, ‘non-native’ species have been vilified for driving beloved ‘native’ species to extinction and generally polluting ‘natural’ environments,” a team of 19 researchers write in Nature. “Intentionally or not, such characterizations have helped to create a pervasive bias against alien species that has been embraced by the public, conservationists, land managers and policy-makers, as well by as many scientists, throughout the world.”

One problem, they write, is that the “native-versus-alien” worldview ignores the fact that although some introduced species can have harmful impacts – especially in places like islands – they can also bring benefits. So while native North American pine beetles are now a major threat to trees, introduced honeysuckle vines and tamarisk trees (pictured) have become key habitat for some birds. And numerous efforts to eradicate invasives have proved expensive failures that make “little ecological or economic sense.”

Another challenge is “that human-induced impacts, such as climate change, nitrogen eutrophication, urbanization and land use change are making the native-versus-alien species dichotomy in conservation increasingly meaningless.” It is “impractical,” they add, “to try to restore ecosystems to some ‘rightful’ historical state.”

Conservationists shouldn’t abandon efforts to stop new invasions or solve serious problems caused by introduced species, they conclude. “But we urge conservationists and land managers to organize priorities around whether species are producing benefits or harm to biodiversity, human health, ecological services and economies.” David Malakoff | June 15, 2011

Source: Mark Davis et al. Don’t Judge Species On Their Origins. Nature, 9 June 2011, Vol. 474 (2011).

Image Elizabeth Makings/ASU