There’s a big conversation going around in the ecology world right now, sparked by a two-page article in the journal Nature by 19 (!) co-authors, all prominent ecologists. They argue for a change in the paradigm around introduced species to reflect ecosystem functions rather than categorization as “invasive”:
We are not suggesting that conservationists abandon their efforts to mitigate serious problems caused by some introduced species, or that governments should stop trying to prevent potentially harmful species from entering their countries. 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. Nearly two centuries on from the introduction of the concept of native-ness, it is time for conservationists to focus much more on the functions of species, and much less on where they originated.
The article is receiving a fair bit of criticism from within the academic world, such as this from restoration ecologist Nate Hough-Snee. More conversation at the Ecological Society of America here and at Smithsonian Science here.
A few points I’d like to make.
–The full article is available here for $32. I have to say I don’t understand the economics of academic writing – they seem grossly distorted, and like a barrier to access. (Yes, I’m sure there are structural reasons for this…)
–The permaculture teaching community, especially in the Northeast, has been beating the drum around changing the invasive species paradigm for many years. Dave Jacke, Jono Neiger, and Eric Toensmeier have, in particular, taken leadership around bringing similar lines of thinking forward publicly. It’s exciting to see these arguments laid out clearly in a more mainstream publication.
–The core point the authors are making should, I think, be uncontroversial – that introduced species should be assessed on a case-by-case and landscape-by-landscape basis rather than through the lens of a blanket categorization of a whole species as “invasive”. I would like to add that: the reason land use changes create favorable conditions for introduction of new species, is that the wholescale landscape alteration and intense soil disturbance of the modern world’s infrastructure and economy create new available niches for the usually disturbance-adapted introduced species to establish in. And, those intensive levels of disturbance are not inevitable, but reflect choices of individuals and groups about how to manage landscapes. And those choices can change with education, training, and living models of how to manage landscapes in a more regenerative manner.
–I really like the systems thinking revealed in the authors pointing out that biological islands – whether literal islands or figurative ones like lakes and ponds – are, in fact, quite vulnerable to disruption and extinction/extirpation from introduced species. That’s a super important “weakest-link” factor for all of us to keep in mind.
–Hough-Snee’s concluding criticism of the article seems to be that the invasive species paradigm shouldn’t be questioned publicly, because it will be misinterpreted by the public as “invasives are fine” and will lead to decreased funding for restoration and removal-of-invasives projects. I think this is more than a little disingenuous. Warning that certain points the article makes are “dangerous…in a day and age of limited money, personnel, and resources” has nothing to do with whether the article represents clear and accurate thinking.
–Also, Hough-Snee may be correct that most restoration ecologists are already focusing on the highest-impact introduced species, but there’s a significant private industry as well around introduced species removal – home-use pesticides, landscaping companies, etc. – that’s responding to the available market for those products and services, which is based in large part on the semi-informed perceptions of private landowners. Which are, in my experience, not necessarily likely to be focused on the highest-impact species, but are often focused instead on the “nuisance” species like Japanese Knotweed, Autumn-Olive, and Japanese Barberry, to name a few. All of these examples are filling very clear ecological niches in highly disturbed environments, offering significant uses and functions to people (food and medicine for Japanese Knotweed, nitrogen fixation and major fall food source for Autumn-Olive, medicine for Japanese Barberry), AND are very manageable within a context of creating a productive landscape mosaic.
–I think the ultimate question here is not actually about science and policy, but about worldviews, and about our relationships to our landscapes and ecosystems. More difficult to respond to, because it defies any technological or political “solution” – but probably a more effective (and much more peer-to-peer and community-based) leverage point for those of us who aren’t already within the existing larger decision-making system.