Protecting ecosystems from non-native species stems from a “biological bias,” says biologist Mark Davis. Instead of dividing the world into native and non-native environments, scientists ought to judge species based on what they do, he says, not where they come from.
Sam Rosenzweig | December 2011 Issue
We’re used to dividing the world into native and non-native ecosystems. What’s wrong with that?
“All species were non-native at one time. How long does a species need to be at a place before it is considered native? ‘Native’ and ‘non-native’ is a dichotomous categorization [overlaid] onto what is actually an ecological continuum.”
So how should scientists be assessing species instead?
“They should focus more on the effects of species than on where they originated. Non-native species are just species. From our perspective, some are going to be helpful, some are going to cause harm and most will be relatively benign. The best example in the U.S. is the honeybee, which is not native and provides billions of dollars in economic benefits. Others, such as some introduced berry-producing shrubs, provide food for native animals or help increase the amount of nitrogen in farm soils. There are plenty of native species that cause great harm. Poison ivy and poison oak are native. The insect killing the most trees in North America at this time is the mountain pine beetle, a native species.”
What makes standing up against non-native species so popular?
“People don’t like change, especially when it happens very fast. A lot of people are opposed to the rapid globalization that is taking place. This has resulted in a revitalization of nationalism and local culture and concerted opposition to new ideas, new people and new ways of doing things. For many, the anti-non-native-species perspective represents the anti-globalization response.”
Is that harmful?
“The consequences are huge, since the nativism paradigm has distorted many conservation efforts to get rid of non-natives and restore native species to a site and resulted in a lot of money spent on what have often turned out to be largely fruitless efforts. You can garden your backyard and maintain or keep out whatever species you want, but you can’t garden nature.”
Photo: Beatrice Murch via Flickr
This is really irresponsible.
Yes, the point is the damage that is done, and people can argue nomenclature until the cows come home, but humans bringing aggressive species into ecosystems that have no preparation for it is akin to what Europeans did to the Native Americans with smallpox.
Spending energy worrying about what you call it and saying that trying to fight invasives is a waste of energy is beyond irresponsible.
Shame on you, Ode. This is not up to your standards.
This article made me think of the book Invasive Plant Medicine (http://greendragonbotanicals.com/products/books/invasive-plant-medicine-by-timothy-scott.html)…a way to appreciate and utilize the “invasives/non-natives”.
What is wrong with dividing the world into native and non-native ecosystems is that the distinction should really be between balanced and unbalanced ecosystems. When an ecosystem has an imbalance between predator and prey, it is either temporary and it fixes itself or we have what we are experiencing on the planet today. When a native species no longer has a predator the ecosystem is unbalanced. The supreme predator on our planet is homo sapien with its predator being itself through its actions of imbalance for motives of individual gain rather than survival of the species.
And how often have we been wrong in juding what an introduced species will do for the ecosystem? Nature is full of surprises that we come to learn when the imbalance increases by our attempts to fix.
I learned from Stephen Harrod Buhner’s book, “The Lost Language of Plants”, that so-called weeds and invasive species show up where their medicine can be used to heal the imbalance. Nature Intelligence constantly tries to restore balance and species know where to move to help out, such as the ragweed showing up on the East Coast as a remedy to the increased incidence of Lyme Disease. Fascinating stuff!
Ode needs to do a better job of being scientifically correct rather than sociologically provocative. The examples of “good” and “bad” plants, whether native or not, is shallow and misses the point entirely. Our work with habitat conservation and restoration shows that the human introduction of non-natives, which we do much better and much more quickly than the rest of nature, frequently introduces species that are entirely out of context. Natural checks and balances within an ecosystem can be totally disrupted by such introductions, such as salt cedar in the southwest US, which is taking over areas of rare and essential surface and high ground water. We still see too much of Ode’s ambivalence about humanity. Forget about it. Apply scientific ecosystem principles and we see how much trouble we have caused.
John D. Criste, AICP
I’m impressed by the insight and articulation of these four preceeding comments. If a website can be judged by it’s contributors… Anyway, I hope more human efforts are aimed at promoting biodiversity… not the genetically modified variety. I hope we, as humans, use our intelligence to promote the elements in nature that we are interdependent upon.
Evolution has carefully determined the suitability and ecological balance of species in certain evironments around the planet over millions of years. Humans have the ability to transport those species into new environments at a rapid pace, and therfore the risk of artificially introducing new species without careful, long-term observation and analysis must be considered dangerous (or at least destabilising), not only for humans, but for ecosystems in general. The spread of humans may also be considered part of the global evolutionary process, however nature will determine ultimately whether our interference creates positive or negative impacts for our own species. It is then up to us how we manage the pace at which changes to ecological systems occur.
I know the most about the invasive situation in the upper midwest of the U.S. and it’s quite dire. Where there were once open oak savannas and prairies there are now European Buckthorn and Japanese honeysuckle jungles. If there is still enough light for plants on the forest floor, it’s filled with garlic mustard, instead of native wildflowers. There are non-natives that are less dire, but they are typically ecological dead zones. It’s interesting to learn about the complex and interactive goings on of a white oak for instance, and the over twenty native moths that depend on it. A Norway maple (in the midwest) however doesn’t have any such ecosystem…maybe it will in hundreds if not thousands of years…
The berries produced by European buckthorn give birds severe diarrhea. The bright red berries of the non native honeysuckles are changing the color of cedar waxwings tails and are disrupting their breeding habits. Studies have shown than birds and their nests are more easily predated than on native shrubs. The extra nitrogen produced by buckthorn only encourages more alien quick growing species to sprout, not slow growing oaks.
Pine beetle is thought to be out of control because of man made global warming and increase droughts. This article is severely misguided on so many fronts.
This issue has nothing to do with globalization in terms of human mores and culture. I certainly agree with Leigh that it is irresponsible of Ode to publish it and I’m disappointed.
It’s true that the ultimate point is what the plants do in the ecosystem, but non- natives are highly suspect simply because they so often turn into a disaster. Honeybees are one of the very few exceptions of a non-native that is helpful.
Articles like this undermine the importance of keeping our natural heritage from disappearing.