Julianne Couch: Rethinking Invasive Species

Sustainable City Network:

Toby Query has worked as a natural resources ecologist for the city of Portland, Ore., Watershed Revegetation Program since 1999, and manages several hundred acres of forests and wetlands in the city. Under his watch, more than 3 million native seedlings and many tons of native grass and wildflower seeds have been planted. He also is the founder of Portland Ecologists Unite!, a monthly discussion group working to improve land management practices and increase the resiliency of the community of ecologists.

Through the years, Query said, he has slowly shifted his thinking from one that “combats evil invasives” to a more nuanced approach.

Many are doing great work on preventing non-native species movement to our wild places. In Lakeshore Living, Kristof and I advocated continuing this important work, and we spoke to the need to rethink some of our other efforts relating to non-native species. We fear that the system has become too Black & White. Why do we think this? Some invasive species management should be considered wrecks. Let me explain this and my concerns.

First, environmental harm, ecosystem harm, or ecological harm is purely a human concept. Every ecological study of a non-native species finds that the non-native created “environmental harm” or had a consequence to the environment (consistent with the Ecological Principle - that Many things are connected to other things). Second, if a species causes economic harm (or human harm) natural management agencies will manage the species, whether native or not (e.g., wolf, cormorant, or sea lamprey). Thus most invasive species thought today can be simplified to:
Non-native = BAD

Non-native species management is really a question of values – Human Values. Aldo Leopold recoiled on the anti-weed talk in his time. We are recoiling on the same phenomena today. War on Non-natives… War on Terror… War on…. Our language is anti-nature. We recoil at the Black & White, and we recognize the nuances and complexity of this issue.

One example of our invasive species management wreck is curly-leaf pondweed management in many lakes. Why do I say this is a wreck? First, we are allowing the destruction of fish habitat. Second, since we are taking an action, the burden is on us to demonstrate in the range of lakes that are now treated that there is little or no negative impact to native plant communities. This has yet to be done. Therefore, these treatments seem imprudent. The science has not changed substantially, but attitudes have.

Some history. Minnetonka Lake, an important Minnesota lake, had curly-leaf pondweed near the turn of the last century. In 1937 Dr. John Moyle recommended planting curly-leaf pondweed. Some of you might wonder why Dr. Moyle advocated planting of curly-leaf pondweed. Moyle was always ahead of his time — he was the only genius that the MN DNR has employed. On this issue, he is still ahead of his time. I suspect that once we get past the current Black & White view of non-native species, that management agencies will be recommending the use of curly-leaf pondweed in limited conditions. It may be the best aquatic plant for fish habitat in some of our altered lakes.

Our Black & White system now targets genotypes of a native species, common reed (Phragmites). This requires genetic testing. How impure does a population have to be to be called invasive? The control of common reed in our lakes seems irresponsible, given that humanity has substantially reduced the common reed in many lakes. It should be noted that that it has not been demonstrated that the genetic code or the different haplotypes of common reed were introduced by humans. Phragmites has a cosmopolitan distribution, and common reed stands are protected in Europe and North America because of their important ecological functions. Phragmites has considerable genetic variation, with geographical varieties.

Is there a problem with our NON-Native Species Fundamentalism? We think so! It decreases the value of species like Phragmites and may reduce our commitment to protecting similar species. I worry that our risk assessment is not inclusive of the ecological values of Phragmites regardless of the varietal designation, and the various actions related to promoting the perceived ‘evil' nature of this plant has decreased the perceived ecological value of this important plant. I have seen this with my own eyes — government staff denigrating this native plant because of the application of an 'invasive' label. I’m saddened by this fact.

Since non-native species management is really just a question of values. Scientists are beginning to probe those values. For example, Fischer et al. 2014 [PLoS One] investigated Professional vs. Public Attitudes on Non-Native Species in a limited context. They stated: “Professionals tended to have more extreme views than the public, especially in relation to nativeness and abundance of a species.” Also from this study was the finding that professionals perceived non-natives to be less beautiful, more abundant, and detrimental than the public. Less beautiful?

Instead of the simple equation where non-native = bad. We encourage you to think about some of the complexity, to address values directly, and to have more goals than a simple statement on reducing invasive species.

We advocate for the reduction of human-assisted migration of unwanted species. In our book we suggest three additional goals. First, if a species isn’t threatening something we value, then we shouldn’t manage it at the expense of other species. The first principle we should have regarding non native species is the ‘First Do No Harm’ principle – Recently arrived non-native organisms may be managed provided that little or no harm occurs to others. For curly-leaf pondweed, we may be harming native plant communities in many of the lakes allowed to be treated. The management science related to curly-leaf pondweed is still young; therefore, we shouldn’t be allowing the current level of habitat destruction.

Second, natural-resource management agencies should prioritize places where they wish to re-create and maintain the native co-evolved diversity. Where exactly does the management agency wish do this? Can it say or list? Why or why not?

Third, recognize that a big all-out war on non-native species cannot be won. It seems old-fashioned to manage for yesterday’s conservation goal of native biodiversity — managing for wildness rather than nativeness seems more important today. We can admire the beauty of all organisms regardless of when they arrived. I’m working for nature and conservation of natural features. I’m not at war with other species. We should prudently increase species diversity in our domestic places, and conserve diversity in our wild places. And we could communicate these thoughts to the public.

Shouldn’t we have the courage to challenge the current fad or fashion, such as latest war on non-native species living with us today? And finally, we, as biologists, should have the wisdom to see the beauty of nature, no matter when it arrived or how it got here.