Thinking about restoration: invasive weeds

We spend a lot of time worrying about the impacts of invasive species in the Green Cities world.  As we say in the 20-Year Forest Management Plans, “The dominance of nonnative plant species…is a major cause of biodiversity loss and ecosystem degradation in urban forest.  These invasive weeds lack natural population control and are capable of rapid reproduction; they can quickly blanket the understory and prevent native plants from reseeding.”  It would seem that getting rid of them would be the smart thing to do, so get rid of them we do.  Volunteers in Seattle have spent tens of thousands of hours grubbing out blackberry and rolling up ivy in parks across the city.  The work isn’t easy and can easily leave one cursing the invasive scourge.  The clear-and-present danger invasives pose to our cherished natives, in harmony with the blood, sweat and tears needed to remove them has created the perfect environment for what I call ‘The War on Weeds.’  Grab your hand tiller or pulaski and HAVE NO MERCY!  It is an easy way to get motivated and a good outlet for aggression.  But, it can be a morally dangerous mindset.

A volunteer group sizes up an ivy patch at last week's Day of Caring event in Interlaken Park
A volunteer group sizes up an ivy patch at last week's Day of Caring event in Interlaken Park

Invasive weeds are our fault.
Humans are the vectors for the introduction of new species in areas all over the world.  Globalization has led to a redefinition of boundaries; the world is getting smaller.  Species have always traveled (on the wind, waves and winged creatures) and have always disrupted established ecosystems, just at a much slower pace.  Stability was achieved and species were naturalized, but it took time.  We have given organisms a lot more chances (sometimes intentionally), a lot faster modes of travel, and we have also created the disturbances that new species need to take hold.  The problems we experience with invasive species are entirely our fault, so why should we blame the plants which are simply filling the niche we have carved for them?

Aside from ignoring the root (no pun intended) of the problem, I believe the ‘War on Weeds’ is morally questionable as well.  Anthropomorphizing plants draws unnecessary comparisons between unwanted plants and unwanted people.  We can’t allow ourselves to adopt the same antiquated perspectives of the eugenicists of the early 20th century.  We should be embracing diversity and accommodating change instead of fighting whole-heartedly to protect ‘our own.’  The things that make our native trees unique are in the ecological role they play for our region’s fauna and the services they provide to our cities, not their status as Northwest icons.  Native conifers do an amazing job at retaining stormwater, preventing erosion, sequestering carbon, scrubbing pollutants, providing habitat, etc.  Invasive plants are typically not as good at these things.

The Green Cities Partnerships are really good at looking at the big picture, which I believe is the way to go.  If we frame our efforts positively, we will get a lot farther than if we are focusing on ‘eradication for the sake of eradication.’  We should also be working to demonstrate to others why we’re better off not introducing these species and creating the disturbances in the first place.  You can still buy English ivy for your garden at local nurseries.  Huh?  Our communities have the opportunity to embrace change and ferry the health of our urban forests through tough times, but only if we recognize that we hold the keys to the solutions as well as the problems.

More to come in the next few months.

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