In Defense of Nature

 

Let “Invasive” Plants Do Their Job

A Common Buckeye is one of many late-summer species of butterflies that finds nourishment at Black Knapweed in the author’s garden. One of the last plants to cease blooming in fall, it feeds tiny bees and hover flies active late in the season due to climate-change-induced warmth. And American Goldfinches benefit by feeding on its seeds.

ALL TEXT AND PHOTOS © Marlene A. Condon

 

An edited version of this article was published April 9, 2021 in the Bay Journal.

 

https://www.bayjournal.com/opinion/forum/let-invasive-plants-do-their-job-so-the-natives-can-take-over/article_7387fc70-93c6-11eb-a929-03fb0e9b107b.html

“The eye sees only what the mind is prepared to comprehend”—French philosopher Henri Bergson

 

The January-February issue of the Bay Journal reports that nonnative Hydrilla (Hydrilla verticillata) “has become important in the Bay as a ‘pioneer’ species, colonizing unvegetated areas and making them suitable for native grasses.” People working for the federal government long ago realized that alien plants performed better than native plant species to repair degraded environments, which is why many plants now referred to as “invasive”—such as Autumn Olive (Eleagnus umbellata)—were brought here. This species helped with mine reclamation in the 1830s.

 

Was it a mistake to bring such plants to this country to help fix man’s destructive impact upon the environment? No. With an increasing human population accompanied by development of the land, and increasingly warmer and droughty conditions in places like Virginia due to manmade global climate change, so-called invasive species would be the unintended savior for our wildlife—if only folks would take the time to educate themselves about soil science and how the natural world works.

 

For example, it's common to see abandoned fields and roadsides in Virginia filled with Autumn Olive as you drive throughout the Commonwealth. You could easily believe the dogmatic precepts that these Asian plants “pushed out” native plants and took their place, but such erroneous information combined with your deceptive perception would fool you. Without an assessment of prior use of the land and knowledge of soils, you can’t possibly come to a reality-based conclusion about why certain plant species grow in these areas.

 

Unused fields formerly accommodated either half-ton cows that trod over them day after day, or crops that required heavy machinery to prepare the soil, to sow seeds, and to care for and harvest the plants every year. Roadsides are leftover disturbed areas following road construction. Both fields and roadsides typically contain nutrient-poor, compacted soil. Little organic matter was returned to the soil to enrich cow or crop fields, and topsoil removal by roadway construction uncovered dense subsoil containing few organisms or nutrients.

 

Therefore, the plants you view as you drive along highways bordered by neglected farm fields are the plants capable of growing well in almost inhospitable conditions resulting from human activity. They rehabilitate the soil for the benefit of native plants that require good (i.e., crumbly, nutritive) soil in which to grow well. Only after the “pioneers” (as with Hydrilla) have done their work can such plants move into these impaired locations.

 

Native-pioneer plant species are few in Piedmont Virginia (where I live), consisting mainly of Eastern Redcedar (Juniperus virginiana), Virginia Pine (Pinus virginiana), Eastern White Pine (Pinus strobus, in mountainous and foothill areas), Broomsedge (Andropogon virginicus), and, though not actually native to this part of the state, Black Locust (Robinia pseudoacicia). You will often see these plants joined by Autumn Olive, a hint that supposedly invasive plants are simply nonnative-pioneer plants, increasing the diversity of plant life and thus animal life in these areas.

 

Autumn Olive shrubs and Black Locust trees in fields and roadsides share an extremely useful attribute: the ability to fix nitrogen and thus enrich poor soil (a desirable trait often employed by gardeners growing peas and beans). Such plants serve as Mother Nature’s nitrogen cooperative, working with soil bacteria that enrich the soil by adding this vital nutrient to it so people don’t need to squander oil reserves manufacturing synthetic fertilizer.

 

Unfortunately, the predominant narrative nowadays is that everyone must remove supposedly invasive plants that are mistakenly believed to have displaced native plants while not offering their ecological benefits to the environment. It’s a false narrative, but not surprising, given that people are prepared to understand only what their own biases and limited experiences allow. Yet, anyone can find out for himself the truth about these plants. It’s not rocket science; you simply need to observe the natural world without preconceived notions and grow these plants on your property.

 

I’ve observed in my own yard how Black Knapweed (Centaurea nigra), Japanese Honeysuckle (Lonicera japonica), Autumn Olive, and Paulownia (Paulownia tomentosa) feed our pollinators with blooms, birds and mammals with fruits/seeds/or buds, and even furnish nesting material and/or sites. In years when deer overpopulated the area, they denuded my yard of most native plants, which would have destroyed all habitat if I hadn’t included commonly disparaged invasives in my yard that deer didn’t eat. These ungulates are often unrecognized for their role in making many alien plants appear invasive.

 

In the severe drought years of 2002 and 2003, I witnessed how native species withered alongside the roads as I drove to Shenandoah National Park to give monthly slide presentations. Meanwhile, alien species continued to flourish despite drought and drying winds.

 

If you care about wildlife, ignore the siren call of voices who frame the invasive-plant movement in terms of morality (i.e., your “duty” to destroy these plants). They couldn’t be more wrong.

NATURE ADVICE: 

It may not be long before localities begin to ban the growing of so-called invasive plants on your private property. People must speak out against such laws that will only bring harm to our wildlife. Government officials are not experts on this issue; they respond to the people who make a ruckus. Enlighted citizens must raise their voices so the truth can be heard and given due consideration.