In Defense of Nature

Invasion Biology: Perception Trumps Reality

Numerous pollinators, such as this Tiger Swallowtail, obtain nourishment from the blooms of Autumn Olive (Eleagnus umbellata). Their feeding fertilizes the flowers, which then provide fruits by late summer for birds and mammals.

ALL TEXT AND PHOTOS © Marlene A. Condon

 

 

One definition of perception is “a thought, belief, or opinion, often held by many people and based on appearances”.

 

https://dictionary.cambridge.org/us/dictionary/english/perception

 

It’s the perfect description for the field of invasion biology that deals with plants. When particular nonnative plants became noticeable in number alongside roadways, trails, and in fields, folks suddenly became aware of them and concluded these species had “pushed out” the native plants they felt should be in these locations. But their assumption was based only upon what they were seeing. While seeing can sometimes equate to believing, seeing can be quite deceiving, especially in regards to this issue. I can make clear this point by sharing a true story from my life.

 

I made the decision to work for a year before going to college. My parents did not have money to pay my way, and I didn’t want to end up thousands of dollars in debt by leaving for college when I was 18.

 

My one-year delay turned into five long years. Although I worked sixty-plus-hour weeks, I realized hostessing/waitressing in a restaurant and cashiering in a department store were not going to get me the money needed for college. Therefore, when a managerial position became available at a store 45 minutes away in another town, I jumped at the chance to get it, which I did.

 

Within my first few weeks there, my sister asked me to pick up diapers for her recently born baby. As I was only about 21 and this was the very early seventies before the term “Ms.” had taken hold, I was addressed as “Miss” because I wasn’t married. Immediately word got around that I was a single mother with a baby!

 

Obviously, appearances can be deceiving, and people should refrain from reading too much into them without further investigation. Although it may be difficult for older and younger people alike to grasp how our natural world became so full of plants they mistakenly believe to have “invaded”, that’s no excuse for jumping to conclusions that are, indeed, erroneous.

 

How can I know (and I do know) that the field of invasion biology is way off track? I know because I’ve paid very close attention to the environment throughout my life, which now adds up to many decades of observations.

 

The reason many of the so-called invasive plants exist in the United States is because they were deliberately brought here from other countries. They were known to be effective for preventing erosion by covering disturbed areas (such as that caused by road construction) where most native plants couldn’t possibly return because the soil conditions weren’t right for them. Plants (e.g., Kudzu) continue to grow in such sites, and in developed areas cleared for new construction that has been long delayed or never happened. Invasion biologists overlook the fact that all plants have soil requirements that must be met for them to grow; to home gardeners, it’s known as “right plant, right place”.

 

It’s said again and again that alien plants crowd out native species, but the reality is that they first come up where no, or very few, native plants are already growing. Ground that is compacted and nutrient-poor (either due to construction, trail use, or hundreds of years of cows treading over the landscape) is where nonnative plants fulfill the important role of colonizers that rehabilitate the soil. Over time, native plants can come in, and they do.

 

Invasion biologists must not be gardeners. Otherwise, they couldn’t possibly ignore—as the entire field has done—the truism that environmental conditions dictate which plants can grow in disturbed soils.

 

NATURE ADVICE: 

When I first moved into my newly built house 30 years ago, the topsoil had been graded away and the landscape was as gray, and every bit as devoid of life, as the Moon.

 

By working some of the yard while allowing nature to take its course in other areas of it, I soon had a nature-friendly garden that consisted mostly of non-native plants, some of which are known as “invasive.”  But every one of these plants contributed to a wildlife habitat that has become a haven for a huge diversity of organisms.

 

People are being made to feel guilty for allowing plants to grow that are well established in this country and are providing the structure necessary for superb wildlife habitat. Don’t allow yourself to be dictated to by friends and neighbors misguided by the invasive-plant movement that is, itself, misguided by scientists.