Invasive and Exotic Plant Species in Our Bluff Lands
A healthy and productive natural plant community – forest or woodlands, prairie or grasslands, banks and borders of streams and ponds, and, even, the borders that run between – is composed of many different species. Unlike the agricultural field, which is a monoculture of one plant type grown for cropping purposes, the very diversity of species in a natural area is what makes it both suitable habitat for wildlife and for our many uses and enjoyments. The diversity of plants and the diversity of wildlife that is sustained themselves keep a natural area both healthy and productive. Invasive plants can transform a natural landscape, reducing plant diversity and thereby destroying both wildlife habitat and our rich natural heritage.
An “invasive” plant species may be defined as an aggressive plant type that grows rapidly, reproduces greatly, and out-competes other plant species. Over time, invasive plant species can replace other plants, leading to a loss of plant diversity and, in some cases, a monoculture of one species. Most, but not all, invasive plants in our area are ‘exotic,’ or nonnative species.
An ‘exotic invasive’ plant species may be defined as a plant type that was introduced from a (usually) distant area, but that grows and reproduces well in the new area due to a combination of the following four factors:
1. Similarity in climate and growing conditions.
2. Innate adaptability of the plant to grow and reproduce within a wider range of growing conditions.
3. Absence of predators – either things that consume the plants or its seeds – in the new area.
4. Lack of competition from the native species which may have lesser tolerance and adaptability to grow and reproduce within the altered growing conditions that the exotic invasive itself creates.
We can follow the path and history of many exotic invasives from the date of their first introduction to our nation and trace their spread across the landscape. Some came here as hitchhikers or stowaways; for example, both Spotted Knapweed and Canada Thistle were accidentally introduced contaminants in imported hay and in agricultural seed. But many exotic invasive species were purposefully brought in and, in some cases, carefully nurtured. In broad terms, exotic invasive plants were introduced – and some continue to be planted – for three main reasons:
1. Garden ornamentals: plants introduced for color, or fragrance, or novelty. Japanese honeysuckle, for example, was first introduced as a “pretty ground cover.”
2. Problem solvers: plants introduced as easy solutions to complex problems. Kudzu was promoted as an easy solution for erosion control.
3. Benefit to wildlife: Bush and Japanese honeysuckles occasionally still are recommended as deer browse; Autumn Olive similarly was touted as a favored seed crop for wildlife.
Some exotic invasives initially were recommended for all three purposes – multiflora rose was supposed to be a pretty living hedge that would both control erosion and provide food for wildlife!
The supposed benefits of exotic invasives not only didn’t pan out, the unintended consequences of their introductions continue to do damage. In economic terms alone the cost of invasive plants in the United States now is estimated at more than $40 billion per year.
What can we do?
- Learn to identify invasive plants and remove them from your property.
- Don’t plant invasive plants – even if you live in an urban setting, birds can spread seeds far distances.
- Volunteer to assist with invasive plant removal.
- Pass the information on and tell friends, relatives, and neighbors about the problem.
For specific information about the *baddest of the bad” plant invasives in our bluff lands, and for information about control measures and techniques, please click on the links under this section’s menu in the top horizontal bar, or follow the links, here:
Doing Your Own Invasive Plant Control