Invasive Species Week 2017 runs from July 9 through 15. An invasive species is any plant that is not native to our area, but has been introduced, either intentionally or unintentionally.

It grows or reproduces aggressively in an area, establishing itself at the expense of native species by out-competing for available water, nutrients and space. They have the potential to alter the ecosystem in their favor and crowd out other species of plants.

Keep in mind that an ecosystem depends on a great number of factors to remain in balance. Predators, parasites, herbivores, diseases and other organisms competing for the same resources limit the number of organisms that are able to survive in a given area. A nonnative plant may not be subject to the same limiting factors. Perhaps it is not affected by the same diseases, or there are no predators or parasites that menace it. The potential exists for the nonnative to out-compete the native for limited resources, and impair the growth of the existing plants.

A native plant is one that occurs naturally in the ecosystem. It is indigenous to the area; originated there, is growing and living naturally. A nonnative, or exotic, plant is one that does not occur naturally in the ecosystem.

Most exotic species introduced into the ecosystem do not become invasive. They are simply living outside their native range of distribution. Most have no effect at all on the ecosystem, and others can be beneficial. Of the 50,000 nonnative species in the United States, only 4,300 are considered invasive. Many nonnatives have become part of our environment, diet and culture. It is thought that 98 percent of the food we raise in the United States is attributable to nonnative crops and livestock.

Ornamental landscape plants, shrubs and trees have been introduced over hundreds of years either for their beauty, connection to ones homeland or economic reasons. Some escape cultivated control and are able to thrive and reproduce on their own. Purple loosestrife, an attractive, brightly colored plant that blooms from late June through August, was introduced to eastern North America in the early to mid-1800s and was available in nurseries in the not too distant past. It is now altering our wetlands. It can tolerate most any moist site, a wide range of environmental conditions, likes all kinds of soil and has no natural predators, be they disease or insect, on this continent. It clearly can out-compete native vegetation.

As an invasive species it replaces native plants, eliminating food, nesting and shelter areas for our wildlife. If wildlife populations are displaced, some may be lost to lack of habitat. Loss of habitat affects fish spawning and waterfowl, which affect recreational values of wetlands, which hurts the economy. This cascade effect is the real danger of an invasive species. It stopped being about a purple flower in moist soil when it began to spread on its own.

If you would like more information on invasive species in the North Country, contact us. We are also available to do presentations for your organization or neighborhood. As always, there is no charge.

Jolene Wallace is the consumer horticulture educator for Cornell Cooperative Extension in Clinton County. Contact her at 561-7450 or jmw442@cornell.edu.

Original post:

Effect of invasives on the ecosystem - Plattsburgh Press Republican