While most of us are aware of the things we commonly do that are harmful to the environment, few know that many people, unknowingly, harbor plants in their backyards that alter natural processes and reduce biodiversity. They’re called invasive plants, or non-native species, and they were brought to the United States from foreign countries for horticultural purposes.
In order to help the public identify invasive plants, Thacher Nature Center in Voorheesville conducts Invasive Sundays all summer long, from 9:15-11 a.m., in which visitors are given a tour of the invasive plants within and surrounding the park and taught how to practice removal techniques.
So what exactly are invasive plants, and why are they such a threat to the survival of our natural habitats?
According to the North Carolina Botanical Gardens at the University of North Carolina, at least 4,000 invasive plants have been brought to the United States, and most of them are not harmful. Yet their research also shows that 79 species of these plants that now grow wild throughout the country and are commonly purchased in nurseries and gardening centers have cost the U.S. economy more than $97 billion annually as a result of crop failure, efforts to save endangered species, and efforts to control and eliminate them.
Although they look innocent enough, and are often aesthetically pleasing, invasive plants often produce copious amounts of seeds, and have aggressive root systems that grow so densely that they smother the root systems of other plants.
Frequently things that are invasive tend to seed prodigiously, and whatever might have kept them in check in their old environment is not doing so in this new environment, said Laurel Tormey Cole, an expert on invasive plants who leads Invasive Sundays at the nature center. She noted that invasive plants are the No. 2 threat, besides habitat loss, to biodiversity in the world.
Most plant species have predators in their natural range that keep their population numbers balanced, but when a foreign plant is introduced to a new environment, it may lack those predators and outnumber other plants that are sources of food for birds, reptiles, and insects. This can result in the decline of wildlife in a given area, or the complete extinction of a species.
The major problem with invasive plants is that many people don’t know they exist, and have continued to plant or purchase them throughout the years.
Take for instance Japanese barberry, a spiny shrub that grows 2 to 8 feet, with pale yellow flowers and bright red berries.
It was first introduced to the United States through Russia in 1875 and first planted in New York City’s Botanical Garden and by settlers for hedgerows, dye and jam. However, in recent years, the plant, commonly found in people’s gardens for decorative purposes, has rapidly spread from people’s backyards into the wild rapidly. It forms dense stands in forests, woodlands, pastures and meadows, and alters soil pH, nitrogen levels, and biological activity in the soil.
Since there is currently no law in the state against selling invasive plants at nurseries, Japanese barberry is commonly purchased by landscapers and homeowners.
Sandy Brousseau, a greenhouse expert at Olsen’s Hardware and Gardening Center on New Scotland Road has been selling Japanese barberry for several years.
`A lot of times they end up taking over a habitat for our natives and become real pests,` she said.
Brousseau said she informs customers about the dangers of the plant, and supports a law against selling them.
`Somebody would have to do a plant-by-plant assessment, and some states should, because it’s not something you want being totally out of control,` she said.
Besides Japanese barberry, there are also several other invasive plants that crowd natural areas in the Capital District. The most prominent are purple loosestrife, spotted knapweed, multi-flora rose, common buckthorn, exotic bush honeysuckle and garlic mustard.
Detailed information and pictures of these plants can be found at the National Park Services Web site, www.nps.gov.
Tormey Cole, who works directly with The Invasive Plant Council, said there has been recent government concern about invasive plants, and discussion about banning the sale of such plants.
However, Tormey Cole said, placing enforcements on nurseries is not the best way to solve the problem.
` I understand that it’s really important to have the nursery industry on board, you can’t dictate externally,` she said. `It’s going to work much better to have them involved in the process.`
For information on invasive plants, visit the Invasive Plant Council’s Web site at www.ipcnys.org, or contact Tormey Cole at Thacher Nature Center 872-0800.
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