They arrive silently and without warning, stowed away in the ballast of commercial ships, or hidden among recreational fishing gear. Some escape from homes and laboratories to make their way into nearby forests and waterways. Others are freed intentionally by people who are tired of caring for them. Many already live among us, spreading viruses and other pathogens wherever they travel.
Invasion of the Grand River Watershed
These invaders have infiltrated much of the United States, including the Grand River Watershed in northeast Ohio, but they are not terrorists or people carrying exotic diseases. They are invasive species -- nonnative plants, animals and pathogens that enter an ecosystem and harm the environment, economy or human health.
Like most areas of the country, the Grand River Watershed is susceptible to invasive species carried into the region by people, or spread naturally over time from adjacent areas. The watershed covers approximately 712 square miles, an area that is drained by the 98-mile Grand River, which flows from Geauga County in Ohio to Lake Erie, east of Cleveland. The river is a designated State Wild and Scenic River, and is home to countless species of plants and animals, including 60 species of rare plants.
Negative Impact of Invasive Species
Not all nonnative -- or alien -- species cause damage. Some live peacefully within an ecosystem, kept in check by the environmental conditions, or other native plants and animals. Sometimes, though, these alien species grow out of control and upset the delicate balance of the existing ecosystem.
When this happens, they can crowd out native plants and animals, or interfere with the natural services provided by the ecosystem -- such as filtering the air and water, or mitigating flood damage. According to the Nature Conservancy, invasive species cost the United States economy $120 billion a year, and negatively impact 42% of the threatened and endangered species in the country.
In Ohio, 700-800 plant species are not native to the state. Fewer -- including approximately 60 plant species -- are considered invasive, meaning they negatively affect forests, parks and wildlife areas.
Some of the most common invasive plants in Ohio are:
- autumn-olive
- buckthorns
- common reed grass
- Japanese honeysuckle and knotweed
- purple loosestrife.
Non-plant invasive species include:
- chestnut blight
- emerald ash borer
- Dutch elm disease
- zebra mussel.
Protecting the Grand River Watershed
Because of the enormous impact that invasive species have on both the environment and economy, state and federal government agencies have dedicated resources to preventing the introduction and limiting the spread of harmful nonnative plants and animals in Ohio.
Conservation groups -- such as the Nature Conservancy and the Western Reserve Land Conservancy -- and citizen volunteers also play an important role in reducing the harm caused by invasive species in the Grand River Watershed. Battling invasive species, however, requires multiple lines of attack.
Waterway, Wetland and Forest Cleanup:
Herbicides and controlled burns are used to remove invasive plant species. In addition, volunteers often physically remove invasive plants during river and wetland clean-up projects in the Grand River Watershed.
Certain invasive animals -- such as mammals -- can be trapped by professionals and relocated to their original habitat range. Aquatic species, such as the zebra mussel, however, are more challenging to remove physically.
Research:
Government and conservancy groups conduct research on the best methods for removing invasive species and reintroducing native species that have been pushed out of the ecosystem. They also work to identify the source of the nonnative species in the Grand River watershed.
“Preliminary studies have shown that if we treat these areas and remove the invasives, the seed banks are rich enough to allow native plants to come back,” said James Cole, bird conservation manager for the Nature Conservancy.
Education:
Educating the public about the impact of invasive species in the Grand River Watershed is time well spent. Many invasive species, especially plants and aquatic animals, come from private gardens or aquariums.
Ohio government and nonprofit organizations publish lists of invasive species. This enables people to easily identify invasive species when they come across them on their property, or to avoid buying them in the first place. In addition, these groups provide lists of native plants that work as alternatives to the invasive species.
While the battle with noninvasive species in the Grand River Watershed is far from over, efforts by government and nonprofit organizations will mitigate the damage done by invasive species, and help preserve will the unique ecosystems of the Grand River Watershed.
Sources
Defenders of Wildlife. “Ohio: Invasive Species.” Accessed October 25, 2011. http://www.defenders.org/programs_and_policy/science_and_economics/invasives/invasives_by_state/ohio_invasive_species.php
Environmental Protection Agency. “Pathways for Invasive Species Introduction.” Accessed October 25, 2011. http://water.epa.gov/type/oceb/habitat/pathways.cfm
Nature Conservancy. “Protecting Native Plants and Animals. Taking on the Invaders of Ohio.” Accessed October 25, 2011. http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/ohio/howwework/invasive-species-protecting-native-plants-and-animals.xml
Nature Conservancy. “Taking on Invasive Species to Save Lake Erie.” Accessed October 25, 2011. http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/ohio/newsroom/the-nature-conservancy-in-ohio-taking-on-invasive-species-to-save-lake.xml
Ohio Department of Natural Resources. “Invasive Plants of Ohio.” Accessed October 25, 2011. http://www.dnr.state.oh.us/tabid/2005/Default.aspx
Ohio Department of Natural Resources. “Ohio's Invasive Non-Native Plants.” Accessed October 25, 2011. http://ohiodnr.com/tabid/2007/Default.aspx
United States Department of Agriculture. “Definition of Invasive Species?” Accessed October 25, 2011. http://www.invasivespecies.org/resources/DefineIS.html
Western Reserve Land Conservancy. “Land conservancies will join forces.” Accessed October 25, 2011. http://www.wrlandconservancy.org/news-2009-08-25.htm
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