|
An On-line Version of an Aquatic Plant Identification Manual for Washington's Freshwater Plants Non-native Invasive Aquatic Plants
|
|
 |
Non-native invasive species refer to plants that spread aggressively and are not native to Washington. All ecosystems, including aquatic systems, are susceptible to invasion by these plants. These invasions can lead to the loss of biological diversity by eliminating habitat for native plants, and can cause a wide variety of other impacts. Prolific growth of plants like Eurasian watermilfoil (Myriophyllum spicatum) can clog irrigation canals, hydroelectric systems, and navigation waterways. Flooding can occur due to obstructed drainage systems. Boating and swimming are impacted and become less desirable, and aesthetics of lakes are often impaired. Dense beds of plants alter water chemistry, temperature, and habitat structure; leading to changes in invertebrate and fish communities. Dense growth may also be a major source of organic matter to the waterbody, and decomposition of these plants may deplete dissolved oxygen. This may lead to problems with odor, color, and taste in the water. Depletion of dissolved oxygen may also cause fish kills. Lake margins are also vulnerable to invasion by non-native plants. Invasive species such as purple loosestrife (Lythrum salicaria) and reed canarygrass (Phalaris arundinaceae), may create large, single-species stands, which reduce diversity and eliminate natural sources of food and cover essential to wetland wildlife. Invasive species have been introduced into North America in a variety of ways. Purple loosestrife was sold as an ornamental landscaping plant. Plants that plague lakes include a number of species introduced by the aquarium industry, such as Brazilian elodea (Egeria densa) and hydrilla (Hydrilla verticillata). Because of their attractive flowers, gardeners and landscapers have planted water hyacinth (Eichornia crassipes) and white waterlily (Nymphaea odorata). Some aquatic species that are now considered to be undesirable were introduced for "restoration" purposes. The U.S. Department of Agriculture (USDA) has promoted invasive species, such as reed canarygrass (Phalaris arundinaceae), as soil binders and forage plants. Agricultural canals, drains, and irrigation systems have further spread aquatic invaders in the western United States. Once introduced into an area, invasive aquatic plants may spread from lake to lake on boats or be carried by birds or other animals. Call the Washington State Department of Ecology or your local Noxious Weed Control Board to report new populations or what appear to be new invasions or particularly thick growths of invasive aquatic species. |
|
|
|