invasive species

invasive species - Jordan Anderson Causes ENVS 201 11/30/06...

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Jordan Anderson Causes ENVS 201 11/30/06 Research The New Zealand mudsnail, Potamopyrgus antipodarum was first discovered in the mid-Snake River, Idaho in the 1980's. It is now rapidly spreading throughout the western USA and has become established in rivers in 10 western states and three national parks. It is a parthenogenic livebearer with high reproductive potential. New Zealand mudsnails are non-native aquatic snails threatening Oregon's rivers, streams, and lakes by competing with native invertebrates and may cause fish populations to decline. Due to their small size and ability to live out of water for several days, mudsnails are expert hitchhikers and anglers and boaters may be unintentionally spreading these harmful snails to new waters around the state. The New Zealand mudsnail often reaches densities greater than 100,000/m² in suitable habitat and has been reported to approach densities as high as 750,000/m² in sections of rivers in Yellowstone National Park. Frequently, these mudsnails will comprise over 95% of the invertebrate biomass in a river. Its invasion has generated much concern about the potential effects it may have on native species, fisheries, and aquatic ecosystems in the western USA. Its spread into new systems is considered to be primarily human caused. Zebra Mussels, Dreissena polymorpha Zebra mussels are native to Eastern Europe and western Asia. Until the mid 1980s there were no zebra mussels in North America. Quickly that changed when they were inadvertently introduced into waters near the Great Lakes region. It is suspected that zebra mussels hitched a ride in ballast water tanks of commercial ships. Zebra Mussels were first discovered in the United States in Lake St. Clair near Detroit,
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invasive species - Jordan Anderson Causes ENVS 201 11/30/06...

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