Our preliminary assessments suggested that current mussel distributions in North America appear to be associated with calcium concentrations in surface waters, said Whittier. Calcium is an important element used in the creation of the mussels shell and basic metabolic functioning.
Given the recent Dreissna incursion into western states and continued uncertainty regarding non-invaded areas in the East the authors developed and evaluated a national-scale map of Dreissena species invasion risk, based on calcium concentrations in streams and rivers. Their primary data were taken from several large-scale surveys made by the US Environmental Protection Agencys (EPA) Environmental Monitoring and Assessment Program. They also utilized data from the EPAs Wadeable Streams Assessment. The scientists then classified ecoregions into mussel invasion risk categories, from very low to high, based on calcium concentrations.
For the 48 contiguous states, regions comprising nearly 21 percent of land area were classified as very low risk or low risk. New England, most of the Southeast, and western portions of the Pacific Northwest fall into these categories.
High risk ecoregions comprised almost sixty percent of land areas. The majority of reported occurrences of Dreissena were in high-risk ecoregions.
There were a few exceptions, mostly in highly variable regions such as the Northern Lakes and Forests ecoregion, the Mississippi Alluvial Plain region, and Appalachian ecoregion.
One must take into account the entire ecology for the species. The case of the zebra mussels in Arkansas River in the very low risk areas, reflects the water source rather than the local conditions. The other key requirement for Dreissena in river systems is the presence of an invaded upstream lake or
|Contact: Annie Drinkard|
Ecological Society of America