The Potential Distribution of Zebra Mussels in the United States

Abstract

Biological invasions are the greatest threat to freshwater biodiversity worldwide (Sala et al. 2000, Lodge 2001). In the United States, the rapid invasion of aquatic ecosystems by zebra mussels (Dreissena polymorpha) has cost tens of millions of dollars (Deng 1996, Leung et al. 2002) and has caused declines in the richness and abundance of endemic unionid mussels, an important component of North American freshwater biodiversity (Griffiths et al. 1991, Williams et al. 1993, Schloesser and Nalepa 1994, Nalepa et al. 1996, Ricciardi et al. 1998). Two questions are crucial for effectively managing the ongoing zebra mussel invasion: Will zebra mussels continue to spread in North America, or do they already occupy most of their potential range? If they continue to spread, will the spread be to regions containing a highly diverse and endemic unionid fauna? Practical questions such as these about the control and management of zebra mussels require reliable, quantitative forecasts of their potential distribution in the United States.