A summary of the distribution of mussels in the St. Croix based on quantitative sampling completed by the Macalester team can be found here.
A map of the St. Croix
access to more of the data on mussels in the river can be found by
There are 41 species of native mussels in the St. Croix River as well as two species of introduced bivalves (zebra mussels and Asian clams).
There are two federally endangered species of mussels - the Higginsi Pearly Mussel (Lampsilis higginsii) and the winged mapleleaf (Quadrula fragosa). In addition there are a number of species listed as endangered or threatened in the states of Minnesota and Wisconsin.
There have been a number of qualitative and quantitative studies of the mussel assemblages of the St. Croix River. Much of the information has been summarize in:
Hornbach, D.J. 2001. Macrohabitat factors influencing the distribution and abundance of naiads in the St. Croix River, MN and WI, USA, pp. 213-230. In G. Bauer and W. Wächtler [eds] Ecology and Evolutionary Biology of the Freshwater Mussels Unionoidea. Ecological Studies Vol. 145 Springer Verlag: Berlin.
In this paper Hornbach has examined the factors which may help to explain the distribution of mussel species in the river. Click here for more information.
In addition Hornbach and researchers at Macalester College have been conducting quantitative studies of populations at 9 sites on the St. Croix River. The methods used can be examined by clicking here.