Pisidium compressum is widespread in Canada and Alaska south of the tree line. It is found throughout the United States and extends into Mexico (Clarke, 1981). Next to
P. casertanum, it is the most common sphaeriid in North America (Mackie, 2007). It is widespread in British Columbia.
This species is most common in lotic environments (creeks and rivers), although it is also common in shallow areas of small and large lakes. It inhabits only perennial water bodies, usually with some current or wave action (Mackie, 2007). It has a preference for sandy bottoms with vegetation, and shallow water (Herrington, 1962), though Clarke (1973) found this species associated with all types of bottom deposit, with mud the most frequent.
Note Author: Ian Gardiner
