This is a rare species found solely in North America's Atlantic coast streams and rivers of various sizes and moderate current.

In the southern portion of its range, it is often found buried under logs or root mats in shallow water (USFWS 1993), where in the northern portion of its range, it may be found in firm substrates of mixed sand, gravel or cobble, or embedded in clay banks in water depths of a few inches to greater than 20 feet (Fichtel and Smith 1995; Gabriel 1995; Gabriel 1996; Nedeau and Werle 2003; Nedeau 2004a, 2004b, 2006).

Michaelson and Neves (1995) documented the reproductive cycle of the dwarf wedgemussel from North Carolina and observed that this species spawns in late summer, becomes gravid in September, and releases glochidia in April.

The only known occurrence in New Brunswick, Canada (Petticodiac River) appears to be historic; no live mussels or spent shells were found during a 1997 survey (Hanson 1998).

The mainstem of the Connecticut River in New Hampshire and Vermont is considered to have the largest remaining dwarf wedgemussel population, consisting of three distinct stretches of sporadically occupied habitat segmented by hydroelectric dams.

In 2001, more than 25 dwarf wedgemussels and hundreds of other mussels (including state-listed species) were killed in the Mill River, Massachusetts, by waste run-off from a small farm.

Recently, severe flooding in the Baltimore and Neversink Rivers in Pennsylvania and New York, respectively, resulted in the destruction of occupied habitat and loss of dwarf wedgemussels.

Resurveys in 2005 of the two sites conducted after the flood event detected one fresh dead dwarf wedgemussel and no live mussels (Cole and White 2006).

Surveys in 2006 indicated that the dwarf wedgemussel population in the Neversink River was adversely affected by flood events, although some live mussels were detected.

In summary, it appears that the populations in North Carolina, Virginia, and Maryland are declining as evidenced by low densities, lack of reproduction, or inability to relocate any dwarf wedgemussels in follow-up surveys.