Endangered Species
Mountain-Prairie Region
Meltwater Lednian Stonefly
Meltwater lednian stonefly
Photo by Joe Giersch

The meltwater lednian stonefly (Lednia tumana) is an aquatic insect in the order Plecoptera (stoneflies).  Stoneflies are primarily associated with clean, cool streams and rivers.  Juvenile meltwater lednian stoneflies are found in snow-melt runoff streams in high elevation, alpine and subalpine streams, most typically in locations closely linked to glacial runoff.  The species is generally restricted to streams with mean summer water temperature less than 10 degrees Celsius (oC) or 50 degrees Fahrenheit (oF).  The meltwater lednian stonefly is found in only a few locations within Glacier National Park, Montana. 

The lednian meltwater stonefly has three distinct life stages – the aquatic egg and nymph – and the terrestrial adults.  Stoneflies spend most of their lifespan in the egg and nymph forms and may complete their life cycles in a single year or in 2 to 3 years.  Adults are short-lived and emerge from the water to mate on vegetation along the stream by July or August.  The females then deposit their eggs in the stream.  The nymph is dark red-brown on its dorsal (top) surface and pink on the ventral (lower) surface, with light grey-green legs.  Mature nymphs range in size from 0.18 to 0.26 inches.  Adults are small also, ranging in size from 0.16 to 0.24 inches.

Recent Actions

August 18, 2009:  After an initial review of a petition submitted by the WildEarth Guardians, the Service determined that the Bearmouth mountainsnail, Byrne Resort mountainsnail, and meltwater lednian stonefly may be warranted for listing under the Endangered Species Act.  With that determination, the Service commenced status reviews for the three species.

Status Review Results

April 5, 2011:  The Service completed a 12-month status review of the meltwater lednian stonefly and determined that the meltwater lednian stonefly is warranted for listing, but is precluded by higher priority actions.  The species listing priority number (LPN) is 4, meaning the identified threats to the species are high in magnitude but the immediacy of the threats is non-imminent.

In the same 12-month finding, we also found that the Bearmouth and Byrne Resort mountainsnails do not warrant protection under the Act.  The Bearmouth mountainsnail and Byrne Resort mountainsnail are terrestrial mollusks commonly called “mountainsnails.”  Because these mountainsnails are not recognized as species by the scientific community, they are not listable entities as defined by the ESA.  Since we have concluded that the two petitioned mountainsnails are not listable entities, an analysis of threats is not required under the ESA.  Therefore, we will take no further action with these species at this time.

Last updated: April 28, 2011