Following rigorous scientific reviews of the best available science, the U.S. Fish and Wildlife Service is proposing to list the longsolid and round hickorynut freshwater mussels, found in streams and rivers in the Eastern U.S., as threatened under the Endangered Species Act.
With today’s action, the Service is also proposing critical habitat and special rules under section 4(d) of the ESA that tailor protections for each species, along with economic analyses on the costs associated with critical habitat designation. The Service found a third eastern freshwater mussel, the purple lilliput, does not warrant ESA protection.
The ESA defines a threatened species as one that is likely to become at risk of extinction (endangered) in the foreseeable future throughout all or a significant portion of its range. ESA protections will benefit these species by raising greater awareness of the threats to them, inspiring conservation partnerships and generating resources on their behalf.
“With animals whose range is spread across several states, it can be hard for any single researcher or biologist to gain an understanding of the big picture,” said Regional Director Leo Miranda. “But that’s exactly what we did over the course of several months, developing the first comprehensive look at the status of these mussels and their plight. This laid the foundation for our decision.”
The Service reached out to species and habitat experts from state wildlife agencies and universities and other researchers. The Service’s assessments went through a rigorous peer-review process.
The Service has proposed rules under section 4(d) of the ESA for the longsolid and round hickorynut mussels. According to these rules, certain actions with a minimal level of disturbance and no anticipated long-term negative impacts to the species would be exempted from prohibitions. Those actions are species restoration efforts by the Service or state wildlife agencies, and stream channel and bank restoration projects for creation of natural, physically stable, ecologically functioning streams, taking into consideration connectivity with floodplain and groundwater aquifers.
Along with the proposal to list the two mussels, the Service proposes designating critical habitat for both species. Critical habitat is defined by the ESA as habitat that is essential to the conservation and recovery of the species. In designated critical habitat areas, federal agencies are required to consult with the Service when they work, fund or permit activities. Critical habitat does not affect private landowners unless they implement an action with such federal involvement. Additionally, it does not affect land ownership or establish a refuge, wilderness, reserve, preserve or other, nor does it allow the government or public to access private lands.
Many of the longsolid and round hickorynut mussel populations occur at sites occupied by other federally protected species with overlapping critical habitat, meaning only a minimal increase in regulatory burden as a result of these new designations.
The proposed critical habitat for the longsolid comprises 12 units, along a total 1,115 river miles, in Alabama, Kentucky, Pennsylvania, Tennessee, Virginia and West Virginia. Proposed critical habitat for round hickorynut comprises 14 units along a total of 921 river miles in Alabama, Indiana, Kentucky, Mississippi, Ohio, Pennsylvania, Tennessee and West Virginia. Eight of the proposed critical habit units for the longsolid and hickorynut overlap in part or whole. All proposed critical habitat for the species are currently occupied and considered essential to the conservation and recovery of the species.
Freshwater mussels are bellwethers of healthy streams and rivers, which support diverse wildlife, water resources and local communities. Freshwater mussels clean water as they feed, filtering their food from the water column, and with it, sediment and other pollutants. The United States is home to a tremendous diversity of freshwater mussels, with about 300 species, though 65% of those are imperiled.
The longsolid is a medium-sized mussel up to five inches long that can live up to 50 years. It prefers a mixture of sand, gravel and cobble stream bottoms and is currently found in small streams and large rivers, such as the Ohio River, in nine states of Alabama, Kentucky, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia. There are currently 60 known populations of the mussel, with 48 of those in poor condition. This is down from an historical high of 162 populations. The mussel has disappeared from Georgia, Indiana and Illinois.
The round hickorynut is a small- to medium-sized mussel up to three inches long, lives up to 15 years and prefers a mixture of sand, gravel and cobble stream bottoms. It is found in the Ohio River and small streams to large rivers in nine states of Alabama, Indiana, Kentucky, Michigan, Mississippi, Ohio, Pennsylvania, Tennessee and West Virginia. With a historical high of 297 known populations, 65 are currently known to exist today, and 45 of those are in poor condition. The mussel is no longer found in Georgia, Illinois or New York.
The longsolid and round hickorynut mussels have suffered from negative impacts commonly found in central and eastern U.S. streams, including habitat degradation and loss of habitat due to poorly managed agriculture and development, genetic isolation, and threats from invasive and non-native species.
The purple lilliput is a small mussel up to 1.5 inches long, with a thick shell, lives up to 12 years and prefers a mixture of sand, gravel, and cobble stream bottoms. It is found in the Tennessee River and small streams to large rivers in the nine states of Alabama, Arkansas, Illinois, Indiana, Kentucky, Michigan, Missouri, Ohio, and Tennessee. Historically there were 272 known populations, with 146 remaining today.
Although this mussel has disappeared from North Carolina and Georgia, and may have disappeared from Oklahoma and Virginia, more than 100 purple lilliput populations are expected to persist, scattered across all six major river basins where it is found for the next 20-30 years. Therefore, although the purple lilliput has declined, the Service found it does not meet the threshold for threatened or endangered under the ESA.