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Neosho Mucket and Rabbitsfoot Mussel
Questions and Answers
Proposed Listing Rule for Neosho Mucket and Rabbitsfoot and Proposed Designation of Critical Habitat
October 16, 2012
1. Which freshwater mussels are proposed for listing under the Endangered Species Act (ESA)?
The Neosho mucket (Lampsilis rafinesqueana) is proposed for listing as endangered. The rabbitsfoot (Quadrula cylindrica cylindrica) is proposed for listing as threatened.
2. What is a freshwater mussel?
Mussels are freshwater animals from the mollusk family, including clams, oysters, scallops, snails, slugs, and squid, as well as freshwater mussels.
Mussels generally live embedded in the bottom of rivers, streams, and other bodies of water. They siphon water into their shells and across four gills that are specialized for respiration and food collection. They primarily feed on disintegrated organic debris, algae, and bacteria. Adults are filter feeders, and generally orient themselves on or near the substrate's surface to take in food and oxygen from the water above them. Juveniles typically burrow completely beneath the substrate’s surface and are pedal (foot) feeders (bringing food particles inside the shell for ingestion that adhere to the foot while it is extended outside the shell) until the structures for filter feeding are more fully developed.
3. Where are they found?
The Neosho mucket is only found in eight rivers and creeks within the Arkansas River basin of Arkansas, Kansas, Missouri, and Oklahoma: the Illinois River in Arkansas; the Cottonwood, Verdigris, Fall, Neosho, and Spring Rivers in Kansas; the Spring, North Fork Spring, and Elk Rivers, and Shoal Creek in Missouri; and the Illinois River in Oklahoma.
The rabbitsfoot is found in 51 rivers and creeks in 13 states (Alabama, Arkansas, Illinois, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Ohio, Oklahoma, Pennsylvania, and Tennessee).
4. Why do they need protection under the ESA?
Both species have experienced a decline in range and population size. Survey data since 1985 shows a dramatic decline in historic ranges and population sizes for both species. Of the eight remaining stream populations of Neosho muckets, there is only one viable population, Spring River in Missouri. The rabbitsfoot still occurs in 36 percent of its historical range; however, its current range is fragmented, and its numbers appear to be declining. Eleven streams (22 percent of extant populations or 8 percent of the historical populations) within the rabbitsfoot's historic range are viable, 23 populations (45 percent of extant populations) are at risk of extirpation; and 17 populations (33 percent of extant populations) show limited recruitment with little evidence of sustainability. These populations are vulnerable and could disappear.
Threats to both the Neosho mucket and the rabbitsfoot include loss and degradation of stream and river habitat due to impoundments, channelization, chemical contaminants, mining, oil and natural gas development, and sedimentation.
5. What is critical habitat?
Critical habitat is defined in the ESA. It refers to specific geographic areas that are essential for the conservation of a threatened or endangered species and that may require special management consideration or protection. These areas are generally, but not necessarily, occupied by the species at the time of designation. Federal agencies are charged with ensuring their actions do not result in the destruction or adverse modification of designated critical habitat. The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area. It does not grant government or public access to private lands.
Critical habitat refers to physical and/or biological habitat features needed for life and successful reproduction of the species. These include, but are not limited to:
6. What physical and biological habitat features do these mussels require?
7. Why is the Service proposing critical habitat in addition to the listing of the mussels?
The ESA requires the Service to identify critical habitat at the time it determines a species should be protected.
8. What geographic areas are proposed as critical habitat?
The Service has proposed 43 critical habitat units totaling 3,441 river kilometers (2,138 river miles) of stream channel, in Alabama, Arkansas, Illinois, Indiana, Kansas, Kentucky, Mississippi, Missouri, Ohio, Oklahoma, Pennsylvania, and Tennessee, for these two mussel species.
9. How did the Service determine which areas to designate as critical habitat?
The Service reviewed the best scientific information available concerning the species’ present and historic range, habitat, biology, and potential threats, and determined that critical habitat is both prudent and determinable. Through this review, the Service identified those areas that contained the physical and biological features needed by these species, and that were necessary for their conservation.
10. Is the Service proposing to designate unoccupied habitat for these species?
All streams in the proposal are occupied by at least one of the species. The Service is not including areas where the species used to live (historical, or believed extant) as part of critical habitat. On the maps, the streams and rivers where these mussels live, and which are being proposed for critical habitat designation, are in bold.
11. Can areas be exempted or excluded from a critical habitat designation?
Yes. Military lands can be exempted from critical habitat designation. The ESA reads “The Secretary shall not designate as critical habitat any lands or other geographical areas owned or controlled by the Department of Defense, or designated for its use, that are subject to an integrated natural resources management plan prepared under section 101 of the Sikes Act (16 U.S.C. 670a), if the Secretary determines in writing that such plan provides a benefit to the species for which critical habitat is proposed for designation.” The ESA also allows for exclusions from critical habitat, provided that the benefits of the exclusion outweigh the benefits of inclusion, and that the exclusion will not result in the extinction of the species. Exclusions are possible for public and private lands that have secure, long-term conservation plans in place that benefit the mussels, and for economic reasons. The Service is not proposing to exclude any areas from this critical habitat designation.
12. What is the impact of designating critical habitat on private lands and private landowners?
The designation of critical habitat on private land has no impact on private landowner activities that do not require federal funding or permits. The designation of critical habitat is only applicable to federal activities.
13. What is the impact of designating critical habitat on federal agencies?
Even when there is no critical habitat designation, federal agencies must consult with the Service on actions that may affect listed species, in order to ensure that any action they carry out, fund, or authorize is not likely to jeopardize a listed species’ continued existence. Where critical habitat is designated, a consultation also ensures that the critical habitat is not destroyed or adversely modified.
14. What is destruction or adverse modification of critical habitat?
Destruction or adverse modification of designated critical habitat is defined in the Service's regulations as a “direct or indirect alteration that appreciably diminishes the value of the critical habitat for both the survival and recovery of a listed species” (50 CFR 402.02). Such alterations include, but are not limited to, adverse changes to the physical or biological features that were the basis for determining the habitat to be critical.
15. Will a critical habitat designation delay federal decisions on permits or funding?
Under the ESA, the Service has specific time frames in which to complete the consultation process with federal agencies. These time frames remain the same with or without designated critical habitat.
16. Does the ESA consider economic consequences as a part of designating critical habitat?
Yes. The ESA requires the Service to consider potential economic impacts of a critical habitat designation when determining whether to designate critical habitat. If the benefits of excluding an area outweigh the benefits of including it, the Service may exclude an area from critical habitat unless the exclusion would result in the extinction of the species.
17. What are the economic impacts associated with the critical habitat designation for these mussels?
The Service will conduct a draft economic analysis of the proposed critical habitat designation, as required under the ESA. The analysis will consider the potential impact of the designation on various sectors of the economy. Based on the best available information, including extensive discussions with stakeholders, the Service will estimate the costs associated with designation and publish a draft Economic Analysis in the Federal Register for public comment at later date.
18. How can I comment on this proposal?
(2) By hard copy: Submit by U.S. mail or hand-delivery to:
19. Who can I contact for more information regarding the proposed critical habitat designation for these two mussels?
U.S. Fish and Wildlife Service, Arkansas Field Office, 110 South Amity Road, Conway, Arkansas 72032, telephone 501-513-4481, or U.S. Fish and Wildlife Service, Also, please visit Docket # FWS-R4-2012-0031 on www.regulations.gov.
Last updated: September 21, 2016