Dismal Swamp Southeastern Shrew

Updated About encyclopedia.com content Print Article Share Article
views updated

Dismal Swamp Southeastern Shrew

Sorex longirostris fisheri

Status Threatened
Listed September 26, 1986
Delisted February 28, 2000
Family Soricidae (Shrews)
Description A tiny, brown, small mammal with a short, broad snout.
Habitat Boggy fields and lowlands forest.
Food Insects, larvae, worms.
Reproduction Litter size of four to ten.
Threats Limited numbers, habitat decline.
Range North Carolina, Virginia

Description

The Dismal Swamp southeastern shrew (Sorex longirostris fisheri ) is a long-tailed, mouse-like small mammal with a short, broad snout. It has a brown back, paler underparts, and buffy feet. This sub-species generally has a duller coat than its relative, Sorex longirostris longirostris, and is 15-25% larger, measuring about 4 in (10 cm) in total length.

Behavior

Little life history information is available, but this species is probably similar to other shrews, which are aggressive, nervous animals that burrow extensively, eat a wide variety of plant matter and insects, and do not hibernate. Shrews breed early in the year; litter size is four to ten, and gestation is 18-22 days. Young are independent in about three weeks.

Habitat

The Dismal Swamp southeastern shrew lives in a variety of habitats, from boggy fields to mature, lowland pine and deciduous forests, but is most abundant in cane stands, regenerating clearcuts, and 10- to 15-year-old forested plots.

The historic Dismal Swamp, a forested wetland community, is characterized by substantial winter flooding, variable soils including deep organic layers, and a mosaic of habitat types. In general, highest densities of Dismal Swamp southeastern shrews are observed in early successional stage habitats, and lowest densities in mature forests. Despite supporting lower densities, mature forests are likely important to the survival of these shrews during periods of drought or fire.

Distribution

Around the beginning of the twentieth century, the Dismal Swamp (more accurately described as a forested peat bog) occupied some 2,200 sq mi (6,000 sq km). Even at that time, its size had been reduced by clearing, draining for agriculture, and construction of the Dismal Swamp Canal in the early nineteenth century. The Dismal Swamp once extended from Nansemond and Norfolk counties, Virginia, south into Camden, Currituck, Gates, Pasquotank, and Perquimans counties, North Carolina. Today, only about 328 sq mi (850 sq km) of the original bog remain.

Until recently, the Dismal Swamp southeastern shrew was thought to be restricted to the Great Dismal Swamp National Wildlife Refuge in southeastern Virginia. However, studies since 1995 found that the shrew occurs more widely in North Carolina and perhaps South Carolina, and is relatively abundant in a wide range of habitats.

Threats

In the Great Dismal Swamp this small mammal is threatened because of its limited distribution and ongoing habitat changes in the swamp. Drying of habitat has diminished the range of this lowland shrew and favored expansion by the more plentiful upland subspecies. The swamp-bound subspecies is at a distinct disadvantage when competing outside the swamp, just as its upland relative is handicapped inside the swamp.

Naturally occurring fires were curtailed with the establishment of the Great Dismal Swamp National Wildlife Refuge in 1973. As a consequence, the Dismal Swampformerly a mosaic of bald cypress, Atlantic white cedar, and more open patches of canehas been replaced by a more homogeneous red maple and black gum forest to the detriment of the Dismal Swamp southeastern shrew.

The Dismal Swamp southeastern shrew also occurs widely beyond the Great Dismal Swamp, and many of these habitats are not at great risk.

Conservation and Recovery

The U. S. Fish and Wildlife Service (FWS) published a Recovery Plan for the Dismal Swamp southeastern shrew in 1995. Various actions were listed to conserve the rare shrew and protect its critical habitat. However, subsequent field studies found that the shrew is more widely distributed than previously believed, is fairly abundant within that range, occurs in a wide variety of habitats, and is genetically secure. Based on that new information, the FWS delisted the Dismal Swamp southeastern shrew in 2000.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
300 Westgate Center Dr.
Hadley, Massachusetts 01035-9589
Telephone: (413) 253-8200
Fax: (413) 253-8308
http://www.northeast.fws.gov/

References

Handley, C. O., Jr. 1979. "Mammals of the Dismal Swamp: A Historical Account." In P. W. Kirk, Jr., ed., The Great Dismal Swamp. University Press of Virginia, Charlottesville.