Endangered and Threatened Wildlife and Plants; Delisting of the
Dismal Swamp Southeastern Shrew (Sorex longirostris fisheri
[Federal Register: February 28, 2000 (Volume 65, Number 39)]
[Rules and Regulations]
[Page 10420-10426]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28fe00-15]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
RIN 1018-AF00
Endangered and Threatened Wildlife and Plants; Delisting of the
Dismal Swamp Southeastern Shrew (Sorex longirostris fisheri
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Final rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service, remove the Dismal
Swamp southeastern shrew (Sorex longirostris fisheri Merriam) from the
List of Endangered and Threatened Wildlife. The Dismal Swamp
southeastern shrew was listed as a threatened species in 1986 under the
Endangered Species Act of 1973, as amended (Act). New data confirm that
this species is more widely distributed than previously believed, is
fairly abundant within its range, occurs in a wide variety of habitats,
and is genetically secure. We conclude that the data supporting the
original classification were incomplete and that the new data confirm
that removing the Dismal Swamp southeastern shrew from the List of
Endangered and Threatened Wildlife is warranted.
EFFECTIVE DATE: February 28, 2000.
ADDRESSES: The complete file for this rule is available for public
inspection, by appointment, during normal business hours at the
Virginia Field Office, U.S. Fish and Wildlife Service, P.O. Box 99,
6669 Short Lane, Gloucester, VA 23061.
FOR FURTHER INFORMATION CONTACT: Cynthia A. Schulz at the above
address, telephone 804/693-6694, extension 127, or facsimile 804/693-
9032.
SUPPLEMENTARY INFORMATION:
[[Page 10421]]
Background
The Dismal Swamp southeastern shrew is a small, long-tailed shrew
with a brown back, slightly paler underparts, buffy feet, and a
relatively short, broad nose (Handley 1979a). It weighs 3 to 5 grams
and measures up to 10 centimeters in length. The species was first
described as Sorex fisheri by C.H. Merriam (Merriam 1895). Merriam's
description was based on four specimens trapped near Lake Drummond,
Virginia, by A.K. Fisher of the U.S. Department of Agriculture's Bureau
of Biological Surveys. Rhoads and Young (1897) captured a specimen in
Chapanoke, Perquimans County, North Carolina, that seemed intermediate
between S. fisheri and the southeastern shrew (Sorex longirostris
Bachman) (Handley 1979b). Jackson (1928) subsequently reduced S.
fisheri to a subspecies of S. longirostris. Three subspecies of
southeastern shrew are now recognized--Sorex longirostris eionis, which
occurs in the northern two-thirds of peninsular Florida (Jones et al.
1991); S. l. fisheri, which occurs in southeastern Virginia and eastern
North Carolina; and S. l. longirostris, which occurs in the rest of the
range that extends through eastern Louisiana, eastern Oklahoma, and
Missouri, then eastward through central Illinois and Indiana, southern
Ohio, and Maryland. Jones et al. (1991) examined the taxonomic status
of these three subspecies and verified substantial size differences.
Jones et al. (1991) found that S. l. eionis was significantly larger in
four cranial measurements when compared with the other two subspecies;
S. l. fisheri was significantly larger in one cranial and one external
measurement; and S. l. longirostris had a relatively short palate and
rostrum, narrow skull, and short foot and tail. This study confirmed
the subspecific status of S. l. fisheri.
Apart from a litter of five young found in a nest in the Dismal
Swamp in 1905, little is known about reproduction or other life history
features of Sorex longirostris fisheri (Handley 1979b). However, more
is known about the life history of other Sorex species, and this
information may apply to S. l. fisheri. Sorex longirostris reproduces
from March through October, and two litters are likely born each year,
with one to six young produced per litter (Webster et al. 1985). Nests
are shallow depressions lined with dried leaves and grasses and are
usually associated with rotting logs (Webster et al. 1985). Young
shrews grow rapidly and are almost adult size when they leave the nest
(Jackson 1928). Sorex longirostris forage on spiders, crickets,
butterfly and moth larvae, slugs, snails, beetles, centipedes, and
vegetation (Webster et al. 1985, Whitaker and Mumford 1972). Little
information is available about the daily activity patterns of S.
longirostris. They forage intermittently throughout the day and night
in all seasons, seem to be most active after rains and during periods
of high humidity, and do much of their foraging in the leaf litter or
in tunnels in the upper layers of the soil (Jackson 1928).
The Dismal Swamp, the type locality for Sorex longirostris fisheri,
is a forested wetland with a mosaic of habitat types located in
southeastern Virginia and adjacent North Carolina. Within the Dismal
Swamp, S. l. fisheri has been found in a variety of habitat types,
including recent clearcuts, regenerating forests, young pine
plantations, grassy and brushy roadsides, young forests with shrubs and
saplings, and mature pine and deciduous forests (Padgett 1991, Rose
1983). Sorex longirostris fisheri has also been collected in utility
line rights-of-way. The highest densities of S. l. fisheri occur in
early successional stage habitats and the lowest densities in mature
forests (Everton 1985), although mature forests are likely to be
important to the survival of the shrew during periods of drought or
fire. Densities of southeastern shrews in early successional stage
habitats are 10 to 30 per hectare (Rose 1995).
Until recently, the distribution of Sorex longirostris fisheri was
considered coincidental with the historical boundaries of the Dismal
Swamp (Handley 1979a, Hall 1981, Rose 1983). After collection of the
original type series, additional S. l. fisheri specimens were collected
from similar habitats in the Dismal Swamp between 1895 and 1902. Prior
to 1980, only 20 specimens of S. l. fisheri were known. In 1980, 15 S.
longirostris fisheri were collected in pitfall traps in Suffolk,
Virginia, from the northwest section of the Great Dismal Swamp National
Wildlife Refuge (Refuge) located in North Carolina and Virginia (Rose
1981).
From December 1980 through July 1982, researchers established 37
pitfall grids in Currituck and Gates Counties, North Carolina and the
Cities of Chesapeake, Suffolk, and Virginia Beach and Isle of Wight and
Surry Counties, Virginia (Rose 1983). This trapping produced 24
specimens from 10 populations classified as Sorex longirostris fisheri,
62 specimens from 9 populations classified as intergrades, and 30
specimens from 7 populations classified as S. l. longirostris. Three
grids each contained one specimen classified as S. l. longirostris,
while the remaining specimens were classified as S. l. fisheri. Rose
(1983) determined that S. l. fisheri was associated with the Dismal
Swamp proper, except for a population north of the Refuge and another
population east of the Refuge. A narrow zone of hybridization (these
populations contained specimens that represent the parent stocks and
individuals that may be hybrids) was found to border the Dismal Swamp
running approximately north/south along its western edge and running
northwest/southeast adjacent to the southeastern corner of the Refuge.
Sorex longirostris longirostris was found to the east and west of the
Dismal Swamp with distinctive populations of S. l. longirostris
occurring within 20 miles of the Dismal Swamp border (Rose 1983). The
results of this analysis indicated that the largest Sorex were located
within the Refuge and the smallest Sorex were located at greater
distances from the Refuge, with specimens of intermediate size on the
margins of the Refuge. This finding suggested that interbreeding of the
two subspecies might be occurring, particularly at the margins of the
Refuge. Rose (1983) tentatively recommended that S. l. fisheri be
listed as threatened primarily because of the potential for contact and
interbreeding with S. l. longirostris. ``If widespread, this
interbreeding can result in an alteration of the gene pools of both
subspecies in the zone of contact, and the integrity of both subspecies
may be lost in the extreme'' (Rose 1983).
Additional study of Sorex was conducted from October 1986 through
June 1989, focusing within the Refuge but also including outlying areas
of the historical Dismal Swamp (Padgett 1991). Particular emphasis was
placed on determining whether the nominate subspecies might be
expanding into the remaining Dismal Swamp proper and interbreeding with
Sorex longirostris fisheri. Padgett's (1991) study indicated that S. l.
fisheri was restricted to the historic Dismal Swamp and that no strong
evidence existed that S. l. longirostris was using roadways to enter
the interior of the Refuge. Between 1989 and 1991, Erdle and Pagels
(1991) collected shrews to further delineate the distributions of S. l.
fisheri and S. l. longirostris in Virginia. Sampling was conducted in
much of the historic Dismal Swamp east of the Refuge and north of the
Virginia-North Carolina State line. Shrews referable to both taxa and
intergrades were represented in the 26 Sorex trapped. These findings
supported the hypothesis that S. l.
[[Page 10422]]
longirostris might be moving into areas of the historical Dismal Swamp.
During the 1990s, many additional areas were surveyed within the
historical Dismal Swamp in Virginia; the specimens found were referable
to S. l. fisheri or S. l. longirostris or were of intermediate size.
Although researchers had significant information on the
distribution of Sorex longirostris fisheri in Virginia, knowledge of
the species in North Carolina was sparse. In the early 1980s, D.W.
Webster from the University of North Carolina-Wilmington collected
Sorex longirostris from southeastern North Carolina (D.W. Webster,
pers. comm. 1997). Using the existing range maps for S. longirostris,
Webster determined the specimens were S. l. longirostris. In the late
1980s, Webster collected S. longirostris from Beaufort County, North
Carolina and realized that those specimens looked the same as those
collected from southeastern North Carolina. Still using the existing
range maps (Webster, pers. comm. 1997), assumed these specimens were S.
l. longirostris. Webster (1992) summarized historical locations of S.
l. fisheri in North Carolina, indicating collection of S. l. fisheri
from Camden, Currituck, and Gates Counties, and that S. l. fisheri
probably inhabits parts of Chowan, Pasquotank, and Perquimans Counties.
Webster continued to collect shrews from coastal North Carolina
throughout the early 1990s (D.W. Webster, pers. comm. 1997).
In January 1994, Webster visited the Smithsonian's National Museum
of Natural History and compared his specimens, collected from
southeastern North Carolina and Beaufort and Gates Counties, North
Carolina, to the specimens at the Smithsonian. He realized that his
specimens were of the same size as the voucher specimen for Sorex
longirostris fisheri from Lake Drummond, the type locality. Charles O.
Handley, at the time curator of mammals for the museum, agreed with
Webster that these shrews were referable to S. l. fisheri based on
size. Based on that information, Webster hypothesized that the
``dividing line'' between S. l. fisheri and S. l. longirostris may be
somewhere between Wilmington, North Carolina and Charleston, South
Carolina.
In May 1994, Webster visited the North Carolina State Museum of
Natural Sciences and found a series of relatively large Sorex
longirostris (not identified to subspecies) from Croatan National
Forest (Jones, Craven, and Carteret Counties) in North Carolina (U.S.
Fish and Wildlife Service 1995). He presumed that this series of shrews
was S. l. fisheri based on his trip to the Smithsonian (D.W. Webster,
pers. comm. 1997). The State museum also had specimens of southeastern
shrews from Chowan, Bladen, and Brunswick Counties that Webster assumed
were S. l. fisheri (D.W. Webster, pers. comm. 1997). In May and June
1994, Webster collected S. longirostris near the town of Warsaw in
Duplin County, midway between Wilmington and Raleigh, North Carolina.
He determined that these specimens were referable to S. l. fisheri
(D.W. Webster, pers. comm. 1997).
Webster et al. (1996a, 1996b) compared Sorex longirostris specimens
from east-central and southeastern North Carolina to specimens from the
Dismal Swamp. They also examined specimens from Charleston County,
South Carolina (near the type locality for S. l. longirostris), and
Citrus County, Florida (the type locality for S. l. eionis), and
representative samples of S. longirostris from throughout the
southeastern United States. They concluded that S. l. fisheri is much
more widespread and ubiquitous than previously believed. Webster's
group undertook an analysis of physical characteristics to better
delineate the geographic distribution of S. l. fisheri in Virginia and
North Carolina. This analysis used 626 S. longirostris from the
southeastern United States (15 from Florida, 375 from North Carolina,
159 from Virginia, and the remaining 77 from Alabama, the District of
Columbia, Indiana, Kentucky, Maryland, Mississippi, Missouri, South
Carolina, and Tennessee). The analysis included six cranial
measurements, palatal length, and braincase length. If available from
specimen tags, the total specimen length, tail length, hind foot
length, and weight were also used. Head and body length or the
difference between total length and tail length were determined where
possible. Significant geographic variation occured in all cranial
measurements; samples from southeastern Virginia, eastern North
Carolina, and southern Georgia and Florida had much larger cranial
characteristics than samples from elsewhere in the range. The
significant geographic variation in external measurements and weight
typically followed the same pattern. A two-dimensional plot of the
samples formed three clusters: (1) shrews from Georgia and Florida that
have longer and overall much wider crania; (2) shrews from southeastern
Virginia and eastern North Carolina that have longer crania with
relatively narrower rostra; and (3) shrews from elsewhere in the range
that were smaller in all cranial measurements. This plot explained 93.2
percent of the total morphometric variation exhibited in S.
longirostris crania. Shrews from the piedmont and mountains of Virginia
and North Carolina were more similar to specimens from the Mississippi
and Ohio River basins than they were to those from the mid-Atlantic
coast.
Webster et al. (1996a, 1996b) established 84 survey sites in a wide
range of habitats throughout North Carolina and Virginia to ensure that
both Sorex longirostris longirostris and S. l. fisheri would be
captured. Of the 84 sites, 49 (58.3 percent) were located in abandoned
fields and powerline rights-of-way that were dominated by herbaceous
vegetation typical of early stages of succession. The other 35 sites
(41.7 percent) were dominated by arborescent vegetation, including such
forest types as longleaf pine/turkey oak, pocosin/bay, Atlantic white
cedar, shortleaf pine, riparian hardwood, and cove hardwood. The
researchers collected 18 species of small mammals, and S. longirostris
was the most abundant and ubiquitous. The researchers divided survey
sites into two groups, those occurring in the newly delineated range of
S. l. fisheri and those occuring in the newly delineated range of S. l.
longirostris. Within each the results were similar. Within its
geographic distribution, S. l. fisheri was the most abundant small
mammal, or shared that distinction with other species at 31 of the 84
sites sampled. Sorex longirostris fisheri was especially abundant in
forested habitats in and adjacent to the Refuge, comprising 84 percent
of the specimens taken. The only habitat sampled where S. l. fisheri
was absent was xeric longleaf pine/turkey oak. Both taxa were found in
a wide range of habitat types and moisture regimes, from early
successional to mature second-growth forest and from well-drained
uplands to seasonally inundated wetlands. Webster (1996a, 1996b)
concluded that ``* * *even the smallest specimens from relatively dry,
upland sites in the Dismal Swamp region clearly are assignable to S. l.
fisheri.''
Gurshaw (1996) examined allozyme variability in specimens of the
southeastern shrew from North Carolina and Virginia to identify
characters that differentiate Sorex longirostris fisheri and S. l.
longirostris and to determine if there are similarities between shrews
from the Dismal Swamp region and the coastal plain of southeastern
North Carolina. She found that shrews from the coastal plain of
southeastern North Carolina grouped most closely with those from the
Dismal Swamp. The
[[Page 10423]]
author found an allele in the shrews from the coastal plain that
represents a genetic distinction from S. l. longirostris. Distribution
of this allele appeared to follow the Fall Line, the boundary between
the piedmont plateau and upper coastal plain in the southeastern United
States.
Webster et al. (1996a, 1996b) concluded that Sorex longirostris
fisheri ``* * * has a much broader geographic distribution than
previously believed, extending from southeastern Virginia to
southeastern North Carolina along the outer coastal plain. In Virginia,
all specimens examined from Isle of Wight County, the City of
Chesapeake, and the City of Virginia Beach are referable to S. l.
fisheri, whereas those from Surry, Sussex, and Southampton Counties are
assignable to S. l. longirostris. In North Carolina, S. l. fisheri is
distributed throughout the coastal counties as far south as New
Hanover, Brunswick, and Columbus Counties.'' Since the conclusion of
that study, S. l. fisheri has been documented in Hyde County, North
Carolina (D.W. Webster, pers. comm. 1997). No trapping for S.
longirostris has been conducted in Onslow, Martin, Pamlico, or Burtie
Counties, North Carolina (D.W. Webster, pers. comm. 1997). Webster
(pers. comm. 1997) does not have any records of S. l. fisheri from
Pasquotank County, although surveys were conducted there in 1995. At
the time of listing, Pasquotank County was listed as a county of
occurrence for S. l. fisheri, however, the literature cited does not
support this designation.
At the time of listing, Sorex longirostris fisheri was believed to
occur in only two cities in Virginia and four counties in North
Carolina. Sorex longirostris fisheri is now known to occur in Beaufort,
Bladen, Brunswick, Camden, Carteret, Chowan, Columbus, Craven,
Currituck, Dare, Duplin, Gates, Greene, Hyde, Jones, Lenoir, New
Hanover, Pender, Perquimans, Robeson, Scotland, Tyrrell, and Washington
Counties in North Carolina and Chesapeake, Suffolk, and Virginia Beach
Cities and Isle of Wight County in Virginia. Information gaps still
exist in the distribution of S. l. fisheri in North Carolina and
potentially South Carolina. Jones et al. (1991) noted a sample of Sorex
specimens from coastal South Carolina that appeared to be similar to S.
l. fisheri, but substantiation is needed regarding the taxonomy of
these specimens.
Previous Federal Action
On December 30, 1982, in our Review of Vertebrate Wildlife for
Listing as Endangered or Threatened Species (47 FR 58454), we
designated the Dismal Swamp southeastern shrew as a category 2
candidate species, meaning that a proposal to list the subspecies as
threatened or endangered was possibly appropriate, but that substantial
biological data were not available at that time to support such a
proposal. Rose (1981, 1983) and Everton (1985) conducted pre-listing
status surveys that documented large shrews within the Refuge, small
shrews outside the Refuge, and intermediate-sized shrews near the
Refuge boundaries.
On July 16, 1985, we published a proposed rule to list the Dismal
Swamp southeastern shrew as a threatened species (50 FR 28821). The
final rule to list the species was published in the Federal Register on
September 26, 1986 (51 FR 34422), and became effective on October 27,
1986. The reasons for listing the Dismal Swamp southeastern shrew were
habitat loss and alteration and possible loss of genetic integrity
through interbreeding with S. l. longirostris.
In the early 1990s, a group of biologists from Virginia held
meetings to discuss information and issues related to the recovery of
the Dismal Swamp southeastern shrew. Initially, most of the effort was
focused in Virginia because of the development pressure occurring
there. In 1992, biologists from North Carolina were included in the
group. The Service then convened an official recovery team, and held
the first meeting in February 1993.
The recovery team completed a draft recovery plan in July 1994, and
we published a notice of availability for the plan in the Federal
Register (59 FR 37260). The recovery plan was finalized on September 9,
1994, and updated on June 13, 1995.
In March 1995, based on questions raised by D.W. Webster about the
shrew's distribution and taxonomy, the Virginia Department of Game and
Inland Fisheries and the Service funded studies to determine if large
shrews are distributed from the Dismal Swamp region southward
throughout the coastal plain of North Carolina, and if the large shrews
from coastal North Carolina are similar to S. l. fisheri from near the
type locality. A combination of morphometric and genetic analyses was
proposed to answer these questions. The results of the morphological
and genetic analyses that followed are discussed in detail in the
Background section of this rule.
In May 1996, we received reports on morphometric variation among
the three Sorex longirostris subspecies (Webster et al. 1996a) and
protein electrophoresis and allozymic variation between S. l. fisher
and S. l. longirostris (Gurshaw 1996) and sent this information to the
recovery team members. The recovery team convened in June 1996 to
discuss the two reports. The consensus of the team was that the results
of both the morphological and genetic analyses conclusively show that
S. l. fisheri is widely distributed along the coastal plain of
southeastern Virginia and eastern North Carolina at least as far south
as Wilmington, North Carolina; that S. l. fisheri uses a wide variety
of habitat types; and that S. l. fisheri is not in danger of genetic
swamping by S. l. longirostris. However, the team agreed that the
reports should undergo independent peer review before further action
was taken and sent them to reviewers in June 1996. Reviewers who
responded concurred with the conclusions of the authors and supported
delisting. Based on comments provided by recovery team members, the
Service, and peer reviewers, the original manuscripts were revised
(Moncrief 1996, Webster et al. 1996b).
Federal involvement with the Dismal Swamp southeastern shrew after
listing has included surveys for new locations and informal and formal
consultations under section 7 of the Act for activities involving a
Federal action occurring in suitable habitat within the historical
Dismal Swamp. No biological opinion reflecting a conclusion that a
project could result in the extinction of this species has ever been
issued.
We published a proposed rule to remove the shrew from the List of
Endangered and Threatened Wildlife in the Federal Register on October
21, 1998 (63 FR 56128).
Summary of Comments and Recommendations
In the October 21, 1998, proposed rule (63 FR 56128) and associated
notifications, we invited all interested parties to submit factual
reports or information that might contribute to the development of a
final rule. We also contacted appropriate State and Federal agencies,
county governments, scientific organizations, members of the recovery
team, and other interested parties and asked them to comment. We
published legal notices soliciting comments in one North Carolina
newspaper, The Wilmington Journal, on November 5, 1998. Legal notices
were also published in two Virginia newspapers, The Virginian-Pilot and
The Suffolk News-Herald, on November 1, 1998.
Ten individuals or organizations submitted comment letters. Two
peer reviewers supported the delisting, and one of the reviewers
provided additional pertinent information that was incorporated into
the final rule. The
[[Page 10424]]
Virginia Department of Game and Inland Fisheries; U.S. Army Corps of
Engineers, Wilmington District; Isle of Wight County, Virginia; and the
North Carolina Department of Environment and Natural Resources,
Division of Parks and Recreation, and North Carolina Natural Heritage
Program supported the delisting. The Virginia Department of
Conservation and Recreation, Hampton Roads Planning District Commission
(representing Cities of Chesapeake, Suffolk, and Virginia Beach), and
Virginia Department of Environmental Quality had no comment. The
Virginia Department of Agriculture and Consumer Services stated that
delisting would have no adverse impacts on their regulatory
responsibilities. We received no additional written or oral comments
during the comment period.
Summary of Factors Affecting the Species
After a thorough review and consideration of all information
available, we have determined that the Dismal Swamp southeastern shrew
should be removed from the List of Endangered and Threatened Wildlife.
Procedures found at section 4(a)(1) of the Act and regulations
implementing the listing provisions of the Act (50 CFR part 424) were
followed. Regulations at 50 CFR 424.11 require that certain factors be
considered before a species can be listed, reclassified, or delisted.
These factors and their application to the Dismal Swamp southeastern
shrew (Sorex longirostris fisheri Merriam) are as follows:
A. The present or threatened destruction, modification, or
curtailment of its habitat or range. Extensive habitat alteration has
occurred within the area historically occupied by the Dismal Swamp. At
the beginning of the twentieth century, the Dismal Swamp occupied 2,000
to 2,200 square miles (mi \2\) (5,200 to 5,700 square kilometers (km
\2\)). Currently, less than 320 mi \2\ (830 km \2\) of the historical
Dismal Swamp remain, 189 mi \2\ (490 km \2\) of which are protected
within the Refuge and the Great Dismal Swamp State Park in North
Carolina. Remnants of the historical Dismal Swamp outside Refuge and
State Park boundaries and land beyond the historical Dismal Swamp
boundaries are disappearing due to development associated with the
rapid growth of the Hampton Roads metropolitan area of southeastern
Virginia. Agricultural and silvicultural conversions (especially in
North Carolina) also contribute significantly to habitat loss. Habitat
loss was a primary reason for listing the Dismal Swamp southeastern
shrew, considered at the time to be endemic to the historical Dismal
Swamp. However, because the species is now known to occur across a much
larger area and in a wider variety of habitats, this threat is not as
significant as was believed at the time of listing.
B. Overutilization for commercial, recreational, scientific, or
educational purposes. At present, the only known method for studying or
monitoring the Dismal Swamp southeastern shrew involves lethal
collection with pitfall traps. Researchers have been permitted to take
individuals of the species to gain an understanding of its taxonomy,
ecology, and distribution. However, because the Dismal Swamp
southeastern shrew has a high reproductive potential and a rapid
maturation rate, limited collection of individuals is not considered
detrimental to healthy populations. Utilization for commercial,
recreational, or educational purposes is not known to occur.
C. Disease or predation. Southeastern shrews are subject to some
predation, most frequently by owls, snakes, opossums, and domestic cats
and dogs (French 1980, Webster et al. 1985). The number of dead shrews
found in woods and on roads suggests that many predators reject the
shrew, probably because of the bad taste associated with their musk
glands (French 1980). We have no evidence that predation or disease is
a significant threat to the Dismal Swamp southeastern shrew.
D. The inadequacy of existing regulatory mechanisms. Wetland
habitats for the Dismal Swamp southeastern shrew will continue to
receive protection indirectly under Section 404 of the Clean Water Act,
which requires the Department of the Army, Corps of Engineers to
regulate certain activities affecting ``waters of the United States,''
including wetlands. Delisting the Dismal Swamp southeastern shrew
removes Federal prohibitions against take and activities involving a
Federal action that would jeopardize the continued existence of the
species. However, because of its wide distribution and use of a wide
variety of habitats, the removal of these protections afforded by the
Act will not pose a significant threat to the Dismal Swamp southeastern
shrew.
The Dismal Swamp southeastern shrew is listed as threatened by the
State of Virginia. Virginia's Endangered Species Act of 1972, as
amended (Code of Virginia Section 29.1-564-568), prohibits the taking,
transportation, processing, sale, or offer for sale of endangered and
threatened species except as permitted. The Virginia Department of Game
and Inland Fisheries provides general protection to wildlife through
State law Section 29.1-521, which prohibits their possession and
capture, including the attempt to capture, take, kill, possess, offer
for sale, sell, offer for purchase, purchase, deliver for
transportation, transport, cause to be transported, receive, export,
import in any manner or in any quantity except as specifically
permitted.
The Dismal Swamp southeastern shrew is listed as threatened by the
State of North Carolina. The species is protected by North Carolina
general statute Article 25, section 113-337, which makes it unlawful to
take, possess, transport, sell, barter, trade, exchange, export, or
offer for sale, barter, trade, exchange, or export, or give away for
any purpose including advertising or other promotional purpose any
animal on a protected wild animal list, except as authorized according
to the regulations of the North Carolina Wildlife Resources Commission.
All States have the option of retaining the Dismal Swamp
southeastern shrew on their various lists. Both the States of Virginia
and North Carolina support the delisting. The State of North Carolina
plans to delist the Dismal Swamp southeastern shrew (H. LeGrand, North
Carolina Natural Heritage Program, pers. comm. 1997). However, because
of its wide distribution and use of a wide variety of habitats, the
removal of State protection will not constitute a significant threat to
the species.
E. Other natural or manmade factors affecting its continued
existence. One of the reasons for listing the Dismal Swamp southeastern
shrew was concern regarding the possible loss of genetic integrity
through interbreeding with the nominate subspecies. Gurshaw (1996)
examined allozyme variability in specimens of the southeastern shrew
from North Carolina and Virginia. She found an allele in the shrews
from the coastal plain that represents a genetic distinction from Sorex
longirostris longirostris and that appeared to follow the Fall Line.
The author stated, ``A cline for this allele may be shifted in the
direction of dispersal in proportion to the direction of gene flow
through barriers such as the Fall Line and population size. If the
populations containing [this] allele are small, they will not have as
many individuals dispersing* * *and gene flow may be restricted
(Endler, 1977). In this study, however, the opposite appears to be
happening. Populations with [this allele] are widespread in eastern
North Carolina and southeastern Virginia, with gene flow carrying
[this] allele above the
[[Page 10425]]
Fall Line in central North Carolina.'' She concluded that genetic
swamping within the Dismal Swamp region was not evident.
Webster et al. (1996a, 1996b) found that intergradation between
Sorex longirostris fisheri and S. l. longirostris is evident in
specimens from the inner coastal plain of Virginia and North Carolina.
The zone of intergradation is relatively narrow in Virginia and
relatively wide in North Carolina, commensurate with the relative size
of the inner coastal plain. Shrews from samples immediately to the east
and west of the present Dismal Swamp were slightly smaller than shrews
from the Dismal Swamp in cranial and external measurements. Padgett et
al. (1987) noted this trend. However, when compared with specimens from
throughout the range of the species, these shrews are referable to S.
l. fisheri.
The following summarizes available information regarding potential
environmental contaminant threats to the Dismal Swamp southeastern
shrew throughout its range. In 1987 and 1989, we conducted a
preliminary study (Ryan et al. 1992) within the Refuge to determine if
contaminants were impacting fish and small mammals. All water (metal-
laden leachate and groundwater) draining the Suffolk City Landfill, at
the time a federally designated Superfund site, enters the Refuge. This
landfill received industrial and domestic wastes, including 30 tons of
organophosphate pesticides in the 1970s. Numerous automobile junkyards
border the Refuge to the north and drain into the Dismal Swamp and the
Refuge. Oil, grease, metals, polycyclic aromatic hydrocarbons (PAHs)
and alkanes (PAHs and alkanes are components of petroleum products) are
common constituents of junkyard and roadway runoff. Agricultural fields
to the north and west of the Refuge contribute surface runoff that may
contain residual herbicides, insecticides, and fungicides.
Our study (Ryan et al. 1992) included analyses for contaminant
residues in the short-tailed shrew (Blarina brevicauda). Short-tailed
shrews trapped near the East Ditch displayed elevated levels of lead,
mercury, and several organochlorine pesticides. The lead levels for
short-tailed shrews exceeded normal ranges and fell within the range
for lead toxicosis according to Ma (1996). Small mammal lead toxicosis
symptoms may include neurological dysfunction, reproductive disorders
(including stillbirths), liver and kidney failure, etc. Apart from
overt symptoms, asymptomatic effects may occur at lower levels and have
significant effects on animal behavior, yet be difficult to evaluate
and/or document. Ryan et al. (1992) found that mercury levels for
short-tailed shrews collected at East Ditch, Badger Ditch, Railroad
Ditch, and Pocosin Swamp were elevated in comparison to levels for
short-tailed shrews collected from the study reference location and
other sites within the Refuge. The mercury levels reported for short-
tailed shrews, although elevated when compared within study area sites,
were below those levels reported in the literature as causing observed
adverse effects. Organochlorine pesticide levels of short-tailed shrews
from the East Ditch were higher than those reported from all other
study sites. However, the levels were below those documented in the
literature for observed adverse effects. In summary, there may be a
contaminant concern for the Dismal Swamp southeastern shrew near the
East Ditch of the Refuge. However, no contaminant analysis has been
conducted on Dismal Swamp southeastern shrews, although we have
recommended further monitoring related to this issue.
Small mammals tend to have limited ranges, and, therefore, elevated
levels of contaminants found in shrews from one location cannot be
interpreted as a condition for shrews throughout the Refuge or range.
Land uses such as agriculture, transportation, and urbanization with
increased impervious surfaces contribute measurable levels of
contaminants to the environment, and many persistent contaminants are
passed through the food web. However, we do not have any information
indicating that contaminants pose a significant threat to the continued
existence of the Dismal Swamp southeastern shrew.
Regulations at 50 CFR 424.11(d) state that a species may be
delisted if (1) it becomes extinct, (2) it recovers, or (3) the
original data for classification were in error. We have determined that
the original data for classification of the Dismal Swamp southeastern
shrew as a threatened species were in error. However, it is important
to note that the original data for classification constituted the best
available scientific and commercial information available at the time
and were in error only in the sense that they were incomplete. Because
Sorex longirostris from the Dismal Swamp were originally classified as
S. l. fisheri based on morphological measurements from a limited number
of specimens, and because specimens from areas bordering the Dismal
Swamp did not have similar morphological measurements, taxonomists
logically concluded that only the largest specimens were S. l. fisheri.
Since the early 1900s, scientists have assumed that small-sized shrews
were S. l. longirostris, resulting in erroneous classification of
shrews found outside, and sometimes within, the historical Dismal Swamp
boundaries. Therefore, the perception of a restricted range for S. l.
fisheri was not a misinterpretation on the part of the Service, but a
longstanding scientific assumption. At the time of listing, no other
interpretation could be reasonably construed from the available data.
We conclude that the data supporting the original classification were
incomplete and that removal of S. l. fisheri from the List of
Endangered and Threatened Wildlife is warranted.
The listing of the Dismal Swamp southeastern shrew as a threatened
species was based on the best information available and was therefore a
valid decision at the time. The data leading to a better understanding
of S. longirostris taxonomy were derived incrementally as a direct
result of the recovery program, and no preceding shrew research
anticipated the outcome of the final morphometric and genetic analyses.
The dual effort to increase the base of available information while
addressing the perceived threats to this subspecies was thus both
legally and scientifically justified up to the point when new
information yielded a significant change in the knowledge of the Dismal
Swamp southeastern shrew's status.
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
faced by this species in determining to make this rule final. Based on
this evaluation, the preferred action is to remove the Dismal Swamp
southeastern shrew from the List of Endangered and Threatened Wildlife
because the shrew no longer meets the definition of ``threatened''
under section 3 of the Act and, therefore no longer requires the
protection afforded by the Act.
In accordance with 5 U.S.C. 553(d), we have determined that this
rule relieves an existing restriction and good cause exists to make
this rule effective immediately. Delay in implementation of this
delisting would cost government agencies staff time and monies on
conducting section 7 consultation on actions that may affect a species
no longer in need of protection under the Act. Relieving the existing
restriction associated with this listed species will enable Federal
agencies to minimize any further delays in project planning and
implementation for actions that may affect the Dismal Swamp
southeastern shrew.
[[Page 10426]]
Effects of the Rule
This action results in the removal of the Dismal Swamp southeastern
shrew from the List of Endangered and Threatened Wildlife. Federal
agencies are no longer required to consult with us to insure that any
action they authorize, fund, or carry out is not likely to jeopardize
the continued existence of this species. There is no designated
critical habitat for this species. Federal restrictions on taking no
longer apply. The 1988 amendments to the Act require that all species
that have been delisted due to recovery be monitored for at least 5
years following delisting. The Dismal Swamp southeastern shrew is being
delisted due to new information. Therefore we do not intend to monitor
the species. We believe that sufficient habitat will remain over the
long term to allow for the continued viability of this species. Within
the Refuge and the Great Dismal Swamp State Park in North Carolina,
management will continue to focus on restoring the hydrological regime
to as close to historical conditions as possible, and efforts are being
made to restore or maintain the habitat mosaic through forestry
practices, all of which will benefit the shrew.
Paperwork Reduction Act
Office of Management and Budget (OMB) regulations at 5 CFR 1320,
which implement provisions of the Paperwork Reduction Act, require that
Federal agencies obtain approval from OMB before collecting information
from the public. Implementation of this rule will not involve any
information collection requiring OMB approval under the Paperwork
Reduction Act.
National Environmental Policy Act
We have determined that we do not need to prepare an Environmental
Assessment, as defined under the authority of the National
Environmental Policy Act of 1969, in connection with regulations
adopted pursuant to section 4(a) of the Act. We published a notice
outlining our reasons for this determination in the Federal Register on
October 25, 1983 (48 FR 49244).
Executive Order 12866
This rule is not subject to review by the OMB under Executive Order
12866.
References Cited
A complete list of all references cited herein is available upon
request from the Virginia Field Office (see ADDRESSES section).
Author
The primary author of this document is Cynthia A. Schulz (see
ADDRESSES section).
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Regulation Promulgation
Accordingly, we amend part 17, subchapter B of chapter 1, title 50
Code of Federal Regulations, as follows:
PART 17--[AMENDED]
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.
4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.
Sec. 17.11 [Amended]
2. Section 17.11(h) is amended by removing the entry for ``Shrew,
Dismal Swamp southeastern, Sorex longirostris fisheri'' under
``MAMMALS'' from the List of Endangered and Threatened Wildlife.
Dated: January 18, 2000.
Jamie Rappaport Clark,
Director, Fish and Wildlife Service.
[FR Doc. 00-4531 Filed 2-25-00; 8:45 am]
BILLING CODE 4310-55-P
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