Federal Register, Volume 59 Issue 18 (Thursday, January 27, 1994)

[Federal Register Volume 59, Number 18 (Thursday, January 27, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-1700]

[[Page Unknown]]

[Federal Register: January 27, 1994]

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DEPARTMENT OF THE INTERIOR
50 CFR Part 17

RIN 1018-AC25

Endangered and Threatened Wildlife and Plants; Proposal to List
the Spruce-Fir Moss Spider as an Endangered Species

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: The Service proposes to list the spruce-fir moss spider
(Microhexura montivaga) as an endangered species under the Endangered
Species Act of 1973, as amended (Act). This spider is currently known
from four mostly small populations located in western North Carolina
and eastern Tennessee. The spider's damp high-elevation forest habitat
is deteriorating rapidly due primarily to air pollution and exotic
insects. The species' current low numbers also increase its
vulnerability to harm from other threats. Listing Microhexura montivaga
as an endangered species would provide protection under the Act.

DATES: Comments from all interested parties must be received by March
28, 1994. Public hearing requests must be received by March 14, 1994.

ADDRESSES: Comments and materials concerning this proposal should be
sent to the Field Supervisor, U.S. Fish and Wildlife Service, 330
Ridgefield Court, Asheville, North Carolina 28806. Comments and
materials received will be available for public inspection, by
appointment, during normal business hours at the above address.

FOR FURTHER INFORMATION CONTACT: Mr. John Fridell at the above address
(telephone 704/665-1195, Ext. 225).

SUPPLEMENTARY INFORMATION:

Background

The spruce-fir moss spider was originally described by Crosby and
Bishop (1925) based on collections made from a site in western North
Carolina in 1923 (Coyle 1981). Only a few specimens were taken, and
little was known about the species until its rediscovery approximately
50 years later by Dr. Frederick Coyle (Western Carolina University,
Cullowhee, North Carolina) and Dr. William Shear (Hampden-Sydney
College, Hampden-Sydney, Virginia) (Coyle 1981). Microhexura montivaga
is one of only two species belonging to the genus Microhexura in the
family Dipluridae (Coyle 1981; Harp 1991, 1992). The other species in
the genus, M. idahoana, occurs only in the Pacific Northwest (Coyle
1981). Diplurids belong in the primitive suborder Mygalomorphae, which
are often popularly referred to as ``tarantulas'' (Harp 1991, 1992).
The genus Microhexura is the northernmost representative of the family
Dipluridae and is also one of the smallest of the mygalomorph spiders,
with adults measuring only 3.0 to 5.6 millimeters (roughly \1/4\ to \7/
16\ inch) (Coyle 1981). Coloration of M. montivaga ranges from light
brown to a darker reddish brown, and there are no markings on the
abdomen (Harp 1992). The carapace is generally yellowish brown (Harp
1992). The most reliable field identification characteristics for the
spruce-fir moss spider are a pair of very long posterior spinnerets and
the presence of a second pair of book lungs, which appear as light
patches posterior to the genital furrow (Harp 1992).
The typical habitat of the spruce-fir moss spider is found in well-
drained moss (and liverwort) mats growing on rocks or boulders, in
well-shaded situations in mature, high-elevation Fraser fir (Abies
fraseri) and red spruce (Picea rubens) forests (Coyle 1981, Harp 1992).
The moss mats cannot be too dry (the species is very sensitive to
desiccation) or too wet (large drops of water can also pose a threat to
the spider) (Harp 1992). The spider constructs its tube-shaped webs in
the interface between the moss mat and rock surface (Coyle 1981, Harp
1992), though occasionally the web extends into the interior of the
moss mat (Harp 1992). The tubes are thin-walled and typically broad and
flattened with short side branches (Coyle 1981, Harp 1992). There is no
record of prey having been found in the webs of the spruce-fir moss
spider nor has the species been observed taking prey in the wild, but
the abundant springtails (collembolans) in the moss mats provide the
most likely source of food for the spider (Coyle 1981, Harp 1992).
Males of the species mature during September and October, and
females are known to lay eggs in June. The egg sac is thin-walled and
nearly transparent, and it may contain seven to nine eggs. The female
remains with the egg sac and, if disturbed, will carry the egg sac with
her fangs. Spiderlings emerge in September (Coyle 1981). The means of
dispersal of the spiderlings from the parental moss mat is not known,
but ``ballooning,'' a process by which the spiders use a sheet of silk
played out into the wind to carry them into the air, has been suggested
as a possible means of long-range dispersal (Harp 1992). The life span
of the species is also unknown, but Coyle (1981) estimated that it may
take 4 years for the species to reach maturity.
From 1989 through 1992, status surveys were conducted for the
spruce-fir moss spider (Harp 1991, 1992). Based on the results of these
surveys, the spider is presently known to exist at only four
locations--three sites in North Carolina and one in Tennessee. Of the
four remaining populations, only one appears to be relatively stable.
This population is located along the Avery/Caldwell County line in
North Carolina. The other two populations in North Carolina are located
in Swain County. Both of these Swain County populations are extremely
small, with only one spruce-fir moss spider having been found at each
of these two sites in recent years (Harp 1991, 1992). The spruce-fir
forests at these two Swain County sites are rapidly declining. The
Tennessee population is located in Sevier County. This population was
considered healthy in 1989 but is currently believed to be declining in
numbers and is endangered by habitat loss/alteration (Harp 1992). The
high-elevation spruce-fir forests throughout much of the species'
historic range are being decimated by the balsam wooly adelgid (Adelges
piceae), an exotic insect pest, and possibly by air pollution (acid
precipitation) and other factors not yet fully understood. The death
and thinning of the forest canopy results in locally drastic changes in
microclimate, including increased temperatures and decreased moisture
leading to desiccation of the moss mats on which the spruce-fir moss
spider, and possibly its prey base, depend for survival.
The spruce-fir moss spider is not included in the Service's notice
of review for animal candidates published in the Federal Register of
November 21, 1991 (56 FR 58804). However, because of concerns expressed
by some individuals for the spider's status, the Service contracted in
1990 for a survey of both historic and potential habitat of the
species. The results of the survey, which was completed in 1992,
indicate that the spider is undergoing a rapid decline in distribution.
Presently only one relatively stable population is known to survive,
and while currently considered to be healthy, this population is
potentially threatened by the same factors that are believed to have
resulted in the decline and/or extirpation of the species elsewhere
within its historic range.
Species appearing in the candidate notices of review are assigned
to either category 1, 2 or 3. In conjunction with the current proposed
rule, the Service has approved the spruce-fir moss spider as a category
1 candidate. Category 1 represents those species for which the Service
has enough substantial information on biological vulnerability and
threats to support proposals to list them as endangered or threatened
species.
The Service has met and been in contact with various Federal and
State agency personnel and private individuals knowledgeable about the
species concerning its status and the need for the protection provided
by the Act. On December 31, 1992, the Service notified appropriate
Federal, State, and local government agencies and landowners, in
writing, that a status review was being conducted and that the species
might be proposed for Federal listing. A total of ten written comments
were received. The National Park Service, the North Carolina Division
of Parks and Recreation, and three private individuals (including the
owner of the site containing the Avery/Caldwell County, North Carolina,
population) expressed strong support for the potential listing of the
spruce-fir moss spider as an endangered species. The U.S. Soil
Conservation Service, Tennessee Wildlife Resources Agency, Tennessee
Department of Environment and Conservation, Tennessee Valley Authority,
and the North Carolina Department of Agriculture stated that they had
no new or additional information on the species or threats to its
continued existence. No negative comments were received.

Summary of Factors Affecting the Species

Section 4(a)(1) of the Endangered Species Act (16 U.S.C. 1531 et
seq.) and regulations (50 CFR part 424) promulgated to implement the
listing provisions of the Act set forth the procedures for adding
species to the Federal lists. A species may be determined to be an
endangered or threatened species due to one or more of the five factors
described in Section 4(a)(1). These factors and their application to
the spruce-fir moss spider (Microhexura montivaga) are as follows:

A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range

The spruce-fir moss spider is known to be endemic only to high-
elevation spruce-fir forests of western North Carolina and eastern
Tennessee. Historically, the species has been reported from four sites
in North Carolina and one in Tennessee. In North Carolina the species
has been recorded from two sites in Swain County, one in Yancey County,
and one in Avery and Caldwell Counties (Coyle 1981, Harp 1992). In
Tennessee, the species is known from only one site in Sevier County
(Coyle 1981).
During 1989 and through 1992, both historic and potential habitat
of the species was surveyed (Harp 1991, 1992). No new populations of
the spruce-fir moss spider were discovered, and of the five previously
recorded populations, only one--the Avery and Caldwell County, North
Carolina, population--appears to be stable (Harp 1992).
The Yancey County, North Carolina, population appears to have been
extirpated, and only a single individual could be found at each of the
two sites in Swain County, North Carolina (Harp 1992). The population
in Sevier County, Tennessee, was surveyed in 1989 and was considered to
be relatively healthy at that time (Harp 1991). However, revisits to
this site in 1992 indicated the population level is declining,
apparently in conjunction with a rapid decline in the forest canopy
occurring at the site and associated desiccation of moss-mat habitat
(Harp 1992).
The spruce-fir moss spider is very sensitive to desiccation and
requires situations of high and constant humidity (Coyle 1981; Harp
1991, 1992). Loss of forest canopy leading to increased light and
decreased moisture on the forest floor (resulting in desiccation of the
moss mats) appears to be the major cause for the loss and decline of
the spruce-fir moss spider at all four of these sites and the major
threat to the species' continued existence. In a 1991 letter to Keith
Langdon (National Park Service, Great Smoky Mountains National Park),
Dr. Frederick Coyle (Western Carolina University) indicated that the
spruce-fir moss spider was common at one of the sites in Swain County,
North Carolina, as late as 1983 but was extremely rare by 1988. In his
letter to Keith Langdon, Dr. Coyle stated that many of the moss mats at
this site had become dry and loose, which he suspected was due largely
to deterioration of the forest canopy at the site. Fraser firs at all
four of these sites (the Swain and Yancey County sites in North
Carolina and the Sevier County, Tennessee, site) have suffered
extensive mortality, believed to be primarily due to infestation by the
balsam wooly adelgid (J. Harp, Oak Ridge National Laboratory, personal
communication, 1993), a nonnative insect pest believed to have been
introduced into the United States from Europe (Eager 1984).
Atmospheric deposition of pollutants, primarily affecting the red
spruce (Harp 1992), may also be a major factor (either directly or
indirectly) in the decline of the forest canopy at these sites. It has
been estimated that the red spruce at the site in Yancey County, North
Carolina, where the species is now believed to be extirpated, have lost
75 to 90 percent of their foliage (Krahl-Urban et al. 1988), possibly
due to acid precipitation. The death and thinning of the canopy trees
within these stands also cause the remaining trees to be more
susceptible to wind and other storm damage, which has become a major
concern at the Sevier County, Tennessee, site (J. Harp, personal
communication 1992).
The spruce-fir forest at the site harboring the Avery/Caldwell
County, North Carolina, population of the spruce-fir moss spider has
not experienced the degree of decline that has occurred (and is
occurring) at the other sites known to support (or to have supported)
populations of the spider. However, the same factors that are believed
to have resulted in the decline of the spruce-fir forest and the
associated loss of suitable moss-mat habitat at these other sites
potentially threaten this population and its habitat at this site as
well.

B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes

The spruce-fir moss spider is not currently known to be
commercially valuable; however, because of its extreme rarity and
uniqueness, it is conceivable that it could be sought by collectors. It
is one of only two members of the genus Microhexura, it is the only
representative of the primitive family Dipluridae in eastern North
America, and it is one of the smallest of the world's ``tarantulas.''
While collecting or other intentional take is not presently identified
as a factor contributing to the species' decline, the low numbers, slow
reproductive rate, and extremely restricted range of the spruce-fir
moss spider make it unlikely that the species could withstand even
moderate collecting pressure.

C. Disease or Predation

It is presently unknown whether disease or predation have played a
role in the decline of the spruce-fir moss spider. Further research is
needed in this area. While predation is not thought to be a significant
threat to a healthy population of the spruce-fir moss spider, it could
limit the recovery of the species or contribute to the local
extirpation of populations already depleted by other factors. Possible
predators of the spruce-fir moss spider include pseudoscorpions,
centipedes, and other spiders (Harp 1992).

D. The Inadequacy of Existing Regulatory Mechanisms

Neither the State of North Carolina nor the State of Tennessee
include arachnids on their lists of endangered and threatened species;
therefore, the species is unprotected in both States. Federal listing
would provide protection for the spruce-fir moss spider throughout its
range by requiring Federal permits to take the species and by requiring
Federal agencies to consult with the Service when activities they fund,
authorize, or carry out may affect the species.

E. Other Natural or Manmade Factors Affecting its Continued Existence

Only one of the four remaining populations of this species appears
stable. The other three surviving populations are extremely small, and
all four populations are geographically isolated from one another.
Therefore, the long-term genetic viability of these populations is in
doubt. Also, the restricted range of each of the surviving populations
makes them extremely vulnerable to extirpation from a single event or
activity, such as a severe storm, fire, land-clearing or timbering
operation, pesticide/herbicide application, etc. Because they are
isolated from one another, natural repopulation of an extirpated
population would be unlikely without human intervention.
The Service has carefully assessed the best scientific and
commercial information available regarding the past, present, and
future threats faced by this species in determining to propose this
rule. Based on this evaluation, the preferred action is to list the
spruce-fir moss spider (Microhexura montivaga) as an endangered
species. The species has been greatly reduced in numbers throughout the
majority of its historic range and presently is known to occur at only
four locations. At two of these locations, only lone individuals--one
at each location--have been observed in recent years; at a third
location the species has undergone a rapid decline in numbers and is
endangered by further habitat degradation/alteration. Only one of the
remaining populations appears to be stable at this time, and it is
potentially threatened by many of the same factors that are believed to
have resulted in the extirpation or decline of the other historically
known populations. Due to the species' history of population loss and
decline and the extreme vulnerability of the surviving populations,
endangered status appears to be appropriate for this species. Critical
habitat is not being proposed for this species at this time for the
reasons discussed below.

Critical Habitat

Section 4(a)(3) of the Act, as amended, requires that, to the
maximum extent prudent and determinable, the Secretary propose any
habitat of a species that is considered to be critical at the time the
species is proposed to be endangered or threatened. The Service's
regulations [50 CFR 424.12(a)(1)] state that designation of critical
habitat is not prudent when one or both of the following situations
exist: (1) The species is threatened by taking or other activity and
the identification of critical habitat can be expected to increase the
degree of threat to the species or (2) such designation of critical
habitat would not be beneficial to the species. The Service finds that
designation of critical habitat is not prudent for this species. Such a
determination would result in no known benefit to the spruce-fir moss
spider, and designation of critical habitat could further threaten the
species.
Section 7 of the Endangered Species Act requires that Federal
agencies insure that their actions are not likely to jeopardize the
continued existence of listed species, or result in the destruction or
adverse modification of critical habitat. (See the ``Available
Conservation Measures'' section for a further discussion of Section 7.)
As part of the development of this proposed rule, Federal and State
agencies were notified of the spider's general distribution, and they
were requested to provide data on proposed Federal actions that might
adversely affect the species. No specific projects were identified.
Should any future projects be proposed in areas inhabited by the
spruce-fir moss spider, the involved Federal agency will already have
the general distribution data needed to determine if the species may be
impacted by their action. If needed, more specific distribution
information would be provided.
Three of the four surviving populations of the spruce fir moss
spider are considered to be extremely small, and suitable habitat at
each of the four sites still supporting the species is very limited.
The precarious status of the species means that any Federal action with
the potential to result in significant adverse modification or
destruction of the species' habitat would also likely jeopardize its
continued existence. Under these conditions, no additional protection
for the spruce-fir moss spider would accrue from critical habitat
designation that would not also accrue from listing the species.
Consequently, when listed, habitat protection for the spruce-fir moss
spider will be accomplished through the Section 7 jeopardy standard and
Section 9 prohibitions against take.
In addition, the spruce-fir moss spider is very rare and unique,
and taking for scientific purposes and private collection could pose a
threat if specific site information was released. The publication of
critical habitat maps in the Federal Register, local newspapers, and
other publicity accompanying critical habitat designation could
increase the collection threat. The locations of populations of these
species have consequently been described only in general terms in this
proposed rule. Any existing precise locality data would be available to
appropriate Federal, State, and local government agencies from the
Service office described in the ``ADDRESSES'' section; from the
Service's Raleigh Field Office, P.O. Box 33726, Raleigh, North Carolina
27636-3726; the Service's Cookeville Field Office, 446 Neal Street,
Cookeville, Tennessee 38501; and from the North Carolina Wildlife
Resources Agency, North Carolina Natural Heritage Program, Tennessee
Wildlife Resources Agency, and Tennessee Department of Environment and
Conservation.

Available Conservation Measures

Conservation measures provided to species listed as endangered or
threatened under the Act include recognition, recovery actions,
requirements for Federal protection, and prohibitions against certain
practices. Recognition through listing encourages and results in
conservation actions by Federal, State, and private agencies, groups,
and individuals. The Act provides for possible land acquisition and
cooperation with the States and requires that recovery actions be
carried out for all listed species. The protection required of Federal
agencies and the prohibitions against taking and harm are discussed, in
part, below.
Section 7(a) of the Act requires Federal agencies to evaluate their
actions with respect to any species that is proposed or listed as
endangered or threatened and with respect to its critical habitat, if
any is being designated. Regulations implementing this interagency
cooperation provision of the Act are codified at 50 CFR Part 402.
Section 7(a)(4) requires Federal agencies to confer informally with the
Service on any action that is likely to jeopardize the continued
existence of a proposed species or result in the destruction or adverse
modification of proposed critical habitat. If a species is subsequently
listed, Section 7(a)(2) of the Act requires Federal agencies to ensure
that activities they authorize, fund, or carry out are not likely to
jeopardize the continued existence of such a species or to destroy or
adversely modify its critical habitat. If a Federal action may affect a
listed species or its critical habitat, the responsible Federal agency
must enter into consultation with the Service. The Service has notified
Federal agencies that may have programs which could affect the species.
Federal activities that could occur and impact the species include, but
are not limited to, the carrying out or issuance of permits for
construction, recreation or development actions that could result in
the loss or thinning of the high-elevation forest canopy, and pesticide
or herbicide applications for the control of noxious insects or weeds.
It has been the experience of the Service, however, that nearly all
Section 7 consultations have been resolved so that the species has been
protected and the project objectives have been met.
The Act and implementing regulations found at 50 CFR 17.21 set
forth a series of general prohibitions and exceptions that apply to all
endangered wildlife. These prohibitions, in part, make it illegal for
any person subject to the jurisdiction of the United States to take
(includes harass, harm, pursue, hunt, shoot, wound, kill, trap, or
collect; or to attempt any of these), import or export, ship in
interstate commerce in the course of commercial activity, or sell or
offer for sale in interstate or foreign commerce any listed species. It
also is illegal to possess, sell, deliver, carry, transport, or ship
any such wildlife that has been taken illegally. Certain exceptions
apply to agents of the Service and State conservation agencies.
Permits may be issued to carry out otherwise prohibited activities
involving endangered wildlife species under certain circumstances.
Regulations governing permits are at 50 CFR 17.22 and 17.23. Such
permits are available for scientific purposes to enhance the
propagation or survival of the species and/or for incidental take in
connection with otherwise lawful activities. In some instances, permits
may be issued during a specified period of time to relieve any undue
economic hardship that would be suffered if such relief were not
available. Such permits are not expected for the spruce-fir moss spider
since the species is not in trade.

Public Comments Solicited

The Service intends that any final action resulting from this
proposal will be as accurate and as effective as possible. Therefore,
comments or suggestions from the public, other concerned government
agencies, the scientific community, industry, or any other interested
party concerning this proposed rule are hereby solicited. Comments
particularly are sought concerning:
(1) Biological, commercial trade, or other relevant data concerning
any threat (or lack thereof) to this species;
(2) The location of any additional populations of this species and
the reasons why any habitat should or should not be determined to be
critical habitat as provided by Section 4 of the Act;
(3) Additional information concerning the range, distribution, and
population size of this species; and
(4) Current or planned activities in the subject area and their
possible impacts on this species.
Final promulgation of the regulation on the spruce-fir moss spider
will take into consideration the comments and any additional
information received by the Service, and such communications may lead
to a final regulation that differs from this proposal.
The Endangered Species Act provides for a public hearing on this
proposal, if requested. Requests must be received within 45 days of the
date of publication of the proposal. Such requests must be made in
writing and should be addressed to the Field Supervisor, U.S. Fish and
Wildlife Service, Asheville Field Office, 330 Ridgefield Court,
Asheville, North Carolina 28806.

National Environmental Policy Act

The Fish and Wildlife Service has determined that an Environmental
Assessment, as defined under the authority of the National
Environmental Policy Act of 1969, need not be prepared in connection
with regulations adopted pursuant to Section 4(a) of the Act. A notice
outlining the Service's reasons for this determination was published in
the Federal Register on October 25, 1983 (48 FR 49244).

References Cited

Coyle, F. A. 1981. The Mygalomorph Genus Microhexura (Araneae,
Dipluridae). Bull. Amer. Mus. Nat. Hist. 170:64-75.
Crosby, C. R., and S. C. Bishop. 1925. Two New Spiders From the Blue
Ridge Mountains of North Carolina (Araneina). Ent. News. 36:142-146,
Figures 1 and 2.
Eager, C. 1984. Review of the Biology and Ecology of the Balsam
Wooly Aphid in Southern Appalachian Spruce-fir Forests. IN: P.S.
White (ed.), The Southern Appalachian Spruce-Fir Ecosystem: Its
Biology and Threats. Research/Resources Management Report SER-71.
U.S. Dept. of Interior, National Park Service.
Harp, J. M. 1991. Status of the Spruce-fir Moss Spider, Microhexura
montivaga Crosby and Bishop, in the Great Smoky Mountains National
Park. Unpubl. report to the National Park Service, U.S. Department
of the Interior. 12 pp. plus appendix.
________. 1992. A Status Survey of the Spruce-fir Moss Spider,
Microhexura montivaga Crosby and Bishop (Araneae, Dipluridae).
Unpubl. report to the North Carolina Wildlife Resources Commission,
Nongame and Endangered Wildlife Program, and the U.S. Fish and
Wildlife Service, Asheville, North Carolina. 30 pp.
Krahl-Urban, B., H.E. Papke, K. Peters, and C. Shimanski. 1988.
Forest Decline. U.S. Environmental Protection Agency and German
Ministry of Research and Technology, 137 pp.

Author

The primary author of this proposed rule is John A. Fridell, U.S.
Fish and Wildlife Service, Asheville Field Office, 330 Ridgefield
Court, Asheville, North Carolina 28806 (704/665-1195, Ext. 225).

List of Subjects in 50 CFR Part 17

Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, and Transportation.

Proposed Regulation Promulgation

Accordingly, the Service hereby proposes to amend part 17,
subchapter B of chapter I, title 50 of the Code of Federal Regulations,
as set forth below:

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; Public Law 99-625, 100 Stat. 3500; unless otherwise
noted.

2. Sec. 17.11(h) is amended by adding the following, in
alphabetical order, under ARACHNIDS, to the List of Endangered and
Threatened Wildlife, to read as follows:

Sec. 17.11 Endangered and threatened wildlife.

* * * * *
(h) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Vertebrate population
----------------------------------------------- Historic range where endangered or Status When listed Critical Special rules
Common name Scientific name threatened habitat
--------------------------------------------------------------------------------------------------------------------------------------------------------
Arachnids

* * * * * * *
Spider, spruce-fir Microhexura montivaga. U.S.A. (NC, TN)...... NA................... E .............. NA NA
moss.

* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------

Dated: November 23, 1993.
Richard N. Smith,
Acting Director, Fish and Wildlife Service.
[FR Doc. 94-1700 Filed 1-26-94; 8:45 am]
BILLING CODE 4310-55-P