[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] ----------------------------------------------------------------------- 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. ----------------------------------------------------------------------- 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