2011-17864. Endangered and Threatened Wildlife and Plants; Petition To List Grand Canyon Cave Pseudoscorpion

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of 12-month petition finding.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), announce a 12-month finding on a petition to list the Grand Canyon cave pseudoscorpion (Archeolarca cavicola) as threatened or endangered with critical habitat under the Endangered Species Act of 1973, as amended (Act). After review of the best scientific and commercial information available, we find that listing the Grand Canyon cave pseudoscorpion is not warranted at this time. However, we ask the public to submit to us any new information that becomes available concerning the threats to the Grand Canyon cave pseudoscorpion or its habitat at any time.

DATES:

The finding announced in this document was made on July 19, 2011.

ADDRESSES:

This finding is available on the Internet at http://www.regulations.gov at Docket Number FWS-R2-ES-2011-0044. Supporting documentation we used in preparing this finding is available for public inspection, by appointment, during normal business hours by contacting the U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office, 2321 W. Royal Palm Road, Suite 103, Phoenix, AZ 85021; telephone [phone]; facsimile [phone]. If you use a telecommunications device for the deaf (TDD), please call the Federal Information Relay Service (FIRS) at [phone]. Please submit any new information, comments, or questions concerning this finding to the above address.

FOR FURTHER INFORMATION CONTACT:

Steve Spangle, Field Supervisor, U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office, 2321 W. Royal Palm Road, Suite 103, Phoenix, AZ 85021; telephone [phone]; facsimile [phone]. If you use a telecommunications device for the deaf (TDD), please call the Federal Information Relay Service (FIRS) at [phone].

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(B) of the Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition containing substantial scientific or commercial information indicating that listing the species may be warranted, we make a finding within 12 months of the date of receipt of the petition. In this finding we determine that the petitioned action is: (a) Not warranted, (b) warranted, or (c) warranted, but immediate proposal of a regulation implementing the petitioned action is precluded by other pending proposals to determine whether species are threatened or endangered, and expeditious progress is being made to add or remove qualified species from the Lists of Endangered and Threatened Wildlife and Plants. Section 4(b)(3)(C) of the Act requires that we treat a petition for which the requested action is found to be warranted but precluded as though resubmitted on the date of such finding, that is, requiring a subsequent finding to be made within 12 months. We must publish these 12-month findings in the Federal Register.

Previous Federal Actions

The Grand Canyon cave pseudoscorpion was formerly a candidate 2 species, a taxon for which information in our possession indicated that proposing to list was possibly appropriate, but for which persuasive data on biological vulnerability and threats were not available to support a proposed listing rule (54 FR 554; January 6, 1989). The designation of candidate 2 species was discontinued in 1996; therefore, the species has no candidate status.

On June 25, 2007, we received a formal petition dated June 18, 2007, from Forest Guardians (now WildEarth Guardians), requesting that we do the following: (1) Consider all full species in our Southwest Region ranked as G1 or G1G2 by the organization NatureServe for listing, except those that are currently listed, proposed for listing, or candidates; and (2) list each species under the Act as either endangered or threatened with critical habitat. The petitioners presented two tables that collectively listed 475 species for consideration and requested that the Service incorporate all analyses, references, and documentation provided by NatureServe in its online database http://www.natureserve.org/​ into the petition. The petition clearly identified itself as a petition and included the appropriate identification information, as required in 50 CFR 424.14(a). We acknowledged the receipt of the petition in a letter to WildEarth Guardians dated July 11, 2007.

On December 16, 2009, we made a 90-day finding that the petition presented substantial scientific information indicating that listing 67 of the 475 species may be warranted; the Grand Canyon cave pseudoscorpion (incorrectly referenced as the Grand Canyon cave scorpion) was in that group of 67 species. Based on the evaluation of the information provided in the petition, we determined that the petition presented substantial information to indicate that listing the Grand Canyon cave pseudoscorpion may be warranted due to the present or threatened destruction, modification, or curtailment of its habitat or range resulting from groundwater pollution and recreational impacts, and to the inadequacy of existing regulatory mechanisms resulting from unregulated visitation. The 90-day finding and our initiation of a status review was published in the Federal Register on December 16, 2009 (74 FR 66866). This notice constitutes the 12-month finding on the June 18, 2007, petition to list the Grand Canyon cave pseudoscorpion as threatened or endangered.

Species Information

Species Description

In 1978 W. Calvin Welbourn collected one female specimen of the Grand Canyon cave pseudoscorpion (Class Arachnida, Order Pseudoscorpionida, Family Garypidae) in Grand Canyon National Park's Cave of the Domes. This specimen was first described by Muchmore (1981, p. 55). Welbourn's unpublished report (1978, p. 40) stated that the specimen was an undescribed troglophile. A troglophile is a species that can spend its entire life within caves, does not exhibit adaptations for living in caves, but can also be found in suitable habitats outside of caves, such as mines or animal burrows. This is in comparison to troglobites, which are species that are found exclusively in caves and have developed adaptations for cave life, such as heightened sense of hearing, touch, and smell. The Grand Canyon cave pseudoscorpion was recognized within the genus Archeolarca and was given the species name cavicola in recognition of its subterranean habitat where it was collected by Welbourn (1981, p. 55). The specimen collected in 1978 is the only one known to exist. No other individuals are known to have been collected since 1978, although very little effort has been made to collect this or other species in the genus (Service 1991, p. 3).

Pseudoscorpions are tiny arachnids bearing large chelae, or claws, but lacking a telson, or stinger, that true scorpions possess. The specimen of Grand Canyon cave pseudoscorpion, when compared to other species of pseudoscorpions, such as Archeolarca welbourni and Archeolarca guadalupensis, was considered large (0.12 inches (in) or 3.03 millimeters (mm)), had longer appendages, more reduced posterior eyes, and fewer setae (stiff bristles present on the body) on its upper dorsal section (Muchmore 1981, p. 56). Muchmore (1981, pp. 52-56) described three new species of Archeolarca, and concluded that the Grand Canyon cave pseudoscorpion showed the greatest overall adaption to the cave environment. Welbourn (1978, p. 40) noted that the specimen appeared to be similar to the pseudoscorpions from earth cracks in Wupatki National Mountain, Arizona, approximately 75 miles (121 kilometers (km)) south of Grand Canyon National Park. Other species in the genus Archeolarca have been reported in California, Utah, Texas, and Oregon (Muchmore 1981, p. 56; Peck 1998, p. 23).

Distribution

The Cave of the Domes in Grand Canyon National Park is currently the only known location for the Grand Canyon cave pseudoscorpion. Welbourn (1978, pp. 36-41) conducted a regional study of cave fauna on Horseshoe Mesa of the Grand Canyon from 1977 to 1978. Eight caves were examined including Babylon Cave, Crystal Forest Cave, Land's End Cave, Middle Cave, Scorpion Cave, Tse An Cho Cave, Tuning Fork Cave, and Cave of the Domes. All caves except Land's End Cave and Scorpion Cave were visited twice. On each visit, Welbourn (1978, p. 36) describes examining the walls, ceilings, and floors for animals and invertebrates. He identified 12 invertebrates from the 8 caves. The Grand Canyon cave pseudoscorpion was found only in the Cave of the Domes (Welbourn 1978, pp. 38-41).

Wynne et al. (2008a, pp. 235-246) summarized all published and unpublished literature on cave-dwelling invertebrates within Grand Canyon National Park, as well as cave trip reports on file at Grand Canyon National Park Museum Collections. The literature review examined 9 studies conducted between 1975 and 2001 representing surveys of 15 caves in Grand Canyon National Park. Wynne et al. (2008a, pp. 237-238) reported 37 cave-dwelling invertebrates with the Grand Canyon cave pseudoscorpion referenced only in the Cave of the Domes. This species may possibly be endemic to Cave of the Domes. In fact, a study of patterns of endemism of eastern North American cave fauna reported that within the Pseudoscorpionida is a high level of single-cave endemism compared to other cave taxa (Christman et al. 2005, pp. 1444, 1447). However, cave biological research in Grand Canyon National Park is quite limited (Wynne 2010, pers. comm.; Drost 2010, pers. comm.) and more invertebrate surveys need to be conducted before we can conclude that the Grand Canyon cave pseudoscorpion is endemic to the Cave of the Domes. Further, because many cave-dwelling organisms are hard to find, cave inventories cannot be considered complete without intensive invertebrate trapping, baiting of the entity, and multiple site visits (Wynne 2010, pers. comm.). We cannot describe the distribution based on a single specimen; therefore, we are not able to determine the distribution of the Grand Canyon cave pseudoscorpion.

Habitat and Biology

Most species of pseudoscorpions occur in tropical and subtropical areas throughout the world, although pseudoscorpions can also be found in temperate zones (Weygoldt 1969, pg. 108). They are found in a great variety of habitats, but one essential feature appears to be the presence of small crevices where they can retreat. All pseudoscorpion species spend most of their lives within these crevices and seldom appear on open ground. These small crevices can be found in rocks, tree bark, leaf litter, nests of birds and other small mammals, and buildings. Another important habitat factor is humidity; most pseudoscorpions prefer high humidity, although some species are found in arid conditions, such as deserts (Weygoldt 1969, pp. 108-111).

There are few studies on the ecology and habitat preferences of specific species of pseudoscorpions. We have no specific information about the habitat and biology of the Grand Canyon cave pseudoscorpion because the species is known from only one specimen. Accordingly, we can only speculate about their habitat requirements and biology based on the scant general information known about pseudoscorpions.

Welbourn (1978, p. 37) observed that the single most important limiting factor for the cave fauna on Horseshoe Mesa, which includes Cave of the Domes, was the lack of moisture. Welbourn (1978, p. 37) reported that most of the caves surveyed were dry and dusty with low relative humidity, and that most of the caves examined, including Cave of the Domes, received moisture from rainfall that percolates through the limestone above. Welbourn (1978, p. 40) reported collecting the species “in the Cross passage of Cave of the Domes in some organic material (grass).” According to the Grand Canyon National Park's hydrologist, the Cave of the Domes is considered to be a dry cave with no discharge or pools, but that the Cave of the Domes has some small ephemeral drip zones (Rice 2010, pers. comm.). We do not know if the location where the Grand Canyon cave pseudoscorpion was found was optimal habitat or an accidental find, but if pseudoscorpions prefer humid locations, this location may not represent optimal habitat.

Some species of pseudoscorpions are known to be phoretic (use another species for transportation) on other arthropods such as flies, beetles, and wasps. Pseudoscorpions will attach themselves (not as parasites) to the legs and appendages of the adult arthropod, which permits them to “hitchhike.” According to Poinar et al. (1998, p. 79), the principal benefit of pseudoscorpion phoresy is dispersal; that is, to reach a new habitat with an adequate supply of food. We can only speculate on the presence of the one specimen of Grand Canyon cave pseudoscorpion in Cave of the Domes, but perhaps it was carried there and deposited by an arthropod.

The Park Service's biological report (Hill et al. 1998, pg. 16) from Cave of the Domes indicated that packrat middens (nests) were observed inside Cave of the Domes. The report stated that a packrat midden was found “in the second room of the cave”. Pseudoscorpions are often present in rodent nests (Francke and Villegas-Guzmán 2006, p. 289). Muchmore (1991, pers. comm.) stated that the genus Archeolarca does not usually inhabit caves but rather is found in packrat nests, although packrat middens are sometimes found in caves. Francke and Villegas-Guzmán (2006, p. 297) conclude that pseudoscorpions most likely coexist with a particular rodent species in a mutualistic association (a relationship between two species where both species derive benefits) in which pseudoscorpions feed on adult and larval fleas, which reduces the parasite load within the host nest. The benefits to the pseudoscorpion include the host nest providing suitable microclimate, especially in semiarid regions, as well as food (i.e., mites, fleas, flies and their larvae). It is possible that this species may be associated with packrat middens or other small mammal nests within Cave of the Domes, but we cannot draw that conclusion based on one specimen.

In summary, we lack sufficient information on the species to reach conclusions about the biology or the habitat needs of the Grand Canyon cave pseudoscorpion. This is primarily because we know of only one specimen, and we cannot make scientifically sound conclusions regarding habitat characteristics and biology based on a single specimen.

Factors Affecting the Grand Canyon Cave Pseudoscorpion

Section 4 of the Act (16 U.S.C. 1533) and implementing regulations (50 CFR part 424) set forth procedures for adding species to, removing species from, or reclassifying species on the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, a species may be determined to be endangered or threatened based on any of the following five factors:

(A) The present or threatened destruction, modification, or curtailment of its habitat or range;

(B) Overutilization for commercial, recreational, scientific, or educational purposes;

(C) Disease or predation;

(D) The inadequacy of existing regulatory mechanisms; or

(E) Other natural or manmade factors affecting its continued existence.

In making this finding, information pertaining to the Grand Canyon cave pseudoscorpion in relation to the five factors provided in section 4(a)(1) of the Act is discussed below.

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

The Arizona Game and Fish Department (2003, p. 2) stated that a threat to the Grand Canyon cave pseudoscorpion was groundwater pollution. Our previous discussion in the Habitat and Biology section indicates that Cave of the Domes, where the species was collected, is considered dry and has very little ephemeral water (i.e., small drip zones). Further, the specimen was found associated with dry, organic material (grass) in Cave of the Domes. This description of the site where the Grand Canyon cave pseudoscorpion was collected seems unlikely to be affected by groundwater pollution because it is relatively dry, and based on a single specimen we are unable to determine the type of cave habitat associated with this species. Additionally, we have no specific information regarding the presence or introduction of contaminants or pollutants in water sources on Horseshoe Mesa, which could percolate into the Cave of the Domes. Therefore, we are unable to determine if groundwater pollution is a threat.

Cave of the Domes is the only cave in Grand Canyon National Park for which visitation is allowed. It is unknown whether recreation is modifying or destroying the Grand Canyon cave pseudoscorpion's habitat. A report from the Grand Canyon National Park (Western Speleological Institute 1954, pp. 1-2) stated that the cave has been badly vandalized and floor deposits have been marred by trampling. However, it is unknown if this damage affects the pseudoscorpion's habitat because that habitat is unknown. We note that vandalism and trampling have been identified as potential threats to other pseudoscorpion species, such as the Empire cave pseudoscorpion (Microcreagris imperialis) (Muchmore and Cokendolpher 1995, pp. 174-175) and the Tooth cave pseudoscorpion (Tartarocreagris texana) (Service 1994, pp. 62-63). If the Grand Canyon cave pseudoscorpion occupies packrat middens, as do other pseudoscorpions in the genus Archeolarca, then recreational foot traffic may be a discountable impact; however, we are lacking sufficient information on the habitat for this species. As such, we are unable to determine if recreational activity is affecting the Grand Canyon cave pseudoscorpion or its habitat.

In summary, given the paucity of biological information regarding the Grand Canyon cave pseudoscorpion and its habitat, we cannot determine or conclude that habitat degradation due to groundwater pollution or recreational activities in the Cave of the Domes is a threat to the species now or in the foreseeable future.

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

Any commercial, recreational, scientific, or educational collection activities, including the collection of pseudoscorpions, would require a permit by the National Park Service. Because of this regulation, there is no data suggesting that overutilization for commercial, recreational, scientific, or educational purposes pose a threat to the species. There are no known commercial or recreational uses for Grand Canyon cave pseudoscorpions. Therefore, we find that the Grand Canyon cave pseudoscorpion is not threatened by overutilization now or in the foreseeable future.

Factor C. Disease or Predation

We have no information to indicate that the Grand Canyon cave pseudoscorpion is subject to disease or predation. We have not encountered any information that indicates the contrary; however, in the absence of evidence that this factor may constitute a threat to the species, we cannot determine or conclude that the Grand Canyon cave pseudoscorpion is threatened by disease or predation now or in the foreseeable future.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

Under the current National Park Service policy, all caves in Grand Canyon National Park are closed to visitation by recreational users except for the Cave of the Domes. The Park Service has the authority, under the Federal Cave Resources Protection Act of 1988, to close areas to visitors if there is significant degradation of a resource or the threat of degradation or damage. On Park Service lands, all caves are deemed “significant,” and the Park Service protects the caves, including biological, cultural, and paleontological resources within the caves. The decision to regulate visitors or close the cave to recreational use is made by the Park Superintendent with supporting documentation from resource managers. Official criteria for determining recreational access to Grand Canyon National Park caves has not been established, but the initiation of a Cave Management Plan is planned.

Cave of the Domes is located beneath Horseshoe Mesa and is well known to hikers and cavers. The Web site http://www.birdandhike.com provides a detailed overview of the cave, including photos and directions to the trailhead and to the mouth of the cave. The Web site http://www.kaibab.org also provides information about Cave of the Domes and states that many formations have been damaged by careless individuals and asks visitors to treat the cave with respect. As stated above, we lack data to assess the effect of recreation on the petitioned species. Therefore, due to the lack of information regarding impacts of recreational visitors and the Park Service's ability to close the area if additional information comes to light, we find that the Grand Canyon cave pseudoscorpion is not threatened by inadequacy of regulatory mechanisms now or in the foreseeable future.

Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence

Model predictions are that temperatures in the Southwestern United States will continue to increase, with extreme weather events (such as heat waves, drought, and flooding) occurring with more frequency due to global climate change (Archer and Predick 2008, p. 24). It is unknown how cave-adapted taxa will respond to global climate change. Baseline information on ecosystem structure and community structure is lacking for many caves, and we do not know how cave-dwelling species will respond to rising temperatures. Different layers of a cave may be affected differently, depending on their depth. (Wynne et al. 2008b, p. 241). There will most likely be a lag effect; caves with shallow vertical depth are predicted to have a more immediate response than caves with deeper vertical depth (Wynne 2010, pers. comm.). We have no information on the geophysical properties of Cave of the Domes. Researchers are currently attempting to understand the geophysical properties of caves as they relate to cave depth, the potential effects of rising surface temperatures on cave temperatures, and how the physiological requirements of cave-dwelling and cave-adapted species are affected by climate change (Drost 2010, pers. comm.). Based on the best available information, we cannot determine or conclude that climate change is a threat to the Grand Canyon cave pseudoscorpion now or in the foreseeable future.

Finding

As required by the Act, we considered the five factors in assessing whether the Grand Canyon cave pseudoscorpion is threatened or endangered throughout all or a significant portion of its range. We examined the best scientific and commercial information available regarding the past, present, and future threats faced by the Grand Canyon cave pseudoscorpion. We reviewed the petition, information available in our files, other available published and unpublished information, and we consulted with recognized invertebrate experts and the Grand Canyon National Park biologist and hydrologist.

In considering what factors might constitute threats, we must look beyond the mere exposure of the species to the factor to determine whether the species responds to the factor in a way that causes actual impacts to the species. If there is exposure to a factor, but no response, or only a positive response, that factor is not a threat. If there is exposure and the species responds negatively, the factor may be a threat and we then attempt to determine how significant a threat it is. If the threat is significant, it may drive or contribute to the risk of extinction of the species such that the species warrants listing as threatened or endangered as those terms are defined by the Act. This does not necessarily require empirical proof of a threat. The combination of exposure and some corroborating evidence of how the species is likely impacted could suffice. The mere identification of factors that could impact a species negatively is not sufficient to compel a finding that listing is appropriate; we require evidence that these factors are operative threats that act on the species to the point that the species meets the definition of threatened or endangered under the Act.

Based on our review of the best available scientific and commercial information pertaining to the five factors, we found no evidence to indicate that there are threats to the species or its habitat, from any of the five factors. For this reason, we conclude that the Grand Canyon cave pseudoscorpion does not meet the definition of a threatened or endangered species and are, therefore, recommending a finding of “not warranted.”

We request that you submit any new information concerning the distribution and status of, or threats to, the Grand Canyon cave pseudoscorpion to our U.S. Fish and Wildlife Service Office (see ADDRESSES) whenever it becomes available. New information will help us monitor the Grand Canyon cave pseudoscorpion and encourage its conservation. If an emergency situation develops for the Grand Canyon cave pseudoscorpion or any other species, we will act to provide immediate protection.

References Cited

A complete list of references cited is available on the Internet at http://www.regulations.gov and upon request from the U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office (see ADDRESSES).

Author(s)

The primary authors of this finding are the staff members of the Arizona Ecological Services Field Office.

Authority: The authority for this section is section 4 of the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

Dated: June 21, 2011.

Rowan W. Gould,

Acting Director, Fish and Wildlife Service.