Endangered and Threatened Wildlife and Plants; 12-Month Determination on a Petition To Revise Critical Habitat for the Mount Graham Red Squirrel

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

12-Month determination.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), announce a 12-month determination on a petition to revise critical habitat for the Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis) under the Endangered Species Act of 1973, as amended (Act). The petition requests that the Service expand the subspecies' critical habitat designation to include currently occupied mixed conifer habitat and all historically occupied habitat outside the current critical habitat designation. Our 12-month determination is that we intend to assess revisions to the subspecies' critical habitat after a species status assessment and revised recovery plan for the Mount Graham red squirrel are completed.

DATES:

The determination announced in this document was made on August 3, 2021.

ADDRESSES:

This determination is available on the internet at http://www.regulations.gov at Docket No. FWS-R2-ES-2021-0012. Information and supporting documentation that we received and used in preparing this finding is available for public inspection pursuant to current COVID-19 restrictions. You may contact the U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office, Tucson Sub-Office, 201 N Bonita, Suite 141, Tucson, AZ 85745 for further information about these restrictions. Please submit any new information, materials, comments, or questions concerning this finding to the above mailing address.

FOR FURTHER INFORMATION CONTACT:

U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office, Attn: Jeff Humphrey, to the mailing address in ADDRESSES, telephone: 602-242-0210, or email: incomingazcorr@fws.gov. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Relay Service at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(D)(ii) of the Act (16 U.S.C. 1531 et seq.) states that within 12 months after receiving a petition to revise a critical habitat designation that is found to present substantial information indicating that the requested revision may be warranted, the Secretary will determine how he or she intends to proceed with the requested revision, and will promptly publish notice of such intention in the Federal Register.

Previous Federal Actions

On June 3, 1987, we published in the Federal Register (52 FR 20994) a final rule listing the Mount Graham red squirrel (red squirrel) as an endangered subspecies of the red squirrel, or pine squirrel (T. hudsonicus species account: Steele 1998, p. 1), pursuant to the Act. We concluded that the Mount Graham red squirrel was endangered because its range and habitat had been reduced and its habitat was at risk due to a number of factors, including the proposed construction of an astrophysical observatory, occurrences of forest fires, proposed construction and improvement of roads, and recreational development at high elevations. The rule concluded that red squirrels might also suffer due to resource competition with the introduced Abert's, or tassel-eared, squirrel (Sciurus aberti).

On January 5, 1990, we published in the Federal Register (55 FR 425) a final rule designating approximately 769 hectares (ha) (1,900 acres (ac)) in three separate units as critical habitat for the Mount Graham red squirrel. Critical habitat encompasses the Mount Graham Red Squirrel Refugium, which resulted from a July 1988 biological opinion and subsequent Arizona-Idaho Conservation Act of 1988 (Pub. L. 100-696, November 18, 1988), on Hawk and Plain View peaks (about 688 ha (1,700 ac)), as well as areas outside the Refugium on Heliograph and Webb Peaks (about 81 ha (200 ac)). The main attribute of critical habitat at that time was existing dense stands of mature (about 300 years old) spruce-fir forest, which has since been damaged by drought, insects, wildfire, and associated wildfire-suppression activities.

On January 11, 2006, we initiated a 5-year review of the Mt. Graham red squirrel (71 FR 1765); that 5-year review was completed on January 15, 2008. On May 27, 2011, we announced the availability of, and requested public comments on, a draft recovery plan, first revision, for the Mount Graham red squirrel (76 FR 30957).

Petition History

On December 14, 2017, we received a petition from the Center for Biological Diversity, Maricopa Audubon Society, and the Mount Graham Coalition requesting that critical habitat for the Mount Graham red squirrel be revised under the Act, on an emergency basis. The petition requests that the Service expand the subspecies' critical habitat designation to include currently occupied mixed conifer habitat and all historically occupied habitat outside the current critical habitat designation. In general, the petitioners recommend expanding the current designation of critical habitat to include mixed conifer and spruce-fir forest above 7,500 feet (ft) (2,286 meters (m)), including specific areas currently occupied by the Mount Graham red squirrel at Grant Hill, Riggs Lake, Turkey Flat, and Columbine. The petition clearly identified itself as such and included the requisite identification information for the petitioners, required at 50 CFR 424.14(c). Because the Act does not provide for petitions to revise critical habitat in an emergency, we considered it as a petition to revise critical habitat for the red squirrel.

We published our 90-day finding on the petition to revise critical habitat for the Mount Graham red squirrel on September 6, 2019 (84 FR 46927). We determined that the petition presented substantial scientific information indicating that revising critical habitat for the Mount Graham red squirrel under the Act may be warranted, thus initiating the review that led to this 12-month determination.

This 12-month determination addresses the petition's request to revise the Mount Graham red squirrel's currently designated critical habitat.

Species Information

Mount Graham red squirrels are found only in the high-elevation forests of the Pinaleño Mountains in the Safford Ranger District of the Coronado National Forest in southeastern Arizona. The subspecies inhabits upper elevation, mature to old-growth associations in mixed conifer and spruce-fir forests above approximately 7,500 ft (2,286 m).

Mount Graham red squirrels are highly territorial (C.C. Smith 1968, pp. 33-34) and create middens within their territory. The middens in each squirrel's territory consist of piles of cone scales in which squirrels cache live, unopened cones as a food source for over-wintering and during times of cone failure (M.C. Smith 1968, pp. 308-309; Finley 1969, all; Steele and Koprowski 2001, p. 67). Placement of these middens tends to be on gentler, non-southerly-facing slopes in healthier, older forested areas with higher canopy closure, basal area, and number of large live trees (Finley 1969, p. 237; Zugmeyer and Koprowski 2009, p. 179; Hatten 2014, p. 111). This type of placement allows specific moisture levels to be maintained within the midden, thereby creating prime storage conditions for cones and other food items, such as mushrooms, acorns, and bones (Finley 1969, p. 237; Brown 1984, pp. 66-67; USFWS 1993, pp. 5-7; Zugmeyer and Koprowski 2009, p. 179). They also seem to prefer areas with snags, piles and tangles of downed timber, and a higher volume of logs that provide cover and safe travel routes, especially in winter, when open travel across snow exposes them to increased predation, as the species does not hibernate. Wood et al. (2007, p. 2362) determined that midden site selection occurs not only at the microclimate level (where conditions are appropriate for cone storage), but also on a larger scale that encompasses other features found on the landscape, usually in areas with a high number of healthy trees and correspondingly high seedfall. There appears to be no differentiation in selection of midden sites based on sex (Alanen et al. 2009, pp. 204-205).

Within their territory, Mount Graham red squirrels build nests in hollow trees, in hollow snags, in hollow logs, outside trees in nests of grass or foliose lichens (called dreys or bolus nests), or in holes in the ground (C.C. Smith 1968, p. 58; Leonard and Koprowski 2009, p. 132). Nests may be built in natural hollows or abandoned cavities made by other animals, such as woodpeckers, and enlarged by squirrels (USFWS 1993, p. 11). Nest site selection by Mount graham red squirrels is strongly influenced by stand composition, particularly density of corkbark fir, mature (large) trees, and decaying logs (Merrick et al. 2007, p. 1961). The availability of larger snags and cavity-containing trees, especially aspen, is of particular importance for this population, as they provide preferred nesting locations (Merrick et al. 2007, p. 1961).

Critical Habitat

Current Critical Habitat Designation

On January 5, 1990, we published a final rule (55 FR 425) designating critical habitat for the Mount Graham red squirrel as mature spruce-fir forest in:

1. Hawk Peak-Mount Graham Area. The area above the 10,000-ft (3,048-m) contour surrounding Hawk Peak and Plain View Peak, plus the area above the 9,800-ft (2,987-m) contour that is south of lines extending from the highest point of Plain View Peak eastward at 90° (from true north) and southwestward at 225° (from true north).

2. Heliograph Peak Area. The area on the north-facing slope of Heliograph Peak that is above the 9,200-ft (2,804-m) contour surrounding Heliograph Peak and that is between a line extending at 15° (from true north) from a point 160 ft (49 m) due south of the horizontal control station on Heliograph Peak and a line extending northwestward at 300° (from true north) from that same point.

3. Webb Peak Area. The area on the east facing slope of Webb Peak that is above the 9,700-ft (2,957-m) contour surrounding Webb Peak and that is east of a line extending due north and south through a point 160 ft (49 m) due west of the horizontal control station on Webb Peak.

12-Month Determination

Pursuant to the provisions of the Act regarding revision of critical habitat and petitions for revision, we now publish notice of how we intend to proceed with the requested revision. As described below under How the Service Intends to Proceed, we intend to assess potential revisions to the subspecies' critical habitat after a species status assessment (SSA) and a revision of the Mount Graham red squirrel's recovery plan are complete.

How the Service Intends To Proceed

Section 4(b)(3)(D)(ii) of the Act states that if we find that a petition presents substantial information indicating that a revision to critical habitat may be warranted, then within 12 months of receiving the petition we are to indicate how we intend to proceed with the requested revision and promptly publish a notice of our intention in the Federal Register. We intend that any revisions to critical habitat for the Mount Graham red squirrel be as accurate and comprehensive as possible. Therefore, completing the SSA and a revised recovery plan will inform any future revisions to critical habitat for the red squirrel. Once the SSA and revised recovery plan are complete, a rulemaking process will be initiated if revisions to the subspecies' critical habitat are determined to be appropriate.

The currently designated critical habitat, as well as areas that support the subspecies but are outside of the current critical habitat designation, will continue to be subject to conservation actions implemented under section 7(a)(1) of the Act. Actions affecting the Mount Graham red squirrel or its designated critical habitat are subject to the regulatory protections afforded by section 7(a)(2) of the Act, which requires Federal agencies, including the Service, to ensure that actions they fund, authorize, or carry out are not likely to jeopardize the continued existence of any listed species or result in the destruction or adverse modification of critical habitat.

References Cited

A complete list of references cited in this rulemaking is available on the internet at http://www.regulations.gov and upon request from the Arizona Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).

Author

The primary authors of this document are the staff members of the Arizona Ecological Services Field Office, U.S. Fish and Wildlife Service.

Authority

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