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Daily Rules, Proposed Rules, and Notices of the Federal Government

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2012-0061; 4500030113]

RIN 1018-AY51

Endangered and Threatened Wildlife and Plants; 12-Month Finding for the Lemmon Fleabane; Endangered Status for the Acuna Cactus and the Fickeisen Plains Cactus and Designation of Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule; 12-month finding.
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 12-month finding on a petition to list as an endangered or threatened speciesErigeron lemmonii(Lemmon fleabane). After a review of the best available scientific information we find that listing the Lemmon fleabane as an endangered or threatened species is no longer warranted, and therefore we are removing this species from the candidate list. We propose to listEchinomastus erectocentrusvar.acunensis(acuna cactus) andPediocactus peeblesianusvar.fickeiseniae(Fickeisen plains cactus) as an endangered species, and we propose to designate critical habitat for both cactus species under the Endangered Species Act of 1973, as amended (Act). If finalized, the effect of these regulations would be to add acuna cactus and Fickeisen plains cactus to the List of Endangered and Threatened Plants and to designate critical habitat for these species.
DATES: We will accept comments received or postmarked on or before December 3, 2012. Comments submitted electronically using the Federal eRulemaking Portal (seeADDRESSESsection, below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for public hearings, in writing, at the address shown in theFOR FURTHER INFORMATION CONTACTsection by November 19, 2012.
ADDRESSES: (1)Electronically:Go to the Federal eRulemaking Portal:http://www.regulations.gov. In the Keyword box, enter Docket No. FWS-R2-ES-2012-0061, which is the docket number for this rulemaking. Then, in the Search panel on the left side of the screen, under the Document Type heading, click on the Proposed Rules link to locate this document. You may submit a comment by clicking on "Comment Now!"

(2)By hard copy:Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R2-ES-2012-0061; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.

We request that you send comments only by the methods described above. We will post all comments onhttp://www.regulations.gov. This generally means that we will post any personal information you provide us (see the Information Requested section below for more information).

The coordinates or plot points or both from which the critical habitat maps are generated are included in the administrative record for this rulemaking and are available athttp://www.fws.gov/southwest/es/arizona/, http://www.regulations.govat Docket No. FWS-R2-ES-2012-0061, and at the Arizona Ecological Services Field Office (seeFOR FURTHER INFORMATION CONTACT). Any additional tools or supporting information that we may develop for this rulemaking will also be available at the Fish and Wildlife Service Web site and Field Office set out above, and may also be included in the preamble and/or atwww.regulations.gov.

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 (602) 242-0210; facsimile (602) 242-2513. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION: Executive Summary

Why we need to publish a rule.Under the Endangered Species Act of 1973, as amended a species may warrant protection through listing if it is an endangered or threatened species throughout all or a significant portion of its range. The Act sets forth procedures for adding species to, removing species from, or reclassifying species on the Federal Lists of Endangered and Threatened Wildlife and Plants. This document consists of a 12-month not-warranted finding and withdrawal ofErigeron lemmonii(Lemmon fleabane) from the candidate list, and a proposed rule to listEchinomastus erectocentrusvar.acunensis(acuña cactus) andPediocactus peeblesianusvar.fickeiseniae(Fickeisen plains cactus) as endangered species and to designate critical habitat. For the remainder of this document, these species will be referred to by their common names.

The Endangered Species Act provides the basis for our action.Under the Act, we can determine that a species is an endangered or threatened species based on any of 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.

We have determined that the Lemmon fleabane does no longer warrant listing. Through our five factor analysis, we have determined that the previously recognized threats to the Lemmon fleabane do not rise to a level of significance such that the species is in danger of extinction now or likely to become so in the foreseeable future.

We have determined that the following are threats to the acuña cactus:

• United States—Mexico border activities including inadequacy of regulatory mechanisms, and

• Predation by native insect and small mammal predators, in combination with other natural or manmade factors, including natural environmental variability and climate conditions such as drought.

We have determined that the following are threats to the Fickeisen plains cactus:

• Livestock grazing;

• Nonnative, invasive species; and

• Predation by native small mammal predators, in combination with other natural or manmade factors, including natural environmental variability and climate conditions such as drought.

This rule also proposes designation of critical habitat for both species.Under the Act, we must, to the maximum extent prudent and determinable, designate critical habitat for any species that is determined to be an endangered or threatened species. We are required to base the designation on the best available scientific data after taking into consideration economic and other impacts. We can exclude an area from critical habitat if the benefits of exclusion outweigh the benefits of designation, unless the exclusion will result in the extinction of the species. In total, we are proposing approximately 21,740 hectares (ha) (53,720 acres (ac)) for designation as critical habitat foracuña cactus (Table 1) and approximately 19,901 ha (49,186 ac) for the Fickeisen plains cactus (Table 2). The proposed critical habitat for acuña cactus is located in Maricopa, Pima, and Pinal Counties, Arizona. The proposed critical habitat for the Fickeisen plains cactus is in Coconino and Mohave Counties, Arizona.

Table 1—Proposed Critical Habitat for the Acuña Cactus Federal Ha
  • (Ac)
  • State Ha
  • (Ac)
  • Tribal Ha
  • (Ac)
  • Private Ha
  • (Ac)
  • Total Ha
  • (Ac)
  • 11,953
  • (29,536)
  • 5,773
  • (14,266)
  • 2,256
  • (5,575)
  • 1,757
  • (4,342)
  • 21,740
  • (53,720)
  • Table 2—Proposed Critical Habitat for the Fickeisen Plains Cactus Federal Ha
  • (Ac)
  • State Ha
  • (Ac)
  • Tribal Ha
  • (Ac)
  • Private Ha
  • (Ac)
  • Total Ha
  • (Ac)
  • 6,671
  • (16,486)
  • 5,617
  • (13,883)
  • 3,865
  • (9,554)
  • 3,748
  • (9,263)
  • 19,901
  • (49,186)
  • We are preparing an economic analysis.To ensure that we consider the economic impacts of designating critical habitat, we are preparing an economic analysis of the proposed designation.

    We will seek peer review of the methods we used in our proposal.We are seeking comments from independent specialists to ensure that our proposal is based on scientifically sound data, assumptions, and analyses.

    We are seeking public comment on this proposed rule.Anyone is welcome to comment on our proposal or provide additional information on the proposal that we can use in making a final determination on the status of these species.

    Information Requested

    We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other concerned governmental agencies, Native American tribes, the scientific community, industry, or any other interested parties concerning this proposed rule. We particularly seek comments concerning:

    (1) These species' biology, range, and population trends, including:

    (a) Habitat requirements for pollination, reproduction, and dispersal;

    (b) Genetics and taxonomy;

    (c) Historical and current range including distribution patterns;

    (d) Historical and current population levels, and current and projected trends; and (e) Past and ongoing conservation measures for these species, their habitat or both.

    (2) The factors that are the basis for making a listing determination for a species under section 4(a) of the Act (16 U.S.C. 1531et seq.), which are:

    (a) The present or threatened destruction, modification, or curtailment of their 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 their continued existence.

    (3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to these species and existing regulations that may be addressing those threats.

    (4) Additional information concerning the historical and current status, range, distribution, and population size of these species, including the locations of any additional populations of these species.

    (5) Any information on the biological or ecological requirements of the species, and ongoing conservation measures for the species and its habitat;

    (6) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531et seq.), including whether there are threats to these species from human activity, the degree of which can be expected to increase due to the designation, and whether that increase in threats outweighs the benefit of designation such that the designation of critical habitat is not prudent.

    (7) Specific information on:

    (a) The amount and distribution of these species and their habitat;

    (b) What may constitute “physical or biological features essential to the conservation of these species,” within the geographical range currently occupied by these species;

    (c) Where these features are currently found;

    (d) Whether any of these features may require special management considerations or protection;

    (e) What areas, that were occupied at the time of listing (or are currently occupied) and that contain features essential to the conservation of these species, should be included in the designation and why;

    (f) What areas not occupied at the time of listing are essential for the conservation of these species and why.

    (8) Land use designations and current or planned activities in the areas occupied by these species or proposed to be designated as critical habitat, and possible impacts of these activities on these species and proposed critical habitat.

    (9) Information on the projected and reasonably likely impacts of climate change on these species and proposed critical habitat.

    (10) Any foreseeable economic, national security, or other relevant impacts that may result from designating any area that may be included in the final designation. We are particularly interested in any impacts on small entities, and the benefits of including or excluding areas from the proposed designation that are subject to these impacts.

    (11) Whether our approach to designating critical habitat could be improved or modified in any way to provide for greater public participation and understanding, or to assist us inaccommodating public concerns and comments.

    (12) The likelihood of adverse social reactions to the designation of critical habitat and how the consequences of such reactions, if likely to occur, would relate to the conservation and regulatory benefits of the proposed critical habitat designations.

    (13) Information on certain populations of Fickeisen plains cactus. Specifically, there are eight populations where the Fickeisen plains cactus has been documented, but these areas have not been visited in over 18 years. Five populations are located on the Arizona Strip and are referred to as: Beanhole Well, Marble Canyon, Salaratus Draw, South Canyon, and Toquer Tank. The sixth population is located in proximity to Mays Wash that is south of the Town of Gray Mountain among Federal, State, and private lands. The last two populations are on the Navajo Nation. These eight areas are proposed as critical habitat for the Fickeisen plains cactus. We are seeking any information on specific population status of the Fickeisen plains cactus at these locations, whether these locations are currently occupied and contain the features essential to the conservation of the species, and the condition of the habitat.

    Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.

    Please note that submissions merely stating support for or opposition to the action under consideration without providing supporting information, although noted, will not be considered in making a determination, as section 4(b)(1)(A) of the Act directs that determinations as to whether any species is an endangered or threatened species must be made “solely on the basis of the best scientific and commercial data available.”

    You may submit your comments and materials concerning this proposed rule by one of the methods listed in theADDRESSESsection. We request that you send comments only by the methods described in theADDRESSESsection.

    If you submit information viahttp://www.regulations.gov,your entire submission—including any personal identifying information—will be posted on the Web site. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions onhttp://www.regulations.gov.Please include sufficient information with your comments to allow us to verify any scientific or commercial information you include.

    Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection onhttp://www.regulations.gov,or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Arizona Ecological Services Field Office (seeFOR FURTHER INFORMATION CONTACT).

    Organization of Document

    The layout of this rule is as follows: The 12-month not-warranted petition finding and candidate withdrawal for the Lemmon fleabane; the proposed listing of the acuña cactus and the Fickeisen plains cactus; the proposed critical habitat for the acuña cactus and the Fickeisen plains cactus.

    12-Month Petition Finding and Candidate Withdrawal for the Lemmon Fleabane

    This section summarizes the status and potential threats that we evaluated in order to determine that listing Lemmon fleabane is not-warranted and to remove it from candidate status. Additional material that we relied on is available in the Species Assessment and Listing Priority Assignment Form for Lemmon fleabane. This form is available on our national endangered species Web site:http://www.fws.gov/endangered/(search for “Lemmon fleabane” in the Species Search box).

    On July 1, 1975 (40 FR 27824), the Lemmon fleabane was included among 3,000 plant species under status review. We first identified the Lemmon fleabane as a category 1 candidate species on September 30, 1993 (58 FR 51144). Candidates are those fish, wildlife, and plants for which we have on file sufficient information on biological vulnerability and threats to support preparation of a listing proposal, but for which development of a listing regulation is precluded by other higher priority listing activities. Candidate species were assigned a relative listing priority number in accordance with listing priority guidelines published on September 21, 1983 (48 FR 43098). On the basis of immediacy and magnitude of threats, as well as taxonomic status, we assigned the Lemmon fleabane a listing priority number (LPN) of 11, which is assigned when threats are of moderate to low magnitude and non-imminent. On October 25, 1999, we changed the LPN to a 5 to reflect threats that are of high magnitude but non-imminent, based on the threat of high severity fire and drought (64 FR 57534). Later, we decided a wildfire or drought would not adversely affect the entire population; therefore, on September 12, 2006, we changed the LPN to an 8, reflecting threats that are of moderate to low magnitude and imminence (71 FR 53756), and this LPN remained in effect until the last Candidate Notice of Review in 2011 (76 FR 66370, October 26, 2011). We now find that listing this species is not-warranted, and we are withdrawing this species from candidate status because the previously recognized threats to the Lemmon fleabane do not rise to the level of significance such that the species is in danger of extinction now or likely to become so in the foreseeable future. Our rationale is explained below.

    The Lemmon fleabane is a tap-rooted perennial plant of the aster family (Nesom 2006, p. 342). The Lemmon fleabane occurs in crevices and ledges, on all aspects of tall, vertical-faced, and very cuspid (pointed) Escabrosa limestone cliffs of a single canyon, Scheelite Canyon, on Fort Huachuca on Department of Defense lands, in Cochise County, Arizona (Warrenet al.1991, p. 5; Malusa 2006, pp. 9-11). The habitat occurs over an area of approximately 50 ha (124 ac), and, as of 2006, the population is estimated to support 954 individuals (Malusa 2006, p. 9).

    The primary threat previously identified for the Lemmon fleabane was high severity wildfire, a phenomenon outside of the established fire history for the forests of the Huachuca Mountains. Scheelite Canyon is a narrow, shady, bedrock-laden cold-air-drainage, with higher humidity and cooler temperatures than surrounding areas; these factors aid in limiting the spread of severe fire within the canyon (Turner and Romme 1994, p. 59; Gebow and Hessil 2006, p. 21; Werthet al.2011, p. 27). In addition, Scheelite Canyon is a southeast to northwest configured canyon that blocks prevailing southwesterly wind. Strong southwesterly wind was a necessary component in the unusual fire behavior documented in recent high severity fires of the Huachuca Mountains, where southwest to northeast configured canyons burned downslope and burned very hot (Leiendecker 2012, pers. comm.).

    Although Scheelite Canyon currently contains a woody fuel load, fire experts believe the Lemmon fleabane itself is relatively safe from fire (Gebow and Hessil 2006, p. 51; Leiendecker 2012, pers. comm.). Recent documentation of two other rare, cliff-dwellingErigeronspecies of the Chiricahua Mountains ofsouthern Arizona indicates that plants growing in cracks within the rockwall may be both resistant and resilient to high severity fire (Malusa 2012, pers. comm.). In the unlikely event of a catastrophic fire within Scheelite Canyon, it would be extremely unlikely that every Lemmon fleabane plant would be extirpated. This is because Lemmon fleabane plants occur on all aspects of rock face, on both sides of the canyon including the entrances of small tributaries, and at all elevations on the canyon wall from the canyon bottom upwards nearly 305 meters (m) (1,000 feet (ft)) to the top of the canyon walls.

    In summary, there is a very small probability that Scheelite Canyon will sustain a catastrophic fire in the future due to the southeast to northwest aspect of the canyon in the landscape; its humid, shady, and cool nature; and the presence of exposed rock outcroppings throughout the canyon lending to a discontinuous fuel load. Should such a fire occur, it would threaten individual plants exposed to flame and heat (Gebow and Hessil 2006, p. 85); however, due to the plants occurring in a variety of locations within the canyon, it is unlikely that all plants would be affected.

    Recreational rappelling was noted as a minor threat to the Lemmon fleabane; however, we conclude that there is a very low probability of this type of activity taking place in Scheelite Canyon because recreational rappelling is not allowed by Fort Huachuca. Further, if unauthorized rappelling were to occur, the damage to Lemmon fleabane plants would be insignificant at the population level.

    In addition to fire and rappelling posing less of a threat to the Lemmon fleabane than previously believed, several conservation measures have recently occurred or are being planned. Although we did not rely on these conservation measures to make our not-warranted finding, they are underway and will benefit the Lemmon fleabane now and into the future. In 2011, the Desert Botanical Garden collected hundreds of viable Lemmon fleabane seeds for long-term storage. This collection and future-planned seed collection by the Desert Botanical Garden may help offset impacts to the species in the event of a devastating wildfire and habitat loss. In addition, the U.S. Forest Service is currently working with Fort Huachuca to reduce fire potential at a landscape level throughout the district and on Fort Huachuca itself (Leiendecker 2012, pers. comm.). Finally, Fort Huachuca and the Service are drafting a conservation agreement which, once signed, will: (a) Ensure the continued monitoring of the Lemmon fleabane population and promote adaptive management based on monitoring results; (b) continue the restrictions on recreational activities in Lemmon fleabane habitat; and (c) encourage further research into the species' life history, population biology and demographics, and distribution.

    Through our five-factor analysis, we have discounted any threats to the species and conclude there are no significant threats to the Lemmon fleabane. We, therefore, conclude that the previously recognized threats to the Lemmon fleabane do not rise to a level of significance such that the species is in danger of extinction now or in the foreseeable future. Additionally, we are not aware of any other potential stressors or threats that may impact the species or its habitat by itself or in combination, including the potential environmental effects that may result from climate change. Current and planned conservation measures will also benefit the Lemmon fleabane, although we are not relying on these conservation actions as the basis for our not-warranted finding. As a result, we have removed this species from the candidate list.

    Acuña Cactus and Fickeisen Plains Cactus Previous Federal Actions

    On July 1, 1975 (40 FR 27824), we published a Review of Status of Vascular Plants identifying the acuña cactus and the Fickeisen plains cactus as among 3,000 native plant taxa being reviewed for possible inclusion in the list of endangered and threatened species. On December 15, 1980, we published a Review of Plant Taxa for Listing as Endangered or Threatened Species and identified the Fickeisen plains cactus as category 1 species (45 FR 82480). Category 1 species were those taxa for which we had on file substantial information on biological vulnerability and threats to support proposing them as endangered or threatened species. The acuña cactus was not included in the 1980 notice. Both the acuña cactus and the Fickeisen plains cactus were included in the February 21, 1990, notice (55 FR 6184) as category 1 species.

    In the September 30, 1993, notice (58 FR 51144) candidate species were assigned a status category indicating their status at that time. Each species was identified as increasing (I), stable (S), declining (D), or unknown (U). The 1993 notice identified the acuña cactus and the Fickeisen plains cactus as category 1-U: unknown, denoting species for which additional survey work is required to determine current trends.

    We discontinued the use of a category system in the February 28, 1996, notice (61 FR 7596) and simply referred to category 1 species as candidate species. The acuña cactus and Fickeisen plains cactus were both assigned an LPN of 6, due to the high magnitude of threats which were non-imminent. We published four Candidate Notice of Reviews between 1997 and 2003, in which the acuña cactus and the Fickeisen plains cactus remained candidate species with an LPN of 6 (62 FR 49398, September 19, 1997; 64 FR 57534, October 25, 1999; 66 FR 54808, October 30, 2001; 67 FR 40657, June 13, 2002).

    On October 30, 2002, we received a petition from the Center for Biological Diversity to list the acuña cactus as an endangered species under the provisions of the Act. On May 4, 2004, the Center for Biological Diversity petitioned the Service to list the acuña cactus and the Fickeisen plains cactus as an endangered species under the Act. Because these species were already candidates for listing, we did not issue findings on the petition. In the Candidate Notice of Review dated September 12, 2006 (71 FR 53756), we revised the LPN of the Fickeisen plains cactus from 6 to 3 based on direct mortality and reduced reproductive capacity resulting from off-road vehicle (ORV) use, trampling associated with livestock grazing, a continuing drought, and herbivory by rabbits and rodents. We also acknowledged that unauthorized collection of the Fickeisen plains cactus was a potential threat but we did not know at that time whether it was a continuing threat. In the notice of December 6, 2007 (72 FR 69034), we revised the LPN of the acuña cactus from 6 to 3 based on continued decline of the species caused by ongoing drought. An LPN of 3 reflects threats that are both imminent and high in magnitude, as well as the taxonomic classification as a subspecies. In plant classification generally, the use of the term variety, such as is used in the plants in this rule, is synonymous with the term subspecies. In the notice of October 26, 2011 (76 FR 66370), we retained an LPN of 3 for both species.

    Background

    For each of the two cactus species, we provide a description of the species, its life history, its habitat, an evaluation of listing factors for that species, and our finding for the species.

    Acuña Cactus

    It is our intent to discuss below only those topics directly relevant to the listing of the acuña cactus as an endangered species in this section of the proposed rule.

    Species Description

    The acuña cactus is a small, spherical cactus, usually single-stemmed, that can be up to 40 centimeters (cm) (16 inches (in)) tall and 9 cm (3.5 in) wide (Arizona Rare Plant Guide Committee 2001, unpaginated; Zimmerman and Parfitt 2003, pp. 194-195). The acuña cactus has 11 to 15 radial spines up to 2.5 cm (1.0 in) long and 3 to 4 mauve-colored, up-turned central spines up to 3.5 cm (1.4 in) long (Arizona Rare Plant Guide Committee 2001, unpaginated; Zimmerman and Parfitt 2003, pp. 194-195). Rose, pink, or lavender flowers 3.6 to 6 by 4 to 9 cm (1.4 to 2.3 by 1.6 to 3.5 in) are produced in March (Arizona Rare Plant Guide Committee 2001, unpaginated; Zimmerman and Parfitt 2003, pp. 194-195). The fruits are pale green, are 1.25 cm (0.5 in) long, and contain small, nearly black seeds (Felger 2000, p. 208). The fruits ripen in April (Arizona Rare Plant Guide Committee 2001, unpaginated).

    Biology

    The acuña cactus relies solely on the production of seeds for reproduction, with pollination highly linked to survival, as the species cannot fertilize itself. Acuña cacti are pollinated by a suite of bees from the Andrenidae, Anthophoridae, Anthophorinae, Halictidae, and Megachilidae families; however, the leafcutter bee (Megachile palmensis) and cactus bee (Diadasia rinconis) are thought to be the primary pollinators (Johnson 1992, p. 406). The maximum distance that either of these bees travel is thought to be roughly 900 m (2,953 ft) (see Critical Habitat section, below).

    Although we do not know the lifespan of acuña cacti, there are individual plants that have been tracked at Organ Pipe Cactus National Monument (OPCNM) since 1977, and are still alive in 2012 (Holm 2012a, pers. comm.). The lifespan of seeds in the seedbank is unknown; however, in independent greenhouse tests of 6 and 4 year-old seed collected from two discrete populations, less than 19 percent and zero percent germination resulted, respectfully (Rutman 2007, p. 7). In tests of 1 and 2 year-old seed, germination ranged from 64 to 100 percent, and tests of seed collected 19 days previously resulted in 82 percent germination (Rutman 2007, p. 7). It is unknown if seed in its natural environment has the same short lifespan as has been demonstrated in these germination trials.

    Taxonomy

    This species was originally described in 1953 by W.T. Marshall asEchinomastus acunensis(Marshall 1953, pp. 33-34). It is known by many synonyms, includingSclerocactus erectocentrusvar.acunensis(Coulter) Taylor andNeolloydia erectocentra(W.T. Marshall) var.acunensisL. Benson (Arizona Game and Fish Department (AGFD) 2004, p. 1). The Cactaceae treatment in the Flora of North America (Zimmerman and Parfitt 2003, pp. 194-195) recognizes the entity asE. erectocentrusvar.acunensis.The other variety, E. erectocentrusvar.erectocentrus(needle-spine cactus), is also recognized as a valid taxon in the Flora of North America. The two varieties are generally considered to be morphologically distinct and geographically isolated, but there have been questions regarding the morphology of some individuals (AGFD 2004, p. 6). To address those concerns, the Service funded a project to analyze the morphological distinctness of the two varieties, which was completed in January 2007. The results of this study suggest that there are four distinct taxonomic groups, including the separation of varietyacunensisand varietyerectocentrus(Baker 2007, pp. 19-21), and we concur with the study results. Therefore, the acuña cactus and the needle-spine cactus are valid and distinct taxa separated morphologically and geographically. Baker (2007, p. 20) recommended nomenclatural changes, based on the International Rules of Botanical nomenclature, but formal name changes were not proposed in his study. Again, we refer to the taxonomy determined by the Flora of North America.

    Habitat

    The acuña cactus occurs in valleys and on small knolls and gravel ridges of up to 30 percent slope in the Palo-Verde-Saguaro Association of the Arizona Upland subdivision of the Sonoran Desert scrub at 365 to 1,150 m (1,198 to 3,773 ft) in elevation (Phillipset al.1982, p. 4; Arizona Rare Plant Guide Committee 2001, unpaginated; AGFD 2011, entire). This species grows on soil overlying various bedrock types including extrusive felsic volcanic rocks of rhyolite, andesite, and tuff, and intrusive igneous rocks composed of granite, granodiorite, diorite, and Cornelia quartz monzonite; Locomotive fanglomerate (sedimentary rock consisting of heterogeneous fragments of all sizes deposited in an alluvial fan and later consolidated) is also locally present (Rutman 2007, pp. 1-2; Anderson 2012a, pers. comm.). Mineralogy of these rocks is varied, with felsic or mafic phenocrysts present, depending on bedrock type (Rutman 2007, pp. 1-2; Anderson 2012a, pers. comm.). Soil texture in these locations varies between bedrock and both coarse- and fine-textured substrates (Rutman 2007, pp. 1-2). Associated plant species includeLarrea tridentatavar.tridentata(creosote bush),Olneya tesota(ironwood),Cercidium microphyllum(palo verde),Ambrosia deltoidea(triangle-leaf bursage), andAcacia greggii(catclaw). The acuña cactus is often noted growing under the protective canopy of these or other associated species (Phillipset al.1982, p. 6; Butterwick 1982-1992, entire; Felger 2000, p. 208; Service 2011a, p. 1; Service 2011b, p. 3), which may act as nurse plants, thereby sheltering seedlings from extreme temperatures and providing some protection from mechanical disturbance (Nobel 1984, p. 316; Suzánet al.1996, p. 635).

    Distribution and Range

    The acuña cactus populations are known from Maricopa, Pima, and Pinal Counties in Arizona and from Sonora, Mexico (AGFD 2004, p. 2). In western Pima County, plants are known from the Puerto Blanco Mountains and adjacent Aguajita Wash and in the foothills of the Growler Mountains south of Dripping Spring on National Park Service (NPS) lands within OPCNM; from the Sauceda Mountains on Bureau of Land Management (BLM) lands; from Department of Defense military lands on the Barry M. Goldwater Gunnery Range (BMGR); and from private lands near Ajo. There is an unconfirmed report of acuña cactus individuals occurring on Tohono O'odham lands in the vicinity of known populations on BLM and BMGR lands; however this has not been verified (Howe 2012, pers. comm.). In Maricopa County, the acuña cactus is known from the Sand Tank Mountains on BLM lands within the Sonoran Desert National Monument. In Pinal County, plants are known from Mineral Mountain on BLM, State, and private lands. In Sonora, Mexico, the acuña cactus occurs on Reserva de la Biosfera El Pinacate y Gran Desierto de Altar (Pinacate Biosphere Reserve) and private ejido (ranch) lands. Available information indicates that the current range of this species does not differ from the historical range, with the exception that the current Ajo populations likely had been part of a larger population thatoccurred before mining activity began there (Rutman 1996b, pers. comm.; Rutman 2007, p. 7). However, there are no survey records for this species in the area prior to mining activity.

    Abundance and Trends

    As the number of dead individuals documented within acuña cactus populations has increased greatly since study began in the 1970s (when tracking first began), it is important to track the number of healthy, unhealthy, and dead individuals. This not only allows us to document trends in total plant numbers, but can help in our understanding of the cause and extent of mortality.

    Federal Land—Organ Pipe Cactus National Monument (OPCNM)

    There is one large area of approximately 1,326 ha (3,277 ac) within OPCNM that contains as many as 2,000 acuña cactus individuals (Rutman 2011, pers. comm.; AGFD 2011, entire). In 1981, this population was estimated to contain 10,000 individuals (Buskirk 1981, p. 3). Within this area, two 20-by 50-m (66-by 164-ft) permanent monitoring plots were established in 1977, with the aim of investigating growth, mortality, and recruitment of this species. Between 1977 and 1981, there was 31 percent mortality in the plots (Phillips and Buskirk 1982, p. 2). Two more plots were added in 1983, and two more in 1988. From 1988 through 1991, the population was thought to be stable or increasing (Johnsonet al.1993, p. 172). From 1993 through 2011, annual mortality was variable, but exceeded recruitment in most years (NPS 2011a, p. 2). In 2011, the total number of individuals recorded in all six plots was 39 adults and 10 juveniles, showing little change since 2010. This however represents a marked decrease since their peak in 1991, when 446 individuals were recorded in the plots, 221 of which were juveniles (Holm 2006, p. 9; NPS 2011a, entire).

    In order to verify the identification and location of plants, specimens are collected, pressed, and placed on sheets that are stored in herbaria. A 1952 herbarium collection from a second location within OPCNM is evidence that a second disjunct population of the acuña cactus occurred historically within OPCNM. Current NPS staff were unaware of this herbarium collection, and the site, reported to be within 3 m (10 ft) of the U.S.-Mexico border, has not been revisited since 1952. Site visits in this area are currently considered dangerous, and therefore no efforts have been made to confirm the location of the population; we do not know if the population exists at this location.

    Federal Land—Bureau of Land Management

    Sauceda Mountains—Within the Coffeepot Area of Critical Environmental Concern (ACEC), there are several small acuña cactus populations, each on less than 2 ha (5 ac) of land.

    In 1982, the BLM (Phoenix District) established three 20-by 50-m (66-by 164-ft) monitoring plots on Coffeepot Mountain. These plots were visited, and data were collected periodically between 1982 and 1992. In 1982, 157 living and 3 dead plants were found within plots. Over the years of study, many new recruits were found; however, there was also ongoing mortality with newly dead individuals documented each year. A census of individuals from both within and nearby the plots in 1987 found 310 living and 332 dead plants (Rutmanet al.1987, p. 2). BLM staff reported a precipitous decline of this population in 1989 (Johnson 1989, p. 1). By the last monitoring visit to the plots in 1992, 150 plants were recorded dead, 22 plants were recorded missing and presumed dead, and 150 plants remained that were either healthy or in some stage of decline (Butterwick 1982-1992, entire). A note to the files in 1991 stated that many individual plants were missing, dead, or dying, and that there appeared to be little regeneration in this population (BLM 1991, p. 1). The plots have not been formally measured since 1992, but the BLM has visited this site 21 times since then to assess general health and threats to the population. Field notes by the BLM botanist in 2007 mentioned that the number of living individuals in and near these plots had been reduced by half since the 2006 site visit (Anderson 2011, p. 2). Because no population estimates were made during either year, it is difficult to know how many plants survive in and around these plots. Field notes do indicate that few juveniles were seen in 2008, and no juveniles were seen in 2009; no mention of juveniles was made in 2010 or 2011 (Anderson 2011, p. 2).

    In 2006, a second population, estimated to be between 50 and 100 individuals, was located 1.2 kilometers (km) (0.75 miles (mi)) northwest of the Coffeepot Mountain monitoring plots in Ryans Canyon (Rutman 2006, p. 2). Rutman (2006, entire) did not mention size class or health of this population. This site has not been revisited.

    A third population was discovered in 2006, 1.4 km (0.87 mi) to the northeast of the Coffeepot Mountain monitoring plots. Approximately 30 acuña cacti were noted there at the time; 25 percent mortality was reported one year later (Anderson 2011, p. 1). An October 2011 site visit by Service and BLM botanists revealed 23 adult and 2 juvenile living and 15 dead plants at this location (Service 2011a, p. 3). A fourth population was discovered by the BLM in March 2011, in a location near the third population; 10 plants were noted. No indications were given as to the age class structure or health of this population (Anderson 2011, entire).

    At a site BLM calls Little Ajo Mountains, southeast of the New Cornelia Mine on less than 0.4 ha (1 ac), the population has fluctuated from 5 plants in 1997, to 7 plants in 2001, to 7 plants in 2006, to 11 plants in 2007, to 7 plants in 2008, and finally to 12 plants (including 5 very small plants) in 2011 (Rutman 2006, p. 2; Anderson 2011, entire; Service 2011a, p. 1).

    Sonoran Desert National Monument—In 2006, approximately 200 individuals were reported from the Sand Tank Mountains in an area less than 25 ha (61.8 ac) in size. In 2007, the site was revisited, and four groups of individuals accounting for 125 of the approximately 200 individuals were mapped (Anderson 2012b, pers. comm.; Anderson 2011, p. 2). No indications were given as to the age class, structure, or health of this population (Anderson 2011, entire).

    Mineral Mountain—There are 3 individual acuña cacti growing on BLM land adjacent to 30 living plants and 22 dead plants on State lands. This population is discussed collectively below under State lands.

    Federal Land—Barry M. Goldwater Gunnery Range

    In 1997, a single adult individual was reported from just north and outside of the populations in the Coffeepot ACEC (Geraghtyet al.1997, p. 5) within Department of Defense (DOD) managed lands on the Barry M. Goldwater Gunnery Range (BMGR); this site has not been revisited.

    State Land

    Mineral Mountain—Plants were collected by Hart in 1992, from the population straddling BLM and State land east of Florence (University of Arizona Herbarium 2011, entire). There were no details of the number of individuals seen, just a map with three locations. In the 1990s, the BLM revisited this site and estimated 100 individuals scattered across 3 ridgelines (Service 2008a, p. 1). In 2008, the Service and BLM searched this area. The Service and BLM found fewer than 20 living and many dead plants; no young plants were seen. In 2011, theService and BLM botanists revisited the location and found 30 living and 22 dead plants scattered across 4 adjacent ridgelines on less than 5 ha (12.4 ac) of land; no juveniles were found (Service 2011b, p. 1).

    Ninety-Six Hills—This population is in the vicinity of Florence on less than 1 ha (2.47 ac) of land. Parfit (1977, p. 1) noted that plants here were common, but very localized. Many plants of various ages and sizes were noted, as well as many dead plants. Engard (1977, p. 1) noted many seedlings and mature plants and also that the plants were abundant locally. Rutman and Krausman (1988, p. 1) found 29 live plants and 6 dead plants in a 2-hour survey in the same general area. Breslin (2008, pp. 3-5) reported that in over 60 hours of survey effort in the area he had located 45 plants, 1 seedling, and 17 dead plants. On March 20, 2008, the Service plant ecologist found 11 live plants and 10 dead plants in a 3-hour survey. In the same general area, C. Butterworth (2008, pers. comm.) found 32 live plants, of various sizes, except seedlings. He noted that seedlings were very noticeably absent. A 2011 2-hour survey by three Service and BLM botanists revealed no living and two dead adults in this same general area (Service 2011b, p. 3). Because this population was not mapped with Geographic Information Systems, it is impossible to know if survey efforts in 1977, 1988, 2008, and 2011 were all conducted in the exact same location within this general area. Therefore, it is not possible to conclude that this population has been extirpated.

    Private Land

    Ajo Area—The combined area of these multiple sites is less than 0.4 ha (1 ac) (Rutman 2007, p. 1).

    An isolated population near Darby Wells was first reported by Heil and Melton (1994, p. 14). Fewer than 10 plants were found at this site in 2007 (Rutman 2007, p. 4). There is no record if juveniles were among the plants found. The site has not been revisited.

    On Indian Village Hill, there were 102 plants in 1996, when the population was first recorded (Rutman 1996b, pers. comm.). In 2006, 30 living and 33 dead plants were found; in 2007, a quick census noted fewer than 40 plants found (Rutman 2006, p. 1; Rutman 2007, p. 4). There is no record if juveniles were among the plants found in either year. In 2011, eight living and seven dead plants were recorded; no juveniles were found (Service 2011a, p. 1).

    There were 16 live and 19 dead plants on Weather Tower Hill in 2006 (Rutman 2006, p. 1). There is no record if juveniles were among the plants found. The site has not been revisited.

    Florence Area—Roadside populations occur on less than 0.4 ha (1 ac) collectively; any additional populations that may be present on private land occur on an unknown quantity of land.

    Roadside Population One—The 2011 site visit revealed 9 living and 2 dead individuals; no juveniles were found, though all 9 were young healthy individuals (Service 2011b, p. 2)

    Roadside Population Two—The 2011 site visit revealed 2 living and 2 dead individuals; no juveniles were found (Service 2011b, p. 2)

    There may be other locations on private lands unknown to Service or BLM botanists.

    Sonora, Mexico

    Felger (2000, p. 208) noted the occurrence of the acuña cactus between 3 and 18 km (2 and 11 mi) southwest of Sonoyta; no population estimates were made. Surveys of 7 groups of plants in this area from 2009 through 2010 revealed 659 living and 942 dead plants growing on approximately 1,700 ha (4,200 ac) (Pate 2011, pers. comm.; Pate 2011, map 1 and map 2). Pate (2012a, pers. comm.) noted seeing a few small seedlings among these plants.

    Summary

    Presented below is the total estimate of living, dead, and juvenile acuña cactus plants in populations visited over multiple years, including census results from 2011 and from previous years if sites have not been revisited or population estimates not updated. Notable trends are the large amount of mortality within the populations that have been visited more than once and the low numbers of juvenile plants in the populations.

    • NPS—2,000 plants, or 58.9 percent of known individuals; estimated in 2011 by NPS staff. This population estimate is down from 10,000 individuals estimated at this location in 1981. Within the OPCNM plots, the number of recorded individuals peaked in 1991, with 446 plants found. In 2011, 49 total individuals including 10 juveniles were noted within these plots.

    • Sonora, Mexico—659 plants or 19.4 percent of known individuals; estimated from 2009 to 2010 surveys. Nine hundred and forty-two dead individuals were also recorded during this survey period. There are no previous estimates from this population. A few juvenile plants were noted during the 2009 to 2010 survey period.

    • BLM—655 plants, or 19.3 percent of known individuals; estimated from 2011 and other recent surveys. At Coffeepot mountain within the largest BLM population, 310 living and 332 dead individuals were recorded in 1987. This population was reduced to 150 individuals by 1992, and was reduced to approximately 75 individuals by 2006. No juveniles were noted since 2008, when a few were seen.

    • Private Land—48 plants (37 near Ajo and 11 near Florence), or 1.4 percent of known individuals; estimated from 2011 and other recent surveys. A single population that was revisited on several occasions showed a total population of 102 individuals in 1996; in 2006, 30 living and 33 dead plants were found. In 2011, just 8 adult plants and no juveniles were recorded from this population.

    • State Land—32 plants, or 0.9 percent of known individuals; estimated from 2011 surveys. At one location in the 1990s, the population was estimated to be 100 individuals; in 2008, only 20 living and many dead plants were found with no juveniles seen. In 2011, 30 living plants were recorded, including a new subpopulation previously not recorded. No juvenile plants were located in 2011. At a second location, in 1977, plants were considered common but localized, and the site supported many plants of various ages and sizes. Surveys of this area in 2008 resulted in the location of 45 adult plants with no juveniles found. In 2011, no living plants and two carcasses were located in this same area.

    • Military BMGR—1 plant, or less than 0.1 percent of known individuals in 1997; the site has not been revisited.

    Summary of Factors Affecting the Acuña Cactus

    Section 4 of the Act (16 U.S.C. 1533), and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, we may list a species 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; and (E) other natural or manmade factors affecting its continued existence. Listing actions may be warranted based on any of the above threat factors, singly or in combination. Each of these factors is discussed below.

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

    Based on the habitat characteristics described above, potential factors that may affect the habitat or range of the acuña cactus are: (1) Urban development and site degradation; (2) livestock grazing; (3) border activities; (4) nonnative, invasive plant species; (5) mining; and (6) drought and climate change.

    Urban Development and Site Degradation

    The immediate threats from urban development include the direct loss of individuals and habitat. Indirect impacts of urban development include fragmentation of acuña cactus and associated pollinator populations, which can reduce genetic vigor of the cactus and result in degradation and fragmentation of habitat adjacent to development. When development occurs, there is also an increased use of habitat for recreational activity, which may also deplete habitat and result in mortality of individuals. The acuña cactus populations in OPCNM and the Sonoran Desert National Monument are protected from the immediate threats associated with urban development due to their National Monument status. National Monuments are lands set aside and managed to protect the natural and cultural resources within; development is minimal, though some site degradation may still occur.

    To meet the country's energy demands, there has been a recent emphasis by the Federal Government to use BLM lands for development of renewable energy. Currently, there are no planned solar or wind energy projects on or near populations of the acuña cactus in the Sauceda, Sand Tank, or Mineral Mountains (Werner 2011, pers. comm.). In addition, most populations on BLM lands are remotely located and relatively inaccessible; therefore, we do not anticipate development in these areas.

    As Arizona's population is expected to continue to grow in the future, both Pinal County and the State Land Department are promoting urban development in the vicinity of Florence (Pinal County 2009, pp. 4, 60, 94; Guthrieet al.2011, p. 1). When the housing market rebounds, it is likely that additional State lands in this area will be sold for urban development (Pinal County 2009, p. 42; Guthrieet al.2011, p. 2). In the vicinity of Florence, there are no current plans for development of State lands known to support acuña cacti. Private lands near Florence containing acuña cacti populations have been for sale as subdivided 16.2-ha (40-ac) parcels for many years. With the recent economic downturn, it is unlikely this land will be sold in the near future. The only known private land populations where access is readily available are at 3 sites near Ajo, totaling less than 0.4 ha (1 ac) and supporting fewer than 40 individuals in total (Rutman 2006, p. 1; Rutman 2007, pp. 1, 4; Service 2011a, p. 1). In most of the privately owned locations, the sites are littered with broken glass, bottles, and trash; however, plants appear little impacted by this habitat degradation (Service 2011a, p. 1; Service 2011b, p. 2).

    Indirect urbanization effects to the areas that support the acuña cactus include ORV activity, which has been reported on BLM lands near both Ajo and Florence. These reports, however, showed no impact on the acuña cactus populations in 1994 (Heil and Melton 1994, pp. 15-16), although habitat degradation and direct loss of individuals is possible from this activity. In 1988, the BLM closed the Coffeepot ACEC to recreational ORV use (BLM 2011, p. 194) and, in 1990, prohibited ORV use outside of designated trails within the Sonoran Desert National Monument (BLM 2011, p. 181). In 2011, the BLM Lower Sonoran Field Office released a Draft Resource Management Plan and Environmental Impact Statement (Draft RMP/EIS) for review (BLM 2011, entire). This document supports the continued prohibition of ORVs outside of designated trails within the Sonoran Desert National Monument (BLM 2011, p. 181). Within the Coffeepot ACEC, alternatives for motorized travel range from no use to limited use on existing routes, but all alternatives restrict travel off of existing routes, thereby reducing the potential for impacts to the acuña cactus (BLM 2011, pp. 181, 185-188). Once finalized, the new RMP/EIS for the Lower Sonoran and the Sonoran Desert National Monument will remain in effect for the next 15 to 20 years (Foreman 2011, pers. comm.). The impacts of ORV activity on State or private lands are unknown; for ORV activity within the border region, see the discussion below of border activities.

    In Sonora, Mexico, scattered populations of the acuña cactus occur within 10 km (6.2 mi) of the town of Sonoyta. Although the area is reported to be little-used and unoccupied except by drug and human smugglers (Pate 2011, pers. comm.), in recent decades and as a result of human demand, the Sonoyta region has been heavily impacted byOlneya tesota(ironwood) andProsopis velutina(mesquite) woodcutting for coal production, brick foundries, and tourist crafts, and the lands' subsequent conversion to exotic grasslands for cattle grazing (Suzánet al.1997, pp. 950, 955). This activity has affected more than 193,000 ha (478,000 ac) of lands in the Sonoyta region (Nabhan and Suzán 1994, p. 64). In a study of ironwoodextraction in northern Mexico, the Sonoyta study sites exhibited the highest number of damaged and dead trees, and had the lowest associated plant diversity (Suzánet al.1996, p. 642). It is likely that habitat parameters for the acuña cactuspopulations in Sonora are impacted by this activity, particularly because ironwood is considered a dominant associate of the acuña cactus (Phillipset al.1982, p. 5) and may serve as a nurse plant for a variety of cacti (Suzánet al.1996, p. 635).

    In addition, the actions of harvesting, burning, loading, and transporting wood and charcoal can result in running over individual acuña cactus and causing injury or mortality of plants, if such actions occur in areas supporting the acuña cactus. Also, human population growth and development in the border region between the United States and Mexico has risen in recent decades (Brown and Caldwell 2008, pp. 1-6); it is reasonable to conclude that the direct and indirect effects of urbanization are likely to increase threats to the acuña cactus populations in this region. The populations are currently split by a major highway, Interstate 8, and a power transmission line; many plants occur within 200 m (660 ft) of these corridors (Pate 2011, map 1 and map 2).

    In summary, the direct and indirect effects of urbanization are threats to a portion of the known populations of the acuña cactus. However, these effects are currently limited to the acuña cactus populations in the vicinity of Ajo and Florence in the United States and in the immediate border region of Sonora, Mexico. These areas collectively make up less than 21 percent of known living acuña cactus individuals across the range of the acuña cactus. The majority of the range in the United States is protected from urban development because populations are on Federal lands, where little or no development will take place. In addition, most populations of the acuña cactus are relatively remote or otherwise protected from the effects of urbanization. We conclude that urban development and site degradation is not currently a threat to any entire population of the acuña cactus. As a result, based on our review of the available information, we conclude that the direct and indirecteffects associated with urbanization are not threats to the acuña cactus and its habitat.

    Livestock Grazing

    In general, grazing practices can change vegetation composition and abundance and cause soil erosion and compaction, reduced water infiltration rates, and increased runoff (Klemmedson 1956, p. 137; Ellison 1960, p. 24; Arndt 1966, p. 170; Gifford and Hawkins 1978, p. 305; Waser and Price 1981, p. 407; Robinson and Bolen 1989, p. 186; Holecheket al.1998, pp. 191-195, 216; and Loftinet al.2000, pp. 57-58). These anticipated effects leave less water available for plant production (Dadkhah and Gifford 1980, p. 979). In addition, livestock can step on or knock over individual acuña cactus. Although other species of cacti may be good survival forage for livestock (Vega- Villasanteet al.2002, p. 499), herbivory of the acuña cactus has not been reported. Livestock grazing levels and habitat condition vary greatly between populations due to varied land ownership and management. A discussion of populations arranged by land management agency follows.

    National Park Service—Beginning in the early 1900s and continuing through the 1970s, lands within OPCNM were grazed heavily, with as many as 3,000 head of cattle and hundreds of burros present at a time when carrying capacity was estimated to be 314 cattle per year (Rutman 1997, p. 364; NPS 2011b, entire). Grazing by domestic animals was halted per NPS policy and has not occurred within OPCNM since 1976 (NPS 1997, p. 33). Lands here continue to recover slowly after loss of soils and vegetation and may take many decades or centuries to recover fully (NPS 2001, pp. 27, 124). Currently, OPCNM supports the largest population of the acuña cactus (59 percent of known living acuña cactus individuals), and we are not aware of historical effects to the population as a result of past livestock grazing.

    Bureau of Land Management—All four populations of the acuña cactus on BLM lands in the Sauceda Mountains have been managed since 1988 in the Coffeepot ACEC, which attempts to apply grazing management practices to ensure perpetuation of botanical diversity within the area and prohibits the development of livestock facilities that would serve to increase livestock use within the area (BLM 2011, p. 141). Collectively these four populations make up 13.1 percent of known living acuña cactus individuals. In 1987, when speaking of the then proposed Coffeepot ACEC, Olwell (1987, p. 1) noted relatively pristine conditions with no immediate threat to the acuña cactus plants. At that time, however, the population of acuña cactus within the Coffeepot ACEC in the vicinity of permanent monitoring plots was reported to have substantial animal activity from cattle, javelina, and jackrabbits, with browsing, grazing, and soil disturbance noted (Rutmanet al.1987, p. 2). Anderson (2011, entire) noted no habitat impacts from grazing in this population during yearly visits from 1994-2011. This population is the farthest population from a single cattle tank (see below) within the ACEC, and therefore is less subjected to livestock pressure.

    In 1970, a cattle tank named Conley Reservoir was established within the Coffeepot ACEC boundary prior to the ACEC designation and remains today (Foreman 2012, pers. comm.). A population of acuña cactus very near this tank was visited by the BLM botanist in 2010, who found abundant prickly pear (Opuntiaspp.), which are known to increase with disturbance and are often cited as an indicator of poor range condition (Anderson 2011, p. 2; Johnson 2000, entire). A site visit in 2011 by Service and BLM botanists found habitat impacts such as soil disturbance from both cattle and feral burros; however, no acuña cactus plants appeared to be directly impacted by these animals (Service 2011a, p. 3). Feral burros also impact vegetation on neighboring military lands (seeDepartment of Defensesection below).

    The new BLM Draft RMP/EIS has implications for future livestock management within the Coffeepot ACEC and the Sonoran Desert National Monument (BLM 2011, entire). According to this document, under Alternative A (the no action alternative), livestock grazing within the ACEC would not change from the current regimes with no livestock facility development permitted (BLM 2011, pp. 32, 141). Under Alternative B, livestock grazing only in times of suitable forage production (ephemeral) would continue to be considered, but perennial stocking rates would be reduced by approximately 40 percent, and no livestock facilities would be developed that would increase livestock use within the area (BLM 2011, pp. 33, 196). Under Alternative C, grazing allotments designated as perennial/ephemeral would be reclassified as perennial only, with no supplemental ephemeral grazing applications considered (BLM 2011, p. 34). Under Alternative D, all allotments currently open to grazing would become unavailable as permits expire (BLM 2011, p. 35). Under Alternative E, the BLM's preferred alternative, current grazing levels and timing would remain the same, but livestock facilities could be developed with the aim of improving natural resource conditions through greater distribution of livestock (BLM 2011, p. 171). It is unclear if additional tanks would, as is implied, relieve pressure on the acuña cactus populations; it is also unclear if this would increase the overall number of cattle (or burros) in the area or the amount of land impacted, thus potentially impacting more acuña cactus populations. Whichever alternative is ultimately chosen, the finalized version of this management plan will remain in effect for 15 to 20 years after signing later in 2012 (Foreman 2011, pers. comm.).

    In 2001, Presidential Proclamation 7397 (Clinton 2001, entire) created the Sonoran Desert National Monument; one population of acuña cactus containing 5.9 percent of known living acuña cacti occur in the Sand Tank Mountains. This area was designated for military purposes in 1941, and has had no livestock grazing for over 60 years (Clinton 2001, p. 2). During a site visit in 2006, no habitat impacts from livestock were reported from this location (Anderson 2011, p. 2). The current livestock management regime of no livestock being permitted within the Sonoran Desert National Monument Sand Tank Mountains acuña cactus population will be maintained for at least the next 15 to 20 years (BLM 2011, pp. 36-40; Foreman 2011, pers. comm.).

    Department of Defense—A single acuña cactus plant was found on BMGR approximately 1 km (0.62 m) to the north of a known population within the BLM Coffeepot ACEC (Geraghtyet al.1997, p. 5). Livestock grazing is not authorized on the BMGR, though some trespass cattle do occur (Whittle 2012, pers. comm.). Feral burros on BMGR are a concern, however, and BMGR managers plan to implement a burro trapping program in the spring of 2012, in an attempt to reduce damage to vegetation (Whittle 2012, pers. comm.).

    Arizona State Trust Lands (State land)—Populations of acuña cactus on State land in the Mineral Mountains a