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CFR Citation: 50 CFR Part 17

RIN ID: RIN 1018-AH40

NOTICE: PROPOSED RULES

ACTION: Endangered and threatened species:

DOCUMENT ACTION: 12-month finding and proposed rule.

SUBJECT CATEGORY: Endangered and Threatened Wildlife and Plants; Proposed Endangered Status for the Sacramento Mountains Checkerspot Butterfly and Proposed Designation of Critical Habitat

DATES: Comments from all interested parties received by November 5, 2001 will be considered. Public hearing requests must be received by October 22, 2001.

DOCUMENT SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to list the Sacramento Mountains checkerspot butterfly (Euphydryas anicia cloudcrofti) as endangered with critical habitat under the authority of the Endangered Species Act (Act) of 1973, as amended (16 U.S.C. 1531 et seq.). This species is restricted to meadows within the mixedconifer forest at approximate elevations between 2,450 and 2,750 meters (m) (8,000 and 9,000 feet (ft)) in the vicinity of the Village of Cloudcroft, Otero County, New Mexico. The species is threatened by destruction and fragmentation of habitat from private and commercial development, habitat degradation and loss of host plants from grazing, encroachment of conifers and nonnative vegetation into nonforested openings, over collection, and, due to its limited range, vulnerability to local extirpations from extreme weather events or catastrophic wildfire including fire suppression activities. This proposal, if made final, would extend the Federal protection and recovery provisions of the Act to this species.

SUMMARY: Critical habitat designations—; Sacramento Mountains checkerspot butterfly,

SUPPLEMENTAL INFORMATION

The Sacramento Mountains checkerspot butterfly (Euphydryas anicia (=chalcedona) cloudcrofti) is a member of the brushfooted butterfly family (Nymphalidae). The adults have a wingspan of approximately 5 centimeters (cm) (2 inches (in)) and they are checkered with dark brown, red, orange, white, and black spots and lines. The taxon was described in 1980 based on 162 adult specimens (Ferris and Holland 1980).

The Sacramento Mountains checkerspot butterfly inhabits meadows within the mixedconifer forest (Lower Canadian Zone) at an elevation between 2,450 and 2,750 m (8,000 and 9,000 ft) in the vicinity of the Village of Cloudcroft, Otero County, New Mexico. The adult butterfly is often found in association with the larval food plants New Mexico penstemon (Penstemon neomexicanus) and valerian (Valeriana edulis), and adult nectar sources such as sneezeweed (Helenium hoopesii). New Mexico penstemon is a narrow endemic species (Sivinski and Knight 1996), restricted to the Sacramento Mountains of southcentral New Mexico. Other plants that have been documented in butterfly habitat include: arrowleaf groundsel (Senecia triangularis), curlycup gumplant (Grindelia squarrosa), figworts (Scrophularia sp.), penstemon (Penstemon sp.), skyrocket (Ipomopsis aggregata), milkweed (Asclepias sp.), Arizona rose (Rosa woodsii), and Wheeler's wallflower (Erysimum capitatum) (U.S. Forest Service (FS) 1999d).

Adult butterflies apparently lay their eggs on Penstemon neomexicanus and perhaps Valeriana edulis, the known larval host plants. After hatching, larvae feed on host plants and, during the 4th or 5th instar (the period between molts in the larval stage of the butterfly), enter an obligatory and extended diapause (maintaining a state of extended inactivity), generally as the food plants die back in the fall from freezing. Some larvae may remain in diapause for more than one year, depending on environmental conditions. During diapause, larvae probably remain in leaf or grass litter near the base of shrubs, under the bark of conifers, or in the loose soils associated with pocket gopher (Thomomys bottae) mounds (Moore 1989; T. Narahashi, Lincoln National Forest, pers. comm. 1999; G. Pratt, University of California, pers. comm.1998; C. Nagano, Fish and Wildlife Service, pers. comm. 1999, E. Hein, Fish and Wildlife Service, pers. obs.). Once larvae break diapause, they feed and grow through three or four more instars before pupating (entering the inactive stage within a chrysalis) and emerging as adults. Diapause is generally broken in late spring (MarchApril) and adults emerge in midsummer (JuneJuly).

The extent of the historical range of the Sacramento Mountains checkerspot butterfly is not known due to limited information collected on this subspecies prior to its description (Ferris and Holland 1980). However, based upon the location of its meadow habitat, the general trend of commercial and private development in suitable habitat, and the encroachment of conifers into suitable habitat due to fire suppression on public and private lands, we believe that it once occupied a more extensive, but still limited area. This conclusion that the butterfly likely had a continuous distribution within currently developed areas and that its range was more extensive is further supported by the following considerations. First, extensive recent searches of apparently suitable habitat failed to locate the species (FS 1999d; 2000a; 2000d; Hager and Stafford 1999; Holland 1999; Ferris and Holland 1980; Toliver et al. 1994; Cary and Holland 1992; C. Nagano, pers. obs.; E. Hein, pers. obs). Second, butterflies in the genus Euphydryas are known to be restricted to specific habitats and are widely collected and well studied (Ehrlich et al. 1975; Cullenward et al. 1979; Murphy and Weiss 1988). If the Sacramento Mountains checkerspot butterfly were more widespread and common in areas north of the Mescalero Nation or further south of Cloudcroft below the known elevational range of the butterfly, we would expect specimens to have been collected or reported. However, this has not been the case despite the fact that butterflies in this genus are very popular to collect (C. Nagano pers. comm. 1999), and lepidopterists have surveyed and collected throughout the Sacramento Mountains (Ferris and Holland 1980; Cary and Holland 1992; Toliver et al. 1994; Hager and Stafford 1999).

The type locality for the butterfly is Pines Campground, and its description is based upon individuals collected at that location in 1964, 1976, and 1978. Although the Sacramento Mountains were extensively surveyed by lepidopterists, the known range of the butterfly in 1980 was described as,
``* * * an area of perhaps 12 square miles (mi) (2.6 to 5.2 square kilometers (km)) around the type locality'' (Ferris and Holland 1980). Toliver et al. (1994) published all of the known location records, and the estimated extent of the range of the butterfly prior to 1997 was about 8 hectares (ha) (20 acres (ac)),
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primarily from two campgrounds (Holland 1999). From 1981 to 1996, there were no documented surveys for the butterfly (R. Holland, Albuquerque, New Mexico, pers. comm. to R. GaleanoPopp Lincoln National Forest 1997; FS 2000). By 1997, the known range of the species had decreased to less than onehalf ha (Holland 1999). However, in 1997, the FS and Holland conducted limited surveys for the Sacramento Mountains checkerspot butterfly. The FS also conducted surveys during 1997, 1998, 1999, and 2000 to estimate the range of the butterfly (FS 1999d, 2000a, 2000d). Based on data gathered by the FS during 19971999, Holland (1999) described the range of the butterfly as, ``* * * now known to extend as much as 8 km (5 mi) away from the Village of Cloudcroft'' but he still considered the range `` * * * remarkably limited.''

The subspecies has been documented at 15 general localities (i.e., the geographic extent of occupied areas were not delimited and discrete populations were not identified) (FS 1999a, 1999b, 1999d, 2000a, 2000d). The known range of the butterfly is within an 85 square km (33 square mi) area, within which the distribution of the butterfly is patchy and disjunct. The known range of the butterfly is delimited on the north by the Mescalero Apache Nation lands, on the west by Bailey Canyon at the mouth of Mexican Canyon, on the east by Spud Patch Canyon and on the south by Cox Canyon (FS 2000a, 2000d). The potential range of the butterfly to the east and west is likely restricted because the nonforested areas are below 2,450 m (8,000 ft) in elevation and the majority of Sacramento Mountains checkerspot butterflies have been consistently documented at higher elevations (FS 1999a 1999b, 1999d, 2000a, 2000d). We do not know if the range of the butterfly extends into the lands owned by the Mescalero Apache Nation because, to our knowledge, no surveys have been conducted on their lands. It is also unknown whether suitable habitat is present on the lands owned by the Mescalero Apache Nation (Holland 2001). Nevertheless, there does not appear to be a significant amount of suitable habitat present on the lands owned by the Mescalero Apache Nation within the known elevational range of the Sacramento Mountains checkerspot butterfly (i.e., between 2,450 and 2,750 m (8,000 and 9,000 ft)) and proximal (i.e., provides connectivity) to butterfly localities. We solicited, but have not received, any information or comments from the Mescalero Apache Nation. More information would help clarify the status of the butterfly on these lands.

The FS used a Geographic Information System (GIS) to model the extent of existing Sacramento Mountains checkerspot butterfly habitat (FS 1999b). The model was built using nonforested openings visible on 1:24,000 scale orthophoto quadrangles, elevation, and known occupied locales. Based on the model, the FS estimated there were 2,104 ha (5,198 ac) of potential habitat, composed of 1,034 and 1,070 ha (2,553 and 2,645 ac) on private and FS lands, respectively (FS 1999b).

Extensive surveys for larvae and the adult butterflies were conducted within and outside of the modeled potential butterfly habitat during the Sacramento Mountains checkerspot butterfly's seasons of activity in 1997, 1998, 1999, and 2000 (FS 1999b, 1999d, 2000a, 2000d). These surveys partially groundtruthed the GIS model and documented that the distribution of the butterfly within the known range is patchy, disjunct, and generally located in nonforested openings along drainages, roadways, campgrounds, and valleys. The butterfly was documented on both FS and private lands (FS 1999a, 1999b, 1999d, 2000a, 2000d). We believe the modeled potential habitat is an accurate representation of suitable habitat (habitat that can be used by the butterfly). Based on GIS maps and the model provided by the FS, about 46 of 202 ha (114 of 498 ac) and 240 of 813 ha (592 of 2,010 ac) of suitable habitat surveyed during 1998 and 1999, respectively, were occupied by the butterfly. Seven hundred acres were surveyed during 2000, but it is unknown what proportion of the suitable habitat is currently used by the butterfly (i.e., the data only indicate the total acres surveyed and do not differentiate between areas currently used or unused by the butterfly) (FS 2000d). Nevertheless, survey areas during 1999 and 2000 overlapped and went beyond the boundary of the areas surveyed in 1998. Therefore, these data represent the best available information on the area used by the butterfly (determined by surveys) within suitable habitat. Based on these data, it appears that 15 to 35 percent of suitable habitat is currently used by the Sacramento Mountains checkerspot butterfly. Thus, we estimate that 316 to 736 ha (780 to 1,819 ac) of the suitable 2,104 ha (5,198 ac) are currently used by the Sacramento Mountains checkerspot butterfly.

Although the surveys conducted by the FS were directed at estimating the range of the Sacramento Mountains checkerspot butterfly, the individuals seen were also estimated. In 1997 and 1998, 595 adults and 114 larval tents (communal webs that contain larvae) were documented at 15 general localities, whereas the surveys in 1999 documented 1,629 adults, 26 postdiapause larvae, 800 prediapause larvae, and an unknown number of larval tents at generally the same localities, and surveys during 2000 documented approximately 1,000 adults, 26 postdiapause larvae, and 157 larval tents (FS 1999a 1999b, 1999d, 2000a, 2000d; Pittenger 1999). No new butterfly localities were documented during the 2000 field season, although the known range of the butterfly was expanded slightly (FS 2000d). Surveys were also conducted by the FS on 231 ha (570 ac) within the Smokey Bear Ranger District, north of the Mescalero Apache Nation during 1999, but did not document any Sacramento Mountains checkerspot butterflies (FS 2000a). None of these data provide a basis for estimates of actual population size, because no formal population estimation procedures were used. The surveys conducted by the FS are the result of one or more surveyors walking through suitable habitat and counting or estimating the number of individuals observed.

Because the Sacramento Mountains checkerspot butterfly has a life history pattern similar to other butterflies in the genus Euphydryas that exist as metapopulations, it is likely that this butterfly has a metapopulation structure (Murphy and Weiss 1988; Harrison 1989; Hanski and Gilpin 1991). A metapopulation is a set of local populations within an area, where typically migration from one local population to other areas containing suitable habitat is possible, but not routine. Movement between areas containing suitable habitat (i.e., dispersal) is restricted due to inhospitable conditions around and between areas of suitable habitat. Because many of the areas of suitable habitat may be small, and support small numbers of butterflies, local extinction of these small populations may be common. A metapopulation's persistence depends on the combined dynamics of these local extinctions and the subsequent recolonization of these areas by dispersal (Hanski 1999, Hanski and Gilpin 1991, 1997, McCullough 1996). We believe habitat loss has reduced the size of and connectivity between patches of suitable butterfly habitat. The reduction in the extent of meadows and other suitable nonforested areas has likely eliminated
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connectivity among some localities and may have increased the distance beyond the normal dispersal ability of the Sacramento Mountains checkerspot butterfly, making recolonization of some patches following local extinction more difficult (Cullenward et al. 1979; Hanski 1999). In addition, habitat reduction lowers the quality of remaining habitat by reducing the diversity of microclimates and food plants for larvae and adult butterflies (Murphy and Weiss 1988; Thomas et al. 1996; Hanski 1999).

Based on available information on topography, soils, and vegetation, it is likely that the distribution of the Sacramento Mountains checkerspot butterfly was more extensive and continuous prior to the increase in commercial and private development, construction of roads, overgrazed range conditions, and the encroachment of conifers and subsequent decrease in the amount of nonforested lands. Many of the remaining Sacramento Mountains checkerspot butterfly populations are likely small and/or not viable (i.e., are likely to become extirpated in the near future). The isolated localities and limited geographic range of the butterfly indicate that the species is particularly vulnerable to perturbations (disturbances that impact the habitat and host plants associated with the species), which could lead to extinction (Ehrlich et al. 1972; Thomas et al. 1996).

Previous Federal Action

On January 28, 1999, we received a petition from Mr. Kieran Suckling of the Southwest Center for Biological Diversity in Tucson, Arizona, dated November 1998, which requested that we emergency list the Sacramento Mountains checkerspot butterfly as endangered. The petitioner stated that the species merits listing because of its restricted range, adverse impacts resulting from a proposed FS land transfer, improvements to a FS campground, construction of homes and other structures, aggressive nonnative weeds that may be affecting the larval food plants and adult nectar sources, global climate change, and livestock overgrazing. The petitioner requested emergency listing due to the perceived immediate threats to the species' continued existence from a proposed land transfer between the FS and the Village of Cloudcroft in the Sacramento Mountains in Otero County, New Mexico.

In accordance with section 4(b)(3)(A) of the Act, we published notice of our finding in the Federal Register on December 27, 1999 (64 CFR 72300), that the petitioner presented substantial information indicating that listing may be warranted, but that emergency listing was not warranted, and commenced a status review. In that notice we requested any additional data or scientific information concerning the status of the species including additional historical and current population data, pertinent information on biology or life history, information on habitat requirements, and information on immediate and future threats to the butterfly and areas inhabited by the species. During the twomonth comment period, we received eight comments from individuals or agencies. One commentor supported, and four opposed listing the species; one requested the references cited; and two provided general comments or data on the Sacramento Mountains checkerspot butterfly. We received most substantive data relating to life history, current range, and threats from the Lincoln National Forest. The Sacramento Ranger District in the Lincoln National Forest has been instrumental in avoiding or minimizing some recent potential impacts to the butterfly on their lands. We incorporated these and other pertinent data into this proposal.

Section 4(b)(3)(B) of the Act requires the Secretary of the Interior to reach a final decision on any petition accepted for review within 12 months of its receipt. That decision, to be published in the Federal Register, must be one of the following findings: (1) The petitioned action is not warranted; (2) the petitioned action is warranted (a proposed regulation is published); or (3) the petitioned action is warranted, but the immediate proposal is precluded by listing actions of higher priority. On July 31, 2001, the United States District Court for the District of New Mexico, in Center for Biological Diversity v. Gale A. Norton, CIV 010258 PK/RLP ordered us to complete and submit for publication to the Federal Register a 12month finding for the Sacramento Mountains checkerspot butterfly within 30 days. This proposed rule constitutes our 12month petition finding that listing as endangered is warranted for the Sacramento Mountains checkerspot butterfly.

Peer Review

In accordance with interagency policy published on July 1, 1994 (59 FR 34270), upon publication of this proposed rule in the Federal Register, we will solicit expert reviews by at least three specialists regarding pertinent scientific or commercial data and assumptions relating to the taxonomic, biological, and ecological information for the Sacramento Mountains checkerspot butterfly. The purpose of such a review is to ensure that decisions are based on scientifically sound data, assumptions, and analyses, including the input of appropriate experts. We will send these peer reviewers copies of this proposed rule immediately following publication in the Federal Register. We will invite these peer reviewers to comment, during the public comment period, on the specific assumptions and conclusions regarding the proposed designation of critical habitat.

Summary of Factors Affecting the Species

Section 4 of the Endangered Species Act and regulations (50 CFR part 424) promulgated to implement the listing provisions of the Act set forth the procedures for adding species to the Federal lists. A species may be determined to be an endangered or threatened species due to one or more of the five factors described in section 4(a)(1). These factors and their application to the Sacramento Mountains checkerspot butterfly are as follows:
A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

The threats that have been identified are commercial and private development, FS activities, fire suppression and wildfire, highway and forest road reconstruction, recreational impacts, domestic livestock grazing, nonnative vegetation, and insect control.

Commercial and Private Development

Commercial and private development is a significant threat to the Sacramento Mountains checkerspot butterfly. Habitat conversion activities from commercial and private development have likely already reduced many historic Sacramento Mountains checkerspot butterfly localities to nonviable states. Approximately fifty percent of all lands that might support the butterfly are in private ownership, subject to ongoing and future development activities. Much of these private lands are currently being developed for residential or commercial uses (FS 1986; FS 1997; E. Hein, pers. obs.; Holland 2001). Commercial and private development has been and is currently encouraged by the Village of Cloudcroft (Southeastern New Mexico Economic Development District 1974; Cloudcroft Area Sustainability Team 1995; J. Wilson, Lincoln National Forest, pers. comm. 2000). Within the known range of the Sacramento Mountains
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checkerspot butterfly, there are two golf courses, at least 12 private developments, the Village of Cloudcroft, schools, several recreational parks, a ski area, and a network of paved, gravel, or dirt roadways.

The elevation, habitat, soils, and topography of these developed areas appear similar to areas that are known to be used by the butterfly and are either fragmenting or near to localities that support butterflies. For example, a subdivision on the east side of the Village of Cloudcroft is currently developing and eliminating approximately 10 ac of suitable, and likely currently used, butterfly habitat. This and other recent or proposed developments have or will likely fragment the distribution of the butterfly and eliminate butterfly localities or prevent the Sacramento Mountains checkerspot butterfly from moving between areas of suitable habitat (Murphy and Weiss 1988). Therefore, we believe that these private and commercial development activities have likely eliminated or interrupted dispersal of butterflies between suitable habitat patches and thus affected the metapopulation dynamics of the Sacramento Mountains checkerspot butterfly.

The construction of homes, businesses, and associated infrastructure in the habitat of the Sacramento Mountains checkerspot butterfly could directly affect the species through mortality or result in indirect effects, such as the introduction of nonnative plants and animals or loss of movement corridors (Holland 2001). Ground disturbance and vegetation clearing for commercial or private development can disturb soils, remove or eliminate diapause sites (i.e., leaf litter and grasses) and larval or adult food plants, and kill or injure individuals (Wilcox and Murphy 1985; Murphy and Weiss 1988; C. Nagano, pers. comm., E. Hein, pers. obs.). We have observed nonforested areas of private lands that historically were probably suitable butterfly habitat; however, some of these areas currently contain thick mats of oat grass (Arrhenatherum elatius), pastures devoid of vegetation from livestock grazing, and filled stock ponds and/or dammed wetlands that have eliminated suitable habitat of the Sacramento Mountains checkerspot butterfly.

The butterfly likely occupies a significant amount of private lands since habitat used by the butterfly occurs on FS land that is immediately adjacent to these areas and the elevational and habitat characteristics are contiguous (FS 2000a). Based on a GIS model, the FS estimated that there were 1,034 ha (2,553 ac) of potential habitat on private lands (FS 1999b). Because of the groundtruthing and butterfly surveys conducted using the model, we believe that this amount is a reasonable approximation of the maximum amount of suitable habitat present on private lands. Based upon butterfly and habitat surveys conducted by the FS, we have estimated that between 15 to 35 percent of suitable habitat is occupied by the Sacramento Mountains checkerspot butterfly (E. Hein, pers. obs.). Therefore, 155 to 362 ha (383 to 894 ac) of private land may be occupied by the butterfly and nearly all of the suitable habitat on private land is at risk from commercial and private development and the direct or indirect impacts thereof.

The population of the Village of Cloudcroft and vicinity has increased by 34 percent since 1970, and the number of housing units that were constructed during this period has increased by 50 percent (U.S. Census Bureau 1998; New Mexico Economic Development Department 1999). Based upon electrical power service and demand, the Village of Cloudcroft and surrounding areas within the range of the butterfly have sustained population growth of about 2.5 percent per year; these levels are projected to increase (FS 1999e). New subdivisions currently are being constructed on private land and there are many properties for sale ranging from less than 1 ha (2.5 ac) to at least 100 ha (250 ac) that appear to contain suitable nonforested habitat. Further, a 9hole golf course is being discussed as a community recreational goal and objective for the Village of Cloudcroft in 2005 (Cloudcroft Area Sustainability Team 1995). Nonforested lands within the range of the Sacramento Mountains checkerspot butterfly are generally preferred by commercial and private developers, because these areas are less costly to develop (i.e., there are no trees to clear and the land generally lacks steep topography and is accessible from roads). This may result in a disproportionate impact on butterflies and their habitat. For example, Holland (1999, 2001) reported that the butterfly historically occurred in two meadows totaling 8 ha (20 ac) in the early 1980s; these areas were reduced by private development to less than 0.4 ha (1 ac) by July 1997.

In addition, heavy clearing and mowing activities on improved (i.e., with existing structures) or unimproved private lands, to reduce the threat of wildfire or improve the residential appearance, could eliminate larval or adult food plants and/or localities that are used by the Sacramento Mountains checkerspot butterfly. Additionally, the conversion of native landscapes to nonnative vegetation (e.g., lawns or gardens) could fragment localities, eliminate movement corridors, cause additional loss of suitable habitat (Wood and Samways 1991, Holland 2001). Developing areas reduce blocks of native vegetation to fragments that are insularized, creating a matrix of native habitat islands that have been altered by varying degrees from their natural state. Given the development pressures and history of construction in the vicinity of the Village of Cloudcroft, the remaining butterfly localities are at risk of extirpation.

FS Activities

We are aware of FS projects proposed within the known range of the butterfly that have the potential to adversely affect the Sacramento Mountains checkerspot butterfly. For example, the following projects are in various stages of planning or construction: (1) A capital improvement project for three campgrounds; (2) a new power line, service road, and corridor; (3) livestock grazing activities in several allotments, one of which encompasses over 44,921 ha (111,000 ac); and (4) a land transfer to the Village of Cloudcroft (FS 1999a, 1999b, 1999f, 2000; Service 1999, 2001).

One campground located near the Village of Cloudcroft contains one of the greatest known concentrations of the Sacramento Mountains checkerspot butterfly. Reconstruction activities in this campground are proposed for the year 2003, including replacement of existing or construction of new bathroom facilities, traffic control barriers, picnic tables, and campfire pits (FS 1999a, 1999b). Similar to trampling (see discussion below), these ground disturbance activities have the potential to directly (e.g., by crushing larvae) and indirectly (e.g., by destroying food plants) impact this species. We are providing technical assistance to the FS in an attempt to avoid or minimize adverse impacts to the Sacramento Mountains checkerspot butterfly. The FS intends to begin work on a management plan to address the conservation of the Sacramento Mountains checkerspot butterfly and to address future potential impacts in the near future (M. Crites, Lincoln National Forest, pers comm. 2000); however, no plan has been developed to date.

The FS is proposing to transfer land pursuant to the Townsite Act to the Village of Cloudcroft (FS 1997; 2001a). The proposed land transfer would involve 33 ha (81 ac) on 5 different parcels. Sacramento Mountains
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checkerspot butterflies have been observed on three of the five parcels (numbers 3, 4, and 5) and in adjacent lands (FS 1997, 1999a, 1999b, 1999d, 2000, 2001a, E. Hein, pers. obs.). The Village of Cloudcroft and the FS agreed to eliminate from the current land transfer proposal three other parcels (numbers 6, 7, and 8), in which a number of Sacramento Mountains checkerspot butterflies have been observed (FS 1999a, 1999b, 2001a). The stated purpose for the proposed land transfer is to provide additional land for commercial, industrial, educational, and recreational expansion and permit controlled growth (Village of Cloudcroft 1996). Development of these parcels would be consistent with past and current community development policies and objectives of encouraging commercial and private development in and around the Village of Cloudcroft (Southeastern New Mexico Economic Development District 1974; Village of Cloudcroft 1996; J. Wilson, pers. comm. 2000). A decision on the five parcels will be finalized this fiscal year (FS 2001a). If the parcels of land currently used by the butterfly are transferred and subsequently developed, habitat used by the butterfly could be further degraded or eliminated, suitable habitat further fragmented, and the movement of butterflies between local populations may be restricted.

The FS has eliminated some proposed projects (e.g., the construction of new administrative building) in habitat used by the butterfly. They have also taken some actions to protect and manage the Sacramento Mountains checkerspot butterfly, including instituting a butterfly closure order (see discussion below), fencing a portion of one butterfly locality, and conducting butterfly surveys to determine range and occupancy (FS 1999a, 1999b, 1999h, 2000a, 2000d). These actions have been beneficial, especially for increasing our knowledge of this species. However, we believe that other multiple use priorities on FS lands, such as range management, road maintenance, or capital improvement projects, may adversely impact this species (e.g., see discussion on road maintenance below).

Fire Suppression and Wildfire

The results of 100 years of fire suppression in the Sacramento Ranger District currently threatens the Sacramento Mountains checkerspot butterfly. Fire exclusion and suppression have reduced the size of grasslands and meadows by allowing the encroachment of conifers, and these trends are projected to continue (FS 1995, 1999h). Officials on the Lincoln National Forest reported that high forest stand densities exist on 35 percent of mixed conifer forests and 22 percent of ponderosa pine forests, and that insect and dwarf mistletoe infestations occur on 57 and 64 percent of their ponderosa pine forests, respectively (GAO 1999a). The natural fire regime historically maintained nonforested openings and meadows. Prior to 1900, the mean natural fire interval for forests in the Sacramento Mountains was about 4 to 5 years (Kaufmann et al. 1998). These frequent, lowintensity, surface fires historically maintained a forest that was more open (i.e., more nonforested patches of different size, more large, older trees, and fewer dense thickets of evergreen saplings) than it is currently (Kaufmann et al. 1998). Such lowintensity fires are now a rare event.

It is likely that fire exclusion and cattle grazing have severely altered and increased the threat of wildfire in ponderosa pine (Pinus ponderosa) and mixed conifer forests in the semiarid western interior forests, including New Mexico (Belsky and Blumenthal 1997). For example, ponderosa pines have increased from 19 to 64 trees per ha (46 to 158 per ac) from 1911 to 1995, and mixed conifers increased from 92 to 192 trees per ha (227 to 475 per ac) from 1906 to 1995, in the Sacramento District of the Lincoln National Forest (FS 1999h). Further, there has been a general increase in the dominance of woody plants, with a decrease in the herbaceous (nonwoody) ground cover (FS 1995) used by the butterfly (FS 2000a). These data indicate that the quality and quantity of the available butterfly habitat is decreasing range wide. Alternatively, restoration of natural processes and conditions may be difficult because of permanent impairment of areas from soil loss; the presence or dominance of noxious weeds, and the need to protect existing homes and businesses (FS 1995). Therefore, we believe that fire exclusion has substantially affected the species and will likely continue to significantly degrade the quality and quantity of suitable habitat. Additionally, future actions to manage or reduce the threat of wildfire will likely be more difficult to implement because of continued private development and the risk of fires escaping.

The Sacramento Mountains checkerspot butterfly is extremely vulnerable to catastrophic (i.e., highintensity and large) wildfires in suitable butterfly habitat. Fire has caused the extirpation of populations of other butterflies in the genus Euphydryas (Murphy and Weiss 1988; 62 FR 2313). Future wildfires within the known range of the Sacramento Mountains checkerspot butterfly will likely be large scale, and, under current conditions, are imminent (FS 1999h). Large fuel accumulations (e.g., the encroachment of conifers into meadows and the development of mats of Kentucky blue grass (Poa pratensis) and oat grass (Arrhenatherum elatius)) can lead to intense soil heating and deep heat penetration, which could be lethal to the food plants and the various life stages of the Sacramento Mountains checkerspot butterfly (Society of American Foresters 1984). During the last 50 years in the Sacramento Mountains, at least nine catastrophic wildfires have burned over 34,000 ha (90,000 ac) (Kaufmann et al. 1998). In the next few years, the Sacramento Ranger District may have a catastrophic burn that eliminates some or all of the remaining butterfly habitat.

From 1.2 to 14.3 percent of various forest cover types totaling about 202,347 ha (0.5 million ac) are predicted to burn between 1994 and 2005 in the southwestern region of the FS (FS 1995). The Government Accounting Office (GAO) (GAO 1999a, 1999b) reported that the FS and scientists generally agree that the efforts to reduce the threat of large, intense, uncontrollable, destructive wildfire will likely fail because funding is inadequate for a cohesive fire management strategy to be implemented. In completing its Forest Plan, the Lincoln National Forest selected an alternative that had one of the highest overall fire risks, because the proposed fire protection and suppression budget provided less protection than most of the other alternatives considered (FS 1986). The FS concluded that the preferred alternative had one of the greatest probabilities of serious uncontrolled wildfires relative to other alternatives considered (FS 1986). Whether recent funding increases for FS fire risk reduction actions can result in sufficient implementation to reduce fire threats to the butterfly over the short term is unclear.

For instance, the threat of wildfire has been recognized as significant since the latest Lincoln National Forest Plan (FS 1986). The Sacramento Ranger District of the Lincoln National Forest has recently approved a longterm fire management plan to reduce the threat of catastrophic wildfire in the wildlandurban interface (FS 1999h). This plan will treat about 5,666 ha (14,000 ac) of about 202,347 ha (0.5 million ac) that were the subject of a fire danger assessment on the Sacramento Ranger District. The District's assessment found about 53,419 ha (132,000 ac) had a high
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risk potential for fire ignitions, and about 89,032 ha (220,000 ac) had high fuel characteristics. The project proposes to reduce the high fire risk on the District through thinning and prescription burns on about 15 percent of the 142,452 ha at risk (352,000 ac) (FS 1999h). The FS has also recently proposed thinning 97 ha (239 ac) on the western edge of the Village of Cloudcroft (FS 2000c). The FS concluded that these projects are not expected to change the existing habitat conditions for the butterfly, or positively or negatively impact the butterfly (FS 1999h, G. Garcia, pers. comm. 2000).

Recently, the Southwestern Region of the FS initiated a program to reduce the risk of catastrophic crown fire in the wildland urban interface (FS 2000e). This program is designed to reduce fuel loads to protect life, property, and natural resources. Approximately 1.9 million acres are proposed for fuel load reduction within the National Forests in Arizona and New Mexico. These treatments are anticipated to be implemented slowly, with 20 to 30 projects beginning this fiscal year 2001, and the remainder of the projects spread over a 5 to 8 year period (J. Agyagos, FS, pers. comm.). The GAO also recently reported that Federal agencies are not organized to effectively and efficiently implement the national fire plan (GAO 2001). Therefore, it is unknown whether the proposed treatments will effectively reduce the risk of catastrophic wildfire to the butterfly or its habitat.

We believe that the reduction of fire risk may be very limited in geographic extent; consequently, the only potential for short term benefits for the butterfly may be a decrease in the amount of atrisk area and/or interrupting or reversing the encroachment of conifers in some areas to create or enlarge nonforested areas suitable for the butterfly. There are no fire risk reduction projects at nine of the known butterfly localities, and the prescriptions near the other six localities will be limited. Therefore, we concur with the FS that it is highly probable that the overall risk of fire or the encroachment of conifers will not be significantly reduced or eliminated by these efforts. We are not aware of any other projects to address the risk of fire on the Sacramento Ranger District. FS officials agree that when catastrophic fires occur, they will likely permanently damage soils, habitat, and watershed functioning (FS 1986; GAO 1999a).

The GAO reported that only 1025 years remain to resolve the increasing threats of catastrophic wildfire before widespread damage from uncontrollable wildfires becomes inevitable. A random event, such as catastrophic fire, is highly probable and could easily destroy part of a Sacramento Mountains checkerspot butterfly locality or entire localities, or decrease a locality to so few individuals that risk of extirpation from genetic and demographic problems would increase.

The GAO concluded that the FS will likely not be able to meet its goal of reducing the threat of wildfire by 2015 because efforts and resources will need to be divided between reducing accumulated fuels on highrisk areas and maintaining lowrisk conditions on other areas. For instance, the budget for fire suppression in the Lincoln National Forest plan was nearly double that of hazard protection (FS 1986). The GAO concluded that the threats and costs associated with wildfires, together with the urgent need to reduce the threats, make them the most serious immediate problem related to forest health in the interior West. We believe that this risk of wildfire is one of the most significant threats facing this species and projects resulting from increased fire risk funding will need to be implemented before significant risk reduction for the butterfly is achieved.

Highway and Forest Road Reconstruction

Construction of roadways has historically eliminated or reduced the quality or quantity of Sacramento Mountains checkerspot butterfly habitat (see also Factor E) (Pittenger 1999; E. Hein, pers. obs.), increasing the risk of extinction throughout all or a significant portion of the species' range. The reconstruction of forest roads is a threat to the Sacramento Mountains checkerspot butterfly, causing elimination of larval food and adult host plants, crushing of butterflies, and increasing the amount of soil erosion or dust. Because roads are usually sited in open nonforested areas, larval food and adult nectar plants are frequently found in large concentrations along roadways (E. Hein, pers. obs.). These areas can similarly contain aggregations of pre and postdiapause larvae, because bare soils provide sites for thermoregulation (maintenance of a constant internal body temperature regardless of environmental temperature) (Porter 1982). Therefore, activities that disturb suitable habitat adjacent to roadways can impact very high quality sites, important for the development of various life history stages (e.g., prediapause instar development). We have recently observed road grading activities on FS and private lands that cleared at least 1 ha (2.4 ac) of larval and adult food plants, and may have directly killed individual larvae through crushing (E. Hein, pers. obs.). Butterflies in the adjacent nongraded areas may also be indirectly affected by soil erosion or dust covering and killing food plants (Farmer 1993). We believe that road maintenance activities can cause localized adverse impacts to the Sacramento Mountains checkerspot butterfly.

The New Mexico State Highway and Transportation Department (NMSHTD) recently improved portions of an approximately 3.2 km (2 mi) long stretch of State Highway 130 between the Village of Cloudcroft and the intersection of SH 130 and Sunspot Road (Metric Corporation 1996; Steve Reed, NMSHTD, pers. comm. 1999). The project cleared all vegetation by scraping and widening the road and shoulders, constructing retaining walls, adding drainage ditches and culverts, and reconstructing a curve. In 1998 and 1999, Sacramento Mountains checkerspot butterflies were located within the construction footprint (FS 1999a, 1999b; 1999d, E. Hein, pers. obs.); however, none were observed during surveys in 2000 and 2001 (E. Hein, pers. obs.). In July 1999, topsoil and vegetation were scraped and Sacramento Mountains checkerspot butterflies were likely killed (E. Hein, pers. obs.). Some topsoil and larval food plants were stockpiled and used in the revegetation when the project was completed. However, fewer than 10 New Mexico penstemon were replanted in the revegetation effort and the area is currently overgrown by noxious weeds (see discussion below). In addition, extensive retaining walls and roadsides were constructed with rocks and little to no soils may preclude revegetation in some areas that were likely used by the Sacramento Mountains checkerspot butterfly as corridors (Haddad and Baum 1999; Haddad 1999). The NMSHTD will monitor the revegetation areas for the recruitment and survival of larval food plants and adult nectar sources, and to determine whether the butterfly recolonizes the area. The NMSHTD is also conducting a fiveyear study on the natural history of the butterfly to increase the knowledge of the species (NMSHTD 2000; Pittenger 2001).

Recreational Impacts

Offhighway vehicles (OHVs) pose a threat to the butterfly through direct crushing of eggs, larvae, pupae, or thermoregulating adults located on bare soils, leaves, or grasses within or adjacent to trails and roads. Because each larval web of the butterfly contains from 10 to 100 prediapause larvae (T.
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Narahashi, pers. comm. 1999), hundreds to thousands of individuals could potentially be impacted in some localities. Thermoregulation sites are chosen by some Euphydryas sp. larvae for their solar radiation absorbance characteristics (Porter 1982). This site selection behavior is likely to occur with the Sacramento Mountains checkerspot butterfly because of relatively low temperatures during spring and summer months (E. Hein, pers. obs.). Postdiapause larvae in the genus Euphydryas can also be gregarious and cluster in areas of open soils, such as trails and roads, to thermoregulate (C. Nagano, pers. obs.; E. Hein, pers. obs.; Porter 1982; Weiss et al. 1987; Osborne and Redak 2000). We know of other butterflies that have also been impacted from OHVs (e.g,. Neonympha mitchellii mitchelli, 56 FR 28825; Glaucopsyche lygdamus palosverdesensis, Arnold 1987; Apodemia mormo langei, Fish and Wildlife Service 1984; Euphydryas editha quino, 62 FR 2313; G. Pratt, pers. comm. 1998; M. Elvin, Fish and Wildlife Service, pers. comm. 2000).

Offhighway vehicle use is increasing in many western states (GAO 1995), and on the Lincoln National Forest (FS 1986, 1993). The FS estimated there were 1,368 km (850 mi) of OHV routes on their lands in the Southwestern region, with at least 80 km (50 mi) being added annually (FS 1986). OHVs can cause significant environmental damage to both vegetation and animals (including butterflies) (Webb and Wilshire 1983), and are causing vegetation and erosion on FS land, primarily in meadows, riparian areas, and steep slopes (FS 1986). The authorized and unauthorized use of OHVs can adversely affect Sacramento Mountain checkerspot localities (FS 2000a). Executive Orders 11644 and 11989 were issued in the 1970s to establish policies and procedures for regulating OHVs. Compliance with these executive orders has been mixed; for example, incomplete inventories of open and closed OHVs routes, inadequate mapping and signing of routes, and limited monitoring of the effects of OHVs on natural resources have been the primary deficiencies (GAO 1995). Similar OHV problems exist on the Sacramento Ranger District, where, despite efforts by the FS to alleviate OHVrelated impacts to the Sacramento Mountains checkerspot butterfly, problems are still occurring. For example, the FS recently posted signs indicating that OHVs were not allowed in an area that currently supports the Sacramento Mountains checkerspot butterfly after noticing OHV tracks through a monitoring plot (FS 2000a). Although the Lincoln National Forest has closed areas to OHVs in the past, these efforts have not been effective in stopping unauthorized OHV use in nonforested areas (Fish and Wildlife Service 1994; Forest Guardians 1999), even when the area was partially fenced (T. FiedlerHarper, pers. obs. 1999).

The Sacramento Mountains checkerspot butterfly may also be threatened by impacts from mountain bikes. The butterfly is found along and adjacent to several popular mountain biking routes, including trails that are traversed in an annual 2day bike race during midMay when postdiapause larvae are actively thermoregulating in these areas (FS 2000a; M. Crites, pers. comm. 1999; E. Hein, pers. obs). This race regularly attracts several hundred racers.

Mountain bikes may be directly or indirectly affecting larval food plants, nectar sources, or various life stages of the butterfly through the development trail ruts, the loss of residual topsoil and vegetation, increased erosion, the creation of stretches of standing water or muddy trail/road conditions, the development of parallel tracks, and the establishment of unauthorized trails (Cessford 1995). For example, following the bike race, we found crushed larval food plants along part of the race course that bisects one of the campgrounds that currently supports the butterfly (E. Hein, pers. obs.). Moreover, a recent study found that 58 percent of National Forests surveyed reported evidence of resource damage from mountain bikes (Chavez 1996).

Although the potential impact of mountain biking activities on butterflies has been infrequently studied, we know of other invertebrates that are impacted by bicycle traffic (e.g. Cicindela ohlone) (65 FR 6952). Moreover, mountain bike impacts are similar to other recreational impacts, and are likely to result in soil compaction, erosion, or the elimination or reduction of vegetation (Liddle 1975; Cessford 1995; Trails and Wildlife Task Force 1998). The significance of direct mortality on population viability is unknown at this time, but is considered a potential threat to the butterfly, particularly if bicycle traffic through areas used by the butterfly increases.

Hiking and camping pose a threat to the butterfly because of the development of trails, barren areas, and trampling, but the potential significance of these impacts has not been quantified. The development of parallel tracks, muddy trails, and erosion through meadows and non forested areas may affect the butterfly through the reduction or elimination of larval and adult food plants (Boyle and Samson 1985; Kuss 1986; Hampton and Cole 1988). Cole (1995) reported that erect vegetation is readily damaged by trampling, with erect forbs, similar to the food plants of the butterfly, less resistant than those with matted or rosette (circular cluster of plant parts or leaves) growth. Meadows or nonforested areas, which may also be suitable habitat or support the Sacramento Mountains checkerspot butterfly, are favored locations for many campers (Hampton and Cole 1988; Cole 1989 and references therein). We observed a variety of these impacts (e.g., barren ground, trampled food plants, multiple trails, vehicle tracking, etc.) in areas used by larval and adult life stages of the Sacramento Mountains butterflies; these impacts are likely reducing the quality or quantity of suitable habitat in and around developed campgrounds or undeveloped campsites known to support the Sacramento Mountains checkerspot butterfly (E. Hein, pers. obs.). The FS indicated they would monitor trampling impacts at two campgrounds (FS 1999j). Although we have not received any information from the FS regarding trampling, we have documented larval webs and food plants within campsites that were trampled or crushed (E. Hein, pers. obs.).

Recreational resource damage and impacts to the Sacramento Mountains checkerspot butterfly are likely to increase in the near future. For example, the Forest contained 240 km (150 mi) of managed trails in 1986; however, the need for future trails is expected to increase and at least 25 percent more trail miles are needed to match demand (FS 1986). Developed (e.g., campground stays) and dispersed recreation (i.e., hiking, backpacking, camping, trail biking) in 1986 were projected to rise over 2.4 and 1.4 times, respectively, through the first quarter of the 21st century (FS 1986). In fact, by the end of the projected 50year period of the Lincoln National Forest Plan (2036), the demand for dispersed recreation was expected to continue increasing and would exceed the projected capacity by 26 percent (FS 1986). In fact, the demand for developed recreation, which is generally greatest from May through September (the same activity period for the Sacramento Mountains checkerspot butterfly), often exceeded capacity in 1986. Moreover, the FS reported that the amount of recreational use left limited opportunity for a site to rest and rehabilitate during peak activity and use periods (FS 1986).

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We are aware of other sensitive butterflies that have been similarly impacted in and around developed FS campgrounds (e.g., Pyrgus ruralis lagunae, G. Pratt pers. comm. to E. Hein, 1998). Although proposed capital improvement projects for several FS campgrounds are needed to offset the high demand for developed recreation, these projects and the associated recreational impacts also have the potential to adversely affect the Sacramento Mountains checkerspot butterfly (see discussion under FS activities). We believe impacts to the butterfly from these recreational uses is ongoing and will continue.

Domestic Livestock Grazing

The Sacramento Mountains checkerspot butterfly has been and continues to be adversely affected by domestic livestock grazing. Grazing can eliminate or reduce the food plants used by larvae and the nectar plants used by adults, compact the soil, and eliminate or reduce ground cover by herbaceous plant and litter (Scholl 1989; Fleischner 1994; Belsky and Blumenthal 1997; Donahue 1999). The effects of grazing on the Sacramento Mountains checkerspot butterfly are largely a result of range management of domestic livestock. If domestic livestock are closely managed to minimize the loss or elimination of native vegetation used by the butterfly, then range management will likely have a negligible affect on the Sacramento Mountains checkerspot butterfly. Overgrazing has occurred in the valleys of the Sacramento Ranger District of the Lincoln National Forest over the last several decades (Fish and Wildlife Service 1993). Furthermore, overgrazing by stock animals has led to extinctions of some butterfly populations in the United States, including butterflies in the genus Euphydryas (Ehrlich 1989; Murphy and Weiss 1988; Weiss et al. 1991).

Overgrazing in the Lincoln National Forest has likely eliminated or reduced larval host plant and adult nectar sources of the Sacramento Mountains checkerspot butterfly. Similarly, overgrazing has compacted soils, decreased water infiltration, and increased water runoff, erosion, and dense conifer recruitment, severely altering the entire forest and meadow landscape in semiarid western interior forests, including those in New Mexico (Belsky and Blumenthal 1997). In fact, herbaceous plants and grasses have been effectively removed from the Sacramento Ranger District by intensive overgrazing (FS 1995). Overgrazing can substantially reduce the availability of native nectar plants for some butterfly species and could be contributing to regional declines and extinctions (e.g,. Euphydryas editha bayensis; Murphy and Weiss 1988; Speyeria zerene myrtleae; Launer et al. 1992). The availability of nectar and the amount consumed by female butterflies greatly influences the number of eggs produced and subsequent adult recruitment and long term population survival (Murphy et al. 1983; Boggs and Ross 1993 cited in Launer et al. 1992;).

We believe that widespread and intensive livestock grazing, leading to a reduction or elimination of residual plant or ground cover (i.e., little to no leaf or grass litter), has been detrimental for this butterfly, because the quality and quantity of larval and adult food plants and diapause sites have been reduced or eliminated. For example, the only variables that are consistently documented with Sacramento Mountains checkerspot butterfly presence are the occurrence of Helenium hoopesii (adult nectar source), mesic (neither extremely wet or extremely dry) soils, canopy cover less than 5 percent, and greater than 70 percent herbaceous cover (FS 2000a). Past and current range management within the range of the Sacramento Mountains checkerspot butterfly has led to the reduction or elimination of Helenium hoopesii and herbaceous ground cover (FS 1995; Belsky and Blumenthal 1997; Lincoln National Forest 1999). Trampling, primarily from cattle, can also kill butterfly larvae, eggs, and pupae (White 1986; Weiss 1999). White (1986) estimated that up to 35 percent of the total population of various life stages of butterflies in the genus Euphydryas can be lost to crushing in areas where heavy grazing occurs.

The amount of Helenium hoopesii, an adult nectar source, on range allotments in the Sacramento Ranger District is lower than it was in the 1970s and 1980s and the current range condition of four cattle allotments within the known range of the Sacramento Mountains checkerspot butterfly are poor to fair (R. Newman, Lincoln National Forest, pers. comm. 1999). Present range conditions within nonforested areas are declining (R. Newman, pers. comm. 1999), probably because cattle tend to concentrate in these areas (Belsky and Blumenthal 1997). Both larval and adult food plants are needed to sustain viable butterfly populations. For example, in some areas, if larval food plants are present, but nectar sources are absent, the habitats for other butterflies in the genus Euphydryas have remained unoccupied for at least a decade (Brown and Ehrlich 1980). In the Lincoln National Forest, permitted cattle grazing in 1980 exceeded capacity by about 33,000 AUMs and was projected to continue until about 2026 (FS 1986). Similarly, excessive forage utilization has been occurring since at least 1991 on the Sacramento allotment, the largest allotment in the Sacramento Ranger District (64 FR 24132).

A low to moderate level of grazing can sometimes be beneficial for sensitive butterflies in systems where nonnative grasses are palatable to domestic livestock or native ungulates or if native ungulate grazing (e.g., elk (Cervus elaphus)) was a component of the historical ecosystem (Weiss 1999, Weiss et al. 1991). Grazing levels in the known range of the Sacramento Mountains checkerspot butterfly continue to degrade the quantity and quality of suitable habitat. However, if a decrease in domestic livestock use is offset by an increase in native ungulate use, the result may be similarly degraded range conditions. This has been observed for at least one allotment within the range of the butterfly (R. Newman, pers. comm. 1999). Additionally, cattle must be properly managed during drought to avoid adversely affecting butterfly populations by overgrazing food plant and nectar sources. The lack of range management adjustments on the Lincoln National Forest during drought has resulted in extensive resource damage from domestic livestock grazing (Kaufmann et al. 1998).

Cattle grazing currently occurs in allotments where butterflies have been observed (FS 1999a, 1999b, 1999d 1999i, 2000a, 2000d). Data are lacking on longterm trends for Sacramento Mountains checkerspot butterfly localities that are grazed, but a study has recently been initiated to determine the effect of grazing on the Sacramento Mountains checkerspot butterfly (FS 2001b). Nevertheless, the co occurrence of butterflies and domestic livestock does not demonstrate that the Sacramento Mountains checkerspot butterfly is not being adversely impacted by current range management. It is possible that these areas could be population sinks (i.e., areas where the presence of butterflies is only being maintained by immigration from other source populations) (Boughton 1999). We recently assisted the Forest Service in designing an experiment to investigate the influence of range management activities on the butterfly and its food plants (Service 2001).

Nonnative Vegetation

Nonnative vegetation threatens the Sacramento Mountains checkerspot butterfly by outcompeting and reducing
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or eliminating food plants for larvae and nectar plants used by adults (FS 1995; Federal Register 62:2313; Weiss 1999). A significant long term threat to the Sacramento Mountains checkerspot butterfly is the change in community structure due to invasive nonnative plants. On the Lincoln National Forest, 12 aggressive nonnative plant species, including Russian knapweed (Acroptilon repens), musk thistle (Carduus nutans), oat grass, and teasel (Dipsacus sylvestris) have increased by 30 percent since the early 1990s; this trend is expected to increase (GAO 1999a). An estimated 3,238 ha (8,000 ac) of private lands are similarly infested with noxious weeds within the Smokey Bear and Sacramento Districts, and a minimum of 1,244 ha (3,075 ac) of FS lands are infested within the Sacramento District (FS 1996). A 1993 FS survey found that approximately 737 ha (1,822 ac) in the vicinity of the Village of Cloudcroft had infestations of noxious weeds (FS 1999a). Infestations are expanding in nonforested openings and within road rightsofway, with the densities of weeds increasing where they have not been treated (FS 1999a). Russian knapweed, musk thistle, oat grass, and teasel are found along major roads within rightsofway or mountain meadows, and small openings in the forest, from 2,130 to 2,750 m (7,000 to 9,000 ft) (Fish and Wildlife Service 1993; FS 1996). These four plants are the most common noxious weeds within the range of the butterfly in the Lincoln National Forest. Nonnative vegetation has caused the extinction of some populations of butterflies in other areas (Weiss 1999).

These nonnative plants can significantly affect the plant community structure. For example, Russian knapweed produces compounds that suppress the growth of other plant species, allowing it to form dense stands (FS 1996). Other species, such as musk thistle and teasel, can also reduce grass and native forb production and change meadow/ grassland habitats structurally and compositionally (FS 1995). Moreover, nonnative grasses, such as oat grass, can outcompete native forbs through the buildup of thatch (Huenneke et al. 1990). Nearly 30 percent of mountain meadows and over half of some individual meadows were dominated by noxious weeds on the Sacramento Ranger District in 1995 (FS 1995). The Lincoln National Forest treated 992 ha (2,452 ac) of noxious weeds annually from 1997 to 1999 (FS 2000b). However, these treatments eliminated only 116 ha (287 ac), and another 91 ha (225 ac) of noxious weeds were documented (FS 2000b). These data indicate the severity of noxious weed infestations within the known range of the Sacramento Mountains checkerspot butterfly. These infestations threaten the butterfly, primarily through the reduction or elimination of larval or adult food plants.

The application of herbicides to control nonnative vegetation may also be a threat to the Sacramento Mountains checkerspot butterfly. The NMSHTD and the FS both use herbicides and mowing to control noxious weeds. The herbicides Escort and RoundUp have been used by the FS to control nonnative plants, primarily Russian knapweed, musk thistle, and teasel in canyons and along highway rightsofway within the range of the butterfly. About 1,416 ha (3,500 ac) above 2,450 m (8,000 ft) have been treated (FS 1999a). The toxicity of Escort for insects is low to moderate, depending on application rate and timing (Dupont 1999). Alternatively, control of musk thistle on about 162 ha (400 ac) of private lands within the District is accomplished using picloram and/or 2, 4D (FS 1996), and musk thistle has also been controlled on FS lands using glyphosphate (FS 1993). The herbicide 2,4D is detrimental to native plants and has a moderate toxicity for insects (Cornell University 1998c), such as butterflies. Glyphosphate has low toxicity, but is a nonselective systemic herbicide (Cornell University 1998d). One area, which is proximate to habitat that supports the butterfly, was treated with glyphosphate in 1993. In 1999, the area contained almost no Sacramento Mountain checkerspot butterflies (FS 2000a). It is unknown if this absence is related to the herbicide application. Nevertheless, there is a potential for direct and indirect impacts on the Sacramento Mountains checkerspot butterfly from the application of herbicides.

Insect Control

The application of carbaryl and Bacillus thuringensis (BT) to control insects poses a threat to the Sacramento Mountains checkerspot butterfly. The petitioner reported that the entire DouglasFir forest in the Sacramento Mountains was treated in 1984 with either carbaryl or BT to control an outbreak of forest insects. Carbaryl is considered moderately to highly toxic and is lethal to many nontarget insects, whereas BT can kill the larval stage of many insects, including butterflies (Cornell University 1998a, 1998b). These insecticides were applied during months when butterfly larvae were not in diapause; however, the areas which were treated with carbaryl or BT were heavily wooded and are not areas that were inhabited by the butterfly. Nevertheless, drift of these insecticides into areas used the butterfly could have occurred. It is unknown what affect these treatments may have had on the Sacramento Mountains checkerspot butterfly because we have no pretreatment data for comparison. There has been a recent outbreak of tussock moth (Orgyia pseudotsugata) in the Sacramento Mountains (G. Garcia, pers. comm. 2000). The FS may attempt to control the outbreak using a virus specific to the tussock moth, BT, or an application of insecticide (G. Garcia, pers. comm. 2000). Future applications of carbaryl or BT may pose a potential risk for the viability of Sacramento Mountain checkerspot butterfly localities. Conclusion for Factor A

The Sacramento Mountains checkerspot butterfly appears to exhibit much of the same behavior, life history, and patchy distribution as other wellstudied species in this genus. The patchy distributional pattern is expected in many butterflies in the genus Euphydryas and other species, because they exist as metapopulations and at any instant butterflies may be using some areas and not others (Hanski and Gilpin 1991). Suitable habitat within the range of the species can play a pivotal role in maintaining natural metapopulations, especially butterflies that may have limited dispersal abilities (Murphy and Weiss 1988; see discussion below). However, if populations are extirpated and the metapopulation becomes so fragmented that individuals are unable to disperse between suitable patches, natural recolonization probability will not offset the extinction probability, and will result in population extinction. Some butterfly localities may be linked by linear or open patches of suitable, nonforested areas, such as highway rightsofway (Haddad 1999; Haddad and Baum 1999). If movements through these linkage

FOR FURTHER INFORMATION CONTACT Eric Hein, Endangered Species Biologist, New Mexico Ecological Services Field Office, at the above address (telephone 505/3462525, ext. 135; facsimile 505/3462542).