Endangered and Threatened Wildlife and Plants; Proposed Rule To List the Laguna Mountains Skipper and Quino Checkerspot Butterflies as Endangered

SUMMARY: The Fish and Wildlife Service (Service) proposes to list the

Laguna Mountains skipper (Pyrgus ruralis lagunae) and quino checkerspot

(Euphydryas editha quino) butterflies as endangered species throughout

their respective ranges in southwestern California and northwestern

Baja California, Mexico pursuant to the Endangered Species Act of 1973,

as amended (Act). The Laguna Mountains skipper occupies two montane

meadow habitats in a very restricted range within San Diego County,

California. The quino checkerspot is locally distributed in sunny

openings within chaparral and coastal sage shrublands in portions of

Riverside County, California and northwestern Baja California, Mexico.

These species are threatened by one or more of the following factors:

Grazing, urban development, collection by lepidopterists and other

human disturbance, stochastic events, and the inadequacy of existing

regulatory mechanisms to provide for their conservation. This proposed

rule, if made final, would extend protection under the Act to these

species.

DATES: Comments from all interested parties must be received by October

3, 1994. Public hearing requests must be received by September 19,

1994.

ADDRESSES: Comments and materials concerning this proposal should be

sent to the Field Supervisor, U.S. Fish and Wildlife Service, Carlsbad

Field Office, 2730 Loker Avenue West, Carlsbad, California 92008.

Comments and materials received will be available for public

inspection, by appointment, during normal business hours at the above

address.

FOR FURTHER INFORMATION CONTACT: Ms. Marjorie Nelson at the above

address (telephone 619/431-9440).

SUPPLEMENTARY INFORMATION:

Background

The Laguna Mountains skipper (Pyrgus ruralis lagunae) is a small

butterfly within the skipper family (Hesperiidae). It is about 3

centimeters (cm) (1 inch) in length and is distinguished from the rural

skipper (P. ruralis ruralis) by extensive white wing markings that give

it an overall appearance of white rather than mostly black (Scott

1981). The Laguna Mountains skipper is found in wet montane meadow

habitats.

Pyrgus ruralis lagunae is one of two recognized subspecies of the

rural skipper, Pyrgus ruralis (Boisduval). Scott (1981) first described

Pyrgus ruralis lagunae from a collection made in 1956 by F. Thorne in

the Laguna Mountains of San Diego County California, based upon

population isolation and color differentiation. The Laguna Mountains

skipper is restricted to the Laguna Mountains and Mount Palomar in San

Diego County.

The other subspecies of the rural skipper (Pyrgus ruralis ruralis)

ranges from the mountains of British Columbia and Alberta south to

central California, Nevada, Utah, and northern Colorado (J. Brown,

Dudek and Associates, in litt., 1992) and has darker wings than the

Laguna Mountains skipper.

Three other species in the genus Pyrgus occur in San Diego County:

the common checkered skipper (P. communis); the small checkered skipper

(P. scriptura); and the western checkered skipper (P. albescens). The

Laguna Mountains skipper can be distinguished from all three of these

species by the whitish appearance of the adults and the use of a single

larval host plant in the rose family (Horkelia clevelandi) (Garth and

Tilden 1986, Scott 1986). In addition, the western checkered skipper

and southern California populations of the small checkered skipper are

restricted to desert areas (Garth and Tilden 1986).

The Laguna Mountains skipper is currently found at one site in the

Laguna Mountains and one site on Mount Palomar in San Diego County,

California (Dr. John Brown, in litt., 1992). The total population of

the Laguna Mountains skipper is estimated to be fewer than 100

individuals (Murphy 1990; Brown 1991; J. Brown, in litt., 1992). The

Laguna Mountains population is restricted to a relatively small fenced

area where cattle cannot reach the larval host plant (G. Pratt, as

cited in Murphy 1990; Dave Hogan, San Diego Biodiversity Project, pers.

comm., 1993). The Laguna Mountains skipper was sighted and collected on

Mount Palomar in 1991 by D. Lindsley (J. Brown, in litt., 1992; Dr.

John Brown, pers. comm., 1993). The Mount Palomar population is

extremely small where only five specimens have been reported in this

century (J. Brown, in litt., 1992).

Horkelia clevelandi (Cleveland's horkelia) is the larval host plant

of the Laguna Mountains skipper. Cleveland's horkelia occurs along the

margins of pine meadows in the Laguna, Cuyamaca, Palomar, and San

Jacinto Mountains of southwestern California and northwestern Baja

California, Mexico at 1200 to 2500 meters (m) (4000 to 8000 feet) in

elevation. Although a butterfly's distribution is generally defined by

the presence of its larval host plant, it may be further restricted by

other physiological or ecological constraints. The Laguna Mountains

skipper is currently found in a few open meadows of yellow pine forest

between 1500 to 2000 m (5000 and 6000 feet) in elevation; historically,

this species was found at elevations between 1200 and 2500 m (4000 to

6000 feet). It may have occurred throughout the higher elevations of

San Diego County (Murphy 1990; Brown 1991; J. Brown, in litt., 1992;

and references cited therein). Murphy (1990) reported that there were

at least six populations of this species in the Laguna Mountains in the

1950's and 1960's (at Big Laguna, Little Laguna, East Laguna, Laguna

Lake, Boiling Springs, and Horse Heaven) (see also J. Brown, in litt.,

1992). Most specimens of the Laguna Mountains skipper were collected

from Horse Heaven Springs near Mount Laguna (Murphy 1990). Until

rediscovery in 1983 by J. Emmel, the last known sightings of the

skipper in the Laguna Mountains were from 1972. Until specimens were

collected in 1991, the last known sightings from Mount Palomar were

from 1980 and, prior to that, from 1939 (Brown 1991; J. Brown, in

litt., 1992).

The Laguna Mountains skipper is apparently bivoltine (two

generations per year). The adult flight season occurs from April to May

with a complete or partial second brood flight in late June to late

July. A partial second brood indicates that this butterfly may have a

flexible or variable diapause (state of suspended activity). The Laguna

Mountains skipper may have evolved a unique mechanism for coping with

the low diurnal temperatures it encounters during its spring flight,

which is unusually early for butterflies in the Laguna Mountains (Brown

1991). It is assumed that the life history of the Laguna Mountains

skipper is similar to that of the nominate subspecies (Pyrgus ruralis

ruralis), which diapauses as a full grown larvae and adults live 10 to

20 days (J. Brown, in litt., 1992).

The quino checkerspot, Euphydryas (= Occidryas) editha quino (Behr)

is a small member of the brush-footed butterfly family (Nymphalidae).

It is about 3 cm (1 inch) in length and checkered with dark brown,

reddish, and yellowish spots. It is one of 12 recognized subspecies of

Euphydryas editha (editha checkerspot) (Garth and Tilden 1986). The

quino checkerspot can be distinguished from other subspecies of

Euphydryas editha by its wing coloration pattern and overall body size.

The quino checkerspot tends to be larger with redder wings. The light

spots on the wings tend to be fewer and more disjunct than in the other

subspecies (Garth and Tilden 1986). Euphydryas editha quino is

geographically disjunct from them. This taxon is also phenotypically

similar to two other species of butterfly that occur within its range.

The Chalcedon checkerspot (E. chalcedona) is more yellow and is

slightly larger than the quino checkerspot. Gabb's checkerspot

(Chlosyne gabbii) is smaller than the quino checkerspot and has orange

instead of red markings (Orsak 1977).

The quino checkerspot was first described in 1863 by Hans Herman

Behr, an entomologist with the California Academy of Sciences in San

Francisco, as Melitaea quino based on a specimen from coastal San Diego

County, California. It was subsequently recognized by Comstock (1927)

as a race of Euphydryas editha (Boisduval). For many years, E. e. quino

was inappropriately recognized as E. e. wrightii. This error was

rectified by J. Emmel based on a study of Behr's notes and available

specimens (D. Murphy, Center for Conservation Biology, Stanford

University, in litt., 1988; Allen 1990). The genus Euphydryas, which is

widely represented throughout North America, has been subdivided into

closely related species groups (Scott 1986). The genus Euphydryas is

also referred to as Occidryas, but many authors retain the former name

(e.g., Scott 1986; Harrison et al 1988; Murphy 1990; Brown 1991).

The quino checkerspot is restricted to sunny openings on clay soils

formed from gabbro parent materials within shrubland habitats of the

interior foothills of southwestern California and northwestern Baja

California, Mexico (G. Ballmer, in litt., 1991). Similar to the Laguna

Mountains skipper and butterflies in general, its distribution is

defined primarily by that of its larval host plant but is further

restricted by other factors. The primary larval food plant of the quino

checkerspot is Plantago erecta (dwarf plantain, family Plantaginaceae).

However, the larvae may also use Plantago insularis and Orthocarpus

purpurescens (owl's clover, family Scrophulariaceae) (White 1974; Greg

Ballmer, University of California at Riverside, pers. comm., 1993).

These plants grow in or near meadows, vernal pools, and lake margins in

upland shrub communities including sparse chaparral, and chaparral

mixed with coastal sage scrub. This butterfly is generally found at

sites where high densities of the host plant occur (J. Johnson, in

litt., 1989; D. Hawks, University of California at Riverside, in litt.,

1992) and was found at a variety of elevations from about sea level to

about 1200 m (4000 feet). Within these areas, the quino checkerspot may

be preferentially selecting sites where exposure to winter sun is

greatest (Allen 1990). These habitats, like the quino checkerspot

butterfly, were once commonly found along coastal bluffs, mesas, and

inland foothills (Brown and Faulkner 1984).

The quino checkerspot may have been one of the most abundant

butterflies in San Diego, Orange, and western Riverside Counties during

the early part of the 20th century (Murphy 1990). The original range of

the quino checkerspot extended as far south as Valle de la Trinidad in

northwestern Baja California, Mexico, and as far north as Point Dume in

Los Angeles County (Allen 1990). Currently, only six to seven small

populations are known within the United States. Five to six populations

occur near Vail Lake in southwestern Riverside and north-central San

Diego Counties (G. Ballmer, in litt., 1990 and 1991; David Hawks,

entomologist, University of California at Riverside, pers. comm.,

1993). One other population is known to occur (as of 1991) near Upper

Otay Lake in San Diego County (Murphy, in litt., 1991). Although the

latter population has likely been extirpated (Murphy, pers. comm.,

1994). At least one population exists in Mexico, in the Sierra Juarez

near Tecate (Murphy, in litt., 1991). Adult quino checkerspot

butterflies were not seen at several historically occupied sites in

Mexico during a survey in the spring of 1993 (unpubl. Service data). No

estimates of population size for the quino checkerspot are currently

available.

Adult quino checkerspot butterflies live from 4 to 8 weeks. The

flight season occurs from mid-January to late April, and peaks between

March and April. The eggs hatch in about 10 days, and the larvae begin

to feed immediately. Fourth instar (development stage) larvae enter an

obligatory diapause, as summer approaches and their larval food plant

senesces. Extended periods of diapause may occur during times of

drought (G. Ballmer, in litt., 1990). Post-diapause larvae develop

through four more instars and then pupate to emerge as adults in the

early spring (Murphy and White 1984).

Previous Federal Action

On June 3, 1991, the Service received a petition dated May 27,

1991, from Mr. David Hogan of the San Diego Biodiversity Project, to

list four butterfly species as endangered under the Endangered Species

Act of 1973, as amended (16 U.S.C. 1531 et seq.): the Laguna Mountains

skipper (Pyrgus ruralis lagunae), Hermes copper (Lycaena hermes),

Thorne's hairstreak (Mitoura thornei), and Harbison's dun skipper

(Euphyes vestris harbisoni). The petition cited loss and degradation of

habitat, through various causes, as the major threat to these

butterflies. On July 12, 1993, the Service found that the petition

contained substantial information indicating that the requested action

may be warranted for the Laguna Mountains skipper, but not for the

other three butterflies listed above. The latter finding was made

because sufficient information was not available regarding the threats

to and biological vulnerability of these taxa. An announcement of these

findings were published in the Federal Register on July 19, 1993 (58 FR

38549). The Laguna Mountains skipper, Hermes copper, Thorne's

hairstreak, and Harbison's dun skipper are currently classified as

category 2 candidates for Federal listing (November 21, 1991; 56 FR

58804). Category 2 includes taxa for which information in the Service's

possession indicates that listing is possibly appropriate but for which

the Service lacks substantial information upon which to base a proposal

to list as endangered or threatened.

On September 30, 1988, the Service received a petition dated

September 26, 1988, from Dr. Dennis Murphy of the Stanford University

Center for Conservation Biology, to list the quino checkerspot

butterfly (Euphydryas editha quino) as endangered under the Act. At the

time this petition was submitted, this taxon had not been seen for

several years and was thought to be extinct. Extant populations of the

quino checkerspot were reported by Dr. Murphy in a letter dated August

1, 1991, which again requested the Service to consider the petitioned

action. The status of the quino checkerspot has been under review by

the Service since 1984 when it was classified as a category 2 candidate

for Federal Listing (May 22, 1984; 50 FR 37958). This taxon is

currently classified as a category 1 candidate (November 21, 1991; 56

FR 58804), meaning that information in the Service's possession is

sufficient to support a proposal to list as endangered or threatened.

This proposed rule constitutes the final finding for the petitioned

action to list the Laguna Mountains skipper as warranted. In addition,

this proposed rule constitutes the 90-day finding that the petition for

the quino checkerspot butterfly presented substantial information that

the action may be warranted and the final 12-month finding for this

petition that the action is warranted.

Summary of Factors Affecting the Species

Section 4 of the Endangered Species Act (16 U.S.C. 1533) and

regulations (50 CFR part 424) promulgated to implement the Act set

forth criteria and procedures for adding species to the Federal Lists.

A species may be listed due to any one or a combination of the five

factors listed in section 4(a)(1) of the Act. These factors and their

application to the Laguna Mountains skipper (Pyrgus ruralis lagunae)

and the quino checkerspot (Euphydryas editha quino) are as follows.

A. The Present or Threatened Destruction, Modification, or Curtailment

of Its Habitat or Range

The habitats and the ranges of the two species considered herein

have been substantially reduced by urban and agricultural development

and recreational activities and are further threatened with

destruction, modification, and curtailment. The Laguna Mountains

skipper and the quino checkerspot currently occur within very

restricted ranges and are extremely localized in their present

distributions.

The habitat requirements for these two butterflies are primarily

defined by their larval host plants. The removal or degradation of

these plants, as well as that of nectar sources for adults, leads to

the elimination of the affected population.

In the case of the Laguna Mountains skipper, habitat destruction

and degradation from overgrazing and trampling of its larval host plant

by domestic cattle is considered to be the primary factor responsible

for its decline (Murphy 1990; D. Hogan, in litt., 1991; J. Brown, in

litt., 1992). The larval host plant (Cleveland's horkelia) is itself a

rare species and only found in the Laguna, Cuyamaca, and San Jacinto

Mountains of southwestern California, and northwestern Baja California,

Mexico. The only known extant skipper population in the Laguna

Mountains is found in the El Prado campground area of the Cleveland

National Forest (Murphy 1990; D. Hogan, pers. comm., 1993). This area

is protected from grazing cattle by a fence. Although the larval host

plant is found throughout the campground, it is subject to trampling by

people (D. Hogan, pers. comm., 1993).

Sunny openings within chaparral and coastal sage scrub occupied by

the quino checkerspot butterfly have been degraded by grazing and (to a

small degree) destroyed by urban development. Fifty to seventy-five

percent of the known range of the quino checkerspot has been lost since

1900 due to habitat degradation or destruction (Brown 1991). The

primary larval food plant, Plantago erecta, can be displaced by exotic

plants, which invade once the ground is disturbed by discing, grading,

and/or grazing (J. Johnson, in litt., 1989; G. Ballmer, in litt.,

1990). The food plant then recolonizes in sites where grass does not

grow well, like cattle trails and road edges, where quino checkerspot

larvae are subject to trampling (D. Hawks, pers. comm., 1993).

The encroachment of urban development in rural Riverside County

potentially threatens one of the quino checkerspot populations near

Vail Lake. This area is growing rapidly and is projected to be fully

developed within the decade (Monroe et al. 1992). The Vail Lake area is

included in a Community Plan that provides for subdivision of parcels

into 20-acre (9 hectare (ha)) lots (M. Freitas, in litt., 1993).

Additional development in this area is expected to further reduce and

degrade habitat of the quino checkerspot through construction of homes

and roads, and increases in cattle and horse grazing, fire frequencies,

and the distribution and abundance of exotic plants. An existing

recreational vehicle park and marina at Vail Lake attracts unauthorized

use of all terrain vehicles (ATV's) within natural habitat areas. ATV's

increase the fire hazard and destroy habitat through creation of

trails. Evidence of ATV use is apparent at one of the quino checkerspot

localities near Vail Lake, where a recently created dirt road bisects

the center of the habitat (G. Ballmer, in litt., 1991). Quino

checkerspot habitat at this locality has been disced in part; these

disturbed areas no longer support this species, while the surrounding

undisturbed areas do (G. Ballmer, in litt., 1991).

Bureau of Land Management-administered lands and Forest Service

Wilderness Areas are currently contiguous with privately-owned quino

checkerspot habitat near Vail Lake. As Riverside County becomes more

densely populated, fragmentation and degradation of this contiguous

habitat is expected.

Any residual individuals remaining near the last known population

of the quino checkerspot in San Diego County would be threatened by a

proposed urban development project on Otay Mesa. The preferred

alternative for the Otay Ranch New Town Plan (the largest planned

community in the southwestern United States) would result in the loss

of 5,600 ha (14,000 acres) of upland shrub communities, or about 52

percent of their extent within the project area. The effects of this

project on the quino checkerspot are not known at this time but may be

significant. Habitat loss due to grazing and clay mining are the

primary threats to the quino checkerspot butterfly in Mexico.

B. Overutilization for Commercial, Recreational, Scientific, or

Educational Purposes

Overcollection is a potential threat to both the Laguna Mountains

skipper and the quino checkerspot because they are rare butterflies.

Johnson (in litt., 1989) has noted that the number of quino checkerspot

colonies has been reduced since lepidopterists, eager to include rare

species in their collections and to obtain surplus specimens for

exchange or sale to other lepidopterists, have visited the few

remaining colonies steadily throughout the flight season. ``Where the

populations may already be small, this depredation by collectors may so

weaken the colonies as to end their existence. I have witnessed

examples of this with other species of Lepidoptera whose loss of

habitat has restricted the species to isolated colonies. These have

then been wiped out by intensive collection by lepidopterists.'' (J.

Johnson, in litt., 1989). The remaining populations of the quino

checkerspot butterfly near Vail Lake are threatened by overcollection.

In the spring of 1993, these populations were the subject of scientific

collections for voucher specimens and captive-rearing (D. Hawks, pers.

comm., 1993). In addition, at least two collections of about six

specimens each have been made by private collectors for non-scientific

purposes (unpubl. Service data).

A significant threat to the survival of both species considered

herein is the potential for vandalism by landowners who may view the

presence of sensitive species as an obstacle to development. The

habitat of the largest and most dense quino checkerspot population in

the Gavilan Hills of Riverside County was deliberately disced, in 1984

or 1985, to eliminate this population (J. Johnson, in litt., 1989).

C. Disease or Predation

Disease is not known to be a factor affecting the species

considered herein. There are no known predators of the Laguna Mountains

skipper. However, there is evidence that predation is a threat to the

quino checkerspot. Studies conducted by David Hawks (pers. comm., 1993)

indicate that predation has contributed to the decline of the quino

checkerspot at sites where habitat has been invaded by non-native plant

species, which may also harbor predatory arthropods. Historical quino

checkerspot habitat sites that have been heavily invaded by

Mediterranean plant species also have high sowbug (Oniscus sp.) and

earwig (Forficula sp.) densities. Sowbugs and earwigs prey upon

butterfly eggs. These predators, as well as the non-native plant

species that support them, are absent from natural sites currently

occupied by the quino checkerspot butterfly (D. Hawks, pers. comm.,

1993).

Although specific parasites are unknown for the Laguna Mountains

skipper and the quino checkerspot, Johnson (in litt., 1989) speculates

that parasitism can eliminate a butterfly colony. ``* * * butterfly or

moth populations will build up on the food plants for three or four

years, then one will begin to find examples of larvae or pupae with

parasites. The parasitism increases for two or three seasons, when

nearly all of the larvae or pupae are affected, the moth or butterfly

population disappears completely from the observed area, remains absent

for some years, then the cycle is repeated'' (J. Johnson, in litt.,

1989). This cycle can only continue if the affected area is

recolonized, which is difficult when the host-butterfly population is

small, fragmented, and isolated. In general, however, outbreaks of

disease or parasitism are more likely to occur under conditions of high

population densities. The Laguna Mountains skipper occurs in low

population densities; most populations of the Quino checkerspot also

occur at low densities.

D. The Inadequacy of Existing Regulatory Mechanisms

Existing regulatory mechanisms that could provide some protection

for both the Laguna Mountains skipper and the quino checkerspot

include: (1) Listing under the California Endangered Species Act; (2)

adequate consideration under the California Environmental Quality Act

(CEQA) and the National Environmental Policy Act (NEPA); (3) local laws

and regulations; (4) occurrence with other species protected by the

Federal Endangered Species Act; and (5) land acquisition and management

by Federal, State, or local agencies, or by private groups and

organizations for the conservation of these species.

Neither of the species discussed herein is under consideration for

listing under the California Endangered Species Act.

The status of and threats to the Laguna Mountains skipper and the

quino checkerspot, as discussed under Factor A above, reflect the

failure of CEQA, NEPA, and local laws and regulations to protect and

provide for the conservation of these species. Although there are

several regional conservation planning efforts underway within the

range of the Laguna Mountains skipper and the quino checkerspot, none

have been completed, approved, funded, or implemented.

The Service is not aware of any overlap in distribution between the

Laguna Mountains skipper and any State or Federally listed species. At

some localities, the quino checkerspot co-occurs with the coastal

California gnatcatcher (Polioptila californica californica), a

Federally listed threatened species. However, the habitat requirements

for the quino checkerspot are different than for the gnatcatcher.

Some protection is afforded to the Laguna Mountains skipper on

Forest Service land. However, this protection is limited to a

campground area that is subject to human disturbance. Considering the

small population size and extremely limited distribution of the Laguna

Mountains skipper, this protection is insufficient to conserve the

species. In the case of the quino checkerspot, some protection may be

provided to one population by its occurrence, in part, on Bureau of

Land Management land near Vail Lake in Riverside County. However, this

Federal land is currently subject to off-road vehicle activity (G.

Ballmer, in litt., 1991).

The Service is not aware of any regulatory mechanisms that protect

the quino checkerspot in Mexico.

E. Other Natural or Man-Made Factors Affecting Its Continued Existence

The extremely restricted range and localized distribution, and

small population size of the Laguna Mountains skipper and the quino

checkerspot makes them vulnerable to the effects of fragmentation,

especially with regard to stochastic events (e.g., see Gilpin and Soule

1986). For example, the Mount Palomar population of the Laguna

Mountains skipper is known from one site, where five specimens were

taken. A chance event could easily extirpate this population of the

skipper.

Although both butterflies occur in fire adapted ecosystems, a

single fire event could eliminate affected populations. Orsak (1977)

reported that a quino checkerspot population near Hidden Ranch, Black

Star Canyon, in the Santa Ana Mountains of Orange County was apparently

destroyed by a fire in 1967. (As discussed in the Background section

above, the quino checkerspot is now extirpated from Orange County.) The

only site known to be occupied by the Laguna Mountains skipper in the

Laguna Mountains is subject to cattle grazing and trampling by both

cattle and people.

Interconnected populations can act as reservoirs to maintain

populations that may be subject to periodic extirpation (Murphy and

White 1984, Harrison et. al 1988). If a stochastic event eliminates a

population of either species (due to factors discussed in this rule),

few (if any) neighboring populations are available to recolonize the

area. No information is available regarding the vagility of the Laguna

Mountains skipper. The sedentary behavior of the quino checkerspot

diminishes the probability that natural, long distance dispersal could

reestablish most extirpated local populations.

Periodic droughts (like those recently occurring in southwestern

California) can adversely affect both of the species considered herein.

Drought is known to decrease numbers of butterflies (Thorne 1963).

Drought conditions may cause loss or early senescence of the larval

host plant prior to completion of larval development, or lower the

nutritional quality of the host plant (e.g., water content). Drought

can also reduce the quantity and quality of adult nectar sources.

Larval starvation and extirpation of local populations during periods

of drought have been documented for Euphydryas editha (White 1974,

Ehrlich et al. 1980).

Habitat fragmentation can affect the genetic heterogeneity of small

isolated populations like those of the Laguna Mountains skipper and the

quino checkerspot. Small, fragmented populations are subject to a

higher frequency of genetic drift and inbreeding. As a consequence,

genetic variation of the population and individual heterozygosity is

decreased. That can lead to inbreeding depression and lowered fitness

of individuals. Low genetic diversity may decrease the ability of a

species to adapt to changing environmental conditions. Genetically

homogenous populations may be at a greater risk of extinction from

environmental or demographic stochasticity (e.g., from fire or drought

events) than are large, diverse populations that can more readily

recover from such events. For example, variation in the length of

diapause among butterfly offspring requires genetic heterogeneity (see

Seger and Brockman 1987). If a population is variable in diapause

length, it has a lower risk of losing an entire cohort to adverse

environmental conditions during any given season. Individuals with

prolonged diapause may survive if drought causes high mortality during

the next season. A large population or metapopulation can maintain the

genetic heterogeneity needed to maintain the population during these

kinds of events.

The quino checkerspot is somewhat adapted to unpredictable weather

patterns but requires sufficient patches of suitable habitat to respond

to this environmental stochasticity. The quino checkerspot's dispersal

capabilities vary considerably depending upon rainfall patterns and the

resulting availability of adult nectar sources and larval food plants.

For example, a San Diego County population of the quino checkerspot

exhibited an increase in numbers as a result of favorable weather

(Murphy and White 1984). The greater number of larvae defoliated the

larval food plants. This central core area was left without sufficient

egg-laying sites for females, and adults went for greater dispersal

distances in search of additional suitable habitat. Ideally these

dispersing adults would have found marginally suitable areas, and in

subsequent generations would have returned to a central core area. In

this case, the mass dispersal failed to restore populations in

previously occupied habitat, and the butterflies have not re-colonized

the original site (Murphy and White 1984; Murphy, pers. comm. 1994).

The Service has carefully assessed the best scientific and

commercial information available regarding the past, present, and

future threats faced by these two taxa in determining to propose this

rule. Based on this evaluation, the Service finds that the preferred

action is to list the Laguna Mountains skipper and the quino

checkerspot as endangered. The range and habitat of these species has

been substantially reduced by historical activities associated with

urban and agricultural development and recreational activities. These

two taxa are threatened by one or more of the following factors:

Habitat alteration and destruction resulting from urban and

agricultural development, grazing, overcollection, recreational

activities, inadequate regulatory mechanisms, and displacement of the

larval host plant by exotic species. The extremely restricted range,

localized distribution, and small population size of both butterflies

makes them very vulnerable to extinction by the factors listed above as

well as by stochastic events such as fire and drought. For these

reasons, the Service finds that the Laguna Mountains skipper and the

quino checkerspot are in imminent danger of extinction throughout all

or a significant portion of their ranges. Threatened status would not

accurately reflect the diminished status and threats to these species.

Other alternatives to this action were considered but not preferred

because not listing these species would not provide adequate protection

and would be inconsistent with the purposes of the Act. Critical

habitat is not being proposed for these taxa for the reasons discussed

below.

Critical Habitat

Critical habitat, as defined by section 3(5)(A) of the Act, means:

(i) The specific areas within the geographical area occupied by a

species, at the time it is listed in accordance with the Act, on which

are found those physical or biological features (I) essential to the

conservation of the species and (II) that may require special

management considerations or protection; and (ii) specific areas

outside the geographical area occupied by a species at the time it is

listed, upon a determination that such areas are essential for the

conservation of the species.

Section 4(a)(3) of the Act requires that critical habitat be

designated to the maximum extent prudent and determinable concurrently

with the determination that a species is endangered or threatened. The

Service's regulations (50 CFR 424.12(a)(1)) state that designation of

critical habitat is not prudent when one or both of the following

situations exist: (1) The species is threatened by taking or other

human activity, and identification of critical habitat can be expected

to increase the degree of such threat to the species; or (2) such

designation of critical habitat would not be beneficial to the species.

The Service finds that designation of critical habitat is not

prudent at this time for the Laguna Mountains skipper and the quino

checkerspot. The quino checkerspot, mostly occurs on privately owned

lands with little or no Federal involvement, although the Bureau of

Land Management owns a portion of one site. The additional protection

provided by the designation of critical habitat to a species is only

achieved through section 7. Therefore, the designation of critical

habitat would not appreciably benefit the quino checkerspot.

Publication of precise maps and descriptions of critical habitat for

the quino checkerspot and the Laguna Mountains skipper could result in

additional habitat destruction through trampling, discing, and grading

as well as collection. As discussed under Factor B in the ``Summary of

Factors Affecting the Species'' section of this proposal, habitat for

the one of the largest quino checkerspot colonies was graded in

Riverside County to deliberately eliminate that population, and a

number of quino checkerspot colonies have been subject to collection by

lepidopterists for trading and similar purposes.

Available Conservation Measures

Conservation measures provided to species listed as endangered or

threatened under the Endangered Species Act include recognition,

recovery actions, requirements for Federal protection, and prohibitions

against certain practices. Recognition through listing encourages and

results in conservation actions by Federal, State, and private

agencies, groups, and individuals. The Endangered Species Act provides

for possible land acquisition and cooperation with the States and

requires that recovery actions be carried out for all listed species.

The protection required of Federal agencies and the prohibitions

against taking and harm are discussed, in part, below.

Section 7(a) of the Act, as amended, requires Federal agencies to

evaluate their actions with respect to any species that is proposed or

listed as endangered or threatened and with respect to its critical

habitat, if any is being designated. Regulations implementing this

interagency cooperation provision of the Act are codified at 50 CFR

part 402. Section 7(a)(4) requires Federal agencies to confer with the

Service on any action that is likely to jeopardize the continued

existence of a proposed species or result in destruction or adverse

modification of proposed critical habitat. If a species is subsequently

listed, section 7(a)(2) requires Federal agencies to insure that

activities they authorize, fund, or carry out are not likely to

jeopardize the continued existence of such a species or destroy or

adversely modify its critical habitat. If a Federal action may affect a

listed species or its critical habitat, the responsible Federal agency

must enter into formal consultation with the Service.

Federal agencies expected to have involvement with the Laguna

Mountains skipper and the quino checkerspot include the Forest Service

and Bureau of Land Management due to the presence of habitat and

populations within their jurisdiction. The Immigration and

Naturalization Service may need to evaluate the effects of its

activities on the quino checkerspot, which is known to occur near the

international border in San Diego County.

The Act and its implementing regulations found at 50 CFR 17.21 set

forth a series of general prohibitions and exceptions that apply to all

endangered wildlife. These prohibitions, in part, make it illegal for

any person subject to the jurisdiction of the United States to take

(including harass, harm, pursue, hunt, shoot, wound, kill, trap,

capture, collect, or to attempt any of these), import or export,

transport in interstate or foreign commerce in the course of commercial

activity, or sell or offer for sale in interstate or foreign commerce

any listed species. It is also illegal to possess, sell, deliver,

carry, transport, or ship any such wildlife that has been taken

illegally. Certain exceptions apply to agents of the Service and State

conservation agencies.

Permits may be issued to carry out otherwise prohibited activities

involving endangered wildlife species under certain circumstances.

Regulations governing such permits are at 50 CFR 17.22 and 17.23. Such

permits are available for scientific purposes, to enhance the

propagation or survival of the species, and/or for incidental take in

connection with otherwise lawful activities. In some instances

involving trade, permits may be issued for a specified time to relieve

undue economic hardship that would be suffered if such relief were not

available. The Laguna Mountains skipper and quino checkerspot are not

involved in trade, and such permit requests are not expected.

Requests for copies of the regulations on listed wildlife and

plants and inquiries regarding them should be addressed to the U.S.

Fish and Wildlife Service, Ecological Services--Endangered Species

Permits, 911 Northeast 11th Ave, Portland, Oregon 97232-4181 (telephone

503/231-6241).

Public Comments Solicited

The Service intends that any final action resulting from this

proposal will be as accurate and as effective as possible. Therefore,

comments or suggestions from the public, other concerned governmental

agencies, the scientific community, industry, or any other interested

party concerning this proposed rule are hereby solicited. Comments

particularly are sought concerning:

(1) Biological, commercial trade, or other relevant data concerning

any threat (or lack thereof) to these taxa;

(2) The location of any additional populations of these species and

the reasons why any habitat should or should not be determined to be

critical habitat as provided by section 4 of the Act;

(3) Additional information concerning the range, distribution, and

population size of these taxa; and

(4) Current or planned activities in the subject area and their

possible impacts on these species.

The final decision on this proposal will take into consideration

the comments and any additional information received by the Service,

and such communications may lead to a final regulation that differs

from this proposal.

The Endangered Species Act provides for a public hearing on this

proposal, if requested. Requests must be received within 45 days of the

date of publication of the proposal. Such requests must be made in

writing and addressed to the Field Supervisor of the Carlsbad Field

Office (see ADDRESSES section).

National Environmental Policy Act

The Fish and Wildlife Service has determined that an Environmental

Assessment or Environmental Impact Statement, as defined under the

authority of the National Environmental Policy Act of 1969, need not be

prepared in connection with regulations adopted pursuant to section

4(a) of the Endangered Species Act of 1973, as amended. A notice

outlining the Service's reasons for this determination was published in

the Federal Register on October 25, 1983 (48 FR 49244).

References Cited

A complete list of all references cited herein are available

upon request from the Carlsbad Field Office (see ADDRESSES section).

Author

The primary author of this proposed rule is Marjorie Nelson of

the Carlsbad Field Office (see ADDRESSES section).

List of Subjects in 50 CFR Part 17

Endangered and threatened species, Exports, Imports, Reporting and

recordkeeping requirements, and Transportation.

Proposed Regulations Promulgation

PART 17--[AMENDED]

Accordingly, it is hereby proposed to amend part 17, subchapter B

of chapter I, title 50 of the Code of Federal Regulations, as set forth

below:

1. The authority citation for part 17 continues to read as follows:

Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.

4201-4245; Pub. L. 99-625, 100 Stat. 3500, unless otherwise noted.

2. It is proposed to amend Sec. 17.11(h) by adding the following,

in alphabetical order under INSECTS, to the List of Endangered and

Threatened Wildlife:

Sec. 17.11 Endangered and threatened wildlife.

* * * * *

(h) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------

Species Vertebrate population

--------------------------------------------------- Historic range where endangered or Status When listed Critical Special

Common name Scientific name threatened habitat rules

--------------------------------------------------------------------------------------------------------------------------------------------------------

* * * * * * *

Insects

* * * * * * *

Butterfly, Laguna Pyrgus ruralis lagunae.. U.S.A. (CA)............. NA..................... E ........... NA NA

Mountains skipper.

* * * * * * *

Butterfly, quino Euphydryas (=Occidryas) U.S.A. (CA), Mexico..... NA..................... E ........... NA NA

checkerspot. editha quino.

* * * * * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------

Dated: July 24, 1994.

Mollie H. Beattie,

Director, Fish and Wildlife Service.

[FR Doc. 94-18932 Filed 8-1-94; 8:45 am]

BILLING CODE 4310-55-P