[Federal Register Volume 59, Number 149 (Thursday, August 4, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18932]


[[Page Unknown]]

[Federal Register: August 4, 1994]


_______________________________________________________________________

Part III





Department of the Interior





_______________________________________________________________________



Fish and Wildlife Service



_______________________________________________________________________



50 CFR Part 17



Endangered and Threatened Species: Cuyamaca Lake Downingia; San Diego 
Fairy Shrimp; Laguna Mountains Skipper, et al.; Proposed Rules
DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AC84

 

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

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule and petition findings.

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

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