Endangered and Threatened Wildlife and Plants; Revised Designation of Critical Habitat for the Quino Checkerspot butterfly (Euphydryas editha quino, 28776-28862 [E9-13800]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 74, Number 115 (Wednesday, June 17, 2009)]
[Rules and Regulations]
[Pages 28776-28862]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-13800]



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Part II





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Endangered and Threatened Wildlife and Plants; Revised Designation of 
Critical Habitat for the Quino Checkerspot butterfly (Euphydryas editha 
quino); Final Rule

Federal Register / Vol. 74, No. 115 / Wednesday, June 17, 2009 / 
Rules and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2008-0006; 92210-1117-0000-B4]
RIN 1018-AV23


Endangered and Threatened Wildlife and Plants; Revised 
Designation of Critical Habitat for the Quino Checkerspot butterfly 
(Euphydryas editha quino)

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are 
designating final revised critical habitat for the Quino checkerspot 
butterfly (Euphydryas editha quino) under the Endangered Species Act of 
1973, as amended (Act). Approximately 62,125 acres (ac) (25,141 
hectares (ha)) of habitat in San Diego and Riverside Counties, 
California, are being designated as critical habitat for the Quino 
checkerspot butterfly. This final revised designation constitutes a 
reduction of approximately 109,479 ac (44,299 ha) from the 2002 
designation of critical habitat for the Quino checkerspot butterfly.

DATES: This rule becomes effective on July 17, 2009.

ADDRESSES: The final rule, final economic analysis, and map of critical 
habitat will be available on the Internet at https://www.regulations.gov 
at Docket No. FWS-R8-ES-2008-0006 and https://www.fws.gov/carlsbad/. 
Supporting documentation we used in preparing this final rule will be 
available for public inspection, by appointment, during normal business 
hours, at the U.S. Fish and Wildlife Service, Carlsbad Fish and 
Wildlife Office, 6010 Hidden Valley Road, Suite 101, Carlsbad, CA 
92011; telephone 760-431-9440; facsimile 760-431-5901.

FOR FURTHER INFORMATION CONTACT: Field Supervisor, U.S. Fish and 
Wildlife Service, Carlsbad Fish and Wildlife Office (see ADDRESSES 
section). If you use a telecommunications device for the deaf (TDD), 
call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    We intend to discuss only those topics directly relevant to the 
designation of critical habitat for the Quino checkerspot butterfly 
under the Endangered Species Act, as amended (16 U.S.C. 1531 et seq.), 
in this final revised critical habitat designation. For more 
information on the taxonomy, biology, and ecology of the Quino 
checkerspot butterfly, refer to the final listing rule published in the 
Federal Register on January 16, 1997 (62 FR 2313), the original final 
critical habitat rule published in the Federal Register on April 15, 
2002 (67 FR 18356); the Recovery Plan for the Quino Checkerspot 
Butterfly (Euphydryas editha quino) (Service 2003a); and the proposed 
revised critical habitat designation published in the Federal Register 
on January 17, 2008 (73 FR 3328).

New Information on Subspecies' Description, Life History, Ecology, 
Habitat, and Range

    We received little new information pertaining to the description, 
life history, distribution, ecology, or habitat of the Quino 
checkerspot butterfly following the 2008 proposed rule to revise 
critical habitat for this subspecies. The following paragraphs discuss 
the new information that we received, including recent information 
about another host plant species brought to our attention, and 
clarification regarding the subspecies' likely expanded range and 
larval diapause. Please refer to the final listing rule published in 
the Federal Register on January 16, 1997 (62 FR 2313), and the proposed 
revised critical habitat designation published in the Federal Register 
on January 17, 2008 (72 FR 3328), for an in-depth discussion of the 
subspecies' biology.
    In 2008, oviposition and larval development of the Quino 
checkerspot butterfly were recorded for the first time on a native host 
plant, Collinsia concolor (Chinese houses). The Quino checkerspot 
butterfly was observed using numerous individual C. concolor plants at 
multiple locations in Riverside County (Pratt 2008a, p. 1; 2008b, p. 1; 
2008c, p. 1; 2008e, p. 1). Although C. concolor commonly occurs in 
habitats with Plantago erecta (erect plantain), P. patagonica 
(Patagonian plantain), and Anterrhinum coulterianum (Coulter's 
snapdragon) (Pratt 2001, pp. 42-43; Anderson 2008, pp. 2, 3), this 
plant is typically found on north-facing slopes in cooler and moister 
microclimates than where the other host plant species occur (Pratt 
2001, p. 40: Pratt 2008b, p. 1). Quino checkerspot butterflies readily 
oviposit on C. concolor in captivity (Pratt 2001, p. 40). Relatively 
heavy but previously undocumented use of C. concolor at multiple high-
elevation locations suggests that this host plant may become 
increasingly important for maintaining the Quino checkerspot butterfly 
population resilience as habitat conditions become warmer and drier 
(see below and the ``Summary of Comments and Recommendations'' section 
for additional discussion regarding climate change). If C. concolor is 
a novel host plant important for maintaining the resilience of 
established populations, it should also facilitate the subspecies' 
adaptation to environmental change that may result from climate change, 
including range shift (Pimm et al. 2001, p. 531; Thomas et al. 2001, 
pp. 577-581; Parmesan 2006, pp. 644, 645, 647). For example, increased 
preference for a novel host plant allowed the brown argus butterfly 
(Aricia agestis) to use habitats that were too cool for the host plants 
it already used, thus permitting the butterfly species to cross 
previously large geographic gaps in its distribution that lacked its 
formerly preferred host plant (Pimm et al. 2001, p. 531; Thomas et al. 
2001, pp. 577-581).
    Next, we did not discuss repeated diapause (the low-metabolic rate 
resting stage of the life cycle) in our January 17, 2008 (72 FR 3328) 
proposed revision to critical habitat. One peer reviewer suggested this 
was an important aspect of the subspecies' biology (see comment 9 
below); therefore, we are adding discussion here. Diapause occurs 
during the larval stage, primarily during summer and fall (Service 
2003a, pp. 7-8). Captive rearing and observation of Quino checkerspot 
butterfly larvae indicate repeated diapause is relatively common (over 
50 percent likelihood for the first year; Pratt 2006, p. 10) and larvae 
can re-enter diapause up to three times (four diapause periods), but 
more than three diapause periods during an individual's life span is 
unusual (Pratt 2007a, pp. 10-13).
    Finally, the discussion of Edith's checkerspot butterfly 
(Euphydryas editha; the Quino checkerspot butterfly is a subspecies of 
Edith's checkerspot) range shift in our January 17, 2008 (72 FR 33808), 
proposed revision to critical habitat requires clarification. Although 
locally adapted subspecies may shift their distribution within the 
middle of a greater species distribution (which appears to be occurring 
with the Quino checkerspot butterfly's elevation range), the northward 
latitudinal range expansion of subspecies of Edith's checkerspot 
butterfly implied by Parmesan's (1996) study does not apply to the 
Quino checkerspot butterfly. Because the subspecies' current northern 
range edge is approximately 26 miles (mi) (42 kilometers (km)) south of 
the historical range edge, any northward expansion of the Quino 
checkerspot butterfly's current range would

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constitute recolonization within the subspecies' historical latitudinal 
range (San Bernardino and Ventura counties; see Service 2003a, pp. 1-
3).

Behavior and Population Structure

    The best available scientific data indicate that most Quino 
checkerspot butterfly populations have some degree of metapopulation 
structure (Service 2003a, p. 22) and display metapopulation dynamics 
characterized by highly variable habitat occupancy patterns and 
detectability, similar to most subspecies of Edith's checkerspot 
butterfly (Mattoni et al. 1997, p. 111; Service 2003a, pp. 21-27). 
Edith's checkerspot butterfly metapopulation structure is described by 
Ehrlich and Murphy (1987, p. 123) as the subdivision of a population 
into subpopulations that occupy clusters of habitat patches and 
interact extensively. Harrison et al. (1988, p. 360) described Edith's 
checkerspot butterfly metapopulation structure as: ``a set of 
[subpopulations] that are interdependent over ecological time.'' 
Although subpopulations within a metapopulation may change in size 
independently, the probability of a subpopulation existing at a given 
time is not independent, because they are linked by an extirpation and 
mutual recolonization process that occurs every 10 to 100 generations 
(Harrison et al. 1988, p. 360).
    Rare high-density events and dispersal behavior are thought to be 
key elements of Edith's checkerspot butterfly population dynamics that 
structure populations. Harrison (1989, p. 1241) found that although 
dispersal direction from habitat patches seemed to be random in the bay 
checkerspot butterfly (Euphydryas editha bayensis), dispersing 
butterflies were most likely to move into habitat patches when they 
passed within approximately 163 feet (ft) (50 meters (m)) of those 
habitat patches. Dispersing bay checkerspot butterflies tended to 
remain in habitat patches where existing butterfly density was low 
(Harrison 1989, p. 1241). Bay checkerspot butterfly occupancy patterns 
also suggested that unoccupied habitat separated from occupied habitat 
by hilly terrain was less likely to be colonized than habitat separated 
by flat ground (Harrison 1989, p. 1241).
    Harrison (1989, pp. 1241, 1242) concluded that the long-term 
habitat recolonization pattern of her study population was likely due 
to relatively large numbers of bay checkerspot butterflies having 
dispersed from persistent ``source'' subpopulations. Harrison (1989, p. 
1239) found bay checkerspot butterfly habitat within 0.6 mi (1 km) of a 
source subpopulation is 100 percent likely to be colonized by 
immigrants from the source subpopulation. Harrison (1989, p. 1239) also 
recaptured a significant number of individuals in habitat 0.6 mi (1 km) 
from their release point. Over a 5-day period, 5 percent of butterflies 
released at a single location were recaptured in an isolated ``target 
habitat patch'' 0.6 mi (1 km) away (Harrison 1989, p. 1239). Assuming 
mostly random initial movement direction from the release location at 
such a great release distance from the recapture site (Harrison 1989, 
p. 1241), many individuals likely traveled similar or further distances 
outside the study area.
    High habitat colonization rates probably only occur during rare 
outbreak years, when relatively high local densities combine with 
favorable establishment conditions in unoccupied habitat (Harrison 
1989, p. 1242). These rare outbreak events are also thought to play a 
crucial role in Quino checkerspot butterfly metapopulation resilience 
and the subspecies' survival (Murphy and White 1984, p. 353; Ehrlich 
and Murphy 1987, p. 127). Therefore, protection and management of 
source subpopulations likely to provide immigrants to unoccupied 
habitat are required for conservation of the Quino checkerspot 
butterfly (Service 2003a, pp. 22, 25-26, 35, 94).
    Long-distance dispersal has been documented in the Edith's 
checkerspot butterfly, and dispersal propensity is affected by local 
environmental conditions and subspecies' adaptation. White and Levin 
(1981, pp. 348-357) conducted the only mark-recapture movement study 
that included the Quino checkerspot butterfly. White and Levin (1981, 
pp. 348-357) studied within-habitat patch movement of the Quino and bay 
checkerspot butterfly subspecies in southern San Diego County (male bay 
checkerspots were released into Quino checkerspot butterfly habitat 
late in the flight season when offspring survival was not considered 
possible). They concluded that patterns of dispersal changed 
``dramatically'' from year to year (White and Levin 1981, p. 348), and 
the Quino checkerspot butterfly was less sedentary than the more 
heavily studied bay checkerspot butterfly (White and Levin 1981, p. 
105). Although the average mark-recapture distance traveled by a Quino 
checkerspot butterfly in White and Levin's (1981, p. 349) study was 
only 305 ft (93 m), movement records were limited to the local study 
area. White and Levin (1981, p. 349) stated, ``It seems likely from the 
lower rate of return in 1972 and from the observed pattern of out-
dispersal that many marked animals dispersed beyond the area covered by 
our efforts that year. This out-dispersal might make the value for 
average distance [traveled] in 1972 an underestimate of significant 
magnitude.'' Long-distance movement in the bay checkerspot butterfly 
has been documented as far as 4 mi (6.4 km) (Murphy and Ehrlich 1980, 
p. 319) and 3.5 mi (5.6 km) (Harrison 1989, p. 1239).
    The above information indicates that, although Edith's checkerspot 
butterflies appear to be capable of long-distance dispersal, their 
movement propensity is variable and driven by external environmental 
factors. By extension, contiguous habitat between two butterflies 
observed 1.2 mi (2 km) from each other is within reasonable flight 
distance of both individuals and should be considered part of a shared 
home range. Therefore, based on typical long-distance recapture 
records, we conclude that Quino checkerspot butterflies observed within 
approximately 1.2 mi (2 km) of each other in contiguous habitat belong 
to the same population, and contiguous habitat within at least 1.2 mi 
(2 km) of an observed Quino checkerspot butterfly is part of that 
individual's population distribution.
Delineating Population Distributions
    The best scientific data available to us for use in delineating 
Quino checkerspot butterfly population distributions consist of 
geographic information system (GIS)-based habitat information, 
subspecies observation locations, and subspecies movement data from 
mark-release-recapture studies. Population-scale occupancy (a 
population distribution) is defined as all areas used by adults during 
the persistence time of a population (years to decades; Service 2003a, 
p. 24). Focused distribution studies over multiple years are required 
to quantify Quino checkerspot butterfly population distributions. 
Therefore, the Recovery Plan described Quino checkerspot butterfly 
population locations in terms of ``occurrence complexes'' (Service 
2003a, p. 35), which were simple non-habitat-based estimators of 
population distributions (well-mixed or metapopulation structure) and 
population membership of observed butterflies. Occurrence complexes are 
mapped in the Recovery Plan using a 0.6-mi (1-km) movement radius from 
each butterfly observation and may be based on the observation of a 
single individual. Occurrence locations within at least 1.2 mi (2 km) 
of each other are considered to be part of the same occurrence complex, 
as these occurrences are proximal enough that

[[Page 28778]]

the observed butterflies were likely to have come from the same 
population (Service 2003a, p. 35).
    Occurrence complexes may expand due to new butterfly observations, 
or contract due to habitat loss (for example, mapped occurrence 
complexes were limited by development, see Service 2003a p. 78). 
According to recorded Edith's checkerspot butterfly movement distances 
(Gilbert and Singer 1973, pp. 65, 66; Harrison et al. 1988, pp. 367-
380; Harrison 1989, pp. 1239, 1240), occurrence complexes appropriately 
describe the area within which a significant proportion of the habitat 
patch associated with individual observed butterflies is likely to 
occur (see above discussion and Service 2003a, p. 35).
    Some occurrence complexes were identified in the Recovery Plan 
(Service 2003a, p. 35) as ``core.'' Core occurrence complexes are those 
that appear to be centers of population density based on geographic 
size, number of reported individuals, repeated observations, and 
evidence of reproduction. Such population density centers are likely to 
contain ``source'' subpopulations for a Quino checkerspot butterfly 
metapopulation (Murphy and White 1984, p. 353; Ehrlich and Murphy 1987, 
p. 125; Mattoni et al. 1997, p. 111; Service 2003a pp. 25-26), or 
``source'' populations for megapopulations (a group of populations also 
dependent on one another, but on a time scale greater than that of 
subpopulations; Service 2003a, pp. 21, 24, 25-26). A source 
subpopulation is one in which the emigration rate typically exceeds the 
immigration rate, and is thus a source of colonists for unoccupied 
habitat patches (Service 2003a, p. 166). Therefore, for the purposes of 
critical habitat designation, we defined a core occurrence complex as 
an area where at least two of the following criteria apply: (1) 
Surveyors reported 50 or more adults during a single survey at least 
once; (2) immature life stages were recorded; or (3) the geographic 
area within the occurrence complex (within 0.6 mi (1 km) of subspecies 
occurrences) is greater than 1,290 ac (522 ha; the size of the smallest 
Core Occurrence Complex where reproduction has been documented on 
multiple occasions and there are historical collection records 
indicating long-term resilience).
Status and Local Distribution of Populations in Riverside County
    Occurrence data collected in Riverside County since publication of 
the Recovery Plan in 2003 resulted in expansion of all core occurrence 
complexes and merging of some core occurrence complexes with non-core 
occurrence complexes (see discussion below). In particular, occurrence 
data collections in Riverside County since listing (62 FR 2313; January 
16, 1997) have continued almost annually to expand the known elevation 
limit of the subspecies' range (Pratt et al. 2001, pp. 169-171; Service 
2003a, p. 44; Goldberg 2005, pp. 8, 9; Pratt and Pierce 2005, pp. 4-5, 
11-12; Pratt 2005, p. 1; San Bernardino National Forest (SBNF) GIS 
database). The Bautista Road Occurrence Complex (described as non-core 
in the Recovery Plan) is in a relatively high-elevation valley east of 
Temecula and north of the community of Anza, California. Multiple new 
observations have occurred within and around the Bautista Road 
Occurrence Complex (AMEC 2004, p. 6; Mooney Jones and Stokes 2005, p. 
10). Consistent with criteria outlined in the Recovery Plan (Service 
2003a, p. 35) and above, we now consider the Bautista Road Occurrence 
Complex to be a Core Occurrence Complex.
    From 2004 to 2006, multiple new occurrence locations were also 
reported in the community of Anza, and north and northwest of the 
Bautista Road Core Occurrence Complex, Pine Grove Non-core Occurrence 
Complex, and Lookout Mountain Non-core Occurrence Complex. These new 
Non-core Occurrence Complexes are: (1) Cave Rocks within the community 
of Anza, just north of the intersection of Bautista Road and State 
Route (SR) 371 (AMEC 2004, p. 9); (2) Quinn Flat located between Fobes 
Ranch Road and Morris Ranch Road northeast of Quinn Flat and SR 74 
(Pratt and Pierce 2005, pp. 4-5, 11-12; Pratt 2005, p. 1; SBNF GIS 
database); (3) Horse Creek adjacent to Bautista Road, southeast of 
Bautista Spring (AMEC 2004, p. 6; Malisch 2006, p. 1); and (4) North 
Rouse Ridge located on Rouse Ridge in the hills east of Bautista 
Canyon, near where Bautista Road exits the foothills (Goldberg 2005, 
pp. 8, 9; SBNF GIS database ). None of these new observation locations 
met two or more of the criteria needed to categorize them as a core 
occurrence complex. However, these new Non-core Occurrence Complexes 
resulted in: (1) An increased number of known occupied areas near the 
community of Anza; (2) an expansion of the subspecies' known geographic 
range at its northeastern extreme (where it had not been previously 
recorded, but within historical latitudinal limits of the subspecies' 
distribution); and (3) an increase in the subspecies' known elevation 
range (Service Geographic Information Systems (GIS) database).
    Recent monitoring information indicates the Tule Peak and Silverado 
Core Occurrence Complexes described in the Recovery Plan (Service 
2003a, p. 44) are part of a single high-density population distribution 
supporting periodic density increases, similar to historical outbreak 
events (Service 2003a, p. 29), such as the 1977 outbreak in San Diego 
County reported by Murphy and White (1984, p. 351) (see also Ehrlich 
and Murphy 1987, p. 127; Carlsbad Fish and Wildlife Office (CFWO) 2004; 
Pratt 2004, p. 17). Occupancy in the Silverado Core Occurrence Complex 
was first documented in 1998 (Pratt 2001, p. 17), followed by the 
discovery of hundreds of Quino checkerspot adults in 2001 within the 
Tule Peak Core Occurrence Complex (TeraCor 2002, p. 14). Such reports 
of hundreds of adults in the Tule Peak Core Occurrence Complex were 
unprecedented since the 1970s, because, typically, five or fewer 
individuals are reported during project-based surveys (Service GIS 
database).
    In 2004, following a year of above-average host plant density in 
the Anza area (CFWO 2004), another Quino checkerspot butterfly outbreak 
event occurred with even higher abundance than was reported in 2001. An 
estimated 500 to 1000 adult Quino checkerspot butterflies were reported 
from the Silverado Core Occurrence Complex in a single day in 2004 
(Anderson 2007, p. 1; CFWO 2004; Pratt 2004, pp. 16, 17). Additionally, 
more than 30 new occurrence locations with high adult densities were 
reported in 2004 in the vicinity of Tule Peak Road (92 to more than 100 
observations in a single day) south of the Cahuilla Band of Mission 
Indians of the Cahuilla Reservation, California (Cahuilla Band of 
Indians), and the community of Anza (Osborne 2004, pp. 1-6, 8-10; 
Anderson 2007, p. 5; CFWO 2004; Osborne 2007, pp. 13-16). Based on 
these new observations, it is appropriate to merge the Tule Peak 
(core), Silverado (core), and Southwest Cahuilla (non-core) occurrence 
complexes to form a single, expanded Tule Peak/Silverado Core 
Occurrence Complex. This population contains higher densities and 
likely produces more emigrants than any other population within the 
subspecies' range.
    The best available scientific data (including recent outbreaks in 
the closest core occurrence complex) suggest the new Bautista Road Core 
Occurrence Complex supports ongoing range shift for the Quino 
checkerspot butterfly upslope in elevation, and other non-core 
occurrence complexes north of the community of Anza may be the result 
of recent colonization events.

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Parmesan (1996, pp. 765-766) concluded that the average (not actual) 
position of known Edith's checkerspot butterfly populations had shifted 
north and up in elevation, likely due to a warming, drying climate 
(conclusion supported by the technical recovery team, Service 2003a, 
pp. 64, 65). Parmesan (1996, pp. 765-766) compared the distribution of 
the Edith's checkerspot butterfly in the early part of the 20th century 
to its distribution from 1994 to 1996 using historical records and 
field surveys. This study identified a rangewide pattern of local 
Edith's checkerspot butterfly extirpations and noted that 80 percent of 
historically recorded populations in the southern part of the range 
were extinct at the time of the re-census in the mid-1990s (with the 
majority being Quino checkerspot butterfly populations). In contrast, 
historically recorded Edith's checkerspot butterfly populations in the 
mid-latitude part of the species' range experienced only 40 percent 
extirpations, and the extirpation rate in the northern part was as low 
as 20 percent (Parmesan 1996, pp. 765-766). Fewer than 15 percent of 
the Edith's checkerspot butterfly extirpations occurred in the highest 
elevation band (above 7,874 ft (2,400 m)) (Parmesan 1996, pp. 765-766).
    Parmesan (1996, pp. 765-766) concluded that this pattern of 
extirpation indicates contraction of the southern boundary of the Quino 
checkerspot butterfly's overall distribution by almost 100 mi (160 km) 
and a shift in the average location of an Edith's checkerspot butterfly 
occurrence northward by 57 mi (92 km). A parallel elevation gradient in 
extirpations shifted the mean location of Edith's checkerspot butterfly 
populations upward by 407 ft (124 m). A breakpoint in the pattern of 
extirpations occurred at approximately 7,874 ft (2,400 m), with about 
40 percent of all populations below the breakpoint recorded as 
extirpated in suitable habitats, while less than 15 percent were 
extirpated above the breakpoint. This pattern matched trends in 
snowpack dynamics in the Sierra Nevada (where the high-elevation 
populations are found) over the same period as the butterfly study, 
with significant trends toward lighter snowpack and earlier melt date 
below 7,874 ft (2400 m), and heavier snowpack and a (non-significant) 
trend toward later melt date above 7,874 ft (2400 m) (Johnson et al. 
1999, pp. 63-70). This range shift closely matched shifts in mean 
yearly temperature (Parmesan 1996, pp. 765-766; Karl et al. 1996, pp. 
279-292). Parmesan's study found extirpations to be most common at 
lower elevations and latitudes, and the Quino checkerspot butterfly's 
range includes both the lower elevation and lower latitude range 
extremes for Edith's checkerspot butterfly. Therefore, the Quino 
checkerspot butterfly may be the subspecies of Edith's checkerspot 
experiencing the greatest effects associated with changes in climate.
    Studies have demonstrated a correlation of population distribution 
and phenology changes with climate change for many other butterfly and 
insect species in California and around the world (Parmesan et al. 
1999, p. 580; Forister and Shapiro 2003, p. 1130; Parmesan and Yohe 
2003, pp. 38, 39; Karban and Strauss 2004, pp. 251-254; Thomas et al. 
2004, pp. 146-147; Osborne and Ballmer 2006, p. 1; Parmesan 2006, pp. 
646-647; Thomas et al. 2006, pp. 415-416). Metapopulation viability 
analyses of other endangered nymphalid butterfly species indicate that 
current climate trends pose a major threat to butterfly metapopulations 
by reducing butterfly growth rates and increasing subpopulation 
extirpation rates (Schtickzelle and Baguette 2004, p. 277; Schtickzelle 
et al. 2005, p. 89). Most recently, Preston et al. (2008, p. 2506) 
incorporated biotic interactions into niche models to predict suitable 
habitat for species under the range of climate conditions predicted for 
southern California in recent climate change models (see also Hayhoe et 
al. 2004, pp. 12422-12427; IPCC 2007, p. 9).
    Preston et al. (2008, p. 2508) found that Quino checkerspot 
butterfly habitat decreased and became fragmented under altered climate 
conditions based on the climate-only model. For increasing temperatures 
and 110 percent precipitation, there was a shift in habitat to the 
eastern portion of the currently occupied range corresponding with an 
upslope movement of the species to higher elevations in adjacent 
mountains (Preston et al. 2008, p. 2508). The abiotic-biotic model 
(better-performing model) predicted 98 to 100 percent loss of suitable 
Quino checkerspot butterfly habitat when the temperature increased 1.7 
and 2.8 [deg]C (1.5 and 2.5 [deg]F) and when the precipitation was 50 
percent or 150 percent of current levels (Preston et al. 2008, p. 
2508). An increase of less than 1 [deg]C (1.1 [deg]F) with no change in 
current precipitation resulted in no predicted habitat shift, although 
there was an eastward (upslope) shift within the current distributional 
footprint at 110 percent precipitation (Preston et al. 2008, p. 2508). 
Similar climate response patterns in modeled habitat and related and 
co-occurring insect species further support the validity of Parmesan's 
(1996, pp. 765-766) Quino checkerspot butterfly observations and 
conclusions (Preston et al. 2008, pp. 2511, 2512). Therefore, the 
hypothesis of range shift driven by changing climate and precipitation 
patterns occurring in the foothills north of the community of Anza is 
well supported by the best available scientific information.
    Documented environmental changes that have already occurred in 
California (Ehrlich and Murphy 1987, p. 124; Croke et al. 1998, pp. 
2128, 2130; Davis et al. 2002, p. 820; Breshears et al. 2005, p. 
15144), future drought predictions for the state (such as Field et al. 
1999, pp. 8-10; Brunell and Anderson 2003, p. 21; Lenihen et al. 2003, 
p. 1667; Hayhoe et al. 2004, p. 12422; Breshears et al. 2005, p. 15144; 
Seager et al. 2007, p. 1181) and North America (IPCC 2007, p. 9), and 
extirpation of Edith's checkerspot butterfly populations following 
extreme climatic events (Ehrlich et al. 1980, pp. 101-105; Singer and 
Ehrlich 1979, pp. 53-60; Singer and Thomas 1996, pp. 9-39) model and 
predict that prolonged drought and other environmental changes related 
to changing climate patterns will continue into the near future, and 
these changes may affect Quino checkerspot butterfly populations. 
Thomas et al. (2004, p. 147) estimated that 29 percent of species in 
scrublands (habitat for the Quino checkerspot butterfly) face eventual 
extinction, and 7 (with dispersal) to 9 (without dispersal) percent of 
butterfly species in Mexico will become extinct (mid-range climate 
predictions; Thomas et al. 2004, p. 146). During drought conditions in 
2007, surveyors noted that, for the first time since the subspecies was 
listed, no Quino checkerspot butterflies were observed during Riverside 
County surveys or core occurrence complex monitoring (CFWO 2007). 
Therefore, recent subspecies field evidence corresponds with the 
hypothesis that changing environmental conditions throughout the 
subspecies' range is resulting in reduced densities at lower 
elevations.
    Maintenance of the Tule Peak/Silverado and Bautista Road core 
occurrence complexes and habitat connectivity to higher elevation non-
core occurrence complexes is needed to prevent an increase in the 
subspecies' extinction probability and support range shift resulting 
from environmental changes due to changing climate patterns (Service 
2003a, pp. 46, 47; Osborne 2007, pp. 9-10). The Anza/Mount San Jacinto 
foothills area (in and adjacent to the Bautista Road Core Occurrence 
Complex) is proximal to what is likely the highest density

[[Page 28780]]

population that produces the most emigrants within the subspecies' 
range (Tule Peak/Silverado Core Occurrence Complex) and supports the 
greatest elevation gradient within the extant range of the Quino 
checkerspot butterfly. Regardless of range-shift dynamics, this area 
likely supports the most resilient populations within the subspecies' 
current range (see above discussion of recent observations in this 
area). As discussed above, evidence of range shift resulting from 
environmental changes due to changing climate patterns includes the 
following: (1) Parmesan's (1996) subspecies-specific study; (2) Preston 
et al.'s (2008, pp. 2501-2505) subspecies-specific habitat model 
predictions; (3) recent documented Quino checkerspot butterfly outbreak 
events (discussed above); (4) the complete lack of Quino checkerspot 
butterfly observations in Riverside County during 2007 monitoring; (5) 
documented drought conditions and the likelihood that recurrent drought 
conditions will persist into the near future (see above discussion); 
and (6) the discovery of new non-core occurrence complexes in the most 
northern, highest elevation habitat areas (see above discussion of 
recent observations in this area). Parmesan's (1996, pp. 765-766) 
range-shift statistics and Preston et al.'s habitat models (2008, pp. 
2501-2505) predict the following Quino checkerspot butterfly population 
changes: (1) Declines in, and loss of, the southernmost and lowest 
elevation populations (lowest elevation range edge already retracted 
likely due to a combination of development and the 1980s drought), 
especially in drier areas where rainfall is most variable (such as 
southwest Riverside County; Anderson 2000, pp. 3, 6); (2) increases in 
the density in the highest elevation populations, especially in wetter 
areas (such as the Anza area; Service 2003a, p. 44); and (3) 
establishment of new populations higher in elevation where range shift 
is least impeded by habitat loss due to land-use changes (such as the 
Mount San Jacinto foothills; Service GIS database and satellite 
imagery).
    The highest elevation core occurrence complexes (Tule Peak/
Silverado and Bautista Road) also support the highest (co-occurring) 
diversity of host plant species (Plantago patagonica, Antirrhinum 
coulterianum, Collinsia concolor, Cordylanthus rigidus (rigid bird's 
beak), and Castilleja exserta (purple owl's-clover)) within the range 
of the Quino checkerspot butterfly, a factor known to increase 
population resilience (Service 2003a, p. 17) and mitigate the effects 
of climate extremes on Edith's checkerspot butterfly populations 
(Hellman 2002, p. 925). Therefore, prudent design of reserves and other 
managed habitats near the community of Anza, where the subspecies' 
range is likely expanding upslope in elevation, should include 
landscape connectivity to other habitat patches and ecological 
connectivity (habitat patches linked by dispersal areas; Service 2003a, 
p. 162) to accommodate such range shift (Service 2003a, p. 64).
Status and Local Distribution of Populations in San Diego County
    New Quino checkerspot butterfly observations (Service GIS database) 
between occurrence complexes identified in the Recovery Plan have 
resulted in merging of the Otay Valley (core), West Otay Mountain 
(core), Otay Lakes (core), Proctor Valley (non-core), Dulzura (non-
core), and Honey Springs (non-core) occurrence complexes into a single, 
expanded Otay Mountain Core Occurrence Complex. This merging of 
occurrence complexes in the Otay area was anticipated in the Recovery 
Plan, as authors noted that occupied habitat in the vicinity of Otay 
Lakes and Rancho Jamul appeared to be an area of key landscape 
connectivity for all subpopulations in southwest San Diego County 
(Service 2003a, pp. 53, 54).
    Several widely distributed new observation locations have been 
reported since 2002 in central San Diego County (Dudek 2005, p. 1; 
Faulkner 2005, p. 1; Tierra Environmental Services 2005, p. 4), and 
between Interstate 8 and State Route 94 (TRC 2008, pp. 33-38) resulting 
in four new San Diego County non-core occurrence complexes (Fanita 
Ranch, Sycamore Canyon, and Mission Trails Park, and Barrett Lake). The 
proximity of these occurrence complexes to historical collection 
locations (compare above-cited documents to Service 2003a, p. 3) 
indicates recent detections may reflect short-term increases in 
population densities; however, it is not likely that increasing 
densities will persist, given observed and predicted environmental 
shifts associated with changing climate patterns (see above 
discussion), increasing nonnative plant invasion, and the relative 
isolation of these non-core occurrence complexes from core occurrence 
complexes. Therefore, the best available data indicate that these new 
observation locations may be the result of surveys in areas not 
previously searched and likely represent residual, relatively low-
density populations experiencing a long-term trend of decreasing 
abundance.
    Multiple new Quino checkerspot butterfly observation locations have 
been reported in south-central San Diego County since 2002 east of the 
community of Campo (Dicus 2005a, pp. 1-2; b, p. 1; PSBS 2005a, p. 18; 
2005b, p. 26; O'Conner 2006, pp. 2-4). This cluster of occurrence 
complexes near Campo is over 7 mi (11 km) from the closest previously 
identified core occurrence complex near the community of Jacumba 
(Service 2003a, p. 52; Service GIS satellite imagery and database) and 
over 12 mi (19 km) from the Tecate (non-core) Occurrence Complex 
(Service 2003a, p. 47; Service GIS satellite imagery and database). We 
believe the Quino checkerspot butterfly distribution east of the 
community of Campo is under-documented because of: (1) The small number 
of surveys conducted in this area (Service survey report files); (2) 
the existence of contiguous habitat between observation locations 
(Service GIS vegetation database and satellite imagery); and (3) the 
presence of relatively high densities of Antirrhinum coulterianum and 
Collinsia cocolor host plants in occupied habitat (Bureau of Indian 
Affairs 1992, p. c-5; Allen and Kurnow 2005, pp. 10, 13-16; Dicus 
2005a, pp. 1-2; b, p. 1; PSBS 2005a, p. 18; 2005b, p. 26; O'Conner 
2006, pp. 1-4, Science Applications International Corporation 2006, pp. 
33, 34, 37).
    Methods used in the Recovery Plan (Service 2003a, p. 35) to 
determine membership of occurrence locations in an occurrence complex 
using the sparse available occurrence data would likely underestimate 
the population distribution associated with this obviously independent 
population near the communities of La Posta and Campo. Therefore, 
although not quite proximal enough to be considered a single occurrence 
complex based on overlapping 0.6-mi (1-km) movement distances (Service 
2003a, p. 35), we consider this cluster of new observations near Campo 
to belong to a single new La Posta/Campo Core Occurrence Complex.
    Quino checkerspot butterflies were recently observed in a new 
location in southeast San Diego County that resulted in expansion of 
the Jacumba Occurrence Complex (Essex and Osborne 2005, p. 82). 
Additionally, data collected from the Jacumba Occurrence Complex since 
publication of the Recovery Plan led us to reclassify the Jacumba 
complex as a core occurrence complex. The Jacumba Occurrence Complex 
was not classified as a core occurrence complex in the Recovery Plan 
(Service 2003a, p. 52) due to its relatively small geographic size.

[[Page 28781]]

However, adult Quino checkerspot butterflies are consistently observed 
in the area, even during drought years and under difficult survey 
conditions (high winds) (CFWO 2002-2007; Klein 2007, p. 1). An 
estimated 50 individuals were observed in a single day near Jacumba 
Peak (Pratt 2007b, p. 1). Furthermore, reproduction was documented in 
the Jacumba Occurrence Complex in 1998 and again in 2004 (Pratt 2007c, 
p. 1). Therefore, given ongoing documentation of occupancy (Service 
2004, 2005, 2008), documented reproduction over multiple years (Pratt 
2007c, p. 1), reported observations of large numbers of individuals 
(50; Pratt 2007b, p. 1), and an increased occurrence complex area 
(approximately 522 ac (1,290 ha)), we now consider the Jacumba 
Occurrence Complex to be a core occurrence complex associated with what 
appears to be a relatively resilient population.
    The prediction that drought conditions are likely to continue into 
the near future (Service 2003a, pp. 63, 64; see above discussion) 
highlights the importance of conserving populations locally adapted to 
drier climates and diverse habitat types (Service 2003a, p. 76). The La 
Posta/Campo and Jacumba core occurrence complex habitats are warmer and 
drier than the Otay Mountain Core Occurrence Complex and differ 
substantially in other habitat characteristics (Service 2003a, pp. 36-
54; O'Conner 2006, p. 4). Therefore, maintenance of these core 
occurrence complexes is essential for recovery and survival of the 
Quino checkerspot butterfly in San Diego County. These new core 
occurrence complexes were also the only complexes in the subspecies' 
southern range not affected by the 2003 and 2005 fires. Therefore, new 
information indicates the La Posta/Campo and Jacumba Core Occurrence 
Complexes contribute significantly to reducing the subspecies' 
extinction probability.

Previous Federal Actions

    The Homebuilders Association of Northern California, et al., filed 
suit against the Service in March 2005 challenging the merits of the 
final critical habitat designations for several taxonomic entities, 
including the Quino checkerspot butterfly. A settlement was reached in 
March 2006 that required the Service to re-evaluate five final critical 
habitat designations, including the Quino checkerspot butterfly. The 
settlement stipulated that proposed revisions to the Quino checkerspot 
butterfly designation would be submitted for publication to the Federal 
Register by December 7, 2007, and final revisions would be submitted by 
December 7, 2008. In accordance with a court-approved amendment to the 
settlement agreement, dated December 5, 2007, the proposed revisions 
were published in the Federal Register on January 17, 2008 (73 FR 
3328). Subsequently, a court-approved amendment to the settlement 
agreement dated November 6, 2008, stipulated the Service deliver the 
final revised critical habitat designation to the Federal Register by 
June 6, 2009. For more information on previous Federal actions 
concerning the Quino checkerspot butterfly, refer to the proposed 
revisions to critical habitat published in the Federal Register on 
January 17, 2008 (73 FR 3328).

Summary of Comments and Recommendations

    We requested written comments from the public on the proposed rule 
to revise critical habitat for the Quino checkerspot butterfly during 
two comment periods. The first comment period opened with the 
publication of the proposed rule in the Federal Register on January 17, 
2008 (73 FR 3328), and closed on March 17, 2008. The second comment 
period opened with the publication of the notice of availability of the 
Draft Economic Analysis (DEA) in the Federal Register on December 19, 
2008 (73 FR 77568) and closed on January 20, 2009. During both public 
comment periods, we contacted appropriate Federal, State, and local 
agencies; scientific organizations; and other interested parties and 
invited them to comment on the proposed rule to revise critical habitat 
for this subspecies and the associated DEA. During the comment periods, 
we requested all interested parties submit comments or information 
related to the proposed revisions to critical habitat, including (but 
not limited to) the following: unit boundaries; species occurrence 
information and distribution; land use designations that may affect 
critical habitat; potential economic effects of the proposed 
designation; benefits associated with critical habitat designation; 
areas proposed for designation and associated rationale for the non-
inclusion or considered exclusion of these areas; and methods used to 
designate critical habitat.
    During the first comment period, we received 17 comment letters (15 
letters addressing the proposed revision of critical habitat, and 2 
letters from a single commenter that were not related to proposed 
revisions to critical habitat): two from peer reviewers, three from 
Federal agencies, six from representatives of five Native American 
tribes, and six from public organizations or individuals. During the 
second comment period, we received nine comments addressing the 
proposed critical habitat designation and the DEA. Of these latter 
comments, two were from peer reviewers, two from Federal agencies, two 
from Native American tribes, and three from public organizations or 
individuals. We did not receive any requests for a public hearing.

Peer Review

    In accordance with our Policy for Peer Review in Endangered Species 
Act Activities, published on July 1, 1994 (59 FR 34270), we solicited 
expert opinions from 10 knowledgeable individuals with scientific 
expertise that included familiarity with the subspecies, the geographic 
region in which it occurs, and conservation biology principles. Four 
peer reviewers submitted responses. They provided additional 
information, clarifications, and suggestions that we incorporated into 
the rule to improve the final revised critical habitat rule.
    We reviewed all comments received from the peer reviewers and the 
public for substantive issues and new information regarding the 
designation of critical habitat for the Quino checkerspot butterfly. 
All comments are addressed in the following summary and incorporated 
into the final rule as appropriate.

Peer Reviewer Comments

    Comment 1: One peer reviewer stated they had recently communicated 
with residents in and around the community of Anza and concluded that 
residents moved to this area based on an appreciation of nature and the 
outdoors. The peer reviewer suggested the Service should inform 
residents on how to improve Quino checkerspot butterfly habitat. The 
peer reviewer also asserted that residents of Anza are suspicious of 
government intervention and value their personal freedom more than 
endangered species preservation. The peer reviewer expressed 
willingness to help organize a meeting that would provide private 
landowners from Anza with information on how to preserve the 
subspecies. The peer reviewer concluded that, because of their 
appreciation for nature, Anza residents would be willing to improve 
Quino checkerspot butterfly habitat on their lands, but that 
willingness would be decreased by critical habitat designation; 
therefore, we should exclude any lands in the vicinity of Anza from our 
revised critical habitat designation.

[[Page 28782]]

    Our Response: We agree that species conservation benefits provided 
by landowner partnerships to conserve federally listed species may 
minimize the conservation benefits of designating privately owned lands 
as critical habitat, and we appreciate the peer reviewer's interest in 
participating in such an endeavor. We encourage the peer reviewer to 
continue to communicate and work with residents of Anza (Units 6 and 7) 
to conserve the Quino checkerspot butterfly, within and outside of 
areas that meet the definition of critical habitat. Should residents of 
Anza or surrounding areas be interested in developing a partnership to 
conserve the Quino checkerspot butterfly, Service biologists are 
available to participate and provide information on such partnership 
programs as Safe Harbor Agreements for private landowners. Safe Harbor 
Agreements provide assurances to landowners under the Act that no 
additional future regulatory restrictions will be imposed if 
conservation practices on their land attract or perpetuate federally 
listed species. At this time, there is no formal partnership between 
the peer reviewer, residents of Anza, or the Service to conserve the 
Quino checkerspot butterfly or its habitat, other than the Western 
Riverside County Multiple Species Habitat Conservation Plan (Western 
Riverside County MSHCP; Dudek and Associates, Inc. 2003), under which 
some areas south of the community of Anza are already excluded (see 
``Application of Section 4(b)(2) - Other Relevant Impacts - 
Conservation Partnerships'' section below).
    Comment 2: One peer reviewer observed Quino checkerspot butterflies 
``by the 100s'' near the community of Anza during a subspecies 
``outbreak.'' The peer reviewer observed several unique behaviors in 
the Anza area in 2004 (they stated 2006 but our records indicate 2004), 
including a female deep within a stand of Adenostoma sparsifolium 
(redshank), likely searching for sites to deposit eggs. Despite 
extensive survey efforts prior to this 2004 observation, the peer 
reviewer had never observed Quino checkerspot butterflies in dense A. 
sparsifolium, and previously assumed the subspecies never went into 
such areas.
    The peer reviewer asserted that Quino checkerspot butterflies move 
many more miles during periods of high subspecies density than observed 
during average density years. The peer reviewer hypothesized that, 
under certain environmental conditions, hormonal changes could be 
responsible for the behavioral changes he observed. The peer reviewer 
also noted that, during historical ``outbreaks,'' Quino checkerspot 
butterflies were observed in downtown San Diego. The peer reviewer 
hypothesized this movement behavior may be unique to the Quino 
checkerspot butterfly among Edith's checkerspot subspecies, and 
movement between populations may be important for replacing extirpated 
populations and maintaining gene flow between extant populations. 
Finally, the peer reviewer stated a lack of conserved ``intermediate 
habitat'' between populations may cause extirpation of populations and, 
eventually, subspecies extinction.
    Our Response: We were aware of the peer reviewers' observations and 
had incorporated those observations into our analysis (for example, 
inclusion of closed-woody canopy areas in Primary Constituent Element 
(PCE) 2; see ``Primary Constituent Elements'' section below). We 
appreciate the peer reviewers' insights and contributions to our 
knowledge of the subspecies' biology.
    Although we are not aware of any recorded long-distance movements 
for the Quino checkerspot butterfly, the one within-habitat patch 
movement study completed at Otay Lakes (White and Levin 1981, pp. 350, 
355) concluded that Quino checkerspot butterflies were ``less 
sedentary'' than bay checkerspot butterflies and may disperse greater 
distances. Plasticity and variability of movement behavior is typical 
among Euphydryas spp. (Service 2003a, pp. 10-13), as demonstrated by 
the historical observations of Quino checkerspot butterflies in 
downtown San Diego that were cited by the peer reviewer. These 
observations indicate that, when many individuals were dispersing 
during at least one unusually high-density historical event, developed 
areas did not prevent such movement. Therefore, because the best 
available scientific information supports the need for within-
population movement areas, but does not support the necessity or 
identification of ``intermediate habitat'' for dispersal between 
populations, we included only movement areas within habitat-based 
population distributions in our critical habitat designation (see 
``Criteria Used To Identify Critical Habitat'' section below).
    Comment 3: Based on personal experience maintaining captive 
populations, the peer reviewer asserted that Quino checkerspot 
butterfly populations are more susceptible to inbreeding depression 
than most other butterfly species. The peer reviewer stated that, when 
closely related Quino checkerspot butterfly individuals are bred ``for 
some time'' without out-crossing, they observe greater egg and larval 
mortality than generally observed in butterfly species in the family 
Lycaenidae (coppers and blues). The peer reviewer concluded the Service 
should consider assisting genetic exchange between populations that 
appear to be losing genetic variability, such as the small population 
in Unit 1 (Warm Springs Creek Core Occurrence Complex). The peer 
reviewer stated they suspected low genetic diversity was a primary 
cause of the Gavilan Hills/Lake Mathews population extirpation.
    Our Response: We recognize that the increased mortality observed 
during captive rearing could be indicative of inbreeding depression; 
however, we have no basis upon which to determine whether or not 
populations of the Quino checkerspot butterfly outside of a laboratory 
setting experience inbreeding depression. We agree with the commenter's 
recommendation that an evaluation of the population genetics of this 
butterfly could assist its recovery, and we discussed the possible 
effects of genetic drift and inbreeding depression in the listing rule 
for the Quino checkerspot butterfly (Service 1997, pp. 2319-2320). We 
appreciate this information; however, we do not believe it is relevant 
to our final revised critical habitat designation.
    Comment 4: One peer reviewer stated that populations in Units 6 and 
7 near the community of Anza are ``continuous and not actually 
separate.'' The peer reviewer indicated that extensive suitable habitat 
exists between these two units (especially in Terwilliger Valley), 
which is probably occupied by the Quino checkerspot butterfly. 
Additionally, the peer reviewer noted there are multiple public land 
parcels in the area and some have extensive stands of the food plant 
Antirrhinum coulterianum.
    Our Response: While landscape connectivity does exist between Units 
6 and 7 in the Anza area, and some occupied habitat exists in the area 
that was not included in our proposed revised critical habitat units 
(Cave Rocks and Cahuilla Creek non-core occurrence complexes), habitat 
within the community of Anza is fragmented, and large areas of 
landscape connectivity occur outside our mapped habitat-based 
population distributions (that is, not occupied). Our habitat-based 
population distributions are the best estimate of population occupancy 
based on the best available scientific data. Because the habitat-based 
population distributions are not continuous, we must assume the 
Bautista Road and Tule Peak/Silverado core occurrence complexes and the 
Cave Rocks and Cahuilla Creek non-core

[[Page 28783]]

occurrence complexes are not part of a single population. We determined 
that habitat captured by the core occurrence complex habitat-based 
population distributions in Units 6 and 7 provide the PCEs laid out in 
the appropriate quantity and spatial arrangement essential to the 
conservation of the subspecies. Our criteria used to identify critical 
habitat focused on core occurrence complex habitat-based population 
distributions designed to capture all habitats likely to support 
resilient metapopulations, including those likely to support local 
source or mainland populations (also called subpopulations) and 
movement areas between habitat patches required for metapopulation 
resilience (see Service 2003a pp. 163, 165-166 for term definitions). 
Finally, Terwilliger Valley is not located between Units 6 and 7, it is 
located east of Unit 6 (Unit 7 is north). Please see ``Criteria Used To 
Identify Critical Habitat'' section below for further discussion.
    Comment 5: Two peer reviewers stated the Bautista Road Core 
Occurrence Complex was probably occupied at the time of listing, but 
occupancy was not documented because that area was not adequately 
surveyed at that time. The second peer reviewer asserted that, prior to 
1998, butterfly experts did not know much about habitats near the 
community of Anza, and all high-elevation observations were thought to 
be dispersing individuals because the only known primary host plant, 
Plantago erecta, did not occur above 3,000 ft (914 m) in elevation. The 
second peer reviewer noted that Dr. John Emmel observed a Quino 
checkerspot butterfly [near the community of Anza] along Bautista Road 
in the 1970s. The second peer reviewer also suggested that surveys be 
conducted in higher elevation areas where the Quino checkerspot 
butterfly may eventually colonize to determine if the subspecies is 
absent and to document possible establishment of new populations in the 
future. Finally, the second peer reviewer asserted that movement of 
this subspecies into new areas will not be easy because of inbreeding 
depression (see Comment 3 above), and suggested the subspecies may move 
by local and gradual movements and eventually expand into higher 
elevation sites.
    Our Response: We agree that it is possible that the Bautista Road 
Core Occurrence Complex was occupied at the time of listing; however, 
we have insufficient documentation to support that assertion. We 
received subsequent confirmation of Dr. Emmel's historical Quino 
checkerspot butterfly observation referenced by the peer reviewer. Dr. 
Emmel (2008, p. 1) stated that, on March 26, 1988, he observed what 
appeared to be a single female Quino checkerspot butterfly at the 
intersection of Bautista Road and Tripp Flats Road at 3,840 ft (1,170 
m) elevation. Dr. Emmel (2008, p. 1) further stated that this 
historical observation within the Bautista Road Core Occurrence Complex 
may have been of a dispersing individual from a more southern 
population, and the subspecies may have almost exclusively used 
Plantago spp. in the 1970s and 1980s. Therefore, we are uncertain when 
the Bautista Road Core Occurrence Complex was initially colonized; 
however (as stated above in the ``Background'' section), we believe it 
currently provides colonists to higher elevations and, through this 
mechanism, likely facilitates range shift resulting from environmental 
changes that degrade suitable habitat conditions.
    Inbreeding depression may slow colonization of new areas. However, 
when gene flow is restricted (for example, by mountainous terrain; 
Service 2003a, p. 13), local adaptation can occur quickly because 
peripheral populations are not swamped by genes adapted to 
environmental conditions specific to the range core (Zakharov and 
Hellman 2008, p. 199). Higher rates of local adaptation at a species' 
range edge may counteract any negative effects of inbreeding depression 
on colonization rate. Therefore, we did not base any of our conclusions 
on the hypothesis that inbreeding depression slows colonization of new 
areas in this subspecies.
    Comment 6: One peer reviewer asserted the use of host plant species 
other than Plantago spp. and Antirrhinum coulterianum in Riverside 
County should be investigated before assuming they are not used. The 
peer reviewer stated that the western San Diego County populations may 
also use many undocumented host plants, including Castilleja affinis 
(coast Indian paintbrush), Castilleja foliolosa (woolly paintbrush), 
Collinsia heterophylla, and Antirrhinum nuttallianum (Nuttall's 
snapdragon).
    Finally, the peer reviewer expressed the opinion that Penstemon 
centranthifolius (scarlet bugler) may also be an important Quino 
checkerspot host plant near the community of Anza. The peer reviewer 
stated that they observed Quino checkerspot butterflies in early spring 
near the community of Anza and that subspecies' presence appears to be 
positively correlated with relatively heavy feeding damage on P. 
centranthifolius by an as-yet-undetected herbivore. The peer reviewer 
hypothesized the feeding damage on P. centranthifolius could be caused 
by late-instar Quino checkerspot butterfly larvae because they had 
difficulty detecting Quino checkerspot butterfly larvae on host plants 
other than Plantago spp. The peer reviewer concluded that P. 
centranthifolius might be important for post-diapause larval feeding 
because it is the only potential host plant species available for adult 
egg deposition and post-diapause larval feeding during periods of 
drought. Therefore, the peer reviewer believes P. centranthifolius may 
be an important food source for the Quino checkerspot butterfly larvae 
in high-elevation sites during drought.
    Our Response: We agree the Quino checkerspot butterfly may use 
different host plant species across its range. We provided a list of 
all host plant species where egg deposition has been documented in our 
``Primary Constituent Elements'' section below, including Collinsia 
concolor, documented in 2008 to be used in the field by the Quino 
checkerspot. We appreciate information on potential use of Penstemon 
centranthifolius as a host plant; however, Quino checkerspot butterfly 
use of this potential hostplant species has not been documented, and 
any related changes to this final revised critical habitat designation 
would not be appropriate.
    Comment 7: One peer reviewer noted that, based on his experience, 
Eriodictyon spp. (yerba santa), Chaenactis glabriuscula (pinchusion 
flower), and Ericameria linearifolia (narrowleaf goldenbush) are 
important nectar sources for Quino checkerspot butterfly survival. The 
peer reviewer stated some of the nectar sources on page 3335 of the 
proposed revised critical habitat rule (73 FR 3328; January 17, 2008) 
are not important because they are rarely visited by females and, 
therefore, do not contribute to increased production of eggs or 
subspecies survival.
    Our Response: We appreciate this information based on the peer 
reviewer's experience and have revised our list of nectar source 
examples in the PCEs to include the species named by the peer reviewer. 
The peer reviewer did not specify which nectar sources on the existing 
PCE list they did not believe were important. Our list of nectar 
sources is not exhaustive, and nectar source importance can be site 
specific. Therefore, we believe our current PCE nectar source list is 
appropriate (see ``Primary Constituent Elements'' section below).
    Comment 8: One peer reviewer stated that overcollection did not 
play a role in

[[Page 28784]]

the loss of Quino checkerspot butterfly populations.
    Our Response: The listing rule (62 FR 2313; January 16, 1997) 
identified over-collection as a threat to the Quino checkerspot 
butterfly. The Service has initiated a 5-year review on this subspecies 
and is re-evaluating the magnitude and extent of all threats. We 
appreciate this information; however, we do not believe it is relevant 
to our final revised critical habitat designation.
    Comment 9: One peer reviewer stated that they believe all areas 
containing low shrubs should be included in the PCEs because diapause 
constitutes the majority of the Quino checkerspot butterfly's annual 
life cycle, and larvae diapause in low shrubs such as Eriogonum 
fasciculatum (California buckwheat).
    Our Response: This critical habitat designation includes all 
habitat-based population distributions associated with core occurrence 
complexes (see ``Criteria Used To Identify Critical Habitat'' section 
below), and the PCEs include all vegetation with an open woody canopy, 
including shrublands (see ``Primary Constituent Elements'' section 
below). Therefore, habitat containing low shrubs essential to the 
conservation of the subspecies, such as Eriogonum fasciculatum, is 
included in this final revised critical habitat designation.
    Comment 10: One peer reviewer maintained that the availability of 
prominent hilltops should be ``weighed carefully in any decision 
relating to the possible exclusion of critical habitat and associated 
conservation plans'' because the loss of such courtship areas could 
result in the loss of populations even if other PCEs are present in 
designated critical habitat.
    Our Response: This peer reviewer is apparently concerned that 
exclusion of areas from critical habitat will result in the loss of the 
excluded habitat, especially habitat containing hilltops. Section 
4(b)(2) of the Act authorizes the Secretary to designate critical 
habitat after taking into consideration the economic impacts, national 
security impacts, and any other relevant impacts of specifying any 
particular area as critical habitat. An area may be excluded from 
critical habitat if it is determined that the benefits of exclusion 
outweigh the benefits of designating a particular area as critical 
habitat, unless the failure to designate will result in the extinction 
of the species. We believe the exclusions made in this final revised 
rule are legally supported under section 4(b)(2) of the Act and 
scientifically justified. The peer reviewer specifically commented on 
exclusions where conservation plans are in place. Areas excluded under 
section 4(b)(2) based on completed habitat conservation plans (HCPs) or 
other Service-approved management plans receive long-term protection 
and conservation; therefore, areas excluded from critical habitat 
designation should not result in the loss of the excluded habitat,. As 
discussed below, we fully considered and weighed the benefits to the 
conservation of the subspecies from including the specific areas we 
determined contain the physical and biological features essential to 
the conservation of the Quino checkerspot butterfly (including 
prominent hilltops used for mating) within the habitat conservation 
plan areas, in light of our determination that these areas will be 
adequately protected on lands covered by the Western Riverside County 
MSHCP and the San Diego County Multiple Species Conservation Program 
(MSCP), City of Chula Vista Subarea Plan (see ``Application of Section 
4(b)(2) - Other Relevant Impacts - Conservation Partnerships'' section 
below).
    Comment 11: One peer