The EndangeredEl Segundo Blue Butterfly
Take a Virtual Tour to the Malaga Cove Enclave
Rudolf H. T. Mattoni
Department of Geography, UCLA, Los Angeles, CA 90095-1524
The EndangeredTake a Virtual Tour to the Malaga Cove Enclave
Rudolf H. T. Mattoni
Department of Geography, UCLA, Los Angeles, CA 90095-1524
HISTORICAL PERSPECTIVE
Systematics. The El Segundo Blue butterfly (Euphilotes bernardino
allyni) is one of four subspecies of a polytypic species which belongs to
the E. battoides species complex of many population aggregates not yet clearly defined systematically (Shields and Reveal, 1987; Mattoni, l989; Pratt, unpub.). Although the battoides complex occurs over all of North America west of the Great Plains, from British Columbia to Baja California, E.
bernardino is distributed in southern California, southern Nevada,
Arizona, and northern Mexico, including Cedros Island.
The ESB was formally described by Shields (l975) from specimens collected
in El Segundo. These specimens were taken at the Chevron Refinery site.
Several experts recognized the ESB as distinct prior to its formal
description, including Emmel and Emmel (l973), who illustrated it and
called attention to its potential extinction. The ESB is distinguished
from all other subspecies by a combination of underside black spot size,
amount of orange on the wings, wingspread, foodplant, and other characters
(Table 1 in Mattoni, l989).
Natural History. As with all species in the genus Euphilotes, the ESB
spends virtually its entire life cycle in intimate association with the
flowerheads of some species of buckwheat; in this case the coastal
buckwheat, Eriogonum parvifolium. The almost total involvement of all
stages with a single plant part is unique among North American
butterflies. Adults find one another to mate, usually nectar, lay eggs,
perch, and in most cases probably die, on flowerheads. Thus a
significant array of population regulating mechanisms operate within the
flowerhead environment, for example predation, parasitism, competition,
nutrition and disease. When the time arrives to pupate, however, larvae
either drop or crawl to the ground and burrow into the soil. Typically
they travel at least two inches below grade, but stay within the root and
debris zone where they are protected from desiccation and insulated from
temperature extremes. Factors affecting pupae are almost totally unknown
even though the species spends 90% of its life span in the pupal stage
(see White, l986).
The ESB has one generation per year, as is obligatory for all members of
the E. battoides complex under natural conditions. Adults fly from
mid-June through the end of August, the exact timing depending on weather.
Usually the flight lasts from mid-June to mid-August. The onset of flight
is closely synchronized to the beginning of the flowering cycle of the
foodplant. Fresh females fly to flowerheads upon emerging from their
pupae. There they are found and mated within hours by one of the male
population that is constantly moving from flowerhead to flowerhead. The
females then immediately begin laying eggs. Laboratory data indicate
females produce l5-20 eggs per day, but must continuously nectar to
maintain egg production (Mattoni, unpub.). Although field data indicate
females at Chevron live an average of four days in nature (Arnold, l983),
in captivity females live two weeks and produce up to l20 eggs (Mattoni,
unpub.). Eggs hatch within five to seven days. Larvae undergo four
instars to complete growth, a process taking from l8-25 days. The larvae
develop honey glands by the third instar, and are thereafter usually
tended by the ants Iridiomyrmex humilis or Conomyrmex sp., which may
protect them from parasitoids and small predators. By late August the
flowerheads have generally senesced and the larvae have all pupated
underground. The natural history data are all reported from the
population at LAX.
Mature larvae are highly polymorphic, varying from almost pure white or
pure dull yellow to strikingly marked individuals with a dull
red-to-maroon background broken by a series of yellow or white dashes or
chevrons. They feed in such a manner as to remain concealed by the
flowerhead, their patterning adding to this crypsis. The preferred part
of the flowerhead is young seeds, which are consumed preferentially to
other flowerparts. The latter are loosely webbed together producing the
illusion of an intact flowerhead. One larva requires two-to-three
flowerheads (which equals l0-l5 involucres or 400-500 flowers or their
seeds) to complete development. The discrepancy between longevity of
adults in the field (2.3 to 7.3 days, Arnold, l983) and lab (average l6
days, Mattoni, unpub.) adults is most likely due to predation by lynx and
crab spiders. These spiders were found at a frequency of about one per
200 flowerheads in l987 (Mattoni, unpub.). When l5 man hours of direct
observation of flowerheads was made, only one capture of a male ESB by
lynx spider was seen. The event was rapid, by seizure, with the prey
rapidly imbibed and discarded.
The egg population is chiefly regulated by Trichogramma sp. nr. minutum,
which also attacks the eggs of the common hairstreak and at least two
species of microlepidoptera on the flowerheads. Pratt (l987) found 9% of
l47 eggs of the common hairstreak collected at the LAX dunes in l985
parasitized by the wasp. ESB eggs probably have a similar frequency, but
appear better placed for concealment in comparison to the hairstreak, so
few can be found in nature for testing.
In a sample of 30 mature ESB larvae recovered from flowerheads in l987,
six, or 20%, were parasitized by a braconid wasp, Apanteles thurberiae.
The same wasp also attacked the common hairstreak, the moth Lorita
scarifica (abornana)(Cochylidae), and Aroga sp. (Gelechiidae), the latter
two common microlepidoptera on the flowerheads. The ichneumonid wasp,
Diadegma sp., was found in the hairstreak and both moth populations in
l987, but not in the ESB (Mattoni, unpub.). Pratt (l987) reported the same
pattern in his l985 survey. The most significant feature of both wasp
parasitoids is absence of diapause. Thus they only persist by living on a
continuum of alternate larval hosts over an annual cycle. The same is
true for the Trichogramma egg parasitoid.
Arnold (l983) reported finding pupae parasitized by two unidentified
species of tachinid fly at Chevron. No quantitative data were given. The
tachinid life cycle coincides with that of its ESB host so alternate hosts
are not necessary for its persistence. A set of 28 pupae screened from
sand at LAX, just prior to the 1988 flight, produced no parasites.
Pratt (l987) found larvae of Aroga sp. and Lorita scarifica predominant
in E. parvifolium flowerheads, up to 50 each, in l985. He hypothesized
that these severely reduced the food available to the ESB larvae, but also
had an impact on the ESB by direct predation and indirect harboring of
shared parasitoids. Mattoni (l988) found that a sample of flowerheads
collected in l987 produced 30-50% viable seed sets in spite of herbivory
from all sources.
Historical Range. Distribution of the ESB is dependent on the
occurrance of its foodplant, the coast buckwheat. The butterfly further
appears limited to habitats with high sand content. These sites
historically consisted of the El Segundo sand dunes, including interrupted
extensions to the north into what is present-day Ocean Park, and southerly
to Malaga Cove in Palos Verdes (Figure 1). However, after a gap at Santa
Monica, the foodplant extends further north along the well-drained, low
altitude, steep sandstone slopes of the coastal Santa Monica Mountains and
to the south on similar formations along the Palos Verdes peninsula. The
plant forms a small colony on the sand dune at Point Dume. Variant
ecotypes of Euphilotes bernardino bernardino are associated with mixed
Eriogonum parvifolium and E. cinereum plant populations along the sea
bluffs of Palos Verdes south to San Pedro. The plant populations become
pure stands of E. cinereum above the bluff face in Palos Verdes. Both E.
cinereum and E. fasciculatum, are toxic to El Segundo dunes ESB larvae,
although ESB females will lay eggs on them in free choice experiments
(Mattoni, unpub.).
The active El Segundo sand dunes historically covered about 4.5 square
miles (l295 hectares, 3200 acres), based on data from the l894 geologic
survey (Figure l) and Cooper (l967). An inaccurate figure of 36 square
miles, sometimes miscalculated as l8,000 hectares, has been widely quoted
for the dunes area from the summary of California sand dunes by Cooper
(l967). The misquoted value included pre-Flandrian sand deposits that
formed yet older dunes now having more or less consolidated to form
sandstone. Cooper describes the situation clearly in his figure 2 and
text, but somehow the detail was overlooked and the original
misinterpretation repeated by subsequent authors. This sandstone forms
the underlay or base to the present dunes. The edaphic properties of
these sandstones do not provide proper adaptive conditions for the
indicator sand obligate plants of the dunes community, particularly the
coast buckwheat. At El Segundo, coast buckwheat is a key indicator of
primary, undisturbed coastal sand dunes sites. A diagrammatic cross
section of the El Segundo dune system is given in Figure 2.
The biological community of sand dunes proper is adapted to continuously
moving sand and extreme aridity. Once sand is permanently stabilized,
community composition changes. Sand obligate plant species decrease in
frequency to the benefit of more widespread species and weeds with overall
cover increasing. Animal community composition is likely affected as well.
The dunes and lee deflation plain were undisturbed until rancho
development in the 1840's. Farming was then established on the coastal
prairie to the east of the dunes proper, but generally started at least a
half mile further inland, probably because of agricultural unsuitability
of the poorly drained sandstone soil near the backdune.The dunes
themselves were undisturbed until the late 1880's when the cities from
Redondo Beach to Venice were established, but development was limited.
Prior to that time virtually the entire dunes area was pristine, without
evidence of disturbance. Redondo Beach separated the main dunes from
south Redondo Beach and the Malaga Cove extensions (Figure l), with
development of Venice eliminating the dunes north of the mouth of Ballona
Creek. Conversion of the central part of the dunes was slower.
Construction of the Chevron refinery in l9ll separated the dunes into two
fragments. The southern fragment was gradually converted to residences
starting at the turn of the century and rapidly accelerating in the late
l940s. Habitat values were totally destroyed by the l970s. In the l950s
Henne (pers. comm.) noted a dense ESB population and other rare
Lepidoptera in Hermosa Valley, an area soon after destroyed. In l928 the
grid of streets on the LAX dunes were constructed, but development was
minimal following the l929 crash. It was not until after World War II
that explosive development occurred, with virtually the entire dunes built
upon between l946 and l965, where almost all the land was privately owned.
Construction of the Hyperion wastewater and Scattergood generating plants
in the l940s, along with dense housing on the present LAX dunes, reduced
the northern fragment to about 80 acres of dunes habitat by l960. The l.6
acre Chevron butterfly sanctuary site was isolated by residential
development in the l950s.
The most important events affecting the very recent biological history of
the LAX dune segment was the purchase and clearing of residences from
nearly 200 acres between l966 and l972, construction of the VOR, and the
excavation and re-contouring of about 70% of the backdune in order to
re-align Pershing Drive in l975. The newly recontoured dunes were
stabilized by hydromulch with a presumptive "natural" seed mix and
irrigated with a sprinkler system. Unfortunately, the seeds were
representative of coastal sage and not dune scrub plant community. The
common buckwheat, Eriogonum fasciculatum, was introduced by this activity.
At the same time the foredune to the south and west of the VOR was graded
along with the last coastal prairie fragment between the backdune and
Pershing Drive. From l966 through the late l970s the natural biota of the
LAX dune suffered its major contraction, with about 40 variably
undisturbed acres as refugia for subsequent colonization. The 1990
landform classification resulting from these events is mapped in Figure 3.
The most drastic change was the complete destruction of the Los Angeles
coastal prairie to the lee of the dunes. This community was a Stipa
grassland, with a rich oaacurrance of herbaceous meadow plants and
innumerable intermittent vernal pools. The community is now completely
extinct.
Extrapolating from an estimated carrying capacity of 1,000 ESB per acre on
the backdune and l00 ESB per acre on the foredune (Mattoni, unpub.) the
historic El Segundo dunes system, with about 400 acres of backdune and a
2,800 acre foredune, should have had an average total population of about
750,000 adults per year.
Present Distribution. The ESB is now (1991) restricted to three
locations: the LAX dunes (LAX), the Chevron Refinery dunes (CHEV), and
Malaga Cove (MC) (Figure l, Table 1). In l988 LAX had the largest
population both in terms of area (ca. 4 acres of moderate density and 20
acres of low density populations), number of adult ESB (ca. 2000), and
foodplants (1,114 native plants with 206,045 flowerheads) (Figure 4, Table
2). After the initial habitat restoration program, the foodplant
population was increased to 3358 in 1991 (Figure 5) with an estimated 5000
ESB flying in 1990 (Table 2). CHEV in l986 had an area of 1.6 acres,
about 400 adult ESB, and about 240 natural plants plus about another l,000
surviving introduced cultivated seedlings (Arnold l986). The MC location,
discovered in l983 by J. Morton and T. Leigh, covers about one acre, had a
one-day population count of about 60, and less than 50 plants with 30,000
flowerheads in l984. It is heavily overgrown with ice plant and seriously
eroded. Since l986 the site has been fenced. A 1990 survey (R. Rogers,
pers. comm.) indicates the 1984 status remains stable. Fifteen plants
(3,000 flowerheads) survived to 1986 on a small dune fragment at Playa del
Rey (proposed Ballona Wetlands Reserve). By 1989 half of these buckwheats
died. A male ESB was reported at the locality in l985, but the specimen
was not taken and no stages have been collected since, in spite of several
attempts. A transient ESB was reported on the DWP right-of-way between
CHEV and LAX (R. Rogers, pers. comm.).
The ESB is isolated from its closest relative, a Palos Verde ecotype of
Euphilotes bernardino, by only 2 km at Palos Verdes. To the
north E. bernardino bernardino occurs throughout the Santa Monica
Mountains, where it uses three Eriogonum foodplants: fasciculatum,
cinereum, and parvifolium. E. bernardino bernardino ranges along the
coast to the south, from the bluffs of the Laguna Hills, feeding on the
same three foodplants. Some populations found on the immediate coast, as
at Point Loma, strongly resemble the ESB in appearance. This pattern is
in all likelihood a convergence and does not represent monophyly with the
ESB (Mattoni, l989). There are no blues at Point Dume, which has a small
sand dune and a coastal buckwheat population.
There are no other sites remaining in the historical dunes habitat that
can support more than a few random plants. No further ESB populations
remain to be found, although two locations, the Ballona dunes and the DWP
backdune behind the Hyperion Plant, could be restored to support viable
ESB populations.
PRESERVATION STATUS
Condition of the habitat. The probability of survival of a given species
over time is a function of habitat quality and habitat size relative to a
minimum critical area (Gilpin and Soule, 1986). The spatial loss of the
El Segundo sand dunes habitat to urbanization reached its maximum in the
1970s. The other dune habitats, including restorable sites, cannot be
further developed at this time because of legal constraints, safety, or
geological hazard. Together these sites are sufficient to maintain El
Segundo Blue populations indefinitely, given habitat quality. This
viability analysis is based on potential habitat area and topography that
could support annual adult populations in the order of 100,000
individuals. However, high quality habitat values do not now exist, nor is
there assurance that quality can be maintained over time without some
management. The El Segundo Blue occurs, or could occur, across several
governmental jurisdictions and on private land. Each situation presents
unique problems.
In addition to the three present sites of the El Segundo Blue at LAX,
Chevron, and Malaga Cove; at least three additional sites could be
restored to a native dune ecosystem, thereby providing further assurance
of long term survival (Table 1). These are l) The Los Angeles Department
of Water and Power (DWP) right-of-way for a powerline between the
Scattergood generating plant and Imperial highway at the south end of the
LAX dunes. The site consists of 55 acres of seriously degraded dune and
coastal prairie habitat, including over 5 acres of potentially rich
backdune. Portions of the dune crest and foredune remnant at the adjacent
Hyperion wastewater treatment plant, presently landscaped in exotic
vegetation, could be included as restorable contiguous dune habitat with
an additional 41 acres. Hyperion-DWP would have high value as a habitat
corridor between the LAX and Chevron communities in addition to
functioning as an independent habitat unit. 2) The approximate 7 acre
Playa del Rey backdune, forming the west end of the proposed Ballona
wetlands preserve. 3) Approximately 5 acres of bank lining the Ballona
lagoon that are now (1991) being re-vegetated. A proposal to re-introduce
the ESB onto the first half acre fragment during 1992 is under
consideration. Other potential habitats include Dune park in the city of
Manhattan Beach with a 2 acre degenerate backdune fragment about 2 km
south of Chevron. Although completely open to public use, parts could be
protected and restored. Public school open space of about 1.5 acres each
in Hermosa Beach and Manhattan Beach are potential restoration sites.
Without an active restoration and management program, the outlook for the
long term persistence of the dunes ecosystems necessary to support the El
Segundo Blue is bleak indeed. The centerpiece of any effort must be the
LAX site, as LAX alone contains not only the largest fragment, but the
closest approximation to prehistoric dune ecosystem composition. Of the
302 acres, about 250 acres are actual sand dunes, of which 39 contiguous
acres were at least partially undisturbed, including an almost pristine 2
acres of backdune and 15 acres of foredune. The remainder has either been
extensively sandmined, graded, or built upon; has heavy soil spoils; or
is concrete or asphalt road (Figure 3). Further trauma included heavy
spraying of some sites with oil and introduction of deleterious exotic
plants for sand stabilization, and the invasion of non-native animals
(Mattoni, 1990 a, b).
Notwithstanding a gradual degradation between the l938-1939 biological
survey by Pierce (l939-l940) and the present, most substantive changes
have taken place during the past decade and a half (Mattoni 1990a, b) as a
result of the re-alignment of Pershing Drive, construction of Imperial
Highway, moving sand to build the VOR hill, and fragmentation and scraping
of the coastal prairie. The manifestation of degradation was extirpation
of many native species on the one hand, and the invasion of the site by
exotic plants and animals on the other. The convergence of these forces
predict a grim future. Of 20 native terrestrial mammals recorded by von
Bloeker (in Pierce notes), most of which were present in l975 (LAX-EIR,
l975), only three are extant today. In their place are introduced
Norwegian rats, red fox and opossum. Of 31 species of butterfly breeding
on the site, 7 or 23% have disappeared. Of 18 species of reptiles and
amphibians (von Bloeker, l941), 7 or 39% no longer occur and all 5 scrub
dependent birds (Soule et al. 1988) have disappeared. The situation with
native plants is fundamentally more serious since plants are the base of
food chains and hence ecosystems. A specialized herbivore restricted to
one plant species would be lost with extirpation of its food source, as in
the case of two extirpated butterflies. Of the 73 native plant species
recorded on the sand dunes proper by Pierce et al. 22, or 30%, were not
found by our 1989 survey, and 19 of the 51 surviving species occurred as
less than 100 individuals and faced imminent loss. More seriously,
several alien plants, including two Acacia species and Eriogonum
fasciculatum, had been introduced to the site within the past two decades
with serious consequences. Other exotic species present in l938 have
since become serious competitors to the native plant community. Two
closely related iceplant species, insignificant in l938, are now dominant
across most parts of the foredune thereby closing options on their
occupied territory (D'Antonio, 1986). Storksbills and alien grasses are
also co-opting habitat for native plants. Recently observed Pampas grass
and Myoporum present yet new threats. The LAX dunes history is an
outstanding example of the effects of uncontrolled, often intentional,
introduction of exotic plants which become ecologically devastating.
Photographs of identical portions of the backdune show the changes in the
landscape between 1938 and 1989 (figure 6).
The Eriogonum parvifolium foodplant of the ESB is only found on
undisturbed sand dune habitat. In the fifteen years the LAX dunes have
lain fallow since the massive clearing and excavating activities, only
three individual plants of 1114 counted in l986 were found on disturbed
sites (Figure 4). Why the plant remains restricted is unknown, whether the
limiting factor is poor seed dispersal, seed viability and germination, or
establishment. Thousands of seedlings have been observed across several
sites following winter rains, yet few establish. It is noteworthy that
coastal buckwheat has both highest quality and highest density on the
least disturbed backdune sites (Table 2 and Figure 4: clusters of 119,
154, & 86 plants) where invasive exotics are in low frequency. Within
these sites, and the relatively undisturbed VOR sections (Figure. 3),
native dune scrub plant associations resist significant invasion by
exotics. From photographs and notes of Pierce (l938-l940), many of the
exotic plant species were present in his time, but were not abundant. The
two Acacia species appear exempt from this "exotic exclusion/native
cohesion" phenomenon, however, and threaten a breakdown of the remaining
native ecosystem by altering soil texture and chemistry. Acacia
populations increased from none detectable in l976 to 671 individuals in
l987 and was increasing at an annual rate of 46% prior to removal between
1988-1991. The long lived seed bank of Acacia numbers in the millions and
will require attention for decades.
Ecosystem disturbance through changes in the mammalian community have been profound as both rabbits and mice influence the differential reproductive
efficiency of herbaceous plant species. The absence of mammalian
foraging probably relaxed substantial pressure on seed banks, particularly
the r-strategist European weeds. Loss of small mammals is linked to the
introduction of the European red fox, which themselves now have such
limited food resources that they are driven to garbage scavenging,
lizards, and even large insects.
Of the other habitats, Malaga Cove was last visited during the flight
period of l990. The site was heavily overgrown with iceplant, which
threatens the some fifty buckwheat foodplants, although this site and
population have probably persisted in isolation over the past 40 years.
The site needs further evaluation particularly because the ESB population
has survived in spite of its very small population. According to Pratt
(pers. comm.) the Malaga Cove population is genetically identical
(allozyme frequency) to that of LAX.
The Chevron site has been isolated at least since the mid 1950s,
subsequently carrying an ESB population of about 2000 adults annually from
at least 1965 until l977, when intensive studies on adult population
demography began. While determining population sizes for l977 and l979, a
precipitous drop from an estimated 1328 to 681 between those two years
was noted (Arnold l983). Later Arnold (l986) presented data on densities
of both foodplant buckwheat and ESB for each year since l977, showing a
decline between l977 and l986 from about l850 to 350 adult ESB adults and
420 to 300 Eriogonum parvifolium. Arnold claimed the primary cause for
the declines was stabilization of the dune process of sand movement with
correlated exotic plant growth, buckwheat senescence, and reduced
buckwheat seedling survival. A more likely cause of crashes of both
buckwheat and blue was the impact of the study itself. In small fragile
habitats, particularly steep sand dunes, regular walking during the course
of observation and data collection is a serious problem (Brown, 1987) that
leads to root damage and changing water balances. Another study impact
suggested is the citation by Arnold (l983, p. 90) of rearing 839 El
Segundo Blue larvae for sex ratio determination. Removal of this many
mature larvae from the population could alone explain the drop in
population size from l977 to l979. Further, as pointed out by Murphy
(l984, l988), the use of mark-release-recapture (MRR) methods on
butterflies as delicate as the El Segundo Blue probably profoundly effect
behavior, survival and reproductive dynamics. Even with careful netting,
legs easily break off these fragile animals and lack of legs has
deleterious effects (e.g. Mattoni, l988). The added trampling
necessitated by an intensive MRR program cannot aid recovery.
SOCIO-POLITICAL ASPECTS OF PLANNING
Historical conflicts-LAX dunes. A major cause of conflict arose from events attendant to the expansion of the Mines Field into the Los Angeles International Airport (LAX). The major radar installation (VOR) was
located on a 60 acre site purchased in 1950. Home construction on the
remainder of the dunes continued unchecked until into the 1960s. With
increasing air traffic necessitating construction of the north runway,
safety considerations and the onset of jet age noise, residential living
conditions became increasingly difficult. In a 1965 referendum, over 66%
of homeowners elected to be bought out with the remaining property
condemned. Between l965 and l975, 822 homes were vacated and over 2000
people relocated. The $60 million cost was 75% reimbursed by the federal
government. Almost unnoticed during this hubbub, the ESB was listed as an endangered species in l976 under the Endangered Species Act passed by the congress in l973. All of the LAX dunes south of Sandpiper St. (Figure 3) were proposed as critical habitat in l977, a finding abandoned by modifications to the Act as amended in l978. l976 was also the year the California Coastal Act was enacted in response to a mandate by the voters to guarantee
preservation of coastal environmental values. The 1970s was the first
time signs appeared of a public awareness that all was not right with the
environment. This concern eluded many bureaucrats.
The Los Angeles City Planning Department thereafter began work on a plan
to develop the LAX dunes as a recreational facility, emphasizing a 27 hole
golf course. With recognition of the ESB, the plan was modified to set
aside 80 acres as a conservancy plus 12 acres as a preserve/research/interpretive area. Following requirements set forth by the coastal act, public disclosure and participation processes were initiated and hearings began in early l981. A public interest group, "Friends of the Dunes", was established and battle lines drawn. The essence of organized opposition to any development on the dunes was the position that the dunes contained a rich biota, exemplified by the listed ESB, and should be left as open space which would restore itself by natural plant succession. After eight public hearings, the city submitted the development plan to the Coastal Commission for action in late l983.
Two independent studies of the ESB populations at LAX were performed in
l984. Both studies indicated serious and deteriorating habitat
conditions. Consequently airport officials developed a memorandum of
understanding with both U.S. Fish and Wildlife and the California
Department of Fish and Game to support the recreational complex with the
key provision that development would generate funds to assure restoration
and permanent management of the preserve. A conservancy committee was to
oversee long term objectives. Both federal and state agencies recognized
the golf course as the least objectionable of the funding solutions
because in the long run the sand substratum would remain untouched while
the infrastructure of several acres of roads, foundations, rubble and old
utility appurtenances would be removed. With assurance that the unique
biota were thereby conserved, future generations would have the option to
roll back the golf course with minimum effort. An alternate hypothesis
was advanced that the golf course could be viewed as destruction of ESB
habitat, thereby permitting development of this area for commercial
airport purposes at some indeterminate future.
At its November 12, l985 public meeting, the Coastal Commissioners
followed their staff recommendation and rejected the airport development
plan as inconsistent with the Coastal Act by not assuring preservation of
a unique sensitive habitat. However, the Commission did not accept a
staff recommendation that the airport set aside the entire 302 acre site
as "environmentally sensitive habitat", thereby leaving open exploration
of other options. In its wisdom, the Commission did recognize that the
basic issue of funding was necessary to both maintain and restore the
habitat. What remained unresolved was that denial of an institutional
funding mechanism would number the days of the "environmentally sensitive
habitat".
From studies of population regulation of the ESB discussed above, it was
apparent that survival of the ESB was in immediate jeopardy. In the
public interest, the Board of Airport Commissioners generously provided a
small contract in early l986 to relieve the situation until a permanent
solution could be found. This initial contract was successful in assuring
short term survival of the ESB. In l987 a major biological survey and
ecological evaluation of the site was contracted to provide quantitative
information to elucidate habitat values and open alternatives to resolving
the conflict of providing funding necessary to assure restoration and
management. The study recognized that funding must be developed from some
form of land use at the site. As appealing as restoration of the whole LAX
dune remnant might be, economic realities must be recognized and a
consensus established to provide a viable long term solution.
Other El Segundo Blue butterfly habitats
Recognizing the intent of the law and the role of the ESB as an indicator
of the unique El Segundo dunes ecosystem, several other habitats and
potential habitats must be dealt with. These have been mentioned above and
include: Chevron, Malaga Cove, DWP right-of-way and adjacent Hyperion
property, the Playa del Rey-Ballona backdune, and other miscellaneous
parcels.
CHEVRON:
MALAGA COVE:
DWP RIGHT-OF-WAY / HYPERION:
PLAYA DEL REY - BALLONA BACKDUNE:
BALLONA LAGOON:
Assuring survival of both the ESB and the dunes ecosystem must involve all
of the localities cited above. Site multiplicity alone, assuming
responsible management, will go far in preserving all the sand obligate
plants and animals of the dunes. Although the sites cut across several
political boundaries and public interests, their biological commonality
must be recognized. The sites are summarized in Table l.
BIOLOGICAL ASPECTS OF PLANNING
BACKGROUND INFORMATION. Listing the ESB in l976 was based largely on intuitive information concerning distribution, abundance, and the nature
of threat. Emmel and Emmel (l973) mention that the then undescribed
butterfly was in danger of extinction. Their opinion was later backed by
supporting historical observations of the mass extirpation of other
species on the dunes by urbanization with only remnants left at LAX,
Malaga and Chevron. Arnold (l983, l987) presented quantitative
information on the Chevron populations from l977 to l986 that showed a
steady decline from 1600 to 400 individuals. Transect counts by Mattoni
and Murphy (l984 unpub. rept.) provided population estimates at LAX of
about 800, or about twice Arnold's (l986) MMR estimates from the same
time. For other biological parameters, Shields (l975) first found the
butterfly associated with Eriogonum parvifolium and Arnold (1983) later
gave additional information from Chevron on demographics, dispersal,
foodplant numbers, and parasitoids; but these provided only limited
useful information for developing a conservation plan and management
strategy. Information prior to the Mattoni (1990) report was incomplete
through failure recognize the very significant differences in habitat
structure at different sites.
STUDIES CONDUCTED TO DEVELOP A CONSERVATION PLAN: CHEVRON. The conservation plan Arnold (l986) implemented at Chevron essentially followed conventional wisdom without benefit of a planned study or research program. Detailed numerical estimates of ESB population size, a
cornerstone of the plan, had little relevance to planning other than
reiterating the obvious. Although the plantations of buckwheat foodplant
and removal of iceplant had a salutary effect on the ESB, the efforts did
not address the basic biology of either ecosystem structure or its
restoration. And as mentioned the damage inflicted by the study itself
with extensive and intensive trampling over a small parcel, may have
accounted for some reduction of the ESB.
STUDIES CONDUCTED TO DEVELOP A CONSERVATION PLAN: LAX. As thede facto major dunes preserve in both land area and habitat diversity, attention will be focussed on LAX. After the initial 1984 studies, Pratt and
Mattoni made observations that provided insights explaining the low
relative ESB numbers at LAX. Their judgement was based on population
density of the foodplant, which implied that several times the observed
number of butterflies were to be expected. Operating on a grant from
California Department of Fish and Game, they determined that the critical
threat to the ESB was high density of two moth species Lorita scarifica
and Aroga species. Abundance of the moths was the result of the presence
of introduced common buckwheat that provided them foodplant a month prior
to blooming of the coastal buckwheat. Since the moths are multivoltine,
and the ESB univoltine, the added generation provided a direct competitive
edge as well as high density of the parasitoids they share with the ESB.
The Airport Commission consequently provided emergency funding to remove
the buckwheat and otherwise augment the habitat.
A comprehensive restoration and management plan needs information not only
on the biology of the ESB, but of other components of the ecosystem which
impact not only the ESB, but other sensitive species found at the site.
In order to test ESB population responses, a standard transect was
established for annual monitoring of adult ESB. The transect path was
designed to minimize damage to the substrate. The biological survey of
distribution and abundance of all dunes plants and animals provide data
for a model of the ecosystem to document restoration. The study included
information collected by Pierce and his colleagues in l938-1939,
collections by others, and old aerial and ground photographs. The study
was funded by the Airport Commission a report now available (Mattoni
1990). A comprehensive restoration and management plan is in final
preparation and funding sources are being pursued.
EL SEGUNDO BLUE POPULATION MONITORING. A general estimate of butterfly
population size is needed to evaluate both the impact of management
techniques and status. Although mark-release-recapture (MRR) techniques
can be useful, deleterious effects of such handling on so delicate an
insect cannot be justified. In addition to mortality (reported as 10% in
the mission blue butterfly by Reid and Murphy, l986) and behavior
modification (Morton, l984), any perceived precision MRR might provide is
unsupportable for studies involving fragile endangered species. The
alternative of visually scoring along a regular transect is adequate for
providing needed data, but even here the trampling problem must be
minimized. Since MRR had been used simultaneously with a transect in l984,
crude numbers for calibration are available (Thomas l983). Because of the
unique behavior of adult Euphilotes butterflies, the transect count method
may be more accurate than MRR. Since adult ESB spend over 90% of their
time on flowerheads of the foodplant, moving less than 10% of the time and
then usually only when travelling to a nearby flowerhead, a direct
estimate of the total instantaneous population size is possible by making
a rapid count of adults on flowerheads from a sample of each colony
aggregate, given a count of total number and distribution of flowerheads.
An accurate estimate of total population size over the entire flight
period, however, depends upon estimates of birth and death rates and
immigration and emigration. Because these parameters rely on estimates
only obtainable from MRR, with its faulty assumptions, total population
size estimates from transect counts will have a large error component
(Mattoni, in prep.).
Monitoring is also possible by sampling flowerheads to determine numbers
and species of larvae. The procedure would be useful to estimate
population densities of the two moths which interact with ESB larvae as
well. Lastly, ESB can also be estimated from pupae counted in sifted soil
from the base of foodplants.
DISTRIBUTION. The ESB is limited to the occurrence of its foodplant, but
the relationship is not random. Table 2 lists ESB population counts from
five major clusters of buckwheat foodplant in l984 and 1986-l990 with
numbers of plants and their flowerhead number (Figure 4). The lack of
correlation between butterfly and foodplant is clearest when comparing
clusters 1 and 2 (backdune) with 5 (foredune/VOR). The former each yielded
1.6 butterflies per thousand flowerheads, the latter only 0.14. This
distribution pattern emphasizes the heterogeneity in habitat values, with
the importance of any given plant being its location. The general
distribution of high quality plants largely on the backdune near the toe
of the slope is a key to conservation. The few high quality plants on the
foredune only grow in small depressions with leeward protection.
DISPERSAL. Adult ESB are sedentary animals that spend the bulk of their
time perching and searching for mating opportunities (males) and
ovipositing and feeding (females). From MRR work, a few individuals moved
distances equivalent to the farthest reaches of the habitat (Arnold l986).
Using a different approach, Mattoni and Pratt (unpub.) set out mature
potted foodplants at sites up to 0.5 km. outside their normal distribution
area with the objective of finding offspring of dispersing females. The
results were negative. All the flowerheads of two isolated plants in the
disturbed foredune area (see map, Figure 4) were sampled with no ESB early
stages found on 184 flowerheads in l987. These data indicate dispersal,
and/or distant foodplant locating ability across distances as small as 200
meters, is not common. Although movement between the main buckwheat
clusters is probably more limited than within clusters, from a practical
viewpoint further investigation is not now warranted. For purposes of
population genetics, even with low inter-cluster movement, the population
of LAX is a single unit (Forney and Gilpin, 1989).
The small colonies at Chevron and Malaga Cove are isolated with probably
no effective gene flow possible with the LAX "metapopulation". Recent
data of Pratt (unpub.) found allozyme frequencies of Malaga
indistinguishable from LAX indicating these populations have not been
separated for enough time to permit deviation in frequency of the tested
loci.
Habitat Values. An ecosystem is physically described by the distribution and abundance of all plant and animal species in a circumscribed area, or habitat, to which they are co-adapted. High natural value habitat can
thus be characterized by the community of species found prior to human
interference. Only l ha backdune and 5 ha foredune at LAX can thus be
considered relatively pristine habitat, with another dozen hectares
moderately undisturbed. These pristine sites provide species area curve
models for restoration and foci from which to carry out restoration based.
Alien species require identification with a plan for their regulation.
Particular care must be devoted to assessing whether apparent natives are
historic natives. The common buckwheat was heretofore believed a native
plant of the dunes, for example, yet proved to be a serious threat to the
ESB because it was not.
All extirpated plants must be re-introduced into their proper
micro-habitats. Where precise information is lacking, this can only be
done by over planting and allowing selection to later segregate density
and distribution. Animal re-introduction will require care to avoid
excess herbivory while maintaining assurance of population regulation
within the food web. Re-establishment of the historic mammalian community
is impossible because of isolation and area limitation for megapredator
support. The absence of models for the sequence of introduction of
smaller mammals is another problem.
Biological Program. The biological program is an outline the concerns which affect the viability of the entire plant and animal communities of the dunes ecosystem. Although focus remains on the ESB, over 30 identifiable species of concern and those limited in distribution to
southern California coastal dunes ecosystems will all be aided by
re-establishing an optimal environment for the ESB. Unfortunately
emphasis on the butterfly has been and will remain important since most
non-biologists, including politicians, attorneys, and planners, can more
easily deal with a single organism rather than a complex system that is
both conceptually and in reality vague (Jensen et al. 1990).
The LAX dunes are a leading "hotspot" of biodiversity nationally when
judged by the number of unique species for area size. To date 11 species
have been identified that are endemic to the El Segundo dunes system, with
many more variously listed as species of concern or significance (Table
5). These include the extinct El Segundo giant flower-loving fly,
Raphiomidas terminatus terminatus; the San Diego horned lizard,
Phrynosoma coronatus blainvillei; the seaside calandrinia, Calandrinia
maritima; and the beach spectaclepod, Dithyrea maritima.
Principles that will be utilized to develop a plan include:
There are a number of uncertainties for carrying out the plan which
suggest continuing research, including pollution effects from JP-4 jet
fuel hydrocarbons and borates, high noise levels, and possibly extra low
frequency electromagnetic radiation. There is clearly potential to
perform meaningful experiments for community ecology and to provide
contributions to basic scientific knowledge. The plan must include
provision for local universities and colleges that will enable students to
participate through new research programs.
INSTITUTIONAL PROGRAM
An institutional program will be developed to embody a committee to
represent all parties with vested interests in land use, biology, and
environmental concerns. The committee will set policy to implement the
biological program.and be charged with administering the habitat
conservation plan.
A funding mechanism is crucial to the plan for both the restoration
program and continuing management. The recreational facility plan put
forth for the Department of Airports by the Los Angeles city planning
department in l983 was designed to finance a habitat conservation plan
through fees generated by the facility developer. The privately managed
facility was to include a 27 hole golf course plus an active recreation
area. Nature was to be served through the establishment of a permanent 80
acre conservancy and 12 acre preserve. All undisturbed areas were
included in the 80 acre conservancy.
The matter is unresolved (1991), yet the clear message from data gathered
to date is that without an active program, the dunes ecosystem will
continue to collapse (Mattoni 1990b). At what point the ESB will
disappear cannot be predicted, but the event could be within decades
without further augmentation efforts. Species recently extirpated from
the dunes cannot be restored without manipulated reintroduction because
there are no nearby natural areas. Exotic plants and animals continue
spreading and can only be controlled or eliminated by directed
intervention. The restoration and management program will require funding.
The l983 plan was one approach to solving the problem, although with an
unfavorable land area.
PROGNOSIS
CODA
There are no funds now available and no provision in the LAX charter for
the use of airport funds for either restoration or habitat maintenance.
Although the Department of Airports paid over $300,000 for both the
biological study and initial enhancement programs, their use of general
funds were justified in promoting the 1983 golf course plan.
Over 43 acres have been revegetated to a degree that over 90% of the plant
cover is native (1991). Part of the work was performed by a team of 60 -
140 volunteers. Expansion of the volunteer program is projected to
provide over 30% of the effort to complete the revegetation phase of the
program. The value of volunteers has proved greater than their donated
time alone both in quality and sensitivity of their work and their influence
in the political base.
Among the other parcels: the Hyperion foredune is scheduled for native
revegetation by the Department of Public Works, contact has just been made
for the DWP backdune, the Chevron butterfly garden program continues,
Malaga Cove remains ignored, the Playa del Rey dune restoration project
has been made a hostage by an uncaring developer, but the Ballona Lagoon
restoration and ESB re-introduction plans are proceeding.
Acknowledgments. Gordon Pratt contributed substantial information
concerning many aspects of Euphilotes systematics and biology which are
invaluable to our understanding of these animals. The format of this
report follows that of T. Reid and D. D.Murphy (l987) in their report
"The Endangered Mission Blue Butterfly." For comparative purposes it
seemed valueable to use a standard format to present background
information for planning purposes where diverse interests and institutions
are involved. Selected staff of the Los Angeles Department of Airports
were extremely helpful for many favors and support. In particular Paul
Principe not only made fieldwork a pleasure, but provided graphics
support. The airport commissioners, in particular Ms. Maria Hummer,
generously provided early funding and demonstrated concern for the broader
issues of my biological study of the dunes. Councilwoman Ruth Galanter,
her staff including especially Rubelle Helgesson and Betty Fisher, Mayor
Tom Bradley, and many individuals across several city departments cannot
be commended enough for their efforts and sensitivity to permanently
preserve the ESB, its habitat at three sites, and the entire dunes biotic
community. The California Coastal Conservancy has provided short term
funding until other sources are developed.
Last, but hardly least, I thank Jeremy Thomas, Paul Opler, and Otakar
Kudrna for their comments that helped both enrich and clarify an earlier
version of this paper.
Literature Cited
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(Lepidoptera, Lycaenidae): Island biogeography, patch dynamics, and the
design of habitat preserves. Univ. Calif. Berkeley Pub. Entomology. 99.
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BROWN, D. R. 1986. The effect of human trampling on the dune-mat
vegetation of the Landphere-Christensen Dune Preserve. Rept. to The
Natural Conservancy, San Francisco. 12 pp.
COOPER, W.S. l967. Coastal dunes of California. Geol. Soc. Amer. Mem.
104:1-131.
FORNEY, K. A. and M. E. GILPIN, 1989. Spatial structure and population
extinction: A study with Drosophila flies. Conservation Biology 3: 45-51.
GILPIN, M. E. and M. SOULE 1986. Minimum viable populations: processes of
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_________ 1990. Habitat evaluation and species diversity on the LAX El
Segundo sand dunes. Rept. to the LAX board of airport commissioners.
_________ 1990a. Unnatural acts: succession on the El Segundo sand dunes
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Tables
Figure 1.
Figure 2.
Figure 3.
Figure 4
Figure 5.
Conflict concerning land use of the 302 acre sand dunes parcel at the
western boundary of the Los Angeles International Airport (LAX) centers on
the small butterfly, the El Segundo Blue butterfly (ESB). Since the ESB
was granted protected status in 1976 under the Endangered Species Act of
l973, the real issues involved in its conservation have been obscured by
the polemics of special interest groups that have been arguing without
proper data, or worse, with flawed data. This paper reviews all known
aspects of the history, biology, and conservation issues, concluding with
up-to-date political actions that will affect the survival of the species.
The federal Endangered Species Act of 1973 states that "The purposes of
this act are to provide a means whereby the ecosystems upon which
endangered species and threatened species may be conserved (and) to
provide a program for the conservation of such endangered species and
threatened species,...". The Act goes on to define "critical habitat" as
not only the geographic area where such species occur at the time of
listing, but "specific areas outside the geographic area occupied by the
species at the time it is listed ... upon determination by the secretary
that such areas are essential for the conservation of the species."
Data Requirements.
Table 5 summarizes the role of techniques required to implement
the plan.
Long term survival of the ESB is dependent on a habitat restoration and
management. To best serve the needs of the butterfly, the entire useable
remnant 277 acre El Segundo dunes ecosystem should be conserved. To
conserve the biota, a habitat conservation plan is being prepared which
addresses the following issues:
The re-election of Ruth Galanter for the local city council in summer
1991, in part for her strong stand on protecting the LAX dunes, provided
the climate to establish a new Specific Plan with 200 acres devoted to a
preserve while retaining a 100 acre golf course to satisfy constituency
(Figure 3). The rough areas of the golf course will be vegetated as
native habitat. The Specific Plan was adopted by the Airport Board of
Commissioners, the City Planning Department, and the City Council. Final
approval of the California Coastal Commission is the last step before
implementation. A detailed habitat restoration and conservation plan has
been completed. The major remaining obstacle is funding.
El Segundo sand dunes from the U. S. Geological Survey
of 1894 showing the historical dunes system and its environs.
Surviving El Segundo blue butterfly populations are at LAX,
Chevron, and Malaga Cove. Restorable sites at DWP and Playa del Rey
are indicated.
Diagrammatic cross section of typical El Segundo dune in the
high dune area. Major physical features denoted.
Recent history of land use at LAX El Segundo sand dunes. The land
use pattern correlates with the degree of disturbance to the natural biota
and hence determines habitat value. The boundary of the preserve area
proposed in 1991 is indicated by the heavy line.
Distribution and abundance of Eriogonum parvifolium across the LAX dunes
with the number of plants found in each patch in 1986 (above) and 1991
following interim restoration (below).
Photographs taken in the same position facing northwest from the corner of
Imperial and Pershing, 1938 (above) and 1988 (below). The early
photograph by W. D. Pierce shows Mrs. Pierce in the forground.
