(DRAFT) - Taxonomy
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
TAXONOMY
NAME - LIZARD, LEOPARD, BLUNT-NOSED
OTHER COMMON NAMES - LIZARD, LEOPARD, BLUNT-NOSED; LIZARD, LEOPARD;LIZARD, LEOPARD and SAN JOAQUIN
ELEMENT CODE -
CATEGORY - Reptiles
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - REPTILIA,
ORDER AND SUBORDER - SQUAMATA,
FAMILY AND SUBFAMILY - IGUANIDAE,
GENUS AND SUBGENUS - GAMBELIA,
SPECIES AND SSP - SILUS,
SCIENTIFIC NAME - GAMBELIA SILUS
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Blunt-nosed Leopard Lizard
Gambelia silus (Stejneger, 1890)
KINGDOM: Animal GROUP: Reptile
PHYLUM: Chordata CLASS: Reptilia
ORDER: Squamata FAMILY: Iguanidae
The blunt-nosed leopard lizard is a large, robust long-lived
lizard, measuring up to 127 mm from snout to vent, with a long, round,
tapering, regenerative tail (61-68 percent of the lizards total
length). The head is large, broad and triangular shaped, with a
truncate snout. The hind legs are long and stout, about twice as
long as the fore legs (01,02,06,08,15,24). Adult males are slightly
larger than adult females. Hatchlings emerge at about 41-49 mm snout
to vent length and may reach about 88 mm by their first overwintering.
Compared to females, males have enlarged post-anal scales, larger
femoral pores, enlarged temporal and mandibular muscles and enlarged
tail base (02,06,08).
Coloration is basically gray to brown or yellowish dorsally with
whitish to cream or yellow crossbars encompassing 1-7 scale rows on
back and tail, and dark spots or blotches on back and tail. The spots
are reddish, larger and less numerous on hatchlings. The ventral side
Taxonomy - 1 (DRAFT) - Taxonomy
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
is light colored with yellowish under thighs and tail in some adult
specimens and in juveniles. The head and forelimbs are marbled
and spotted to faintly marked or plain. The underside of the jaw is
spotted or blotchy (01,02,06,08).
Adults exhibit color changes during the breeding season. Females
develop orange or reddish spots on their sides and reddish color
under thighs and tail. Males may develop a rusty or salmon to pinkish
undertone on their entire body except the head (01,02,06,08,18).
Differences have been noted in color and morphology between the
San Joaquin Valley floor and foothill populations (08).
Stejneger originally described the species from the type specimen
taken near Fresno, Fresno County, California. He used the name
Crotaphytus (Holbrook, 1842) silus (Stejneger, 1890). Cope in 1900
placed the blunt-nosed leopard lizard as a sub-species of the common
leopard lizard Crotaphytus wislizenii (Baird and Girard) because of
inconsistencies in the distinguishing morphology criteria used by
Stejneger. Smith in 1946 considered the species separate but
suggested the genus Gambelia (Baird, 1858). Robinson and Tanner in
1962 concluded that the Crotaphytus/Gambelia separation was not valid
and returned to the name used by Cope in 1900. Weiner and Smith in
1965 felt the specific named used by Stejneger was valid. Montanucci
in 1969 rejected the Weiner and Smith conclusion and supported the
Robinson and Tanner sub-specific classification. The following year
Montanucci concluded that the full species status of Stejneger was
valid. Finally, Montanucci, Axtell, and Dessauer in 1975 concluded
that Gambelia/Crotaphytus seperation was valid based on cytogenetic
and habitat adaptation differences and placed both the common and
blunt-nosed leopards in the genus Gambelia at full species level,
thus the present commonly recognized name of Gambelia silus for the
blunt-nosed leopard lizard (06,07,08,11,24).
Blunt-nosed leopard lizard specimens are located at the
University of Kansas Museum of Natural History (No. 121629 and
others), U.S. National Museum (No. 9581-B), Los Angeles County Museum
(No. 65-150 and others). Other locations are University of California
Museum of Vertebrate Zoology, California Academy of Sciences, and
Stanford University. Some of the specimens in these collections are
hybrids between silus and wislizenii taken from the Cuyama Valley area
and adjacent canyons in San Luis Obispo, Santa Barbara and Ventura
Counties, California (06,08,09,10,16).
Other common names used for this species are: leopard lizard,
and San Joaquin leopard lizard (IUCN).
Photographs and drawings of blunt-nosed leopard lizards are
available from the California Fish and Game Department and the U.S.
Fish and Wildlife Service, Sacramento, California. Others sources
with photographs include U.S. Bureau of Land Management, Bakersfield
and Sacramento, California; Los Padres National Forest, Goleta, CA;
Richard Montanucci; and Kristine Tollestrup.
Taxonomy - 2 (DRAFT) - Status
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
STATUS
Coded Status
E: Federal Endangered
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The blunt-nosed leopard lizard (Gambelia silus) has been
designated an Endangered species pursuant to the Endangered Species
Act of 1973 (50 CFR 17.11;P.L. 93-205, 87 Stat. 884; 16 U.S.C.
1531-1540), as amended. The species has this status wherever found
including the State of California.
This species is protected by the Lacey Act (P.L. 97-79,
as amended; 16 U.S.C. 3371 et seq.) which makes it unlawful
to import, export, transport, sell, receive, acquire, or purchase
any wild animal (alive or dead including parts, products, eggs,
or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
BLM -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control (43 CFR 4140). Also
responsible for management/recovery on Bureau of Land
Management lands.
USFS -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public lands under their control. Also responsible
for management/recovery on Forest Service lands. The
Forest Service is responsible for integrating
management, protection, and conservation of Federally
listed species into the Forest Planning process
(36 CFR 219.19 and 219.20).
Status - 1 (DRAFT) - Status
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: California
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: California Dept. of Fish and Game
STATE STATUTE: Calif. Endangered Species Act; Fish and Game
Code, Chapt. 1.5, Art. 1, Sec. 2050.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The blunt-nosed leopard lizard is listed as Croyaphytus silus in
the Convention on Nature Protection and Wildlife Preservation in the
Western Hemisphere (1970), and is listed as endangered under the
common name San Joaquin leopard lizard (Gambelia silus) in the IUCN
Red List of Threatened Animals (1986).
ECONOMIC STATUSES:
None.
67/03/11:32 FR 04001/ - Listed as Endangered.
70/10/13:35 FR 16047/16048 - Preact, Listing.
79/05/21:44 FR 29566/29577 - Notice of Review.
85/07/22:50 FR 29901/29909 - Notice of Review.
87/07/07:52 FR 25522/ - Notice of 5 year review completion.
Status - 2 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
TERRESTRIAL
LAND USE -
Transportation, communications, and Util
Herbaceous Rangeland
Shrub and Brush Rangeland
Mixed Rangeland
Dry Salt Flats
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Riverine, intermittent SB2
Riverine, intermittent SB1
COMMENTS ON HABITAT ASSOCIATIONS -
Blunt-nosed leopard lizards inhabit arid open flatlands, low
foothills, canyon floors, and washes of sandy, gravelly or hardpan to
loam or clay soil and sparse vegetation between elevations of 100 and
2600 feet (01,02,06,08,09,23). They are not usually found on steep
slopes, areas subject to flooding (the lizard favors areas like
intermittent streambeds solely for the soil types, and durring the
rainy season the lizard will avoid these streambeds), nor in dense
vegetation (15). Particular features mentioned for blunt-nosed
leopard lizard habitats include low shrubs, alkali flats, grasslands,
pimple-mounds, alluvial aprons and outwashes, and temporary cover of
rock piles and trash piles. Small mammal burrows, especially of
kangaroo rats, are required for escape cover, nesting, and hibernation
(01,02,06,08,09).
Habitat types are described as follows:
(1) Valley/Plain Grasslands - dominated by goldenbush (Happlopappus),
Arabian grass (Schismus arabicus), jackass clover (Wislizenia
california) and tarweed (Hemizona pallida). Vegetation growth depends
on winter and spring rains. Spring wildflower displays are common.
All vegetation has matured and dried up by summer.
(2) Atriplex grassland - dominated by desert saltbush (Atriplex
polycarpa), quailbush (Atriplex lentiformes), goldenbush
(Happlopappus) and seep-weed (Suaeda fruticosa). This is a perennial
(desert) scrub community of salt tolerant plants. Annual grasses grow
during the winter and spring rainy season and are dried up by summer.
(3) Allenrolfea Grasslands - dominated by iodine bush (Allenrolfea
occidentalis). This is a perennial (desert) scrub community usually
found on compacted soils. Annual grasses grow during the winter and
spring rainy seasons and are dried up by summer.
(4) Suaeda Flats - dominated by seep-weed (Suaeda fruticosa) and
grasses. This is primarily an annual grassland with few perennial
shrubs.
(5) Foothill Grasslands - similar to valley/plain grasslands except
that the terrain is hilly and rings the valley floor and coast range
intermountain plains (24).
Blunt-nosed leopard lizard habitat is associated with cool, wet
winters and hot, dry summers. Temperatures will range from below
freezing to over 100 deg. F. Above ground activities are mostly
limited to air temperatures between 77 and 96 deg. F during the
months of March through October. Flat, open areas in association with
Habitat Associations - 1 low vegetation are preferred. Openings in vegetation created by
secondary dirt roads, the California Aqueduct right-of-way, livestock
grazing, and oil development are utilized by these lizards. Shade
from fence posts and other artificial structures are sometimes used
as shelter from the sun. Small burrows are required for cover,
deposition of egg clutches, and overwintering (24,25,26).
Habitat Associations - 2 (DRAFT) - Food Habits
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
LIFESTAGE FOOD FOOD PART
General Poaceae
General Forb Leaves/Stems
General Arthropods
General Reptilia
Food Habits - 1 (DRAFT) - Environment Associations
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Terrestrial Features: Depressions
G Terrestrial Features: Burrows
G Availability of fence rows: roadside ditches and grassy
Environment Associations - 1 (DRAFT) - Life History
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
Young blunt-nosed leopard lizards (BNLL) are nourished by their
egg yolk until the time they hatch and emerge from their nest-burrows.
From that time on they are primarily insectivorous, although some
plant material and small lizards (including some of their own young)
are sometimes consumed. They are opportunistic feeders with little
preference for food items. The following items have been listed as
consumed by the BNLL: bees, flies, locusts, beetles, lepidoptera,
robber flies, crickets, cicadas, hoppers, ants, spiders, small
lizards, young of fence lizards (Sceloporous) and whiptails
(Cnemidophorus), young Gambelia in spring months, and grass/forb plant
material (02,06,09,16). Blunt-nosed leopard lizards are considered
"sit-and-wait" or "ambush" predators; lizards that remain motionless
until stimulated by actively moving prey (27,28).
HOME RANGE/TERRITORY:
Male BNLL are aggressively territorial during the breeding
season. They will display defensive behavior including open-mouthed
threat, grappling, and biting when other males intrude on their
territory. Territories are about one acre in size and may overlap as
much as 50 feet. Several females may share positions of a male's
territory. Territorial behavior disintegrates at other times of the
year (02,09,13,14,15).
PERIODICITY:
BNLL are diurnal and temperature-oriented. Optimum activity
occurs between 77-95 deg. F air temperature (soil temperatures 86-122
deg. F). During the warm season these temperatures usually occur
between 0800 and 1400 hours. At higher and lower temperatures,
activity is usually reduced. Air temperatures as high as 106 deg. F
are tolerated. Sometimes leopard lizards will seek shade at higher
temperatures to extend their periods of activity (02,09,12).
Above-ground activity of adults is usually from April through
September. Earlier emergence and later activity may occur if mild
weather extends the warm season, however. Adult above-ground activity
is greatest during the breeding season. Males are more active than
females early in the season, becoming less active later. Female
activity is just the reverse. It is speculated that the females must
utilize the later part of the season for feeding to restore their
physical condition following the stress of egg development and
nesting. Adults will overwinter during the cold season from late
September until warm weather resumes in spring, sometimes
as early as late March. Juveniles usually hatch in late July,
although one emergence is recorded as early as 8 July. Juvenile are
active through September and sometimes until mid-October (02,15).
MIGRATION PATTERNS:
BNLL are non-migratory except for minor movement during
population dispersal.
COVER/SHELTER REQUIREMENTS:
Life History - 1 (DRAFT) - Life History
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
BNLL utilize several types of cover for overwintering, nesting,
protection from predators, and escape from intense heat. Small
burrows, especially those of the size excavated by kangaroo rats, are
essential for overwintering through the cold season. Nesting burrow
requirements are apparently quite specific. Although investigation
is limited, it demonstrates that nesting behavior requires burrows and
cavities of certain dimensions. BNLL defense against predators takes
the form of cryptic coloration; crouching motionless; swift movement;
and seeking shelter of vegetation (especially shrubs), burrows of
small mammals (and coyotes, kit foxes, badgers, etc.), and artificial
structures like rock piles, trash piles, fence posts, etc.. They
utilize the shade of burrows, shrubs, and artificial structures for
protection from excessive heat (02,06,08,09,12).
REPRODUCTIVE SITE REQUIREMENTS:
A BNLL nesting site has been described as follows. At about
50 cm below the surface an enlarged chamber is excavated to about
100 mm in diameter and 60 mm in height. Conditions are such that
tunnels leading to the chamber can be plugged with dirt during egg
laying and the exit tunnel can be plugged with dirt after egg laying
(06). There are probably variations of undetermined magnitude for
these criteria, but undoubtedly certain temperature and humidity
conditions are conducive to proper egg development. The nest site
serves for incubation of the eggs and development of the hatchling
lizards until they emerge for above-ground activities (02,06,09).
REPRODUCTIVE CHARACTERISTICS:
BNLL generally mature after their second winter although
some females mature after their first winter (06,18,19).
Courtship begins in April or early May and may extend through
mid-June. A male may mate with several females, although some
male/female pairs have been noted from May to early July and sometimes
to mid-August. It may be that year-to-year pairing may occur (06,09,
15,24). Mating occurs from late April through June. Females
normally produce one clutch of eggs per year, although the presence of
gravid females as late as 17 July suggests that some may produce a
second clutch. Spent females have been found as early as mid-June
(02,06,15). Egg laying begins in June. Based on limited observation,
the process appears as follows. The female enters a burrow
and proceeds to prepare a nest chamber by clawing with her front
feet and pushing dirt out with her hind feet, plugging all
tunnels with dirt. The chamber measures about 100 mm in diameter by
60 mm high and is located about 50 mm below the ground surface. Egg
laying is done one at a time, up to six in a clutch. The mean number
of eggs per clutch varies from 2.0 to 3.5 and mean clutch size appears
to increase in the northern part of their range. Eggs are oval,
15 to 17 mm in diameter and 25 to 28 mm in length. After each egg is
laid, the female covers it with sand or soil. After all the eggs are
laid, the female clears an exit tunnel and departs, plugging the exit
with dirt from the outside, thus resealing the chamber. The entire
process is completed after 5 hours (06,09,08,15,24). Egg incubation
period is about 57 days. Young begin emerging from the nest chamber
usually beginning in late July (one instance of 8 July was noted) and
Life History - 2 (DRAFT) - Life History
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
most of the hatchlings emerge in August (06,09,24).
PARENTAL CARE:
There is no parental care (13).
POPULATION BIOLOGY:
Males usually have a territory of about 1 acre during the
breeding season. Territories may overlap and may be shared by several
females. The mean density of BNLL in good habitat is about 0.5 to 1.0
per acre. In many locations the habitat is less than ideal so overall
densities average well below this. The highest density noted was 4.1
per acre on a 20 acre study site at the Pixley National Wildlife
Refuge in Tulare County. Sex ratios are usually 1:1 on the San
Joaquin Valley floor but tend to approach 2 males per 1 female in
foothill areas (09,15,23,24). Population densities are primarily
limited by the presence of adequate number and size of burrows.
Beyond that, territorial behavior and food supply determine
population densities. The existence of a viable isolated population
depends on the quality and size of a habitat parcel. It is estimated
that about one square mile of good habitat is required for a viable
population (18). A larger contiguous area of lesser quality habitat
would be required to acheive the same level of adequacy. Isolating a
population in this manner also increases it's vulnerability to
extirpation from parasites, disease, predators, and inbreeding.
SPECIES INTERRELATIONSHIPS:
Aside from the presence of adequate supplies of insect food
organisms, BNLL require the burrows of small mammals for shelter. The
burrows of kangaroo rats (Dipodomys sp.) are especially suited in
size. Others of value are burrows of antelope ground squirrel
(Ammospermophilus nelsoni), California ground squirrel (Spermophilus
beecheyi) and valley pocket gopher (Thomomys bottae). Burrows of
larger mammals such as badgers (Taxidea taxus), kit foxes (Vulpes
macrotis), and coyotes (Canis latrans) are used for escape cover
(02,09,24).
Other lizard species usually found co-habiting with BNLLs include
side-blotched lizard (Uta stansburiana), coastal horned lizard
(Phrynosoma coronatum), and western whiptails (Cnemidophorus tigris).
The latter is usually found in inversely proportional numbers
to the BNLL. However, studies in the Taft area of western Kern County
(valley floor/coast range foothill contact zone) showed a positive
correlation, although population densities varied considerably and
averaged quite low, indicating marginal habitat (02,20,25).
Animals that are predatory on BNLL include spotted skunks
(Spilogale putorius), California ground squirrels (Spermophilus
beecheyi), shrikes (Lanius ludovicianus), kestrels (Falco sparverius),
burrowing owls (Speotyto cuniclarius), roadrunners (Geococcyx
californianis), and whipsnakes (Masticophis flagellum). Possible
predators include coyotes (Canis latrans), kit foxes (Vulpes
macrotis), badgers (Taxidea taxus), glossy snakes (Arizona elegaus),
long-nosed snakes (Rhinocheilus lecontei), and king snakes
(Lampropeltis getulus) (02).
Parasites of BNLL include mites (Ophionyssus natricis), chiggers
Life History - 3 (DRAFT) - Life History
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
(Trombicula belkini, Aconatacarus arizonensis), and nematodes (02).
A host of other animals, especially birds are sometimes found in
the same native arid habitats occupied by this species.
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 4 (DRAFT) - Management Practices
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Controlling/Restricting Off-Road Vehicles
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Restricting/regulating human use of habitats
Beneficial Land Acquisition
Beneficial Controlling/Restricting Pesticide Use
Beneficial Maintaining Early Stages of Succession
Beneficial Controlling/Removing Domestic Animals
Adverse Off Road Vehicles
Existing Off Road Vehicles
Adverse Oil Spills
Existing Oil Spills
Adverse Gas/Oil Development
Existing Gas/Oil Development
Adverse Surface Mines
Existing Surface Mines
Adverse Rural Residential/Industrial Areas
Existing Rural Residential/Industrial Areas
Adverse Highway/Railroads
Existing Highway/Railroads
Adverse Soil compaction by heavy equipment in mine areas
Existing Soil compaction by heavy equipment in mine areas
Adverse Flooding
Existing Flooding
Adverse Reservoirs
Existing Reservoirs
Adverse Applying pesticides
Existing Applying pesticides
Adverse Predator control
Existing Predator control
Adverse Grazing
Existing Grazing
Adverse
Existing
Adverse Vegetation Composition Changes
Existing Vegetation Composition Changes
Adverse Fire
Existing Fire
COMMENTS ON MANAGEMENT PRACTICES -
In the past, the primary cause of loss of blunt-nosed leopard
lizards was the agricultural development in the San Joaquin Valley
and adjacent coast range intermountain plains (02). In recent decades
this has become more critical with the development of water projects
for irrigation (09). More recent expansion of urban development and
heavy equipment use for most projects (i.e., development, mining, road
construction, etc.) has also had serious impacts on the lizard's
habitat (01). Other factors noted which influence this species
include heavy oil development and associated sumps and spills;
Management Practices - 1 (DRAFT) - Management Practices
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
highway development and associated road kills of lizards; flooding of
valley floor areas for irrigation water storage; and off-road vehicle
recreation activities (especially in the Kettleman Hills of Fresno,
Kings and Kern Counties, and the Cuyama Valley in San Luis Obispo and
Santa Barbara Counties). Overgrazing by domestic livestock, pest
rodent burrow fumigation, grasshopper and leafhopper control with
DDT and malathion, and wildfires on native vegetation have been
suggested as causing losses in blunt-nosed leopard lizard populations
and habitats. An open pit mine on Brown Material Road in western
Kern County has eliminated leopard Lizard habitat (01,09,14,15,20,24,
25). Another problem that stems from all the above activities is
vegetative composition changes (early successional stages must be
maintained for prime habitat conditions). Blunt-nosed leopard lizards
require relatively undisturbed native land with adequate cover in the
form of small mammal burrows and suitable foods.
The rate of loss of native land habitats in the blunt-nosed
leopard lizard range indicates that their habitat, on the San Joaquin
Valley, floor would be reduced to the remaining preserved lands in the
1990's (14,24). Remaining populations will be increasingly vulnerable
to all forms of impacts in addition to being vulnerable to inbreeding.
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1985. Blunt-nose Leopard Lizard
Revised Recovery Plan. U.S. Fish and Wildl. Serv., Portland, OR.
85 pp.
The prime objective of this recovery plan is to remove the
blunt-nose leopard lizard from the list of Endangered and Threatened
species by maintaining well distributed suitable habitat units with
viable populations within its 1979 range. Isolated habitat units
should be large enough (500-1,000 acres) to prevent the "Island
Effect". The larger the unit, the greater the chances for blunt-nosed
leopard lizard (BNLL) survival. Where large habitats units cannot be
secured, smaller units can be subsituted if they are contiguous or in
close proximity. There may be opportunities in the future to connect
these smaller units with habitat corridors, thereby increasing their
effectiveness.
Actions needed for species recovery and delisting include:
1. Restore and maintain populations at or above 1979 levels within
all habitat areas (especially public lands).
2. Determine occurrence of BNLL on private lands by:
a) First determine potential habitat by photo interpretation,
then
b) Conduct ground surveys to determine presence of BNLL and
habitat in each area.
3. Determine BNLL population levels, habitat requirements, and any
other biological needs.
The density of rodent burrows has been suggested as a factor
which may determine the abundance of the BNLL, and soil types play
a major role in determining the density of rodent burrows. The
BNLL is insectivorous and its food availability is affected by
Management Practices - 2 (DRAFT) - Management Practices
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
several factors such as grazing, plant succession (i.e., maintain
the early successional stage within their habitat), and plant
species composition. Other factors that may impact this species
are, the importance of cover, competitive interactions, the effects
of insect and rodent control programs, and ORV operations.
4. Develop and carry out management programs where species occurs
(i.e. Fish and Wildlife Service, Forest Service, BLM, State,
and private lands).
5. Preserve private lands (habitats) through lease, fee title
purchase, easement, landowner agreement, zoning, etc.
6. Delineate essential habitat for blunt-nosed leopard lizard.
7. Enforce laws and regulations to protect BNLL.
8. Monitor land use changes and population trends.
9. Develop public awareness through public information and education
programs (i.e. audio-visual programs, brochures, and encourage
private and public agencies to seek advice on zoning or development
that may impact BNLL habitat).
No current recovery actions are underway. The State of
California infrequently purchases habitats when willing sellers are
identified. The U.S. Fish and Wildlife Service currently (FY 87)
has not secured funding to acquire BNLL habitat. Study and planning
are proceeding.
Management Practices - 3 (DRAFT) - References
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Anon. [n.d.]. Blunt-nosed leopard lizard (Gambelia silus)
CA Dept. Fish and Game, Fresno.
02 Montanucci, R.R. 1965. Observations on the San Joaquin leopard
lizard, Crotaphytus wislizenii silus, Stejnegar. Herp. 21(4):
270-283.
03 VanDen Burgh, J. 1922. The reptiles of western North America.
Vol. I. Lizards. Occ. papers, Calif. Academy of Sciences 10:1-611.
04 Smith, H.M. 1946. Handbook of lizards. Comstock Publ. Co.,
Ithaca, New York, xi + 557 pp.
05 Strong, F.E. 1965. Pers. comm.
06 Montanucci, R.R. 1967. Further studies on leopard lizards,
Crotaphytus wislizenii. Herp. 23(2):119-126.
07 Montanucci, R.R. 1969. Remarks upon the Crotaphytus - Gambelia
contraversy (Sauria:Iquanidae). Herp. 25:308-314.
08 Montanucci, R.R. 1970. Analysis of hybridization between
Crotaphytus wislizenii and Crotaphytus silus (Sauria:Iquanidae) in
California. Copeia 1970(1):104-123.
09 Snow, C. 1972. Blunt-nosed leopard lizard, Crotaphytus silus.
Habitat Management Series for Endangered Species. Rept. No. 3.
Bur. of Land Mgmt., Denver, CO. 13 pp.
10 Brode, John M. and Dennis C. Stroud. 1974. A list of recorded
localities for the blunt-nosed leopard lizard, Crotaphytus silus,
through 1974. CA Dept. Fish and Game, Sacramento. 7 pp.
11 Montanucci, R.R., R.W. Axtell, and H.C. Dessauer. 1975.
Evolutionary divergence among collard lizards (Crotaphytus), with
comments on the status of Gambelia. Herp. 31(3):336-347.
12 Tollestrup, K. 1976. A standardized method of obtaining an index
of densities of blunt-nosed leopard lizards, Crotaphytus silus.
Unpubl. rept. Contr. No. 14-16-0001-579RF, U.S. Fish and Wildl.
Serv., Sacramento, CA 29 pp.
13 Dick, D. 1977. Habitat disappearing for the leopard lizard.
Outdoor California, Calif. Fish and Game. Pp. 37-38.
14 Nicola, S.L. 1977. Draft Proposed Land Acquisition (Fiscal Year
1979-1980) Pixley Ecol. Reserve, CA Dept. Fish and Game,
Sacramento. 3 pp.
15 U.S. Fish and Wildlife Service. 1978. Environmental assessment,
land acquistion ascertainment report. Blunt-nosed leopard lizard
(Crotaphytus silus), Horse Pasture Unit, Pixley Nat. Wildl. Refuge,
Tulare Co., California. U.S. Fish and Wildl. Serv., Portland, OR
20 pp.
16 Montanucci, R.R. 1978. Discriminant analysis of hybridization
between leopard lizards, Gambelia (Reptilia, Lacertilia,
Iguanidae). Journ. of Herp. 12(3):299-307.
17 Madrone Associates. 1979. Biological assessment, blunt-nosed
leopard lizard (Crotaphytus [Gambelia] silus), Naval Petroleum
Reserve Number I (Elk Hills), Kern County, California. U.S. Navy,
San Bruno, CA.
18 Tollestrup, K. 1979. The ecology, social structure, and forageing
behavior of two closely related species of leopard lizards,
References - 1 (DRAFT) - References
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
Gambelia silus and Gambelia wislizenii. PhD. diss. Univ. of
Calif., Berkeley.
19 Murphy, R.W. 1980. Report on the current status of research on
the taxonomy, life history, habitat requirements and management
options for the blunt-nosed leopard lizard, Gambelia silus, and
the suspected hybrid, Gambelia silus x wislizenii. Unpubl. rpt.
Contr. 40-9ad6-9-514, Bur. of Land Mgmt., Bakersfield, CA. 32 pp.
20 Chesemore, D.L. 1980. Impact of oil and gas development on
blunt-nosed leopard lizards. Contr. YA-521-CT9-118, Bur. of Land
Mgmt., Bakersfield Dist., CA. 60 pp.
21 National Fish and Wildlife Laboratory. 1980. Selected vertebrate
endangered species of the Seacoast of the United States, blunt-
nosed leopard lizard. U.S. Fish and Wildl. Serv., Fort Collins,
CO. 6 pp.
22 Tollestrup, K. 1982. Growth and reproduction in two closely
related species of leopard lizards, Gambelia silus and Gambelia
wislizenii. Am. Midl. Nat. 108(1):1-20.
23 Uptain, Curt, William A. Clark, and Steven M. Juarez. 1985.
Mar-recapture population estimates and visitation indices for the
blunt-nosed leopard lizard (Gambelia silus) at the Pixley National
Wildlife Refuge, Tualre County, California. Final Rept. for:
Contr. No. 10181-9810-3 and 10181-4672-4, USFWS, Delano, CA. 79 pp.
24 U.S. Fish and Wildlife Service. 1985. Blunt-nosed Leopard Lizard
Revised Recovery Plan. U.S. Fish and Wildl. Serv., Portland, OR.
85 pp.
25 Christenseon, Daniel P. [n.d.] Pers. obs. Kernville, CA.
26 Nicol, Kim, and J.M. Brode. 1986. Summary of major studies on the
blunt-nosed leopard lizard (Gambelia silus), 1978-1982. Final
rept. to: U.S. Fish and Wildl. Serv., Sacramento, CA. 14 pp.
27 Pianka, E.R. 1966. Convexity, desert lizards and spatial
heterogeneity. Ecology 47:1055-1059.
28 Huey, R.B. and E.R. Pianka. 1981. ecological consequences of
foraging mode. Ecology 62:991-999.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 U.S. Fish and Wildlife Service. 1985. Blunt-nosed Leopard Lizard
Revised Recovery Plan. U.S. Fish and Wildl. Serv., Portland, OR.
85 pp.
02 California Fish and Game Department. Field Survey Data. CA. Dept.
Fish and Game, Kernville, CA.
03 Christenseon, Daniel P. [n.d.] Pers. obs. Kernville, CA.
04 Tollestrup, Kristine. 1979. The distribution of Gambelia silus
(blunt-nosed leopard lizard) in the western foothills of the San
Joaquin Valley. U.S. Bureau of Land Mgmt., Sacramento, CA 18 pp.
05 Chesemore, D.L. 1981. Blunt-nosed leopard lizard inventory final
report. Contr. no. YA-553-CTO-51, U.S. Bur. of Land Mgmt.,
Bakersfield, CA. 143 pp.
06 Jones, L. 1980. Distributional study of the blunt-nosed leopard
lizard, Gambelia silus, in the southern San Joaquin Valley,
California. Final Rept. Contr. no. YA-512-CT9-97, Bur. of Land
Mgmt., Bakersfield, CA. 143 pp.
References - 2 (DRAFT) - References
Species LIZARD, LEOPARD, BLUNT-NOSED
Species Id ESIS151003
Date 14 MAR 96
07 O'Farrel, T.P., P. McCue, and T. Kato. 1981. Potential of BLM
lands in western Fresno and eastern San Benito and Montery
Counties, California, as critical habitats for the Endangered San
Joaquin kit fox, Vulpes macrotis mutica, and Blunt-nosed leopard
lizard, Crotaphytus silus. Rept. for: Interag. Agrmt. CA-010-
1a1-11, Bur. of Land Mgmt., Sacramento, CA. 46 pp.
08 Jones and Stokes Associates. 1981. Rare and Endangered wildlife
survey within the California aqueduct right-of-way mile post 155.64
to mile post 293.45. Contr. B-53978, CA Dept. of Water Resour.,
Fresno, CA. 22 pp.
09 Nicol, Kim, and J.M. Brode. 1986. Summary of major studies on the
blunt-nosed leopard lizard (Gambelia silus), 1978-1982. Final
rept. to: U.S. Fish and Wildl. Serv., Sacramento, CA. 14 pp.
10 Brode, John M., and Dennis C. Stroud. 1974. A list of recorded
localities for the blunt-nosed leopard lizard, Crotaphytus silus,
through 1974. CA Dept. Fish and Game, Sacramneto, CA. 7 pp.
11 Montanucci, R.R. 1965. Observations on the San Joaquin leopard
lizard, Crotaphytus wislizenii silus Stejneger. Herp.
21(4):270-283
References - 3