| Desert Tortoise
Management |
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| Additional
Desert
Tortoise
pages |
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The
desert tortoise, Gopherus agassizii,
is characterized by a high-dome, brown shell,
often with yellowish centers on each scute,
stout elephantine legs, and males have a
gular (throat) projection and concave surface
on the lower shell (plastron). Desert tortoises
can reach 38 cm (15 inches) in length and
weigh 6 kg (15 pounds). Sexual maturity is
reached at 10-20 years of age and 22 cm (8.7
inches) in length. Female tortoises lay one
or more clutches per year (1-12 eggs per
clutch).
 Primary activity periods revolve around rainfall events, particularly during
the summer monsoon season (August-September), with peak activity in early
mornings and late afternoon. While active, desert tortoises forage on a
variety of plant material, including grasses, wildflowers, fruits etc.
Eggs are laid prior to the summer monsoons (June-July), with reproduction
occurring in late summer to early fall. Eggs are then laid again the next
summer. The nest is often constructed in the female's burrow.
Hatchling and small juvenile tortoise face the greatest number of predators,
including, ravens, hawks, bobcats, and coyotes. The primary predators of
adult tortoises are mountain lions and man.
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| Program
Goal: |
| Our goal
is the conservation and management of the
desert tortoise in Arizona, through cooperation
with local, state and federal agencies and
private landowners. In 1985, these agencies
formed the Arizona Interagency Desert Tortoise
Team (AIDTT), which is responsible for coordinating
research and management of the desert tortoise
in Arizona. Current research includes range-wide
monitoring, population genetics, reproductive
sampling, habitat use analysis, foraging
studies, and disease sampling. |
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| Habitat: |
| In the Mojave
Desert, tortoises are generally found in
the flat inter-montane basins. In the Sonoran
Desert, tortoises are found along rocky slopes
and bajadas, ranging from 155 m (508 feet)
to 1600 m (5,250 feet) in elevation. The
majority of desert tortoises in Arizona are
found in Sonoran Desert habitat. |
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| Distribution: |
| Low- to
middle-elevation deserts in California, southeastern
Nevada, southwestern Utah, and Arizona. In
Arizona, desert tortoises are found in the
northwestern corner through the central and
western parts of the state. Desert tortoises
are divided into two populations: the Mojave
Desert population (populations occurring
north and west of the Colorado River) and
the Sonoran Desert Population (populations
occurring south and east of the Colorado
River). |
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| Status: |
| The United
States Fish and Wildlife Service currently
lists the Mojave population as Threatened.
The Sonoran population is not currently listed
as Threatened or Endangered. In Arizona,
Commission Order 43 prohibits taking desert
tortoises from the wild. Lawfully obtained
individuals may be privately possessed, subject
to specific rules. |
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| Conservation
Needs: |
| Desert tortoises
in the Sonoran Desert typically live in disjunct
populations along the rocky slopes of isolated
desert mountain ranges. Primary conservation
needs focus on habitat issues including:
drought, wildfire, habitat fragmentation,
and invasion of exotic species. Other impacts
include illegal collecting, vandalism, road-kill,
disease, release of captive tortoises, and
predation. Little is known about how desert
tortoises persist in these small disjunct
populations, and current research is focused
on this aspect of their ecology. The AIDTT
is currently working on a Conservation Agreement
for the Sonoran population of the desert
tortoise. The agreement will determine future
direction of management issues based on previous
and ongoing research. |
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| Cautionary
measures: |
| Commission
Order 43 prohibits taking desert tortoises
from the wild. If desert tortoises are observed
in the wild, it is best to let them continue
on their way. Desert tortoises can be lawfully
kept through state-sanctioned adoption facilities.
Once a captive, a tortoise can never be released
back into the wild. While in captivity, diseases
can be transmitted between tortoises. Tortoises
released back into the wild risk spreading
disease through the wild population. The
Arizona Game and Fish Department also list
desert tortoises as Restricted Live Wildlife.
They cannot be imported into or exported
from the state. Federal law also precludes
transport of desert tortoises across state
lines. The Arizona Game and Fish Department
also list desert tortoises as Restricted
Live Wildlife. They cannot be imported into
or exported from the state. Federal law also
precludes transport of desert tortoises across
state lines. |
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| Additional
information: |
Cristina Jones
Turtles Project Coordinator
(623) 236-7767
cjones@azgfd.gov
Audrey Owens
Turtles Project Biologist
(623) 236-7504
aowens@azgfd.gov |
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