Conservation Groups Petition for Stronger State of California Protection of the Desert Tortoise

The Defenders of Wildlife, along with the Desert Tortoise Preserve Committee and Desert Tortoise Council, submitted a petition on March 23, 2020 to the California Fish and Game Commission to change the listing status of Agassiz’s desert tortoise from threatened to endangered. For more background or to read the petition visit:

https://defenders.org/newsroom/conservation-groups-petition-stronger-agassizs-desert-tortoise-protections

Desert Tortoise Preserve Committee Invites Comments on Cal Parks OHV Grant

The Desert Tortoise Preserve Committee (DTPC) invites public comments on its preliminary grant application to the California State Parks Off-Highway Motor Vehicle Recreation (OHMVR) Division. The DTPC is requesting funding to support restoration monitoring and restoration efforts in all areas adjacent to the Desert Tortoise Research Natural Area. The purpose of the Restoration Grants Program, as defined by the OHMVR Division, is to provide Ecological Restoration or Repair to habitat damaged by authorized or unauthorized OHV use. The DTPC seeks funds to continue monitoring and restoration efforts related to unauthorized OHV activity on approximately 4600 acres of conservation land. The DTPC will provide some matching dollars to the project. If funded, the DTPC will be hiring an American Conservation Crew to conduct all restoration monitoring in areas directly adjacent to the DTRNA, use a citizen science approach to report fence damage and illegal incursions, use funds to repair fence damage due to incursions, and control invasive species along boundary areas commonly traveled by OHV users.

The DTPC would appreciate your comments on this project. You can review the grant application, along with those from other agencies, local governments, and non-profits, on-line at www.ohv.parks.ca.gov The public comment period is open from Tuesday, March 3, 2020 to Monday, May 4, 2020. Comments should be sent directly to the OHMVR Division at ohvinfo@parks.ca.gov and to the DTPC at dtpc@tortoise-tracks.org. Late comments will be forwarded to the division separately.

 

DTPC Invites Public Comment on Land Trust Accreditation Application

The DTPC is applying for accreditation through the Land Trust Accreditation Commission (LTAC), an independent program of the Land Trust Alliance.  The LTAC recognizes land conservation organizations that meet national quality standards for protecting important natural places. As an organization dedicated to managing and restoring lands for species of concern, the LTAC accreditation is an important next step for the growth and stewardship activities for the DTPC. The LTAC commission invites public comment regarding our application and how the  DTPC complies with national quality standards.  These standards address the ethical and technical operation of a land trust.

For the full list of standards see http://www.landtrustaccreditation.org/help-and-resources/indicator-practices. To submit a comment, visit www.landtrustaccreditation.org, or email your comment to info@landtrustaccreditation.org. Comments may also be faxed or mailed to the Land Trust Accreditation Commission, Attn: Public Comments: (fax) 518-587-3183; (mail) 36 Phila Street, Suite 2, Saratoga Springs, NY 12866.

Please submit comments to the LTAC by May 1, 2020.

 

The Desert Tortoise Preserve Committee Invites Public Comments on OHV Grant Application

For Immediate Release: March 3, 2016

The Desert Tortoise Preserve Committee (DTPC) invites public comments on its preliminary grant application to the California State Parks Off-Highway Motor Vehicle Recreation (OHMVR) Division.

THE DTPC INVITES PUBLIC COMMENTS ON OHV GRANT APPLICATION

The Desert Tortoise Preserve Committee (DTPC) invites public comments on its preliminary grant application to the California State Parks Off-Highway Motor Vehicle Recreation (OHMVR) Division. The DTPC is requesting funding to support a restoration project in the Eastern Expansion Area of the Desert Tortoise Research Natural Area, adjacent to an authorized OHV route managed by the Bureau of Land Management and California City Police Department. The purpose of the Restoration Grants Program, as defined by the OHMVR Division, is to provide Ecological Restoration or Repair to habitat damaged by authorized or unauthorized OHV use. The DTPC seeks restoration funds to prevent continued habitat degradation related to unauthorized OHV activity on approximately 2,700 acres of conservation lands and to begin the restoration process on disturbed areas by protective fencing. The DTPC will provide some matching dollars to the project. If funded, the DTPC will install wildlife-friendly fencing around areas of contiguous conservation lands, followed by trash removal and control of invasive plant infestations. Where fencing is not feasible, unauthorized routes will be camouflaged to discourage unauthorized use. Additionally, if conditions allow, the DTPC will begin collecting native seed for future revegetation projects.

The DTPC will also request funding to re-instate a responsible recreation education program providing important information to the OHV community. This program is intended to increase public knowledge about the effects of irresponsible OHV use and to help prevent the creation of illegal trails. The DTPC would appreciate your comments on these projects. You can review the grant applications, along with those from other agencies, local governments, and non-profits, on-line at www.ohv.parks.ca.gov. The public comment period is open from Tuesday, March 8, 2016 to Monday, April 4, 2016. Comments should be sent directly to the OHMVR Division at ohvinfo@parks.ca.gov and to the DTPC at dtpc@pacbell.net. Late comments will be forwarded to the division separately. Final grant applications are due May 2, 2016. For more information about the proposed restoration project, a public meeting will be held at the DTPC office in Riverside to provide an overview of both projects. Please contact the DTPC office at (951) 683 – 3872 or dtpc@pacbell.net for additional information.

For more information about the proposed restoration project, please contact Jillian Estrada at (951) 683-3872 or dtpc@pacbell.net.

_____________________________________________________________________

Public Meeting Announcement

The Desert Tortoise Preserve Committee, Inc., would like to announce a public meeting on Thursday, February 12th, at 5:00 to 6:00 PM, at its office at 4067 Mission Inn Avenue, Riverside, CA 92501. During this meeting, the Preserve Manager will present the Committee’s plans to fence its properties around the Desert Tortoise Research Natural Area in Kern County, Ca. These plans will also be on display at the DTPC’s Booth at the upcoming Annual Symposium of the Desert Tortoise Council Annual Symposium on February 20–22, 2015 at Sam’s Town Hotel and Casino, 5111 Boulder Hwy, Las Vegas, NV 89122

THE DTPC INVITES PUBLIC COMMENTS ON OHV GRANT APPLICATION

Desert Tortoise Preserve Committee, Inc.

News Release

For Immediate Release: February 1, 2019

Contact: Jill Estrada (951-683-3872) or dtpc@pacbell.net

 

 THE DTPC INVITES PUBLIC COMMENTS ON OHV GRANT APPLICATION

 

The Desert Tortoise Preserve Committee (DTPC) invites public comments on its preliminary grant application to the California State Parks Off-Highway Motor Vehicle Recreation (OHMVR) Division.

The DTPC is requesting funding for a restoration project in the Expansion Areas of the Desert Tortoise Research Natural Area, which abut authorized OHV routes managed by the Bureau of Land Management and California City Police Department. The purpose of the Restoration Grants Program, as defined by the OHMVR Division, is to provide Ecological Restoration or Repair to habitat damaged by authorized or unauthorized OHV use. The DTPC seeks restoration funds to prevent continued habitat degradation related to unauthorized OHV activity on approximately 640 acres of conservation lands, and to begin restoration of the disturbed areas to their natural state. If funded, the DTPC will install wildlife-friendly fencing around areas of contiguous conservation lands and will use vertical mulching and other techniques for camouflage restoration of unauthorized routes in areas where fencing is not feasible. The DTPC will work with restoration crews and volunteers to remove trash from the restoration sites and to control invasive plant infestations along closed, unauthorized routes.

The DTPC would appreciate your comments on this project. You can review the grant application, along with those from other agencies, local governments, and non-profits, on-line at www.ohv.parks.ca.gov. The public comment period is open from Tuesday, March 5, 2019 until Monday, May 6, 2019. Comments should be sent directly to the OHMVR Division at ohvinfo@parks.ca.gov and to the DTPC at dtpc@pacbell.net. Late comments will be forwarded to the division separately. Final grant applications are due June 3, 2019.

For more information about the proposed restoration project, please contact Jill Estrada at (951) 683-3872 or dtpc@pacbell.net.

Mohave Ground Squirrel Observations, Spring 2011

Mohave Ground Squirrel Observations, Spring 2011

Article and photos by Freya Reder

The Desert Tortoise Research Natural Area (DTRNA) provides protected habi tat not only for the desert tortoise, but for all wildlife and plant species that exist within its boundaries.  The Mohave ground squirrel (Xerospermophilus mohavensis) is one such species. The Mohave ground squirrel is a small herbivorous rodent found only in the western Mojave Desert in desert-scrub habitats.  Because of habitat loss and fragmentation, the Mohave ground squirrel has long received state protection and has been listed as Threatened under the California Endangered Species Act since 1985.  The species is currently under review for federal listing.  Like the desert tortoise, the Mohave ground squirrel has a limited period of activity.  For adults, this active season usually extends from February through July, with the rest of the year spent in dormancy.  For juveniles, this period of activity is extended through August, as additional time is needed for their growth and dispersal from their natal burrows.  Past studies have shown that the amount and timing of winter rains affect Mohave ground squirrel reproduction and that in years with significantly low winter rainfall, Mohave ground squirrels will not reproduce in the spring.  One of the most exciting discoveries for us at the DTRNA this spring was that it proved to be a reproductive year for the Mohave ground squirrel.

I began the season as the Interpretive Naturalist with equal interests in the desert tortoise and the Mojave ground squirrel, due to their threatened status.   Documentation of all species encountered is part of the job of the Naturalist, and so it was with the Mohave ground squirrel.  Having had a few fleeting glimpses, I was interested to see and point out a Mohave ground squirrel to a visiting friend.  We stopped to observe what turned out to be a lactating female, evident by her dark and swollen nipples.  She stood watching us while feeding on unidentifiable seeds in the nearby wash.  Making a mental note, I began to look for this female daily when out walking on the trails, and more often than not was rewarded with a sighting of her.  This lactating female had several dark patches of skin on her back where hair was missing, making her easily identifiable and leading me to refer to her as “Patches” from then on.

A week later, just after opening the gate to the DTRNA, a couple from Ohio arrived. True wildlife enthusiasts, this couple described themselves as primarily birders who also had a “life list” of mammals throughout the world they intended to see.  Today, they had come in search of the Mohave ground squirrel.  I pointed our visitors in the direction of Patches’ burrow, telling them I would catch up with them shortly and we would look for ground squirrels and tortoises together.  When I joined them a short time later on the Animal Loop, I asked if they had luck and they said yes, they had in fact seen 3 juvenile Mohave ground squirrels!  Excited by this news I asked them to show me where they had seen the juveniles.   Thirty meters downstream from Patches’ burrow were three juveniles of undetermined sex basking in the morning sun.  Later the same day, I was rewarded with a sighting of Patches with the juveniles nearby.

Within a short period of time, I began to observe several adult Mohave ground squirrels.  Soon, I spotted another lactating female near the latrine in the Interpretive Center (IC). This female also had dark, swollen nipples but lacked the dark patches of skin on her back. A few weeks later, another separate litter of four juveniles emerged, this time on the entrance road into the DTRNA.  Simultaneou sly, a litter of antelope squirrels emerged in the same area, on the same day, often appearing to use the same burrows.  I took advantage of their proximity to the road to capture some brilliant footage on my camera of the juveniles, two while they were being bitten by red ants. One of these juveniles I captured on film encountering this tiny but formidable foe for the first time face to face. Additionally I observed them feeding on the seeds of checker fiddleneck (Amsinckia tessellata) seeds and red-stemmed filaree (Erodium cicutarium), and the forbs of rose and white wild buckwheat (Eriogonum gracillimum); one individual sampled the dried flower of a goldfield (Lasthenia californica).

A third lactating female was observed while on “morning rounds” with visitors.  I wanted to inspect a tortoise burrow in a nearby mineral assessment mound.  When first approaching the mound I had seen and pointed out a Mohave ground squirrel to the visitors.  Through binoculars I observed while it stood in alarm and then disappeared into the mouth of tortoise burrow.  Upon closer inspection of the tortoise burrow and its fresh tortoise tracks, the ground squirrel’s head appeared a few meters away in the mound.  She glanced at me, chirped twice in alarm, and disappeared into the same hole.  Only in the photographs did I later see that the squirrel was a lactating female.

In preparation for the long period of dormancy during fall and winter, the Mohave ground squirrel must acquire bulk mass in the form of fat reserves in order to survive.  It is common and necessary for them to triple in body weight and mass during this time.   Adult females take longer to acquire bulk mass due to their reproduction; therefore, the male’s state of enormity becomes evident well before that of the females or juveniles.  One male in particular appeared to put on bulk mass well before the others and I began to seek him out daily.

This adult male’s burrow was situated in the same mineral assessment mound previously mentioned, the female now presumably displaced or had simply moved house. He was what I refer to as “user friendly” in his tolerance and seeming disinterest in my presence on foot, providing I approached cautiously.  It was not unusual to spend 15 or 20 minutes, sometimes longer observing and photographing him as he would forage and sometimes cache the seeds of thistle sage (Salvia carduacea) and dried fiddleneck.  Of equal interest to him were Fremont pincushion (Chaenactis fremontii) and creosote (Larrea tridentata) flowers. This male began acquiring bulk mass earlier than any of the other adult males I observed and by this time seemed quite stationary; I observed him foraging no further than a meter or so from one of his burrow entrances.

Excited further by these field observations, I reported my findings to Dr. Kristin Berry who then shared this information with the rest of the Desert Tortoise Preserve Committee (DTPC).  Given that it was clearly a good year for Mohave ground squirrel reproduction in the DTRNA, the DTPC determined that it would be advantageous to survey the surrounding expansion areas for the presence of Mohave ground squirrels. I undertook their request with relish and over the course of the next three weeks undertook the task of surveying these expansion areas by vehicle and on foot.  Recording the geographic locations, date, times, approximate temperature, behavior, forage species, and  the presence or absence of white-tailed antelope squirrels, and using photographic documentation whenever possible, I covered areas of frequent sightings regularly by vehicle and expanded into new, unexplored areas daily.

During the hours of field observation, the Mohave ground squirrels foraged heavily on dry fiddleneck seeds and filaree seeds, both dry and green.  Additionally they were seen foraging on flowers of creosote bush, Anderson’s thorn bush (Lycium andersonii), desert calico (Loeseliastrum sp.), and what appeared to be miniature woolly star (Eriastrum diffusum), and the seeds of little gold poppy (Eschscholzia minutiflora), thistle sage, and Fremont pincushion.   At the end of the three weeks and approximately 75 hours of surveying, we had recorded 69 observations of Mohave ground squirrels in and around the DTRNA.  Based on geographic locations and timing of observations and the physical features of the animals, we estimate at least 32 individuals were sighted, including 19 adults (7 females, 3 males, and 9 of undetermined sex) and 14 juveniles (3 females, 1 male, and 9 of undetermined sex).  The DTRNA is indeed an important area not only for the preservation of the desert tortoise, but also that of the Mohave ground squirrel.  The DTPC hopes to continue studying this species and its habitat needs in and around the Natural Area.

I would like to give special thanks to Denise LaBerteaux from her assistance in sex determination and identification.   Dr. Berry and the other DTPC board members deserve special thanks as well for their prompt response and for launching this field survey.  Lastly, I would like to thank Mary Kotschwar for her unyielding support, encouragement and assistance throughout this study and the season.

 

References

Bartholomew, G.A. and J.W. Hudson. 1960. Aestivation in the Mohave ground squirrel Citellus mohavensis. Bulletin of the Museum of Comparative Zoology 124:193–208.

Best, T. L. 1995. Spermophilus mohavensis. American Society of Mammalogists, Mammalian Species Number 509:1–7.

California Department of Fish and Game. 2011. State & Federally Listed Endangered & Threatened Animals of California.  < http://www.dfg.ca.gov/biogeodata/cnddb/plants_and_animals.asp> Accessed September 9, 2011.

Harris, J.H. and P. Leitner. 2004. Home range and use of space in Mohave ground squirrels (Spermophilus mohavensis). Journal of Mammalogy 85: 517–523.

Harris, J. H., and P. Leitner. 2005 Long-distance movements of juvenile Mohave ground squirrels, Spermophilus mohavensis. Southwestern Naturalist 50: 188-196

 

Source: Tortoise Tracks 31:3 Fall 2011

The Mysterious Mohave Ground Squirrel

THE MYSTERIOUS MOHAVE GROUND SQUIRREL

By Phil Leitner

One of the more remarkable denizens of the California desert is a small brown ground squirrel. About 9 inches from nose to tip of tail, the Mohave ground squirrel (Spermophilus mohavensis) is found only in the western Mojave Desert. Their sophisticated desert survival skills allow them to avoid the extremes of the hostile climate. Hard to find and even more difficult to observe and study, these rare and elusive little rodents have baffled biologists over the years. Now, new efforts are underway to discover their habitat requirements and determine their conservation status.

We do know that Mohave ground squirrels are active only in the spring and summer, when they feed eagerly on the leaves and seeds of native shrubs and annual plants. As the desert dries out in June and July, they fatten in preparation for a long period of dormancy. By midsummer they curl up in their underground nests and allow body temperature, heart rate, and metabolism to fall drastically. In this physiological state, they can survive on stored body fat until the winter rains bring a new flush of green vegetation.

Mohave ground squirrels begin to emerge from their burrows in February, when the males may travel up to a mile per day in search of mates. The success of these amorous excursions becomes evident by the end of March, when litters of 6-9 young are born. The babies grow quickly and are weaned by early May. In just a few weeks, they are ready to set off in search of their own patch of desert. Young Mohave ground squirrels disperse in late May and early June. Often they move in next door to their mother’s home range, but some, especially the young males, can move up to four miles before settling down.

In the Mojave Desert, it is not unusual for the winter rains to fail, creating hard times for all desert wildlife. Mohave ground squirrels have their own approach to coping with drought. If the total winter rainfall is under three inches, they simply don’t reproduce. All available forage is converted to body fat and they can enter dormancy as early as April. Better to try again next year than to give birth to young who probably won’t survive and jeopardize your own chances of putting on enough fat to make it through dormancy. As a result, Mohave ground squirrel numbers decline precipitously after a low rainfall year and two successive years of drought can lead to the extinction of local populations. After a couple of good years, dispersing young may recolonize these areas.

The Mohave ground squirrel has long been listed as Threatened under the California Endangered Species Act. In spite of its protected status, little is known of its habitat needs or even where it still occurs. In many areas within its historic range, there are no recent records. This information is essential to the development of a conservation strategy for the species. The Desert Tortoise Preserve Committee is currently taking the lead in a new research effort, with funding from the California Energy Commission. Field studies began this spring in the Desert Tortoise Research Natural Area, the Pilot Knob Grazing Allotment, and the Kramer Hills to locate populations for long-term ecological study. Much more work will be needed to clear up the mysteries surrounding the Mohave ground squirrel and to assure it a secure future in the Mojave Desert ecosystem.

Source: Tortoise Tracks 19:2 Summer 1999

Alien Annual Plants and the Desert Tortoise

Alien Annual Plants and the Desert Tortoise

 

Notes From An October 4, 1998, CALEPPC Field Trip

Prepared by

 

KRISTIN H. BERRY

 

USGS/BRD, Box Springs Field Station, Riverside, CA 92507

 

        Alien annual plants form a substantial portion of the spring biomass of ephemeral plants in the western Mojave Desert, frequently from 30 to >90%. As such, they are changing the structure and functioning of the ecosystems. We are particularly concerned about their effects on the desert tortoise, a long-lived herbivore and a State and Federal threatened species.

 

Aliens and Their Role in the Diet of the Desert Tortoise. The diet, food preferences, and nutrition of wild desert tortoises have been studied by several graduate students and research scientists during the last 25 years. In the Mojave and Colorado deserts, most tortoises eat succulent, green herbaceous perennial or annual plants, some cacti and, less commonly, grasses. The results of the research project most applicable to the western Mojave Desert can be found in the masters thesis of W. Bryan Jennings, who obtained an MS from the University of Texas at Arlington in 1993. Bryan was supported through funds from the Bureau of Land Management. Bryan is a native Californian, did his undergraduate work at UCSB, and enjoys botanizing. He conducted his research at the Desert Tortoise Research Natural Area on adult male and female tortoises, tracking individuals with radio transmitters. The following is a summary of his findings.
Desert tortoises preferred native over non-native plants. Alien annual plants formed a very small part of the diet (4.65%). Erodium cicutarium (fresh and from previous years) was 3.93%, Schismus was 0.69%, and Bromus was 0.03%. Two particular plant groups were important to the adult tortoises: the legumes (Fabaceae), which comprised over 43% of the diet; and herbaceous perennial plants, which were 30% of the diet. The latter group may play an important role during drought years.
Tortoises knew the locations of favored food plants and spent the majority of time feeding in specific areas which supported the plants, e.g., low hills and washes. The preferred plants were frequently uncommon in the environment and didn’t appear on plant transects. A summary of the top 10 preferred plants (by bite counts, 35,401 total bites observed) for spring is shown below.

 

Species % of bite counts
Lotus humistratus
Mirabilis bigelovii
Euphorbia albomarginata
Astragalus layneae
Lygodesmia exigua
Astragalus didymocarpus
Camissionia boothii
Erodium cicutarium
Chorizanthe brevicornu
Phacelia tanacetifolia
29.69
10.79
10.74
8.20
5.58
4.58
3.86
3.25
2.60
2.01

        Tortoises did not eat perennial shrubs, with the exception of the suffrutescent perennial, Mirabilis bigelovii. This plant formed 36.47% of the diet plants. Mirabilis bigelovii formed only 0.94% of the relative abundance of perennial plants in the environment.
In other parts of the Mojave, other annuals and herbaceous perennials are important, such as Plantago and Sphaeralcea ambigua. The diet of free-ranging juveniles is another critical subject that needs attention. Juvenile tortoises are very small (45-90 mm carapace length) and are likely to require more delicate plants. For example, juveniles probably don’t consume much Mirabilis bigelovii because the leaves are large, heavy and may be out of reach.

Alien Annual Plants, Heavy Metals and Other Toxicants. In 1989 a team of research scientists studying health and diseases of desert tortoise began to salvage and necropsy ill, dying, and recently dead desert tortoises to determine cause(s) of death. The team consisted of Drs. Bruce Homer, Kristin Berry, Elliott Jacobson, Mary Brown, and Mary Christopher. We found that the very ill and dying tortoises often had high concentrations of heavy metals and other toxicants, such as lead, cadmium, nickel, chromium, mercury, molybdenum, and vanadium. We also have associated the presence of elevated levels of such toxicants in the livers and kidneys of tortoises with lesions on their shells. One new shell disease, cutaneous dyskeratosis, was described in 1994. So far, we have discovered no fungal, bacterial, or viral basis for this and other shell diseases in the desert tortoise. Toxicants, nutritional deficiencies, or nutritional deficiencies induced by toxicants are the most likely causes. Of particular interest is the apparent increase in shell diseases in some populations and correlations of increases in shell disease with increasing mortality rates.
Two years ago, the disease research team was expanded to include geologists and geochemists in the USGS: Drs. Maurice Chaffee, Gordon Haxel, Joe Wooden, Roy Knight, and Brenda Houser. We are now looking at the source of the toxicants, particularly mercury and lead, in the western Mojave. We have collected soil and plant samples for analysis, including samples of Schismus and Erodium. Alien plants may be a pathway for toxicants. We hope to have the analysis completed on 50 samples of annual plants (46 elements) in the next year. As part of our interdisciplinary project, we are also looking at concentrations of elements in the bone and scute of tortoise shell. We hope to be able to use bones and scutes of long-dead tortoises for evaluating variation and change in the environment. I hasten to add that alien plants may not be involved at all and that atmospheric pollution may be a factor. We have a lot of work ahead of us on the subject!

Alien Annual Plants and Awns. One of the ill tortoises salvaged for necropsy a few years ago had a plant awn penetrating the gut. The veterinary research pathologist recorded the information but did not save the awn. At that time, he did not realize that it might be important (but he knows now, one of the benefits of an interdisciplinary team). The awns of alien grasses, e.g., “fox tails” are well known for causing medical problems to domestic pets and livestock, and we can assume that the tortoise may be similarly affected. With a tortoise ill and dying from awn-induced damage to the gut, detection would be difficult. The awns of bromes, as common names of ripgut brome and foxtail chess imply, are most likely to be culprits in tortoise habitat. We will have a difficult time planning experiments to determine whether alien grasses irritate or penetrate the gut of tortoises in sufficiently high frequencies to lower survivorship. It would be desirable to have information on whether the impact is confined to a particular size class of tortoises and the frequency of the problem.

Alien Annual Plants and the Weed-Fire Cycle. The flora and fauna of the Mojave and Colorado deserts did not evolve under a regime where fires were widespread and frequent. Fires kill tortoises and damage their habitat. Loss of the cover of shrubs is very serious: shrubs are used for cover from the sun, wind, and cold, as well as protection from predators. The coppice mounds beneath shrubs are used as sites for burrows and pallets. When the shrubs burn, the burrow opening is no longer covered and protected, and the tunnel receives no thermal protection from the shrub. As the weed-fire cycle develops in a particular habitat, the available forage for tortoises also changes to an annual “weedland.”

Livestock Grazing and Alien Annual Plants. In the Mojave and Colorado deserts, livestock consists of sheep, cattle, and feral burros. These animals can (1) disturb or damage soil crusts; (2) reduce cover of vegetation, including shrubs, perennial grasses, and annual plants; (3) alter the composition and diversity of shrubs, perennial bunch grasses, and annuals; and (4) promote the growth and spread of alien plants. They can affect the tortoises in many ways, i.e., by trampling them, by reducing cover of shrubs, by changing the supply of choice food plants, and by contributing to the growth and spread of alien plants that are less desirable food items.

Recovery of Tortoise Habitat Infested with High Biomasses of Aliens. Alien plants pose major challenges to scientists and land managers who are working toward recovery of desert tortoise populations and their habitats. We need to alter the weed-fire cycle, reduce the biomass of undesirable alien grasses and other weeds, and determine how to economically restore degraded habitats.

 

PLANT LIST

CALEPPC Field Trip, October 4, 1998

perennials | cacti | annuals | grasses | mustards | weedy natives

Species marked with an asterisk (*) are aliens

Perennial Shrubs or Herbs

 

Acamptopappus sphaerocephalus (goldenhead)
Ambrosia dumosa (burrobush, burroweed)
Asclepias subulata (milkweed)
Atriplex canescens (four-wing saltbush)
Atriplex confertifolia (shadscale)
Atriplex hymenelytra (desert holly)
Atriplex polycarpa (allscale, cattle spinach)
Atriplex spinifera (Mojave saltbush)
Bebbia juncea (sweetbush)
Chrysothamnus nauseosus (rabbit brush)
Chrysothamnus teretifolius (terete-leaved rubberbrush)
Encelia farinosa (brittle bush)
Ephedra nevadensis (Mormon tea)
Eriogonum inflatum (desert trumpet)
Grayia spinosa (spiny hopsage)
Hymenoclea salsola (cheesebush)
Krameria erecta (Pima ratany)
Krascheninnikovia lanata (winter fat)
Larrea tridentata (creosote bush)
Lepidium fremontii (sweet alyssum)
Lycium andersonii (Anderson thornbush)
Mirabilis bigelovii (wishbone bush)
Petalonyx thurberi (sandpaper plant)
Psorothamnus fremontii (indigo bush)
Salazaria mexicana (paperbag bush)
Senna armata (desert cassia, senna)
Stephanomeria pauciflora (wirelettuce)
Stillingia paucidentata (toothleaf spurge)
Xylorhiza tortifolia (Mojave aster)

Cacti

 

Echinocactus polycephalus (cotton top)
Echinocereus engelmannii (strawberry hedgehog cactus)
Opuntia basilaris (beavertail)
Opuntia echinocarpa (silver cholla)
Opuntia ramosissima (darning needle or cucumber cholla)

Annuals

 

Amsinckia tessellata (checker fiddleneck)
Astragalus sp. (locoweed)
Camissonia boothii (Booth evening primrose)
Camissonia decorticans (woody bottle-washer)
Chaenactis fremontii (Fremont pincushion)
Chaenactis carphoclinia (Pebble pincushion)
Chorizanthe brevicornu (brittle spinflower)
Chorizanthe rigida (rigid spiny-herb)
Cryptantha circumscissa (western forget-me-not)
Cryptantha sp. (forget-me-not)
Descurainia pinnata (tansy mustard)
Dithyrea californica (spectacle pod)
Eriogonum trichopes (little trumpet)
Eriophyllum pringlei (Pringle Eriophyllum)
Eriophyllum wallacei (Wallace Eriophyllum)
*Erodium cicutarium (filaree, stork’s bill)
Erodium texanum (desert heron’s bill)
Eschscholzia glyptopleura (desert gold poppy)
Eschscholzia minutiflora (little gold poppy)
Gilia sp.
Lepidium flavum (pepper grass)
Lotus humistratus (lotus)
Lupinus sp. (lupines)
Malacothrix glabrata (desert dandelion)
Mentzelia albicaulis, Mentzelia sp. (blazing stars)
Pectis papposa (chinch weed)
Pectocarya sp. (the comb-burs)
Phacelia distans, P. tanacetifolia
Rafinesquia neomexicana (desert chicory)

Grasses

 

Achnatherum [Stipa] hymenoides (Indian rice grass)
Achnatherum [Stipa] speciosum (desert needle grass)
*Bromus madritensis ssp. rubens (red brome)
*Bromus tectorum (cheat grass)
Pleuraphis rigida (galleta grass)
*Schismus arabicus, S. barbatus (split grass, Arab grass, Mediterranean grass)

Mustards (All aliens)

 

*Brassica tournefortii
*Descurainia sophia
*Hirschfeldia incana [Brassica geniculata]
*Sisymbrium irio (London rocket)

Weedy Native Species

 

Eremocarpus setigerus (turkey mullein) (Euphorbiaceae)
Ambrosia acanthicarpa (annual burweed, bursage) (Asteraceae)