U.S. Department of the Interior

U.S. Geological Survey

USGS FFS-2005-3098

August 2005

Central Mojave Vegetation Database

Printed on recycled paper

Study Area

Mojave Desert Ecosystem

States

50 0 50 100 Miles

NV UT

AZ

CA

The Mojave Desert Ecosystem, over 25,000 

square miles, encompasses parts of Nevada, Arizona, Utah, and California. The elevation ranges 

from below sea level in Death Valley to over 5,000 

ft. (1,600 m.). Many endangered plants and animals, 

such as the desert tortoise (Gopherus agassizii), 

depend on the Mojave ecosystem. The region faces 

population pressure due to urbanization and suburbanization from Las Vegas, the Colorado River corridor, and in the western Mojave. It supports major 

transportation corridors and is increasingly the 

location of both passive and active tourism, including extensive off-highway vehicle use. Agriculture, 

mining and military activities are management 

priorities in several areas. Public land managers are 

faced with the difficult task of protecting the desert 

ecosystem and ensuring the survival of threatened 

species while supporting sustainable economies, 

communities, and national defense preparedness. 

Scientific, natural, and cultural resource professionals in the Mojave have agreed upon the importance 

of developing protocols to guide land management 

decisions. Scientists of the U.S. Geological Survey 

are working with land managers to compile scientific information into databases, predictive models, 

and maps to allow them to better manage the natural resources 

of the Mojave Desert.

Information on vegetation characteristics (composition and 

cover) in the Mojave is one critical component in understanding 

the desert ecosystem and making management decisions that 

support a sustainable ecosystem. The mapping and description 

of vegetation provides baseline information for fire management 

planning and for understanding long-term changes in 

plant communities. It also provides a context for understanding the suitability of a habitat for wildlife such as 

the endangered desert tortoise. In addition, vegetation 

maps can be combined with other data to create predictive models. For example, information on land use, soil 

texture and biological soil crust cover, when considered 

in conjunction with vegetation cover, can be used to 

estimate wind erosion potential or for planning infrastructure development. 

The U.S. Geological Survey (USGS) led a team that 

recently mapped and described vegetation in the Eastern 

Mojave Desert of California. The vegetation map covers 

over 5 million hectares, or 43% of the Mojave Ecoregion, at a minimum mapping unit of 5 hectares. Existing 

data were reviewed and quantitatively classified, and new 

data were collected from over 1,200 vegetation plots during the project. The team mapped the vegetation types 

using a combination of extensive field measurements, 
Joshua Tree Wooded Shrubland

Alliance:

Yucca brevifolia Wooded Shrubland

Location shown:

 Cima Dome

Coverage: 

 274,280 hectares (5.5% of map area)

Pinyon Woodlands and Shrublands

Alliance:

Pinus monophylla Woodland

Location shown:

 Clark Mountain

Coverage:

 104,846 hectares (0.2% of map area) 

Big Sagebrush Shrubland

Alliance:

Artemisia tridentata Shrubland

Location shown:

 Mid Hills

Coverage:

 81,872 hectares (1.6% of map area)

Mojave Yucca Shrubland

Alliance:

Yucca schidigera Shrubland

Location shown:

 Southern Nopah Range

Coverage:

 156,638 hectares (3.1% of map area)

Galleta Grasslands

Alliance:

Pleuraphis rigida Herbaceous

Location shown:

 East of Superior Lake

Coverage:

 10,215 hectares (0.2% of map area)

Saltbush Complex

Alliance:

Atriplex canescens Shrubland

Location shown:

 Stovepipe Wells

Coverage:

 67,055 hectares (1.3% of map area)

Blackbrush Shrubland

Alliance:

Coleogyne ramosisima Shrubland

Location shown:

 Homewood Canyon

Coverage:

 177,366 hectares (3.5% of map area)

Creosote Bush Shrubland

Alliance:

Larrea tridentata Shrubland

Location shown:

 Stovepipe Wells

Coverage:

 3,410,564 hectares (67.8% of map area)

Agricultural Land Use

Big Sagebrush Shrubland

Blackbrush Shrubland

Creosote Bush Shrubland

Creosote Bush/Brittlebush Mosaic

Desert Holly Shrubland

Dunes

Galleta Grasslands

High Elevation Pine Woodlands

High Elevation Wash System

Hopsage Shrubland

Joshua Tree Wooded Shrubland

Juniper Wooded Shrubland

Lava Beds and Cinder Cones

Low Elevation Wash System

Menodora Shrubland

Mesquite Shrubland

Mid Elevation Wash System

Mining

Mojave Yucca Shrubland

Nevada Joint-Fir Shrubland

Iodine Bush-Seepweed Complex

Pinyon Woodlands and Shrublands

Playa

Rural Development

Saltbush Complex

Saltgrass

Shadscale Shrubland

Sparsely Vegetated

Urban

White Burrobush Shrubland

Central Mojave Vegetation and Land Cover

0 25 50 kilometers
on surficial geology, soil texture, and 

climate to determine the best and 

most sustainable uses for particular 

areas. For example, comparing the 

relative vulnerability of several sites 

could help in deciding the best location for off-road vehicle use. Analyzing recovery times could determine 

where road closures will be most 

effective in restoring habitat. 

The Central Mojave Vegetation 

Database is available on the web and 

includes: a printable GIS coverage 

map, an Access database of field 

data for the vegetation plots, a report 

describing the mapping methods, a 

list of all alliances identified in the 

Mojave Ecoregion, a key to the alliances found in the mapping area, and 

descriptions and pictures of 70 alliances.

These data are available at the USGS Southwest Biological 

Science Center website at http://sbsc.wr.usgs.gov/.

Cooperating Agencies:

Department of Defense Legacy Program

https://www.denix.osd.mil/denix/Public/ES-Programs/Conservation/

Legacy/dodlegacy.html

USGS Recoverability and Vulnerability of Desert Ecosystems

http://geography.wr.usgs.gov/mojave/rvde/

Desert Manager’s Group

http://www.dmg.gov/

Mojave Desert Ecosystem Program

http://www.mojavedata.gov/

San Diego State University

http://www.sdsu.edu/

California Department of Fish and Game

http://www.dfg.ca.gov/

NatureServe (A network connencting science with conservation)

http://www.natureserve.org/

Authors: Kathryn A. Thomas, Janet Franklin, Todd Keeler-Wolf, 

and Peter Stine

For more information, contact:

U.S. Geological Survey

Southwest Biological Science Center

http://sbsc.wr.usgs.gov/

2255 North Gemini Drive

Flagstaff, AZ 86001

(928) 556-7024

attention:

Kathryn Thomas

kathryn_a_thomas@usgs.gov

 

Graphic design by Tina Kister

aerial photography, satellite remote 

sensing, and statistical modeling. 

The method of vegetation classification for a map has a tremendous 

influence on the utility of the data 

for land managers. Quantitative, 

data-driven vegetation classification 

creates an unbiased source of information for scientific and management 

applications. The scientific team used 

the National Vegetation Classification 

(NVC) structure to classify vegetation into alliances. The Federal Geographic Data Committee, a group of 

representatives from various federal 

agencies, created the NVC structure 

to help standardize vegetation classification. This standardized classification provides common terminology 

and procedure so that description, inventory and monitoring of 

vegetation have consistency across agency and state boundaries, 

making vegetation management more effective and efficient. 

Under this system, areas with common vegetation types are 

grouped into vegetation alliances. 

The broader, upper levels of classification describe vegetation by their lifeform, or physiognomy (i.e. tree, shrub, grass). 

At the lower, more specific levels, vegetation is described by 

the plant species that occur. The plant species with the greatest 

cover generally identifies the alliance. In some cases however, 

the plant that is visually dominant, even if it does not have the 

greatest cover, is used to characterize the alliance. The NVC 

name for the alliance is formed by the Latin name for the 

dominant plant and the structure of the community type such as 

Forest, Woodland, Shrubland, or Herbaceous. For example, an 

area dominated by Joshua Trees is labeled as “Yucca brevifolia

Wooded Shrubland”. 

The vegetation map compiled by the USGS depicts vegetation types at two levels. The ‘Land Cover’ label depicts 31 

alliances, alliance groups, and land use types. The team identified 104 vegetation alliances for the entire Mojave ecoregion; 

20 of which the team identified for the first time. Not all of the 

104 alliances occur in the project study area; the final report 

describes 70 alliances found in the study area.

The products from this project are compiled in the Mojave 

Desert Ecosystem Program Central Mojave Database and can 

be used by researchers, land mangers, policy makers, and the 

public. 

In addition, scientists from the USGS Recoverability and 

Vulnerability of Desert Ecosystems (RVDE) program are 

synthesizing this and other scientific information into spatial 

models that help land managers predict how the desert responds 

to disturbance as well as its ability to recover. Maps and models 

of the most relevant landscape characteristics are combined 

with information on ecosystem processes gained from scientific experiments and field studies. As these are refined and 

additional models are developed, they are being combined into 

a set of decision-making tools that can be used by land managers. Prototype models are being developed that examine soil 

compaction, wind erosion, soil crust cover, and vegetation 

recovery. This data can be used in conjunction with information