Mojave Desert Ecosystem

Mojave Desert, photo by John J. Mosesso, NBII Digital Image Library
Mojave Desert. Credit: John J. Mosesso, NBII Digital Image Library

The objectives of the USGS Recoverability and Vulnerability of Desert Ecosystems (RVDE) project are to conduct basic scientific research on ecological processes within the Mojave Desert ecosystem and to use this knowledge to provide land managers with scientific understanding and tools needed to conserve and restore threatened desert landscapes.

The Mojave Desert covers 125,000 square kilometers of southern Nevada, western Arizona, southwestern Utah, and southeastern California. It is home to over 1 million people, including the nation's fastest growing city, Las Vegas, and is within a day's drive of 40 million people.

Coastal Redwood Forests

Redwood National Park [Photo: National Park Service]

Coastal forests are characterized by a cool, moist climate with dry summers and wet, generally snowless winters, which result in highly productive and diverse coniferous forests. This ecoregion includes a variety of forest communities, including Coastal Redwood Forests. Redwood forests are composed of redwoods (an alternative common name for sequoia trees of the region), as well as douglas fir, tanoak, Pacific madrone, redwood sorrel,and a wide variety of mushrooms, mosses and ferns. The Coastal Redwood Forests range from San Simeon, California to Brookings, Oregon, in a narrow strip along the Pacific Ocean. The redwood trees found in Northern California can grow for more than 2,000 years, with some growing to a height of 367 feet (112 m) and a width of 22 feet (7m) at their base. The complex soils on the forest floor contribute not only to the redwoods' growth, but also to a verdant array of greenery, fungi, and other trees. The understory, composed of ferns, leafy redwood sorrels, mosses and mushrooms, help to regenerate the soils.

For more information about Coastal Redwood Forests visit:

Highlight - The Cosumnes River

Cosumnes River in flood
CRG Image Library - Joshua H. Viers

The Cosumnes River is the last undammed river draining the western side of the Sierra Nevada, its waters flowing into the Bay-Delta southeast of Sacramento. Because it is a free-flowing river, it has provided a laboratory for studying the ecological properties of a natural hydrological regime. The University of California, Davis, in collaboration with seven agency and non-profit groups, undertook an eight-year study in the Cosumnes River Watershed to learn more about watershed conservation and restoration. The results of this study are presented at the site of the Cosumnes Research Group.

Regional Ecosystems

California is home to a wide range of incredibly diverse habitats, climate and geography, from high-elevation mountain peaks to extremely arid deserts and a unique coastal climate. These make up the wide range of ecosystems found in the region, including iconic ecosystems such as the California Chaparral and Oak Woodlands; the Central Valley of California; the Sierra Nevada Range; and the Mojave and Sonoran Deserts (Source: The Nature Conservancy's GIS Website).

Ecological regions, or "ecoregions," denote areas of general similarity in ecosystems and environmental resources, and are delineated according to their common physical environment and biological characteristics. Ecoregions are a type of spatial classification tool used by scientists, resources managers, and conservation organizations to regionalize biogeographic areas.

The map below displays the five different Level 2 ecoregions within CAIN, according to the Omernik/US EPA Level 2 classification system. Additional resources for California's ecosystems and ecoregions include the Biogeographic Information & Observation System (BIOS), the the California Ecoregion Browser, the GAP Analysis Program's mapping products for California, and the Napa Vegetation Map.

Level 2 Ecoregions of California [Image: Christine Miller, Big Sky Institute, Montana State University

Image: Level 2 Ecoregions of California [Image: Christine Miller, Big Sky Institute, Montana State University]

Cold Deserts, NPS Cold Deserts
Cold deserts are distinguished by their aridity, unique shrub and cactus vegetation, lack of trees, and topography consisting of plains and tablelands.
Marine West Coast Forest, NPS Marine West Coast Forest
This ecoregion's character is shaped by a cool, moist climate with dry summers and wet, generally snowless winters, which result in highly productive coniferous forests.
Mediterranean California, USBR Mediterranean California
Mediterranean California is distinguished by its warm, mild Mediterranean climate, its shrubland vegetation of chaparral mixed with grassland and oak woodlands, and its agriculturally productive valleys.
Warm Desert, NPS Warm Deserts
Warm deserts, found in the southwest region of the US, are arid regions with unique shrub and cactus vegetation and higher average temperatures than the cold deserts to the north.
Western Cordillera, NPS Western Cordillera
The Western Cordillera ecoregion is characterized by rugged, high, mostly forested mountains with some open, wide valleys.

Resources on California's Ecological Communities
Showing 12 Results
CollapseA Manual of California Vegetation
Description: The following website describes a classification of vegetation developed by the California Native Plant Society (CNPS). It is a digital version of the book A Manual of California Vegetation published through the Society.The information in this website encompasses virtually all of the information in the book with the exception of the literature citations.
Resource Type: Manuals
Resource Format: URL
Publisher: California Native Plant Society
ExpandBiodiversity Inventory of Natural Lands: A How-To Manual for Foresters and Biologists (PDF, 40 pp., 699 KB)
ExpandCalifornia Gap Analysis Project: Statewide Datasets
ExpandCalifornia State University, Stanislaus Endangered Species Recovery Program
ExpandCalifornia Vegetation Map Catalog
ExpandCalifornia Weed Mapping Handbook
ExpandFire and Resource Assessment Program
ExpandGlobal Observation Research Initiative in Alpine Environments - Field Database
ExpandInventory of Rare and Endangered Plants of California
ExpandNapa County Flora
ExpandThe Gap Analysis Program Website/Portal
ExpandThe Vegetation Classification and Mapping Program

About Ecoregions

An ecoregion is a land area defined by ecological and geographical boundaries. Ecoregions are delineated according to their common physical environment (soil, climate, landforms) and biological characteristics (plant and animal communities).

Ecoregions are a type of spatial classification tool used by scientists, resources managers, and conservation organizations to regionalize biogeographic areas. This regionalization is done to organize complex natural systems into discrete units with boundaries.

Ecoregion boundaries indicate a change in the physical environment and ecological structure of a geographic area. While the changes may occur abruptly, change can also be gradual. Therefore, it is important to remember that ecoregion boundaries are approximations of areas of biogeographic change.

Ecoregion Classification

Ecoregion classifications are used to facilitate analyses of biological diversity and assist habitat conservation planning efforts. This type of classification aids management efforts because it facilitates coordination across geopolitical borders (county, city, state, and national). There are a number of different types of ecoregion classification systems that have been created by various management organizations (e.g. the Bailey/ US Forest Service system, the Omernik/US EPA classification, and the World Wildlife Fund classification system). The ecoregion classifications differ in the delineation methods and application. This portal uses the Omernik/US EPA ecoregion classification system.

Classification System

Ecoregions are initially grouped broadly (Level 1), and from there are broken down into more narrow ecological assemblages (Levels 2-4). There are 15 Level 1 ecoregions in North America which delineate the major ecological zones within the continent. These 15 ecoregions are further broken down into 52 Level 2 ecoregions which highlight ecological diversity at the sub-continent level. There are approximately 200 Level 3 ecoregions in North America which describe the physical and ecological characteristics of an area at a regional scale. Level 4 ecoregions are the most narrow and describe ecological assemblages at a localized level.

The NBII Program is administered by the Biological Informatics Program of the U.S. Geological Survey
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