Project Highlight

Sage grouse (Centrocercus urophasianus)
Sage grouse (Centrocercus urophasianus)
Credit: Karen Steenhof, USGS

NBII-Great Basin Information Project Photo Catalogue

The Great Basin Information Project provides consolidated and efficient access to information about the Great Basin and the Columbia Plateau Regions of eastern Washington and Oregon, southern Idaho, northern Nevada and Utah, and portions of northeastern California.  Three major plant communities grow in the Great Basin and Columbia Plateau: sagebrush, salt desert shrub, and pinyon-juniper woodlands.  The Great Basin and Columbia Plateau regions comprise a large area of the western United States, approximately 225,674 sq. miles in size.

Regional Ecosystems

The Pacific Northwest region has incredibly diverse habitats, climate and geography, from snowy mountain peaks to productive forests and sage-filled basins. These make up the wide range of ecosystems found in the region, including iconic ecosystems such as the North Cascades Mountains, Columbia Plateau, Great Basin, Rocky Mountains, and Snake River Plain (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 three different Level 2 ecoregions within PNWIN, according to the Omernik/US EPA Level 2 classification system.

Level 2 Ecoregions of the Pacific Northwest

Image: Level 2 Ecoregions of the Pacific Northwest [Image: 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.
Western Cordillera, NPS Western Cordillera
The Western Cordillera ecoregion is characterized by rugged, high, mostly forested mountains with some open, wide valleys.

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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