In the 2012 President's Budget Request, the National Biological Information Infrastructure (NBII) is terminated. As a result, all resources, databases, tools, and applications within this web site will be removed on January 15, 2012. For more information, please refer to the NBII Program Termination page.
Aerial view of Grand Prismatic Spring [Photo: Jim Peaco, 2001, National Park Service]
In 1872, President Ulysses S. Grant signed a law declaring that
Yellowstone would forever be "dedicated and set apart as a public park
or pleasuring ground for the benefit and enjoyment of the people." With
this designation, the region became the world's first national park.
Today, approximately 3 million visitors each year explore the 3,472
square miles that make up Yellowstone National Park.
Yellowstone
is widely recognized for its unique geothermal activity, resulting from
the Park's position atop an active volcano. In all, Yellowstone is home
to approximately 10,000 thermal features and more than 300 geysers,
including the most famous: Old Faithful.
Populations of five
protected species--bald eagle, grizzly bear, lynx, whooping crane, and
gray wolf--reside in the Park. Over three hundred bird species and over
1,700 species of vascular plants have been recorded across the craggy
mountainsides and open valleys.
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.
Image:
Level 2 Ecoregions of the Mountain Prairie Region [Image: Big Sky Institute, Montana State University]
Cold Deserts
Cold deserts are distinguished by their aridity, unique shrub and cactus vegetation, lack of trees, and topography consisting of plains and tablelands.
South-Central Semi-Arid Prairies
This ecoregion, which comprises the south-central part of North America's Great Plains, is warmer and was once composed of a different mosaic of potential vegetation than the prairie to the north.
Temperate Prairies
Once mostly covered by tallgrass prairie, this ecoregion comprises the eastern part of the Great Plains. Now, most of its productive land is in intensive cropland agriculture.
West-Central Semi-Arid Prairies
This ecoregion, comprising the north-western part of the Great Plains, was once covered by mixed grass prairie. It is drier than the Temperate Prairies and colder than the South-Central Semi-Arid Prairies.
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.
