Environment of the United States
Encyclopedia
The environment
Environment (biophysical)
The biophysical environment is the combined modeling of the physical environment and the biological life forms within the environment, and includes all variables, parameters as well as conditions and modes inside the Earth's biosphere. The biophysical environment can be divided into two categories:...

of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

comprises diverse biotas, climates, and geologies. Environmental regulations and the environmental movement
Environmental movement
The environmental movement, a term that includes the conservation and green politics, is a diverse scientific, social, and political movement for addressing environmental issues....

 have emerged to respond to the various threats to the environment.

Animals

More than 400 mammal, 700 bird, 500 reptile and amphibian, and 90,000 insect species have been documented. Wetlands such as the Florida Everglades
Everglades
The Everglades are subtropical wetlands in the southern portion of the U.S. state of Florida, comprising the southern half of a large watershed. The system begins near Orlando with the Kissimmee River, which discharges into the vast but shallow Lake Okeechobee...

 are the base for much of this diversity.

Fungi

Around 14,000 species of fungi were listed by Farr, Bills, Chamuris and Rossman in 1989. Still, this list only included terrestrial species. It did not include lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...

-forming fungi, fungi on dung, freshwater fungi, marine fungi or many other categories.

Plants

With habitats ranging from tropical to Arctic, U.S. plant life is very diverse. The country has more than 17,000 identified native species of flora
Flora
Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animals is fauna.-Etymology:...

, including 5,000 in California (home to the tallest, the most massive
Sequoiadendron
Sequoiadendron giganteum is the sole living species in the genus Sequoiadendron, and one of three species of coniferous trees known as redwoods, classified in the family Cupressaceae in the subfamily Sequoioideae, together with Sequoia sempervirens and...

, and the oldest
Bristlecone pine
The bristlecone pines are a small group of pine trees that are thought to reach an age far greater than that of any other single living organism known, up to nearly 5,000 years....

 trees in the world).

Human impacts on biota

The country's ecosystems include thousands of nonnative exotic species that often harm indigenous communities of living things. Many indigenous species became extinct soon after first human settlement, including the North American megafauna; others have become nearly extinct since European settlement, among them the American Bison
American Bison
The American bison , also commonly known as the American buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds...

 and California Condor
California Condor
The California Condor is a New World vulture, the largest North American land bird. Currently, this condor inhabits only the Grand Canyon area, Zion National Park, and coastal mountains of central and southern California and northern Baja California...

.

Climate

The U.S. climate is temperate in most areas, tropical in Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

 and southern Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, polar in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

, semiarid in the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...

 west of the 100th meridian
100th meridian west
The meridian 100° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole....

, Mediterranean in coastal California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 and arid in the Great Basin
Great Basin
The Great Basin is the largest area of contiguous endorheic watersheds in North America and is noted for its arid conditions and Basin and Range topography that varies from the North American low point at Badwater Basin to the highest point of the contiguous United States, less than away at the...

. Its comparatively generous climate contributed (in part) to the country's rise as a world power, with infrequent severe drought in the major agricultural regions, a general lack of widespread flooding, and a mainly temperate climate that receives adequate precipitation.

Following World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, the West's cities experienced an economic and population boom. The population growth
Population growth
Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using "per unit time" for measurement....

, mostly in the Southwest
Southwestern United States
The Southwestern United States is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah...

, has strained water and power resources, with water diverted from agricultural uses to major population centers, such as Las Vegas
Las Vegas, Nevada
Las Vegas is the most populous city in the U.S. state of Nevada and is also the county seat of Clark County, Nevada. Las Vegas is an internationally renowned major resort city for gambling, shopping, and fine dining. The city bills itself as The Entertainment Capital of the World, and is famous...

 and Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...

. According to the California Department of Water Resources
California Department of Water Resources
The California Department of Water Resources , is a department within the California Natural Resources Agency. The Department of Water Resources is responsible for the State of California's management and regulation of water usage...

, if more supplies are not found by 2020, residents will face a water shortfall
Water crisis
Water crisis is a general term used to describe a situation where the available water within a region is less than the region's demand. The term has been used to describe the availability of potable water in a variety of regions by the United Nations and other world organizations...

 nearly as great as the amount consumed today.

Geology

The lower 48 states can be divided into roughly five physiographic provinces: the American cordillera
American cordillera
The American Cordillera is a cordillera that consists of an essentially continuous sequence of mountain ranges that form the western "backbone" of North America, Central America, South America and Antarctica. From north to south, this sequence of overlapping and parallel ranges begins with the...

, the Canadian Shield
Canadian Shield
The Canadian Shield, also called the Laurentian Plateau, or Bouclier Canadien , is a vast geological shield covered by a thin layer of soil that forms the nucleus of the North American or Laurentia craton. It is an area mostly composed of igneous rock which relates to its long volcanic history...

, the stable platform, the coastal plain, and the Appalachian orogenic
Orogeny
Orogeny refers to forces and events leading to a severe structural deformation of the Earth's crust due to the engagement of tectonic plates. Response to such engagement results in the formation of long tracts of highly deformed rock called orogens or orogenic belts...

 belt.

Environmental law and conservation

The Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...

 of 1973 protects threatened
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...

 and endangered species
United States Fish and Wildlife Service list of endangered species
This list contains only the bird and mammal species described as endangered by the United States Fish and Wildlife Service. It contains species not only in the U.S. and its territories, but also species only found abroad. It does not contain fish, amphibians, reptiles, plants, or invertebrates,...

 and their habitats
Protected areas of the United States
The protected areas of the United States are managed by an array of different federal, state, tribal and local level authorities and receive widely varying levels of protection. Some areas are managed as wilderness, while others are operated with acceptable commercial exploitation. , according to...

, which are monitored by the U.S. Fish and Wildlife Service.

In 1872, the world's first national park
National park
A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...

 was established at Yellowstone. Another fifty-seven national parks and hundreds of other federally managed parks and forests have since been formed. Wilderness areas have been established around the country to ensure long-term protection of pristine habitats. Altogether, the U.S. government regulates 1,020,779 square miles (2,643,807 km²) , 28.8% of the country's total land area. Protected parks and forestland constitute most of this. As of March 2004, approximately 16% of public land under Bureau of Land Management
Bureau of Land Management
The Bureau of Land Management is an agency within the United States Department of the Interior which administers America's public lands, totaling approximately , or one-eighth of the landmass of the country. The BLM also manages of subsurface mineral estate underlying federal, state and private...

 administration was being leased for commercial oil and natural gas drilling; public land is also leased for mining and cattle ranching.

Environmental issues

As with many other countries there are a number of environmental issues in the United States. Topical issues include the Arctic Refuge drilling controversy and the Bush Administration stance on climate change.

Protected areas

The protected areas of the United States are managed by an array of different federal, state, tribal and local level authorities and receive widely varying levels of protection. Some areas are managed as wilderness while others are operated with acceptable commercial exploitation. By international definitions, the United States has 7448 protected areas, not counting marine areas, as of 2002. These protected areas cover 578,000 square miles (1,500,000 km²), almost 16% of the land area of the United States.[1] This is also one-tenth of the protected land area of the world. U.S. marine protected areas cover an additional 347,000 square miles (900,000 km²) with varying levels of protection.

See also

  • Ecotourism in the United States
    Ecotourism in the United States
    Ecotourism in the United States is commonly practiced in protected areas such as national parks and nature reserves, with the help of the United States National Park Service...

  • List of Superfund sites in the United States
  • MyEnvironment
    MyEnvironment
    is an application built by the United States Environmental Protection Agency to help the public get a sense of environmental indicators in their neighborhood. By keying in a geography, the application comes back with information about the local land, air and water. It mines mostly EPA but also...

     (website)
  • National Conservation Exposition
    National Conservation Exposition
    The National Conservation Exposition was an exposition held in Knoxville, Tennessee, United States, between September 1, 1913 and November 1, 1913. The exposition celebrated the cause of bringing national attention to conservation activities, especially in the Southeastern United States...

  • Timeline of major U.S. environmental and occupational health regulation
  • Watershed Central
    Watershed Central
    Watershed Central is an Environmental Protection Agency website developed to organize information and tools relevant to watershed management from across the country....


Further reading


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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