Pawnee National Grassland | |
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Location | Weld County, Colorado, United States |
Nearest city | Greeley, Colorado |
Coordinates | 40°48′29″N103°59′21″W / 40.80806°N 103.98917°W [1] |
Area | 193,060 acres (781.3 km2) [2] |
Established | 1960 |
Governing body | U.S. Forest Service |
Website | Arapaho & Roosevelt National Forests and Pawnee National Grassland |
Pawnee National Grassland is a United States National Grassland located in northeastern Colorado on the Colorado Eastern Plains. The grassland is located in the South Platte River basin in remote northern and extreme northeastern Weld County between Greeley and Sterling. It comprises two parcels totaling 193,060 acres (78,130 ha) largely between State Highway 14 and the Wyoming border. The larger eastern parcel lies adjacent to the borders of both Nebraska and Wyoming. It is administered in conjunction with the Arapaho-Roosevelt National Forest from the U.S. Forest Service office in Fort Collins, with a local ranger district office in Greeley. [3]
The grassland is in an especially depopulated area of the Great Plains. It saw limited cultivation in the early 20th century but was withdrawn from farming after the Dust Bowl. The communities of Keota and Purcell are located within the grassland. The town of Grover is located directly between the two large parcels of the grasslands near Crow Creek. Briggsdale sits at the southern end where State Highway 14 and State Highway 392 meet. State Highway 71 traverses the eastern unit north of Stoneham. The eastern unit is drained by Pawnee Creek, a tributary of the South Platte. The western unit is largely drained by Crow Creek.
Camping is available at the Crow Valley Recreation Area northwest of Briggsdale. The grassland contains several hiking trails, including one that allows foot access to the Pawnee Buttes, the most notable geologic feature of the grasslands. Bird watching is a popular recreational activity for day hikers, especially at the Chalk Bluffs, a raptor nesting site.
Recreational activities on the Pawnee Grasslands have been somewhat curtailed over the last 10 years due to the discovery of extractable oil and natural gas. According to the US Forest Service, there are 63 active vertical oil and natural gas wells, and less than 3,000 acres of the 193,060 acres is protected from drilling. [4]
The grasslands is a joining of two soil types. In the east are prairie soils that are deep, and dark or reddish. From the west are chernozems of a chestnut, becoming brown. The chestnut soils are the dominant type across the areas. These soils develop in semiarid climates with 15 to 20 inches (38 to 51 cm) of rain annually. They are associated with buffalo grass and blue grama. Around the buttes, the soils are most likely brown soils which are characteristic of cool, semiarid condition and are evidenced by short grasses and shrubs. [5]
Water is available from a Cretaceous period aquifer. Three springs are in the vicinity of the buttes: Nelson Ranch 1 mile (1.6 km) north, old Linglebach Homestead 1 mile (1.6 km) south, and an arroyo 0.51 miles (0.8 km) west. The main access to the aquifer is by windmill pumps. The aquifer is recharged from the west and flows eastward. There are Tertiary and Quaternary aquifers which are recharged by precipitation and seepage from streams. The Brule Formation, where available provides a large quantity of water. [5]
The grassland is a part of the short grass plains of North America. The best example of this ecosystem are preserved around the Pawnee Buttes where grazing and intensive agriculture have had less impact. There are eleven vegetation zones represented with the most unique being the scarp woodlands on the north face of the buttes. Typical of higher elevations, there are limber pines and relicts of an ice-age forest. [5]
The wildlife of the grasslands is best represented near the buttes, with pronghorn, deer, bison, prairie dog, coyotes, black-tailed jackrabbit, and numerous rodents. Nesting birds include the golden eagle and prairie falcons. [5]
Wildflowers bloom from April through September. The best locations for viewing wildflowers are near rocky outcrops or wet potholes, such as are found near the Pawnee Buttes. [6]
Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type. Temperate grassland regions include the Pampas of Argentina, Brazil and Uruguay, and the steppe of Ukraine, Russia, and Kazakhstan. Lands typically referred to as "prairie" tend to be in North America. The term encompasses the lower and mid-latitude of the area referred to as the Interior Plains of Canada, the United States, and Mexico. It includes all of the Great Plains as well as the wetter, hillier land to the east. From west to east, generally the drier expanse of shortgrass prairie gives way to mixed grass prairie and ultimately the richer soils of the tallgrass prairie.
A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on Earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area.
Rangelands are grasslands, shrublands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, savannas, chaparrals, steppes, and tundras. Rangelands do not include forests lacking grazable understory vegetation, barren desert, farmland, or land covered by solid rock, concrete, or glaciers.
The tallgrass prairie is an ecosystem native to central North America. Historically, natural and anthropogenic fire, as well as grazing by large mammals provided periodic disturbances to these ecosystems, limiting the encroachment of trees, recycling soil nutrients, and facilitating seed dispersal and germination. Prior to widespread use of the steel plow, which enabled large scale conversion to agricultural land use, tallgrass prairies extended throughout the American Midwest and smaller portions of southern central Canada, from the transitional ecotones out of eastern North American forests, west to a climatic threshold based on precipitation and soils, to the southern reaches of the Flint Hills in Oklahoma, to a transition into forest in Manitoba.
Aspen parkland refers to a very large area of transitional biome between prairie and boreal forest in two sections, namely the Peace River Country of northwestern Alberta crossing the border into British Columbia, and a much larger area stretching from central Alberta, all across central Saskatchewan to south central Manitoba and continuing into small parts of the US states of Minnesota and North Dakota. Aspen parkland consists of groves of aspen, poplar and spruce, interspersed with areas of prairie grasslands, also intersected by large stream and river valleys lined with aspen-spruce forests and dense shrubbery. This is the largest boreal-grassland transition zone in the world and is a zone of constant competition and tension as prairie and woodlands struggle to overtake each other within the parkland.
The pygmy rabbit is a rabbit species native to the United States. It is also the only native rabbit species in North America to dig its own burrow. The pygmy rabbit differs significantly from species within either the Lepus (hare) or Sylvilagus (cottontail) genera and is generally considered to be within the monotypic genus Brachylagus. One isolated population, the Columbia Basin pygmy rabbit, is listed as an endangered species by the U.S. Federal government, though the International Union for Conservation of Nature lists the species as lower risk.
The black-tailed prairie dog is a rodent of the family Sciuridae found in the Great Plains of North America from about the United States–Canada border to the United States–Mexico border. Unlike some other prairie dogs, these animals do not truly hibernate. The black-tailed prairie dog can be seen above ground in midwinter. A black-tailed prairie dog town in Texas was reported to cover 25,000 sq mi (64,000 km2) and included 400,000,000 individuals. Prior to habitat destruction, the species may have been the most abundant prairie dog in central North America. It was one of two prairie dogs described by the Lewis and Clark Expedition in the journals and diaries of their expedition.
Ord's kangaroo rat is a kangaroo rat native to western North America, specifically the Great Plains and the Great Basin, with its range extending from extreme southern Canada to central Mexico.
The Pawnee Buttes are two prominent buttes in northeastern Colorado. The west butte is located within the Pawnee National Grassland, while the east butte is on private land in Weld County. Rising approximately 300 feet (91 m) above the surrounding plains, the buttes are erosional remnants left standing in isolation as the surrounding High Plains surface has gradually worn away. The lower portions of the buttes are composed of relatively soft, clay-rich sedimentary rock called the Brule formation. The Brule formation is protected by an overlying layer of sandstone and conglomerate sediments called the Arikaree formation, which are more resistant to weathering.
The Blue Mountains ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency (EPA) in the Pacific Northwest, mainly in the state of Oregon, with small areas over the state border in Idaho and southeastern Washington. It is also contiguous with the World Wildlife Fund's Blue Mountain forests ecoregion.
The Northern Basin and Range ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency (EPA) in the U.S. states of Oregon, Idaho, Nevada, Utah, and California. It contains dissected lava plains, rolling hills, alluvial fans, valleys, and scattered mountain ranges in the northern part of the Great Basin. Although arid, the ecoregion is higher and cooler than the Snake River Plain to the north and has more available moisture and a cooler climate than the Central Basin and Range to the south. Its southern boundary is determined by the highest shoreline of Pleistocene Lake Bonneville, which once inundated the Central Basin and Range. The western part of the region is internally drained; its eastern stream network drains to the Snake River system.
Aiken Canyon Preserve is a 1,621-acre (6.56 km2) Nature Conservancy-managed state property in Colorado. It was first observed and named after Charles Aiken, a 19th-century U.S. surveyor, pioneer, and ornithologist who first surveyed the region in the 1870s and identified more than 75 bird species. The preserve consists of foothills, shrub and woodland ecosystems and is 12.4 miles (20.0 km) southeast from Colorado Springs located on the eastern slope of the Rampart Range which is within a smaller foothill system of the Front Range. The surrounding mountain ranges of the Rampart Range and Palmer Divide created the nature preserves sustainable ecosystem. There is also a four-mile (6 km)-loop hiking trail on the preserve.
Pinyon–juniper woodland, also spelled piñon–juniper woodland, is a biome found mid-elevations in arid regions of the Western United States, characterized by being an open forest dominated by low, bushy, evergreen junipers, pinyon pines, and their associates. At lower elevations, junipers often predominate and trees are spaced widely, bordering on and mingling with grassland or shrubland, but as elevation increases, pinyon pines become common and trees grow closer, forming denser canopies. Historically, pinyon-juniper woodland provided a vital source of fuel and food for indigenous peoples of the American Southwest. The nuts continue to be a traditional indigenous food, and because nut-collecting was also adopted by the Spanish in the 1500s, the nuts are also traditionally harvested by some Hispanic communities.
The East Central Texas forests or East Central Texas Plains (33) is a small temperate broadleaf and mixed forests ecoregion almost entirely within the state of Texas, United States. The northern forests perimeter is partially within the southeast Oklahoma border.
Achnatherum richardsonii is a species of grass known by the common names Richardson's needlegrass, spreading needlegrass, and Canada mountain-ricegrass. It is native to northwestern North America, where it is distributed from Alaska and Yukon through the western Canadian provinces south to Colorado.
Carex inops is a species of sedge known as long-stolon sedge and western oak sedge. It is native to northern North America, where it occurs throughout the southern half of Canada and the western and central United States.
Artemisia filifolia, known by common names including sand sagebrush, sand sage and sandhill sage, is a species of flowering plant in the aster family. It is native to North America, where it occurs from Nevada east to South Dakota and from there south to Arizona, Chihuahua, and Texas.
The ecology of the Great Plains is diverse, largely owing to their great size. Differences in rainfall, elevation, and latitude create a variety of habitats including short grass, mixed grass, and tall-grass prairies, and riparian ecosystems.
The Canadian Aspen Forests and Parklands is one of 844 terrestrial ecoregions defined by One Earth. This ecoregion includes parts of the Canadian provinces of Alberta, Saskatchewan, and Manitoba, north-central and eastern North Dakota, most of east South Dakota, and north-central Nebraska in the American Great Plains. The United States Environmental Protection Agency (EPA) defines this ecoregion as the Northern Glaciated Plains.
The Central Plains Biosphere Reserve was a UNESCO Biosphere Reserve located in the western central Great Plains in north-central Colorado in the shortgrass prairie. The 6,210 hectares (24.0 sq mi) reserve encompasses the Central Plains Experimental Range (CPER) administered by the United States Department of Agriculture's Agricultural Research Service.