Pawnee National Grassland is a

United States National Grassland A national grassland is an area of protected and managed federal lands in the United States authorized by Title III of the Bankhead–Jones Farm Tenant Act of 1937. For administrative purposes, they are essentially identical to national forests, ...

located in northeastern Colorado on the

Colorado Eastern Plains The Eastern Plains of Colorado refers to a region of the U.S. state of Colorado east of the Rocky Mountains and east of the population centers of the Front Range. Geography The Eastern Plains are part of the High Plains, which are the western ...

. The grassland is located in the

South Platte River The South Platte River is one of the two principal tributaries of the Platte River. Flowing through the U.S. states of Colorado and Nebraska, it is itself a major river of the American Midwest and the American Southwest/ Mountain West. It ...

basin in remote northern and extreme northeastern

Weld County Weld County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 328,981. The county seat is Greeley. Weld County comprises the Greeley, CO Metropolitan Statistical Area, which is included in the Denver ...

between Greeley and Sterling. It comprises two parcels totaling largely between State Highway 14 and the

Wyoming Wyoming () is a state in the Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the s ...

border. The larger eastern parcel lies adjacent to the borders of both

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the sout ...

and

. It is administered in conjunction with the

Arapaho The Arapaho (; french: Arapahos, ) are a Native American people historically living on the plains of Colorado and Wyoming. They were close allies of the Cheyenne tribe and loosely aligned with the Lakota and Dakota. By the 1850s, Arapaho ba ...

Roosevelt National Forest The Roosevelt National Forest is a National Forest located in north central Colorado. It is contiguous with the Colorado State Forest as well as the Arapaho National Forest and the Routt National Forest. The forest is administered jointly wit ...

from the U.S. Forest Service office in

Fort Collins A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from Latin ''fortis'' ("strong") and ''facere'' ...

, with a local

ranger A Ranger is typically someone in a military/paramilitary or law enforcement role specializing in patrolling a given territory, called “ranging”. The term most often refers to: * Park ranger or forest ranger, a person charged with protecting and ...

district office in Greeley. 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 Dust Bowl was a period of severe dust storms that greatly damaged the ecology and agriculture of the American and Canadian prairies during the 1930s. The phenomenon was caused by a combination of both natural factors (severe drought) a ...

. The communities of Keota and Purcell are located within the grassland. The town of

Grover Grover is a blue Muppet character on the popular PBS/HBO children's television show ''Sesame Street''. Self-described as lovable, cute and furry, he is a blue monster who rarely uses contractions when he speaks or sings. Grover was originall ...

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.

Recreation and access

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 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 above the surrounding plains, the b ...

, the most notable geologic feature of the grasslands.

Bird watching Birdwatching, or birding, is the observing of birds, either as a recreational activity or as a form of citizen science. A birdwatcher may observe by using their naked eye, by using a visual enhancement device like binoculars or a telescope, by ...

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.

Geology

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 Chernozem (from rus, чернозём, p=tɕɪrnɐˈzʲɵm, r=chernozyom; "black ground"), also called black soil, is a black-colored soil containing a high percentage of humus (4% to 16%) and high percentages of phosphorus and ammonia compound ...

of a chestnut, becoming brown. The chestnut soils are the dominant type across the areas. These soils develop in

semiarid A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi- ...

climates with of rain annually. They are associated with

buffalo grass Buffalo grass may refer to * Buffalo grass, sweet vernal grass or vanilla grass ('' Anthoxanthum odoratum'') * Buffalo grass ('' Bouteloua dactyloides'') * Buffalo grass ('' Brachiaria mutica'') * Buffalo grass or sweet grass (''Hierochloe odorata' ...

and

blue grama ''Bouteloua gracilis'', the blue grama, is a long-lived, warm-season ( C4) perennial grass, native to North America. It is most commonly found from Alberta, Canada, east to Manitoba and south across the Rocky Mountains, Great Plains, and U.S ...

. Around the

butte __NOTOC__ In geomorphology, a butte () is an isolated hill with steep, often vertical sides and a small, relatively flat top; buttes are smaller landforms than mesas, plateaus, and tablelands. The word ''butte'' comes from a French word me ...

s, the soils are most likely brown soils which are characteristic of cool, semiarid condition and are evidenced by short grasses and shrubs.An Interpretive Resource Analysis of Pawnee Buttes, Colorado; Dissertation; Robert Jack Badaracco; Colorado State University; Fort Collins, Colorado; March 1971 Water is available from a

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

period

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials ( gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characteris ...

. Three springs are in the vicinity of the buttes: Nelson Ranch ( north), old Linglebach Homestead ( south), and an arroyo ( west). The main access to the aquifer is by

windmill A windmill is a structure that converts wind power into rotational energy using vanes called sails or blades, specifically to mill grain (gristmills), but the term is also extended to windpumps, wind turbines, and other applications, in some ...

pumps. The aquifer is recharged from the west and flows eastward. There are

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

and Quaternary aquifers which are recharged by precipitation and seepage from streams. The

Brule Formation The Brule Formation was deposited between 33 and 30 million years ago, roughly the Rupelian age ( Oligocene). It occurs as a subunit of the White River Formation in Nebraska, Colorado, North Dakota, South Dakota, and Wyoming. It is a sequen ...

, where available provides a large quantity of water.

Shortgrass prairie

The grassland is a part of the short grass plains of North America. The best example of this ecosystem are preserved around the

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. The wildlife of the grasslands is best represented near the buttes, with

pronghorn The pronghorn (, ) (''Antilocapra americana'') is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American a ...

deer Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the re ...

, bison, prairie dog,

wolves The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly un ...

coyotes The coyote (''Canis latrans'') is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological nich ...

, rabbits, and numerous rodents. Nesting birds include the

golden eagle The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known birds of ...

and prairie falcons .

Vegetative zones

*Short grass prairies cover the open flatlands at the below the buttes and the escarpments. They are dominated by

and

. Associated plants include the thread-leaf sedge, ring muhly,

western wheatgrass ''Pascopyrum'' is a monotypic genus of grass containing the sole species ''Pascopyrum smithii'', which is known by the common names western wheatgrass and red-joint wheatgrass, after the red coloration of the nodes. It is native to North America. ...

, and the prickly pear cactus. The western wheatgrass dominates in "

buffalo wallow A buffalo wallow or bison wallow is a natural topographical depression in flat prairie land that holds rain water and runoff. Though thriving bison herds roamed and grazed the great prairies of North America for thousands of years, they left fe ...

s" or other low patches. *Mixed prairie are the lighter and more sandy soils, found on the heights. The dominant plants are the needle and thread grass,

, Junegrass, along with short grass plants. There is a wider mix of vegetation which becomes more noticeable in spring and early summer when broom snakeweed, fringed sage, plus various forbs, including milkvetches, and locoweeds are highly visible. The mixed prairie has the greatest variety of plants. *The little bluestem is found across the entire grasslands, but it dominates in localized plots. These are in the swales and along north facing slopes where the shade will retain water longer. The same applies to soils that are sandy and gravelly. These areas are populated by

little bluestem ''Schizachyrium scoparium'', commonly known as little bluestem or beard grass, is a species of North American prairie grass native to most of the contiguous United States (except California, Nevada, and Oregon) as well as a small area north of t ...

and a mix of Canada rye,

phlox ''Phlox'' (; Greek φλόξ "flame"; plural "phlox" or "phloxes", Greek φλόγες ''phlóges'') is a genus of 67 species of perennial and annual plants in the family Polemoniaceae. They are found mostly in North America (one in Siberia) in di ...

borges Jorge Francisco Isidoro Luis Borges Acevedo (; ; 24 August 1899 – 14 June 1986) was an Argentine short-story writer, essayist, poet and translator, as well as a key figure in Spanish-language and international literature. His best-known bo ...

, and a mix of grasses and forbs. *Shrub steppe areas are similar to the short grass and mixed prairie, but with a greater

alkalinity Alkalinity (from ar, القلوي, al-qaly, lit=ashes of the saltwort) is the capacity of water to resist acidification. It should not be confused with basicity, which is an absolute measurement on the pH scale. Alkalinity is the strength ...

. Thus, the fourwing saltbush dominates these areas. They are found along the bottom of the escarpments. There is a variety of shrubs and forbs, but the key plants will be the saltbush and other alkaline loving plants, i.e., small soapweed and common winterfat. * Arroyos form near the escarpments along major drainage. Arroyos can be up to deep. There is no standing water, but the volume of water from each rain event allows the soils to hold moisture for a longer period. Here the dominant plants are larger shrubs or small trees, Rocky Mountain juniper and

choke cherry ''Prunus virginiana'', commonly called bitter-berry, chokecherry, Virginia bird cherry, and western chokecherry (also black chokecherry for ''P. virginiana'' var. ''demissa''), is a species of bird cherry (''Prunus'' subgenus ''Padus'') nat ...

. The moister soils allow for

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...

, gooseberry, and other shrubs similar to the breaks environment. There will also be

and Canada rye found. *Clay barrens are dominated by the eroding Brule Formation. Here

taproot A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproo ...

s are necessary for survival, such as hooker sandwort, tufted milk vetch, and common commandra. Several of these species use rhizomes to spread, often following small fractures in the clays. Other plants associated with the clay barrens are;

, Indian rice grass, ''

Penstemon ''Penstemon'' , the beardtongues, is a large genus of roughly 250 species of flowering plants native mostly to the Nearctic, but with a few species also found in the North American portion of the Neotropics. It is the largest genus of flowering ...

'', and

evening primrose ''Oenothera'' is a genus of about 145 species of herbaceous flowering plants native to the Americas. It is the type genus of the family Onagraceae. Common names include evening primrose, suncups, and sundrops. They are not closely related to ...

. Where there is active erosion, there are no plants. *Break shrub are areas of broken rock. They can be along the upper edge of an escarpment, shelves on vertical slopes or rocky areas at the bottom of a cliff. These areas provide tenuous holds and deep rooting plants dominate. The skunk brush sumac, and the gooseberry are characteristic. There may also be

mountain mahogany ''Cercocarpus'', commonly known as mountain mahogany, is a small genus of at least nine species of nitrogen-fixing flowering plants in the rose family, Rosaceae. They are native to the western United States and northern Mexico, where they grow ...

, little bluestem, and roses. *Scarp woodlands are found on the north-facing cliff edges and rocky areas. They are in the narrow canyons draining northwards, providing water, and protection against evaporation. Here larger trees can take root, such as

limber pine ''Pinus flexilis'', the limber pine, is a species of pine tree-the family Pinaceae that occurs in the mountains of the Western United States, Mexico, and Canada. It is also called Rocky Mountain white pine. A limber pine in Eagle Cap Wildernes ...

, small

ponderosa pine ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is the ...

s, and Rocky Mountain juniper. These are in addition to the break shrubs found on less protected northern slopes. *Willow Spring is the only natural water source near the buttes. Here water loving peach-leaf willow abound along with a variety of

sedges The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus ''Carex'' wit ...

. *Bare rocks offer a limited chance for growth to

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichens consists of a cor ...

s, '' Caloplaca'', and '' Lanconroa calcarea''. *Road edges receive runoff from the hard pack road surface. Invasive plants move into the initial disturbance and find adequate water to remain. The dominant plants are: Russian thistle, veiny dock, sweet clover, prickly poppy,

kochia ''Kochia'' ''Sunset Western Garden Book,'' 1995:606–607 is a synonym of the genus '' Bassia'', which belongs to the subfamily Camphorosmoideae of family Amaranthaceae Amaranthaceae is a family of flowering plants commonly known as the amara ...

, and sunflower. Native plants include; bee flower, Indian ricegrass, sedges, grasses, and forbs.

Flora

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

.Wildflowers of the Pawnee National Grassland, Pawnee National Grassland, U.S. Forest Service; Greeley, Colorado; 2012 *Blue flax (''

Linum lewisii ''Linum lewisii'' (''Linum perenne'' var. ''lewisii'') (Lewis flax, blue flax or prairie flax) is a perennial plant in the family Linaceae, native to western North America from Alaska south to Baja California, and from the Pacific Coast east to t ...

'') *Buffalo bur ('' Solanum rostratum'') *Cryptantha (''

Cryptantha ''Cryptantha'' is a genus of flowering plants in the borage family, Boraginaceae. They are known commonly as cat's eyes and popcorn flowers (the latter name is also used to refer to the closely related genus ''Plagiobothrys'',Hasenstab-Lehman, ...

'' species) *Groundsel (''

Senecio ''Senecio'' is a genus of flowering plants in the daisy family (Asteraceae) that includes ragworts and groundsels. Variously circumscribed taxonomically, the genus ''Senecio'' is one of the largest genera of flowering plants. Description Mor ...

'' species) *Hartweg evening primrose ('' Calylophus hartwegii'') *Hood's phlox ('' Phlox hoodii'') *Narrow-leaved penstemon ('' Penstemon angustifolius'') *Nuttall's violet ('' Viola nuttallii'') *Pink cleome ('' Cleome serrulata'') *Plains prickly pear cactus ('' Opuntia polyacantha'') *Prairie coneflower ('' Ratibida columnifera'') *Prairie evening primrose ('' Oenothera albicaulis'') *Prairie onion ('' Allium textile'') *Prairie snowball (''

Abronia fragrans ''Abronia fragrans'', the sweet sand-verbena, snowball sand-verbena, prairie snowball or fragrant verbena,Lithospermum incisum ''Lithospermum incisum'' is a species of flowering plant in the borage family known by several common names, including fringed puccoon, narrowleaf stoneseed, fringed gromwell, narrowleaf puccoon, and plains stoneseed. It is native to much of cent ...

'') *Purple ground cherry ('' Quincula lobata'') *Salsify (''

Tragopogon ''Tragopogon'', also known as goatsbeard or salsify, is a genus of flowering plants in the family Asteraceae. It includes the vegetable known as Tragopogon porrifolius, salsify, as well as a number of common wild flowers. Salsifies are forbs gro ...

major'') *Scarlet globe mallow ('' Sphaeralcea coccinea'') *Snow on the mountain ('' Agaloma marginata'') *Star lily ('' Leucocrinum montanum'') *Sunflowers (''

Helianthus ''Helianthus'' () is a genus comprising about 70 species of annual and perennial flowering plants in the daisy family Asteraceae commonly known as sunflowers. Except for three South American species, the species of ''Helianthus'' are native to ...

'' species) *Tansy aster ('' Machaeranthera tanacetifolia'') *Threadleaf yellowrays (''

Thelesperma filifolium ''Thelesperma filifolium'', commonly known as stiff greenthread, or plains greenthread, is a species of flowering plant in the aster family, Asteraceae. It is often found growing in shallow soils. It prefers disturbed sites in dry, sandy or grav ...

'') *Tufted sandwort ('' Arenaria hookeri'') *Western wallflower (''

Erysimum ''Erysimum'', or wallflower, is a genus of flowering plants in the cabbage family, Brassicaceae. It includes more than 150 species, both popular garden plants and many wild forms. The genus ''Cheiranthus'' is sometimes included here in whole o ...

spermum'') *Wooly locoweed ('' Astragalus mollissimus'') *Yucca ('' Yucca angustifolia'')

Gallery

Image:PawneeGrasslandInColorado.PNG, Colorado, with Pawnee National Grassland highlighted in red. Image:Pawnee National Grassland location in Weld County.png,

Weld County, Colorado Weld County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 328,981. The county seat is Greeley. Weld County comprises the Greeley, CO Metropolitan Statistical Area, which is included in the Denver ...

with Pawnee National Grassland highlighted in red. Image:Pawnee National Grassland.JPG, One of the signs marking the entrance to the grassland. This one is at the west side along State Highway 14. Image:Pawnee Grassland Butte.jpg, Rock formation near the Pawnee Buttes. Image:Pawnee Grassland Sunrise.jpg, Sunrise over the grassland. Image:Pawnee Gulley.jpg, A gully near the Pawnee Buttes. Image:Pawnee grass.jpg, View of Pawnee National Grassland from County Rd 116 in February. Image:Thundercloud over the Pawnee.jpg, A thundercloud rolling in over the prairie. Image:Pawnee Prairie.jpg, Uninterrupted prairie Image:Pawnee oil.jpg, Oil wells on

Colorado State Highway 14 State Highway 14 (SH 14) in the U.S. state of Colorado is an east–west state highway approximately long. One of the longest state highways in Colorado, it traverses four counties along the northern edge of the state, spanning a geography from t ...

References

External links

Arapaho and Roosevelt National Forests and Pawnee National Grassland
(United States Forest Service) {{authority control Grasslands of the North American Great Plains National Grasslands of the United States Protected areas of Weld County, Colorado Eastern Plains Grasslands of Colorado