25 – High Plains (4 – level 4 ecoregions)

“Higher and drier than the Central Great Plains (27) to the east, and in contrast to the irregular, mostly grassland or grazing land of the Northwestern Great Plains (43) to the north, much of the High Plains is characterized by smooth to slightly irregular plains having a high percentage of cropland. Grama-buffalo grass is the potential natural vegetation in this region as compared to mostly wheatgrass-needlegrass to the north, Trans-Pecos shrub savanna to the south, and taller grasses to the east. The northern boundary of this ecological region is also the approximate northern limit of winter wheat and sorghum and the southern limit of spring wheat. (USGS, 2006; US EPA, 2013)”

25b – Rolling sand plains

• Topography - The grass-stabilized sand plains, sand dunes and sand sheets of the Rolling Sand Plains ecoregion are a divergence from the mostly loess-covered plains of adjacent ecoregions.

• Land Use - Land use is primarily rangeland, although a few scattered areas have been developed for irrigated cropland using deep wells.

• Soils - Sandy soils, formed from eolian deposits, supported a sandsage prairie natural vegetation type, different from the shortgrass and midgrass prairie of other neighboring level IV ecoregions in the High Plains (25).

• Vegetation - Sand sagebrush, rabbitbrush, sand bluestem, prairie sandreed, and Indian ricegrass were typical plants.

• Other –

Sites to Visit - Andrick Ponds State Wildlife Area, Empire Reservoir, Greater Prairie Chicken Leks/385, Kinney Lake State Wildlife Area, Milton Reservoir, Riverside Reservoir, Sand Creek Massacre National Historic Site, Tamarck Ranch State Wildlife Area
Resources -

25c – Moderate relief plains

• Topography - The Moderate Relief Plains ecoregion is typified by irregular plains with slopes greater than the surrounding at and rolling plains of Ecoregion 25d.

• Land Use - Land use is predominantly rangeland, in contrast to the cropland or mosaic of cropland and rangeland of surrounding ecoregions.

• Soils - Soils are silty and clayey loams, formed from eolian sediments, shallower than the thicker loess-capped uplands of 25d.

• Vegetation - Blue grama-buffalograss was the natural prairie type.

• Other – A

Sites to Visit - Beacher Island Battleground, Cherry Creek Reservoir, Comanche National Grassland, Flagler State Wildlife Area, Lesser Prairie Chicken Lek/Campo, Pawnee Buttes, Pawnee National Grassland, Pawnee National Grassland Birding Loop, Soapstone Prarie Natural Area, South Republican State Wildlife Area
Resources - Vascular plant species of the Pawnee National Grassland

25d – Flat to rolling plains

• Topography - The Flat to Rolling Plains ecoregion is more level and less dissected than the adjacent Moderate Relief Plains (25c).

• Land Use - Dryland farming is extensive, with areas of irrigated cropland scattered throughout the ecoregion. Winter wheat is the main cash crop, with a smaller acreage in forage crops.

• Soils - Soils are generally silty with a veneer of loess.

• Vegetation -

• Other –

Sites to Visit - Barr Lake State Park, Cheyenne Wells, Chivington Reservoir, Comanche Crossing State Historic Site, Horse Creek Reservoir, Jackson Lake State Park, Jumbo Lake, Lower Latham Reservoir, North Sterling Reservoir State Park, Rocky Mountain Arsenal National Wildlife Refuge, Saint Vrain State Park, Sterling Reservoir North, Summit Springs Battlefield, Two Buttes State Wildlife Area, Union Reservoir, Wild Animal Sanctuary
Resources -

25l – Front range fans

• Topography - The Front Range Fans ecoregion flanks the northern Front Range of the Southern Rockies in Colorado.

• Land Use - Land use is changing from mostly cropland and rangeland to more extensive urban development. Development has led to an increase in manmade lakes and gravel pits dotting the region.

• Soils - The soils of the region have more outwash gravels than regions farther east and occupy old terraces, benches, and alluvial fans. The soils are formed from materials weathered from arkosic sedimentary rock, gravelly alluvium, and redbed shales and sandstone. Some soils have a high shrink-swell potential.

• Vegetation -

• Other - Streams tend to be cooler than in other High Plains (25) regions and contain many Front Range aquatic species.

Sites to Visit - Boyd Lake State Park, Chatfield Reservoir, Horsetooth Reservoir East, Hygiene, Longmont, Loveland, Niwot
Resources -