26 – Southwestern Tablelands (7 – level 4 ecoregions)

“The southwestern Tablelands flank the High Plains (25) with red hued canyons, mesas, badlands, and dissected river breaks. Unlike most adjacent Great Plains ecological regions, little of the Southwestern Tablelands is in cropland. Much of this region is in sub-humid grassland and semiarid range land. The potential natural vegetation is grama-buffalo grass with some mesquite-buffalo grass in the southeast, juniper-scrub oak-midgrass savanna on escarpment bluffs, and shinnery (midgrass prairie with open low and shrubs) along the Canadian River. (USGS, 2006; US EPA, 2013)”

26e – Piedmont plains and tablelands

• Topography - The Piedmont Plains and Tablelands ecoregion is a vast area of irregular and dissected plains underlain by shale and sandstone.

• Land Use - Irrigated agriculture occurs along the Arkansas River, and dryland farming is found primarily in the north half of the region.

• Soils -

• Vegetation - The shortgrass prairie contains buffalograss, blue grama, western wheatgrass, galleta, alkali sacaton, sand dropseed, sideoats grama, and yucca. Land use is mostly rangeland. 

• Other - Precipitation varies from 10 to 16 inches, with the lowest amounts found along the Arkansas River between Pueblo and Las Animas.

  • Sites to Visit - Adobe Creek Reservoir State Wildlife Area, Apishapa State Wildlife Area, Bradford Reservoir, Comanche National Grassland, Cottonwood Canyon, Horsecreek Reservoir, John Martin Reservoir North, Lake Henry, Lake Meridith, Lake Pueblo State Park, Lamar, Limon Wetlands, Model Reservoir, Neesopah Reservoir, Purgatory River State Wildlife Area, Queens State Wildlife Area, Two Buttes Reservoir, Willow Creek Park, 7 Lakes Reservoir

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26f – Mesa de Maya/Black mesa

• Topography - The Mesa de Maya/Black Mesa ecoregion contains a broad basaltic mesa and dissected plateaus with steep canyons.

•  Land Use - Low precipitation, low available water capacity, and erodibility limit agricultural use.

• Soils - Soils are formed in materials weathered from basalt, limestone, sandstone, and shale. Rock outcrops are common.

• Vegetation - Juniper and pinyon-juniper woodlands grow along canyons and mesa sides, while grasslands occur on the basalt cap of the mesa. This is the only region in Colorado where small areas of mesquite are found.

• Other – 

  • Sites to Visit - Comanche National Grasslands, Cottonwood Canyon, Jesus Canyon, Picture Canyon

  • Resources - 

26g – Purgatoire hills and canyons

• Topography - The Purgatoire Hills and Canyons ecoregion includes dissected hills, canyons, and rock outcrops.

• Land Use -

• Soils - Unlike Ecoregion 26f, the Purgatoire Hills and Canyons ecoregion is generally more dissected and does not contain the basaltic mesa or soils derived from basalt. Soils are well drained and formed in calcareous eolian sediments and material weathered from sandstone; rock outcrops are common.

• Vegetation - Woodland vegetation is dominated by juniper with less grassland vegetation than found in 26f.  

• Other - The Purgatoire River supports a diverse fish assemblage.

  • Sites to Visit - Picket Wire Canyonlands, Pinyon Canyon

  • Resources - 

26h – Pinyon-juniper woodlands and savannas

• Topography -

• Land Use - Land use is mainly wildlife habitat and rangeland. 

• Soils - Soils tend to be thin and are formed in materials weathered from limestone, sandstone, and shale. Rock outcrops are common.

• Vegetation - Scattered, dissected areas with pinyon and juniper on the uplands characterize the Pinyon-Juniper Woodlands and Savannas ecoregion. The region is a continuation or an outlier of the pinyon-juniper woodlands found in Ecoregion 21d in the Southern Rocky Mountains to the west. 

• Other - Annual precipitation varies from 12 to 20 inches, with the highest amounts found in areas closest to the mountains.

  • Sites to Visit - Lathrop State Park, Martin Lake

  • Resources - 

26i – Pine-oak woodlands

• Topography -

• Land Use - Land use is woodland, wildlife habitat, and some rangeland. Areas of the region are rapidly urbanizing.

• Soils - Soils are formed from weathered sandstone and shale with some outwash on uplands.

• Vegetation - The Pine-Oak Woodlands ecoregion is a dissected plain with dense oakbrush and deciduous oak woodlands combined with ponderosa pine woodlands. The southern portion is known locally as the Black Forest. Although woodlands dominate, the region is a mosaic of woodlands and grasslands. It is somewhat more dissected than the surrounding Foothill Grasslands (26j) ecoregion. The Pine-Oak Woodlands may be an outlier of the ponderosa pine woodlands found in the mid-elevation forests of the Southern Rockies (21) to the west.  

• Other – 

  • Sites to Visit - Castle Rock, Castlewood Canyon State Park

  • Resources - 

26j – Foothill grasslands

• Topography -

• Land Use - Rangeland and pasture are common, with small areas of cropland. Urban and suburban development has increased in recent years, expanding out from Colorado Springs and the greater Denver area.

• Soils - Soils are loamy, gravelly, moderately deep, and mesic. They are formed from weathered arkosic sedimentary rock, gravelly alluvium, and materials weathered from sandstone and shales.

• Vegetation - The Foothill Grasslands ecoregion contains a mix of grassland types, with some small areas of isolated tallgrass prairie species that are more common much further east. The proximity to runoff and moisture from the Front Range and the more loamy, gravelly, and deeper soils are able to support more tallgrass and midgrass species than neighboring ecoregions. Big and little bluestem, yellow Indiangrass, and switchgrass occur, along with foothill grassland communities similar to those of Ecoregion 21d. Although grasslands dominate, scattered pine woodlands similar to those found in 26i also occur.  

• Other - The annual precipitation of 14 to 20 inches tends to be greater than in regions farther east.

26j

26k – Sand sheets

• Topography - The Sand Sheets ecoregion has rolling plains with stabilized sand sheets and areas of low sand dunes.

• Land Use - Land use in this region is mainly rangeland.

• Soils - Soils are formed from wind-deposited and alluvial sands.

• Vegetation - Natural vegetation is primarily sandsage prairie with sand reed grass, blue grama, sand dropseed, needlegrass, and sand sagebrush, and is similar to the Rolling Sand Plains (25b) ecoregion found in the neighboring High Plains (25).  

• Other - Annual precipitation ranges from 10 to 16 inches, less than the Foothill Grasslands to the northwest.

  • Sites to Visit - Chico Basin, John Martin Reservoir, Lamar

  • Resources -