Physiographic features

The Clayey 17-20” PZ ecological site is on nearly level to steeply sloping uplands.

Table 2. Representative physiographic features

Climatic features

MLRA 64 has a continental climate consisting of cold winters and hot summers, low humidity, light rainfall, and ample sunshine. Extremes in temperature are common in some years. The climate results from MLRA 64 being near the geographic center of North America. There are few natural barriers on the Northern Great Plains. Air masses move freely across the plains and account for rapid changes in temperature.

Average annual precipitation ranges from 14 to 20 inches per year. The normal average annual temperature is about 47 °F. January is the coldest month with average temperatures ranging from about 21 °F (Wood, SD) to about 25 °F (Hemingford, NE). July is the warmest month with average temperatures ranging from about 70 °F (Keeline 3 W, WY: 1953–1986) to about 76 °F (Wood, SD). The range of normal average monthly temperatures between the coldest and warmest months is about 55 °F. This large annual range attests to the continental nature of the climate of this area. Wind speed averages about 11 miles per hour annually, ranging from about 13 miles per hour during the spring to about 10 miles per hour during the summer. Daytime winds are generally stronger than nighttime winds. Occasionally, strong storms bring brief periods of high winds with gusts to more than 50 miles per hour.

Growth of cool-season plants begins in early to mid-March, slowing or ceasing in late June. Warm-season plants begin growth about mid-May and continue to early or mid-September. Cool-season plants may green-up in September and October if adequate soil moisture is present.

Table 3. Representative climatic features

Climate stations used

• (1) CHADRON 3NE [USC00251578], Chadron, NE

• (2) PORCUPINE 11 N [USC00396736], Kyle, SD

• (3) HARRISON 4NW [USC00253617], Harrison, NE

• (4) FT ROBINSON [USC00253015], Crawford, NE

• (5) GORDON 6N [USC00253355], Gordon, NE

• (6) PINE RIDGE AP [USW00094039], Pine Ridge, SD

• (7) INTERIOR 3 NE [USC00394184], Interior, SD

• (8) LONGVALLEY [USC00394983], Long Valley, SD

• (9) MARTIN [USC00395281], Martin, SD

• (10) CEDAR BUTTE 1NE [USC00391539], White River, SD

Influencing water features

No riparian areas or wetland features are directly associated with the Loamy 17-20” PZ ecological site.

Wetland description

Not Applicable.

Soil features

The soils in this site commonly have a surface layer of silty loam to clay and have slopes of 0 to 20 percent. The soils are well-drained and formed in alluvium, colluvium, and residuum derived primarily from shale. The surface layer is 3 to 7 inches thick. The texture of the subsurface ranges from silty clay to clay. The soils have a moderately slow or slow infiltration rate. When dry, these soils crack. Surface compaction can occur if the soils are subject to heavy traffic when wet. This site typically has slight to no evidence of rills, wind-scoured areas, or pedestalled plants. Water flow paths are broken, irregular in appearance, or discontinuous and obstructed by numerous debris dams or vegetative barriers. The soil surface is stable and intact. Subsurface soil layers are not restrictive to water movement and root penetration.

Soils correlated to the Clay 17-20” PZ site: Blackpipe, Bufton, Cactusflats, Denby, Higgins, Kyle, Larvie, Metre, Norrest, Okreek, Pierre, and Savo.

Blackpipe and Savo can also be correlated to the Loamy 17–20” PZ ecological site.

The soils are mainly susceptible to water erosion. The hazard of water erosion increases on slopes greater than about 5 percent. Loss of 50 percent or more of the surface layer of the soils on this site can shift the species composition, production, or both.

More information regarding the soil is available in soil survey reports. Contact the local USDA Service Center or use the Web Soil Survey online for details specific to your area of interest.

Table 4. Representative soil features

Animal community

Wildlife Interpretations:
MLRA 64 is in the drier areas of a northern mixed-grass prairie ecosystem in which sagebrush steppes to the west yield to grassland steppes to the east. Prior to European settlement, this MLRA consisted of diverse grassland and shrubland habitats interspersed with varying densities of depressional, instream wetlands and woody riparian corridors. These habitats provided critical life cycle components for many users. Many species of grassland birds, small mammals, reptiles, and amphibians and herds of roaming bison, elk, and pronghorn were among the inhabitants adapted to this semi-arid region. Roaming herbivores, as well as several species of small mammals and insects, were the primary consumers linking the grassland resources to large predators, such as the wolf, mountain lion, and grizzly bear, and to smaller carnivores, such as the coyote, bobcat, fox, and raptors. The prairie dog was once abundant and remains a keystone species within its range. The black-footed ferret, burrowing owl, ferruginous hawk, mountain plover, and swift fox are associated with prairie dog complexes.

Historically, the northern mixed-grass prairie was a disturbance-driven ecosystem in which fire, herbivory, and climate functioned as the primary disturbance factors, either singly or in combination. Following European settlement, livestock grazing, cropland conversion, elimination of fire, energy development, and other anthropogenic factors influenced species composition and abundance. Introduced and invasive species further affected plant and animal communities. The bison was a historical keystone species but has been extirpated in this area as a free-ranging herbivore. The loss of the bison and the reduction of prairie dog populations and fire as ecological drivers greatly influenced the character of the remaining native plant communities and altered wildlife habitats. Human development reduced habitat quality for area-sensitive species.

Within MLRA 64, the Badlands Overflow ecological site includes upland grassland cover with an associated forb and shrub component. It was typically part of an expansive grassland landscape that included combinations of Thin Breaks, Clayey, Claypan, Dense Clay, Loamy, Saline, Sandy, Shallow, Overflow, Subirrigated, and Terrace ecological sites.

Although this ecological site is primarily dominated by tall and medium warm- and cool-season grasses, it can support a shrub community composed of big sagebrush, silver sagebrush, rose, silver buffaloberry, and western snowberry. The presence or absence of this shrub component is an important factor influencing wildlife species composition.

Some areas of the site contain remnant stands of plains cottonwood and other trees. Multiple successional changes can occur as a result of stream channel aggradation and degradation. During periods of favorable climatic conditions in areas that are not significantly grazed, midgrass- and tallgrass-habitat provides denser cover and stabilizes the area along the stream channel. When present, seeps and springs provide vital water supply and localized wildlife habitat, especially for reptiles, amphibians, bats, and game species (both predators and prey).

This site provides habitat for mule deer and pronghorn antelope; grassland- and shrub-steppe-nesting birds; small mammals; mammalian predators; and a variety of reptiles, amphibians, and insects. Within the MLRA, this site provides important riparian habitat. The site also provides foraging and brood rearing habitat for upland game birds, such as the sharp-tailed grouse.

Western Wheatgrass-Green Needlegrass (1.1): A predominance of grasses plus a high diversity of forbs and shrubs in this community favor grazers and mixed-feeders, such as deer and pronghorn. Insects, including pollinators, play a large role in maintaining the forb community and provide a forage base for grassland birds and other species. The complex diversity of plant structures provides habitat for a wide array of migratory and resident birds. Grasshopper sparrow, savannah sparrow, lark bunting, western meadowlark, and sharp-tailed grouse are common and benefit from the structure and composition of this plant community. This site provides important breeding habitat for the loggerhead shrike. This site also provides excellent nesting and brood rearing habitat for sharp-tailed grouse. Diverse prey populations are available for grassland raptors, such as ferruginous hawk, Swainson’s hawk, golden eagle, and prairie falcon.

The diversity of grasses and forbs provides high nutrition levels for small and large herbivores, including voles, mice, least chipmunk, spotted ground squirrel, desert cottontail rabbit, white-tailed jackrabbit, black-tailed jackrabbit, and deer. This ecological site provides excellent wintering habitat for pronghorn. The moderate stature of the plant community provides suitable thermal, protective, and escape cover for small herbivores and grassland birds. Predators that use this plant community include the coyote, American badger, red fox, and long-tailed weasel. This plant community provides habitat for the spadefoot toad and Great Plains toad. An abundance of prey and shade opportunities attract multiple reptile species to this site. Examples include gopher snake, milk snake, prairie rattlesnake, and western ornate box turtle. Lesser numbers of various lizard species are also present.

Western Wheatgrass-Buffalograss-Blue Grama (1.2): Areas that are subject to continuous season-long grazing or to overutilization during extended drought periods become dominated by blue grama and buffalograss. Also, forbs and shrubs increase in diversity and abundance. The density of species such as sharp-tail grouse and desert cottontail generally remain unchanged. However, the shift to shorter plant structure favors expansion of prairie dogs and associated species, such as ferruginous hawk, burrowing owl, tiger salamander, and swift fox. Species such as the horned lark, long-billed curlew, upland sandpiper, white-tailed jackrabbit, and black-tailed jackrabbit increase. Some areas of this plant community are suitable for development of leks for sharp-tailed grouse. The short stature of this plant community limits thermal, protective, and escape cover. Predators that use this plant community include the coyote, American badger, red fox, and long-tailed weasel.

Buffalograss-Blue Grama Sod (2.1): This plant community develops in areas that are subject to continuous season-long grazing or continuous seasonal grazing with concentrated use in the spring. As this community develops, the abundance of forbs increases and the diversity of forbs and shrubs decreases. A shift to short plant structure can favor prairie dogs, leading to an expansion of prairie dog towns and an increase in associated species, such as ferruginous hawk, burrowing owl, tiger salamander, and swift fox. Species such as the horned lark, long-billed curlew, upland sandpiper, white-tailed jackrabbit, and black-tailed jackrabbit increase. This plant community may provide areas suitable for development of leks for sharp-tailed grouse. The short stature of this plant community limits thermal, protective, and escape cover. Predators that use this plant community include the coyote, American badger, red fox, and long-tailed weasel. Species such as the desert cottontail rarely use this site.

Extreme impairment of ecological processes affects offsite aquatic habitats by causing excessive runoff and nutrient loads. Reduced cover and litter result in elevated surface temperatures, which greatly reduce habitat for most amphibians, grassland birds, and mammals.

Threeawn-Annuals (3.1): Areas that are subject to heavy, continuous season-long grazing over many years or to frequent and severe defoliation become dominated by threeawn and annuals. Forbs and shrubs increase in abundance but decrease in diversity. A shift to short plant structure and relatively high percent of bare ground favors prairie dogs, leading to an expansion of prairie dog towns and an increase in associated species, such as swift fox, ferruginous hawk, and burrowing owl. Species such as horned lark, long-billed curlew, upland sandpiper, and white-tailed jackrabbit increase. Species that require moderate cover height rarely use this site. Examples include desert cottontail and grassland nesting birds. The short stature of this plant community limits suitable thermal, protective, and escape cover. Prey populations are reduced and are more vulnerable to predation by raptors and mammals. Predators that use this plant community include the coyote, American badger, red fox, and long-tailed weasel.

Extreme impairment of the ecological processes affects offsite aquatic habitats by causing excessive runoff, nutrient loads, and sediment loads. Reduced cover and litter result in elevated surface temperatures, which greatly reduce habitat for most amphibians, grassland birds, and mammals.

Western Wheatgrass–Non-Native Cool-Season Grasses (<15%) (4.1): Areas that are subject to continuous seasonal grazing, non-use, or no fire become dominated by western wheatgrass, bluegrass, and annuals. Forbs increase in diversity but decrease in abundance. Shrubs remain relatively unchanged in both diversity and abundance. A grass diversity shift to favor invasive species and excessive litter buildup substantially diminishes wildlife habitat quality for grassland nesting songbirds. Juniper and ponderosa pine provide habitat for various small mammals and songbirds in scattered areas.

Invaded State (5.0): This state includes areas that have been invaded and are dominated by species such as smooth brome, Kentucky bluegrass, crested wheatgrass, non-native thistles, field bindweed, hoary cress, and other introduced species. These sites have greatly reduced foraging, reproductive, and escape cover for grassland nesting bird species.

Go-Back (6.1) and Seeded (6.2): These plant communities have separate, highly variable vegetation states. They are derived through distinct management scenarios. These plant communities have been or are highly susceptible to invasion by annual bromegrasses, bluegrasses, crested wheatgrass, and other non-native species. Because secondary succession is highly variable, plant and wildlife species are also variable. This plant community provides habitat for generalist species or early successional species.

Grazing Interpretations:
The following list suggests annual, initial stocking rates for average growing conditions. These estimates are conservative and should be used only as guidelines in the initial stages of conservation planning. Commonly, the current plant composition does not entirely match any particular plant community (as described in this ecological site description). Therefore, a resource inventory is necessary to document plant composition and production. More accurate estimates of carrying capacity should eventually be calculated using the following stocking rate information along with animal preference data and actual stocking records, particularly when grazers other than cattle are involved. In consultation with the land manager, a more intensive grazing management program that results in improved harvest efficiencies and increased carrying capacity may be developed.

The following suggested initial stocking rates are based on 912 lb/acre (air-dry weight) per animal-unit-month (AUM) with a 25 percent harvest efficiency of preferred and desirable forage species (refer to USDA-NRCS, National Range and Pasture Handbook). An AUM is defined as the equivalent amount of forage required by a 1,000-pound cow, with or without calf, for one month.

Plant Community: Western Wheatgrass-Green Needlegrass (1.1)
Average Production (lb/acre, air-dry): 2,000
Stocking Rate (AUM/acre): 0.55

Plant Community: Western Wheatgrass-Buffalograss-Blue Grama (1.2)
Average Production (lb/acre, air-dry): 1,600
Stocking Rate (AUM/acre): 0.44

Plant Community: Buffalo-Blue Grama Sod (2.1)
Average Production (lb/acre, air-dry): 1,000
Stocking Rate (AUM/acre): 0.27

Plant Community: Western Wheatgrass–Non-Native Cool-Season Grasses (4.1)
Average Production (lb/acre, air-dry): 1,700
Stocking Rate (AUM/acre): 0.46

Plant Community: All other plant communities identified in this document have variable annual production values and require onsite sampling to determine initial stocking rates.

Total annual production and stocking rates are highly variable and require onsite sampling.

Total onsite annual production may contain vegetation deemed undesirable or untargeted by the grazing animal. Therefore, AUM values may have been reduced to reflect only preferred or desirable forage species.

Grazing by domestic livestock is one of the major income-producing industries in the area. Rangeland in this area may provide yearlong forage for livestock. During the dormant period, the forage for livestock likely has insufficient protein to meet livestock requirements. Added protein allows ruminants to better utilize the energy stored in grazed plant materials. A forage quality test (either directly or through fecal sampling) should be used to determine the level of supplementation needed.

Hydrological functions

Water is the principal factor limiting herbage production on this site. This site is dominated by soils in hydrologic groups C and D. The infiltration rate is moderate. Runoff potential varies from moderate to high depending on soil hydrologic group and ground cover. In many cases, areas that have greater than 75 percent ground cover have the greatest potential for high infiltration and lower runoff. An exception occurs where shortgrasses form a dense sod and dominate the site. Areas where ground cover is less than 50 percent have the greatest potential to have reduced infiltration and higher runoff. Refer to the USDA-NRCS National Engineering Handbook, Part 630, for hydrologic soil groups, runoff quantities, and hydrologic curves.

Recreational uses

This site provides opportunities for hunting upland game species. The wide variety of plants that bloom from spring until fall have aesthetic value that appeals to visitors.

Wood products

No appreciable wood products are present on the site.

Other products

Harvesting the seeds of native plants can provide additional income on this site.

Other information

Revision Notes: “Previously Approved” Provisional
This provisional ecological site description (ESD) passed quality control (QC) and quality assurance (QA) to ensure that it meets the 2014 NESH standards for a provisional ecological site description.

This ESD is an updated “Previously Approved” ESD that represented a first-generation tier of documentation that, prior to the release of the 2014 National Ecological Site Handbook (NESH), met all requirements as an “Approved” ESD as laid out in the 1997 National Range and Pasture Handbook (NRPH). The document fully described the Reference State and Community Phase in the State-and-Transition model. All other alternative states are at least described in narrative form. The “Previously Approved” ESD has been field-tested for a minimum of five years and is a proven functional document for conservation planning. The “Previously Approved” ESD may not contain all tabular and narrative entries as required in the current “Approved” level of documentation, but it is expected that it will continue refinement toward an “Approved” status.

Site Development and Testing Plan
Future work, as described in an official project plan, is necessary to validate the information in this provisional ecological site description. The plan will include field activities for low-, medium-, and high-intensity sampling, soil correlations, and analysis of the data. Annual field reviews should be done by soil scientists and vegetation specialists. Final field review, peer review, quality control, and quality assurance reviews are required to produce the final document.

Inventory data references

Information presented here has been derived from NRCS clipping data and other inventory data. Field observations from range-trained personnel were also used. Those involved in developing this site include: Stan Boltz, range management specialist (RMS), NRCS; Jill Epley, RMS, NRCS; Rick Peterson, RMS, NRCS; David Steffen, RMS, NRCS; Jeff Vander Wilt, RMS, NRCS; L. Michael Stirling, RMS, NRCS; Phil Young, soil scientist, NRCS; Kent Cooley, soil scientist, NRCS; and Wade Anderson, range professional and rancher.

Other references

Cleland, D.T., J.A. Freeouf, J.E. Keys, G.J. Nowacki, C.A. Carpenter, and W.H McNab. 2007. Ecological subregions: Sections and subsections of the conterminous United States. USDA Forest Service, General Technical Report WO-76D. https://www.fs.fed.us/research/publications/misc/73326-wo-gtr-76d-cleland2007.pdf (accessed 31 January 2019).

High Plains Regional Climate Center, University of Nebraska. 2018. http://www.hprcc.unl.edu/ (accessed 6 April 2018).

Soil Survey Staff. 2018a. Official soil series descriptions. USDA Natural Resources Conservation Service. https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/home/?cid=nrcs142p2_053587 (accessed 22 June 2018).

Soil Survey Staff. 2018b. Web Soil Survey. USDA Natural Resources Conservation Service. https://websoilsurvey.sc.egov.usda.gov/ (accessed 22 June 2018).

Steele, Ken, M.P. Fisher, and D.D. Steele. 2018. Fort Laramie and the Hartville Uplift. In: Geology of Wyoming. https://www.geowyo.com/fort-laramie--hartville-uplift.html (accessed 14 November 2018).

Toledo, D., M. Sanderson, K. Spaeth, J. Hendrickson, and J. Printz. 2014. Extent of Kentucky bluegrass and its effect on native plant species diversity and ecosystem services in the Northern Great Plains of the United States. Invasive Plant Science and Management. 7(4):543–522. Weed Science Society of America.

U.S. Department of Agriculture, Natural Resources Conservation Service. 2003. National range and pasture handbook. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1043055.pdf (accessed 7 January 2018).

U.S. Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. Agriculture Handbook 296.

U.S. Department of Agriculture, Natural Resources Conservation Service. 2012. National engineering handbook, part 630. Hydrology chapters from e-Directives. https://directives.sc.egov.usda.gov/viewerFS.aspx?hid=21422 (accessed 17 January 2018).

U.S. Department of Agriculture, Natural Resources Conservation Service. 2013a. Climate data. National Water and Climate Center. http://www.wcc.nrcs.usda.gov/climate (accessed 30 May 2018).

U.S. Department of Agriculture, Natural Resources Conservation Service. 2013b. National Soil Information System. https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053552 (accessed 25 May 2018).

U.S. Department of Agriculture, Natural Resources Conservation Service. 2017. National ecological site handbook, 1st edition. https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ref/?cid=nrcseprd1291232 (accessed 27 January 2018).

U.S. Department of Agriculture, Natural Resources Conservation Service. 2018a. Electronic field office technical guide. https://efotg.sc.egov.usda.gov (accessed 5 May 2018).

U.S. Environmental Protection Agency. 2018b. EPA level III and level IV ecoregions of the conterminous United States. https://www.epa.gov/eco-research/level-iii-and-iv-ecoregions-conterminous-united-states (accessed 26 April 2018).

U.S. Department of Agriculture, Natural Resources Conservation Service. 2018c. The PLANTS database. National Plant Data Team, Greensboro, NC. http://plants.usda.gov (accessed 22 June 2018).

Contributors

Stan C. Boltz
Rick L. Peterson

Approval

Suzanne Mayne-Kinney, 7/19/2024

Acknowledgments

This ecological site was reviewed and approved at the Provisional Level by David Kraft, Regional ESS, Salina, KS on 2/15/2019.

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