Physiographic features

This site occurs on flood plains of river valleys and in narrow drainage ways of uplands. This site receives runoff from areas higher on the landscape. Flooding is occasional to frequent and sedimentation is common on this site.

Table 2. Representative physiographic features

Climatic features

Annual precipitation averages around 26 inches per year. Occasional strong storms may bring brief periods of high winds with gusts to more than 60 miles per hour.

Growth of native cool season plants begins in early April and continues to about mid June. Native warm season plants begin growth in early June, and continue to early August. Green up of cool season plants may occur in September and October.

Table 3. Representative climatic features

Climate stations used

• (1) CANADAY STEAM PLT [USC00251450], Lexington, NE

• (2) KEARNEY 4 NE [USC00254335], Kearney, NE

• (3) LOUP CITY [USC00254985], Loup City, NE

• (4) GRAND ISLAND AP [USW00014935], Grand Island, NE

• (5) ARNOLD [USC00250355], Arnold, NE

• (6) CENTRAL CITY [USC00251560], Central City, NE

• (7) GOTHENBURG [USC00253365], Gothenburg, NE

• (8) NORTH LOUP [USC00256040], North Loup, NE

• (9) RAVENNA [USC00257040], Ravenna, NE

• (10) SAINT PAUL [USC00257515], Saint Paul, NE

• (11) ANSELMO 2 SE [USC00250245], Anselmo, NE

• (12) COMSTOCK [USC00251835], Comstock, NE

• (13) MASON CITY [USC00255250], Mason City, NE

• (14) BROKEN BOW 2 W [USC00251200], Broken Bow, NE

• (15) BURWELL [USC00251345], Burwell, NE

• (16) OCONTO [USC00256167], Oconto, NE

• (17) OVERTON 3 W [USC00256439], Overton, NE

• (18) STAPLETON 5W [USC00258133], Stapleton, NE

• (19) TAYLOR [USC00258455], Taylor, NE

Influencing water features

This site occurs on nearly level areas that receive additional water from overflow of intermittent or perennial streams, or runoff from adjacent slopes.

Soil features

These very deep soils are subject to inundation by floodwaters and subsequent sedimentation. Most soils are stratified. Textures are dominantly loamy and silty, but sandy textures may occur in the lower part of the root zone. Free water is usually very deep but may be present in the lower part of some profiles during part of the growing season. Organic matter is generally low to moderate in the surface layer.

Major soil series correlated to this ecological site include: Hobbs.

The Reference Plant Community should exhibit slight to no evidence of rills, wind scoured areas or pedestalled plants. Water flow paths are broken, irregular in appearance or discontinuous with numerous debris dams or vegetative barriers. The soil surface is stable and intact. Sub-surface soil layers are non-restrictive to water movement and root penetration. These soils are susceptible to wind and water erosion where vegetative cover is inadequate. Channel cutting, deposition, and removals may occur adjacent to streams.

Table 4. Representative soil features

Animal community

Grazing by domestic livestock is one of the major income-producing industries in the area. Rangeland in this area may provide year-long forage for cattle, sheep, or horses. During the dormant period, the protein levels of the forage may be lower than the minimum needed to meet livestock (primarily cattle and sheep) requirements.

Suggested stocking rates (carrying capacity) for cattle under continuous season-long grazing under normal growing conditions are listed below:

- Reference Community; 4000 lbs/acre production and 1.10 AUM/acre carrying capacity*

- Degraded Grassland Phase; 3500 lbs/acre production and 0.88 AUM/acre carrying capacity*

- Warm-season Shortgrass/Cool-season Community; 2500 lbs/acre production and 0.68 AUM/acre carrying capacity*

- Smooth bromegrass (dryland, unfertilized, > 50 percent plant composistion); 2750 lbs/acre and 0.75 AUM/acre carrying capacity*

* Continuous season-long grazing by cattle under average growing conditions, 25 percent harvest efficiency. Air dry forage requirements based on 3 percent of animal body weight, or 912 lbs/acre (air-dry weight) per Animal Unit Month (AUM). If distribution problems occur, stocking rates must be reduced to maintain plant health and vigor.

Carrying capacity and production estimates are conservative estimates that should be used only as guidelines in the initial stages of the conservation planning process. Often, the current plant composition does not entirely match any particular plant community (as described in this ecological site description). Because of this, a field visit is recommended to document plant composition and production. More precise carrying capacity estimates can be calculated based on actual site information along with animal preference data, particularly when livestock other than cattle are involved. With consultation of the land manager, more intensive grazing management may result in improved harvest efficiencies and increased carrying capacity.

WILDLIFE INTERPRETATIONS:
Major Land Resource Area (MLRA) 71 lies primarily within the loess mixed-grass prairie ecosystem mixed with tallgrass prairie in lower elevations. Prior to European settlement, this area consisted of diverse grassland habitats interspersed with varying densities of depressional wetlands and limited woody riparian corridors. These habitats provided critical life cycle components for many of its users. Many species of grassland birds, prairie dogs and herds of roaming bison, elk, and pronghorn were among the historic inhabitants. Small mammal and plentiful insect species provided for prey in the lower part of the food chain benefitting large predators such as wolves, and mountain lions, as well as smaller carnivores such as coyotes, bobcats, foxes and raptors. In addition, a wide variety of small mammals, reptiles, amphibians and insects were adapted to this habitat.

Historically, the loess mixed-grass prairie was a disturbance-driven ecosystem with fire, herbivory and climate functioning as the primary disturbance factors either singly or in combination. Following European settlement, widespread conversion to cropland, elimination of fire, and habitat fragmentation influenced species composition and abundance. Introduced and invasive species further impacted plant and animal communities. Bison and prairie dogs were historically keystone species but bison and nearly all prairie dogs have been extirpated from the site. The loss of bison and fire as ecological drivers greatly influenced the character of the remaining native plant community and the habitats that they provide. Fragmentation has reduced habitat quality for area-sensitive species such as greater prairie chicken.

Within MLRA 71, most Loamy Overflow ecological site provide grassland or tree cover with an associated forb and limited shrub component. Some of these sites have increased in tree cover if they are not cropped including varius deciduous trees and Eastern redcedar. This site was part of an expansive grassland landscape that included combinations of Loamy Upland, Clayey Overflow (wetland depressions), Loamy Lowland, and Loamy Overflow sites. This site provided habitat for species requiring unfragmented grassland. Important habitat features and components found commonly or exclusively on this site may include upland nesting habitat for grassland birds and game birds, nesting and escape cover for waterfowl; forbs and insects for brood habitat; and a forage source for small and large herbivores. Many grassland nesting bird populations are declining such as dickcissel and Henslow's sparrow. Extirpated species include free-ranging American bison, pronghorn, wolves and swift fox.

Many Loamy Overflow ecological sites have been converted to cropland unless they are subject to frequent flooding. Remaining prairies provide increasingly important habitat for grassland nesting birds, small rodents, small mammals, and a variety of reptiles, amphibians, and insects. Introduced species such as smooth bromegrass, reeds canarygrass (wet areas), Kentucky bluegrass, muskthistle, and Canada thistle have impacted biological integrity of many sites and habitat for some grassland birds such as Baird’s sparrow.

Invasive birds are present such as European starling and house sparrows severely compete with native birds for nests and brown-headed cowbirds parasitize nests.

Tree encroachment on this site has habitat favoring generalist species such as American robin and morning dove.

1. REFERENCE STATE: The predominance of tall and mid statured grasses plus high diversity of forbs and shrubs in this state favors grazers and mixed-feeders, such as deer. Insects such as pollinators play a large role in maintaining the forb community and provide habitat for grassland birds and other grassland dependent species. Sound management of this plant community maintains proper ecological processes preventing impacts to off-site aquatic habitats. This plant community provides habitat for frog, toad and snake species. The complex plant structural diversity provides habitat for a wide array of migratory and resident birds. Henslow's sparrow, Western meadowlark, Northern bobwhite, ringneck pheasants are examples of common birds that benefit from the structure and composition this plant community provides. Diverse prey populations are available for grassland raptors such as Swainson’s hawk, burrowing owl, short-eared owl and great horned owl. Some bird species over-winter in this habitat, such as Western meadowlark, and American crow.

The diversity of grasses, forbs and shrubs provide high nutrition levels for small and large herbivores including moles, mice, ground squirrels, white-tailed jackrabbit, and whitetail deer. The moderate stature of this plant community provides suitable thermal, protective and escape cover for small herbivores and grassland birds. Many wide-ranging predators utilize this plant community including coyote, badger, red fox and weasel (least and long-tailed).

As the plant community degrades to more mid-grasses and less tall grasses, less winter and escape cover are provided. It also provides less cover for predators. As the plant community shifts from tall warm season grasses to mid-height grasses will favor grassland birds that prefer shorter vegetation. This provides for more vision and better habitat for species such as greater prairie chicken, lark bunting, and lark sparrows. Habitat in plant community 1.2 is much the same as 1.1 but provides less winter protection because of the reduced plant height and cover.

2. NATIVE/INVADED GRASS STATE: Although the amount of Kentucky bluegrass in this plant community varies, the lower structural diversity favor grassland birds that prefer lower plant heights and more vision such as greater prairie chickens, lark bunting, and lark sparrows. Increased dominance by Kentucky bluegrass with a lower diversity provides less habitat for ringneck pheasant, Northern bob-white and mixed-feeders, such as whitetail deer and small mammals. Insect populations are somewhat reduced but still play a large role in maintaining the forb community and provide a forage base for grassland birds and other species.

The diversity of grasses,forbs and shrubs provide high nutrition levels for small and large herbivores including voles, mice, ground squirrels, blacktailed jackrabbit (better suited to this plant community than white-tailed jackrabbit), and white-tailed deer. The increase in litter accumulation benefits small mammals such as voles and mice. The moderate stature of this plant community provides suitable thermal, protective and escape cover for small herbivores and grassland birds. Many wide-ranging predators utilize this plant community including coyote, badger, red fox, racoon, and weasel (least and long-tailed).

3. SOD-BUSTED STATE: As the vegetation recovers from previous farming activities, management practices heavily influence the process. Typically resulting from continued heavy continuous season-long grazing without adequate recovery periods between grazing events or from continued non-use and no fire for extended periods of time, Kentucky bluegrass will dominate. Smooth bromegrass may also become prevalent in the non-use situation. The forb component exhibits lower diversity than the reference state and shifts towards increaser/ introduced forbs including sweetclover, yarrow, Cuman ragweed, Missouri goldenrod, Hoary verbena and Ironweed. Pollinator insects will still be prevalent, but a shift to generalists.

The earlier greenup associated with Kentucky bluegrass and smooth bromegrass and lower structural diversity provide habitat for those species that tolerate litter buildup, and shorter stature and increased woody cover typically occurs with this plant community).

Savannah sparrow, American robin, Western meadowlark are common birds that can benefit from the structure and composition of this plant community. The shorter stature of this plant community provides habitat for killdeer, horned lark, black-tailed jackrabbit (better suited to this plant community than white-tailed jackrabbit), and thirteen-lined ground squirrel. Prey populations are reduced and are more vulnerable to predation by raptors and mammalian predators. Burrowing owls may be associated with Richardson’s ground squirrel or other mammal burrows. The short stature of this plant community does not provide suitable thermal/protective cover and escape cover.

4. INVADED WOODY STATE
This state provides habitat for white-tailed deer, racoon, raptors, and birds that favor woody cover. Several raptors or birds of prey, such as the Cooper’s hawk, and sharp-shinned hawk use coniferous forests and woodlands for nesting, nesting materials, and for perching.

Birds that are habitat generalists, such as the Bell’s Vireo, common yellowthroat, Eastern kingbird, morning dove, American goldfinch, Northern bobwhite, field sparrow, solitary vireo, and pigmy nuthatch use woody cover for nesting, food, and breeding habitats.

The woody cover in this plant community state provide habitat for wild turkey and white-tailed deer as long as canopy cover is 25 percent or less or significant open areas exist where grassland or other open habitats are nearby. Raptors or birds of prey, such as the Cooper’s hawk, and sharp-shinned hawk use woody cover for nesting, nesting materials, and for perching. Oppossum, woodland vole, bobcat, racoons are provided excellent habitat as well.

Hydrological functions

Water is the principal factor limiting forage production on this site. This site is dominated by soils in hydrologic group B, with localized areas in hydrologic group C. Infiltration rate is moderate to moderately slow. Runoff potential for this site varies from very low to moderate depending on soil hydrologic group, slope and ground cover. In many cases, areas with greater than 75 percent ground cover have the greatest potential for high infiltration and lower runoff. An example of an exception would be where rhizomatous grasses form a strong 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 Section 4, NRCS National Engineering Handbook for runoff quantities and hydrologic curves).

Recreational uses

This site provides hunting for upland game species along with hiking, photography, bird watching and other opportunities. The wide varieties of plants which bloom from spring until fall have an aesthetic value that appeals to visitors.

Wood products

Local or individual fire wood can be utilized from this site. Red cedar pulpwood can be utilized for veneer and/or cedar furniture. Cottonwood can be harvested for pallets.

Other products

None of appreciable value.

Other information

Revision Notes: “This PROVISIONAL ecological site concept has been QC’d and QA’d to ensure that the site meets the NESH standards for a provisional ecological site that provides basic compiled information in one location. This site should not be considered an Approved ESD until further data entry and editing is completed.

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.

Other references

Other sources used as references include USDA NRCS Water and Climate Center, USDA NRCS National Range and Pasture Handbook, and USDA NRCS Soil Surveys from various counties.

Contributors

Doug Whisenhunt

Acknowledgments

Site Development and Testing Plan:
Future work is needed to validate the information in this Provisional Ecological Site Description. Additional data collection and evaluation may also be needed to develop this ESD to the Approved, then Correlated level. This could include field activities to collect low, medium and high intensity sampling, soil correlations, and analysis of that data. Field reviews of the project plan should be done by soil scientists and vegetation specialists. A final field review, peer review, quality control, and quality assurance reviews of the ESD will be needed to produce the final document.
The State and Transitional Model and corresponding pathways and associated vegetative communities will need to be reviewed and upgraded to adhere to the new guidelines.
Annual reviews of the Project Plan are to be conducted by the Ecological Site Technical Team. The project plan is: ES R071XY029NE MLRA 71