Ecological site R102CY048NE

3. Invasive dominant

4. Annual/pioneer

States 1, 5 and 2 (additional transitions)

1.1. Big bluestem-Little bluestem (Andropogon gerardii-Schizachyrium scoparium)

T1A	-	Non-native grasses increase
T1B	-	Disturbance; annual species dominant
T1C	-	Woody species dominate
R2A	-	Restoration inputs; native warm season grasses dominate
T2A	-	Increasing dominance of cool season grasses
T2B	-	Disturbance; annual species dominant
T2C	-	Woody species dominate
T3A	-	Management inputs; increase of warm season grasses
T3B	-	Cool season grasses dominate the site
T3A	-	Woody species continue to increase and dominant the site
R4A	-	Restoration inputs; warm season grasses dominant
R5A	-	Restoration inputs to promote warm season grasses

State 1 submodel, plant communities

1.2. Little bluestem-Sideoats grama (Schizachyrium scoparium-Bouteloua curtipendula)

1.1A	-	Intense grazing with inadequate recover periods
1.2A	-	Grazing management with adequate recovery periods

State 2 submodel, plant communities

2.1. Subdominant Smooth brome-Kentucky bluegrass (Bromus inermis-Poa pratensis)

2.2. Codominant Smooth brome-Kentucky bluegrass (Bromus inermis-Poa pratensis)

2.1A	-	Increasing dominance of non-native grasses
2.2A	-	Management to promote warm-season grasses

State 1
Native tallgrass

This state comprises the communities within the range of natural variability under historic conditions and disturbance regimes. Patterns created by wildlife use and fire would have created a mosaic of communities across the landscape; however, warm-season tallgrasses are dominant, with a subdominant to minor contribution from native cool-season grasses, forbs, and shrubs. Fire and bison herbivory were the dominant disturbance regimes that historically maintained the tallgrass dominance with a diverse forb component. Furthermore, bison grazing was closely linked to fire patterns as the animals preferred grazing burned areas offering lush regrowth devoid of decadence and of higher nutritive quality. Thus, historic plant communities were subjected to occasional burning and grazing, with substantial rest/recovery periods as the fuel load rebuilt to eventually start this process again. Fire return intervals of 3-4 years served to suppress woody species, particularly the various deciduous tree and shrub species prevalent in adjacent riparian corridors. The degree to which observed conditions represent this state largely depends on how closely the management has mimicked these past disturbance effects.

Dominant plant species

big bluestem (Andropogon gerardii), grass
little bluestem (Schizachyrium scoparium), grass

Community 1.1
Big bluestem-Little bluestem (Andropogon gerardii-Schizachyrium scoparium)

Figure 8. LyO 1.1 mid-July RPC

This is the interpretive plant community and can be found on areas that are properly managed with prescribed grazing that allows for adequate recovery periods following each grazing event. The plant community consists of 85-95% grasses and grass-likes, 5-10% forbs and 0-5% shrubs. Dominant grasses include big bluestem, little bluestem, indiangrass, and switchgrass. Other grasses and grass-likes are sideoats grama, western wheatgrass, and sedges. Forb species are diverse and often include western ragweed and Missouri goldenrod. Common shrubs include western snowberry and eastern poison ivy. This plant community is diverse, stable, and productive. Plant community dynamics, nutrient cycles, water cycles, and energy flow are functioning properly. Plant litter is properly distributed with negligible movement off-site and natural plant mortality is very low. This community is resistant to many disturbances except continuous, season-long heavy grazing, tillage, or non-use. Broadcast herbicide application will dramatically reduce forb diversity and abundance. Total annual production, during an average year, ranges from 2,650 to 3,750 pounds per acre air-dry weight and will average 3,200 pounds.

Dominant plant species

big bluestem (Andropogon gerardii), grass
little bluestem (Schizachyrium scoparium), grass

Figure 9. Annual production by plant type (representative values) or group (midpoint values)

Table 5. Annual production by plant type

Plant type	Low (lb/acre)	Representative value (lb/acre)	High (lb/acre)
Grass/Grasslike	2511	2880	3194
Forb	145	240	370
Shrub/Vine	0	80	180
Total	2656	3200	3744

Figure 10. Plant community growth curve (percent production by month). NE1021, 102C Warm-season. Warm-season grass, MLRA 102C.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	2	7	18	23	26	16	6	2	0	0

Community 1.2
Little bluestem-Sideoats grama (Schizachyrium scoparium-Bouteloua curtipendula)

Midgrasses, typically sideoats grama and little bluestem, dominate the site with tallgrass remnants scattered throughout. While still within the range of natural variability, energy capture, nutrient cycling, and hydrology are not functioning at their full potential relative to the reference condition.

Dominant plant species

sideoats grama (Bouteloua curtipendula), grass
little bluestem (Schizachyrium scoparium), grass

Figure 11. Plant community growth curve (percent production by month). NE1021, 102C Warm-season. Warm-season grass, MLRA 102C.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	2	7	18	23	26	16	6	2	0	0

Pathway 1.1A
Community 1.1 to 1.2

Grazing management which does not provide adequate recovery periods for tallgrass species will shift towards shorter statured species, particularly little bluestem and sideoats grama. Likewise, shortgrasses such as blue grama will also increase. Periods of extended drought will have similar impacts and cause a shift towards mixed-grass/shortgrass prairie species that are better adapted to drier conditions.

Pathway 1.2A
Community 1.2 to 1.1

Grazing management that includes proper stocking rates with adequate recovery periods for the entire grazing unit is usually required to improve or maintain this site. Intensive grazing management using concentrated livestock numbers, combined with long recovery periods, can be beneficial in improving forage utilization, quantity, and quality. Favorable precipitation following drought will promote tallgrass species and facilitate a return to the reference community.

State 2
Native/invaded mix

This state can manifest three ways: 1) the appearance of introduced cool-season grasses, 2) the expansion of deciduous shrubs and/or trees, or 3) some combination of these. Kentucky bluegrass and smooth brome are the primary cool-season grass invaders in this region, commonly found in roadsides, disturbed areas, and pastures intentionally seeded for cool-season forage. Management practices and/or environmental conditions that are not favorable to native grass vigor may allow introduced grasses to invade the site thereby decreasing native diversity and abundance, particularly of forbs. In the absence of the historic fire regime, woody deciduous species may also expand to become an influential component of the community. The invasive component tends to have very high reslience, is extremely difficult to eradicate, and what might be considered a new "contemporary" range of natural variability is seen as competition between the native grasses and introduced/woody species for space and resources.

Dominant plant species

little bluestem (Schizachyrium scoparium), grass
sideoats grama (Bouteloua curtipendula), grass
smooth brome (Bromus inermis), grass
Kentucky bluegrass (Poa pratensis), grass

Community 2.1
Subdominant Smooth brome-Kentucky bluegrass (Bromus inermis-Poa pratensis)

While native grasses still dominate the site, introduced cool-season species have established a foothold in the system and can be found interspersed throughout the stand. The stand may still have a native tallgrass appearance overall, but bluegrass and/or brome can be easily found. Deciduous shrub/tree species may also have begun to expand into areas where they did not persist historically, but the overall appearance can vary depending on the propagation method of a particular species. Seed propagated species, such as Siberian elm, tend to colonize further from the parent plant and affect larger areas, but in lower densities. In contrast, rhizomatous species such as smooth sumac tend to progress as a higher-density encroachment spreading directly from the parent plants.

Dominant plant species

little bluestem (Schizachyrium scoparium), grass
sideoats grama (Bouteloua curtipendula), grass
smooth brome (Bromus inermis), grass
Kentucky bluegrass (Poa pratensis), grass

Figure 12. Plant community growth curve (percent production by month). NE1022, Warm-season dominant, cool-season subdominant.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	2	9	19	23	24	13	7	3	0	0

Community 2.2
Codominant Smooth brome-Kentucky bluegrass (Bromus inermis-Poa pratensis)

This community is comprised of a relatively even mix of native grasses and invasive species overall. This may manifest as a well-distributed interspersion of natives and invaders, as distinct patches wherein the competitors dominate locally, or some combination. Forb diversity and abundance is further diminished.

Dominant plant species

smooth brome (Bromus inermis), grass
little bluestem (Schizachyrium scoparium), grass
Kentucky bluegrass (Poa pratensis), grass
sideoats grama (Bouteloua curtipendula), grass

Figure 13. Plant community growth curve (percent production by month). NE1023, Warm-season, cool-season codominant.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	3	10	23	26	16	10	7	4	1	0

Pathway 2.1A
Community 2.1 to 2.2

Management and/or environmental conditions have afforded a persisting competitive advantage to introduced cool-season grasses, and they begin to dominate the ecological dynamics of the site. The robust invasive component is able to quickly and effectively exploit opportunities to outcompete and displace natives. Repeated summer use of an area will place the bulk of stressor impacts on native plants, reducing native vigor and allowing invaders to thrive. Likewise, a climate pattern limiting natural moisture to the spring and fall months coincides with peak cool-season growth and may support a similar process.

Pathway 2.2A
Community 2.2 to 2.1

The native component remains in an abundance that can facilitate a return towards more historic conditions if management is modified to shift stressor impacts to the invasive species, and promote warm-season grass vigor. Environmental conditions and/or disturbance regimes that strongly favor warm-season grasses can also trend the site towards the reference.

State 3
Invasive dominant

Cool-season invasion has progressed to the point that native species comprise a negligible portion of the community and the aggressively rhizomatous invasives preclude warm-season tallgrass germination and seedling survival. The native component may be completely absent, and the site resembles a seeded pasture. Woody competitiveness for sunlight, water, space, and other resources continues to increase as desirable herbaceous species are shaded out, crowded out, or otherwise suppressed.

Dominant plant species

smooth brome (Bromus inermis), grass
Kentucky bluegrass (Poa pratensis), grass

Community 3.1
Smooth brome-Kentucky bluegrass (Bromus inermis-Poa pratensis)

Figure 14. LyO 3.1 brome w/native remnants

This community is typically composed of smooth brome with bluegrass interspersed among the brome tillers. Warm-season natives, if present, are sparse yet often conspicuous due to pronounced differences in growth habits and metabolic pathways. Community structure and function have been dramatically simplified relative to the reference condition, and very few biotic functional groups are represented in amounts that would influence ecological function. The invasive grass root skein provides good site stability; however, replacement of the deeper roots and complex bunchgrass canopy with the shallower roots and erect tiller canopy of the invaders results in reduced interception and infiltration rates.

Dominant plant species

smooth brome (Bromus inermis), grass
Kentucky bluegrass (Poa pratensis), grass

Figure 15. Plant community growth curve (percent production by month). NE1024, Cool-season. Smooth brome/Kentucky bluegrass.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	4	13	25	28	8	6	9	5	2	0

State 4
Annual/pioneer

Nutrient cycling, hydrologic function, and/or soil stability have been severely altered, and possibly compromised. This is a highly variable state in which the specific plants observed will depend largely on the original community and the nature of the disturbance. This condition encompasses (but is not necessarily limited to) events such as severe fire impacts, heavy continuous grazing, heavy nutrient inputs, and abandoned cropland.

Dominant plant species

snow on the mountain (Euphorbia marginata), other herbaceous
ragweed (Ambrosia), other herbaceous
Texas croton (Croton texensis), other herbaceous
hoary verbena (Verbena stricta), other herbaceous
nightshade (Solanum), other herbaceous
thistle (Cirsium), other herbaceous

Community 4.1
Variable native and introduced

Figure 16. LyO 4.1 overgrazed

This community is heavily dominated by annual plants that thrive in disturbed areas and often includes snow-on-the-mountain, annual ragweed, Texas croton, nightshades, and/or hoary verbena. It is also particularly vulnerable to noxious weed invasion with the most common species being plumeless, musk, and Canada thistles. Leafy spurge becomes more common northward in the MLRA.

Dominant plant species

snow on the mountain (Euphorbia marginata), other herbaceous
ragweed (Ambrosia), other herbaceous
Texas croton (Croton texensis), other herbaceous
nightshade (Solanum), other herbaceous
hoary verbena (Verbena stricta), other herbaceous
thistle (Cirsium), other herbaceous

State 5
Deciduous overstory

Under historic disturbance regimes, frequent and uncontrolled fire and wildlife browsing served to keep woody species in check. However, in the absence of fire (either wild or prescribed), it's not uncommon for the woody trees and shrubs normally limited to riparian areas to expand into the floodplains, regardless of herbaceous community composition.

Dominant plant species

bur oak (Quercus macrocarpa), tree
boxelder (Acer negundo), tree
green ash (Fraxinus pennsylvanica), tree
sedge (Carex), grass
waterleaf (Hydrophyllum), other herbaceous

Community 5.1
Deciduous overstory

Figure 17. LyO 5.1 boxelder overstory

Deciduous woody species have encroached and established, typically with species such as bur oak, boxelder, and green ash. Eastern redcedar is not nearly as prominent as on upland sites, but may still occur. Moister, shaded growing conditions under the tree canopy causes a dramatic shift in understory composition towards species such as sedges, Virginia waterleaf, fowl mannagrass, and smooth Solomon’s seal.

Dominant plant species

bur oak (Quercus macrocarpa), tree
boxelder (Acer negundo), tree
green ash (Fraxinus pennsylvanica), tree
sedge (Carex), grass
waterleaf (Hydrophyllum), other herbaceous

Transition T1A
State 1 to 2

In the presence of introduced cool-season grasses, environmental conditions and/or management that reduces native vigor and stand resilience, and frees up resources (space, sunlight, nutrients, water) will allow for colonization of Kentucky bluegrass and smooth brome. Likewise, similar processes may also allow for deciduous woody shrubs and trees such as smooth sumac, roughleaf dogwood, and Siberian elm to expand.

Transition T1B
State 1 to 4

There are many possible triggers for this transition that may occur as acute events (e.g. plowing) or cumulative impacts of chronic events (e.g. long-term undermanaged grazing.) The absence of deep-rooted perennial cover exposes the site to topsoil loss, open nutrient cycle, and free space which collectively allow for opportunistic annual species to dominate.

Transition T1C
State 1 to 5

The presence of an invasion source coupled with fire exclusion allows cedar seeds to germinate and establish within the herbaceous stand. This typically begins near fencerows, woody draws, etc, and accelerates outward as propagules increase. Lack of intervening action allows cedar expansion to continue, and tree sizes to increase. Cedar will eventually modify site function in ways that promote further encroachment such as rainfall interception and stemflow, heavy duff litter, and shading of the herbaceous understory.

Restoration pathway R2A
State 2 to 1

Eradication of introduced cool-season grasses from this site will require long-term, targeted management efforts to create an adverse environment during the spring and late fall when bluegrass and brome are most actively growing, with favorable conditions during the summer to promote native warm-season species. Targeted practices such as prescribed burning, flash grazing, and herbicide are often employed at strategic times of the year to set back undesirable species. The combination of practices should strive to mimic the historic disturbance regimes to which the desirable native species are best adapted.

Transition T2A
State 2 to 3

If the conditions which initiated and fomented the colonization and expansion of cool-season invasion are not removed or mitigated, stand composition will continue to shift in this direction and begin to resemble a monoculture of bluegrass and/or brome. Due to the dense rhizomatous root mat of brome and bluegrass, native species suffer decreasing opportunities to contribute propagules, and individual plants lost are not replaced by desirable natives.

Transition T2B
State 2 to 4

Transition T2C
State 2 to 5

The presence of an invasion source coupled with fire exclusion allows woody species to establish. This typically begins near fencerows, woody draws, etc, and accelerates outward as propagules increase. Lack of intervening action allows woody species expansion to continue, and tree sizes to increase.

Transition T3A
State 3 to 2

Aggressive intervening actions will be required to simultaneously recolonize native grasses and suppress vigor in undesirable species. Restoration follows the same principles as the R2A pathway, but may also require native range seeding if the latent seedbank is inadequate.

Transition T3B
State 3 to 4

Transition T3A
State 3 to 5

Transition R4A
State 4 to 1

With favorable weather and site stability, it may take just a few years for the site to naturally return to a perennial community. Range seeding can “jump start” the recolonization of desirable species and may re-establish a near reference grass community; although, forb diversity may take longer to recover. Depending on the nature of the disturbance(s), additional ameliorative efforts may be necessary to mitigate accelerated erosion and weedy competition until the seeded perennial community has stabilized. It is possible for a disturbance and/or subsequent processes (e.g. accelerated erosion) to profoundly, and even permanently, alter fundamental soil properties in such a way that the site may never again exhibit its historic structure or function without extraordinary restoration inputs.

Restoration pathway R5A
State 5 to 1

Tree mortality is required to restore a grassland state, however the herbaceous response will depend on many factors such as method(s) used, mortality rates, and the remnant herbaceous species. Mechanical and chemical methods can remove cedars but will have little if any notable impact on the herbs. Reintroducing the historic fire regime will provide the most profound and beneficial effects, and seasonal timing and burn intensity can have significant influence on the herbaceous outcome. As a general rule, hot spring burns will not only kill trees but also stress shallower-rooted invasive cool-season grasses and promote a ahift in favor of the reference community.

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Grass/Grasslike
1	Tall warm-season			2560–2880
	big bluestem	ANGE	Andropogon gerardii	640–1120	–
	switchgrass	PAVI2	Panicum virgatum	160–480	–
	Indiangrass	SONU2	Sorghastrum nutans	160–320	–
	composite dropseed	SPCO16	Sporobolus compositus	0–175	–
2	Mid warm-season			480–960
	little bluestem	SCSC	Schizachyrium scoparium	320–640	–
	sideoats grama	BOCU	Bouteloua curtipendula	160–320	–
3	Cool-season			160–640
	western wheatgrass	PASM	Pascopyrum smithii	160–640	–
	Scribner's rosette grass	DIOLS	Dichanthelium oligosanthes var. scribnerianum	0–160	–
	Canada wildrye	ELCA4	Elymus canadensis	0–160	–
	prairie Junegrass	KOMA	Koeleria macrantha	0–160	–
4	Grass-like			160–320
	sedge	CAREX	Carex	160–320	–
Forb
5	Forb			160–320
	meadow garlic	ALCA3	Allium canadense	0–96	–
	Cuman ragweed	AMPS	Ambrosia psilostachya	0–96	–
	white sagebrush	ARLU	Artemisia ludoviciana	0–96	–
	false boneset	BREU	Brickellia eupatorioides	0–96	–
	purple poppymallow	CAIN2	Callirhoe involucrata	0–96	–
	purple prairie clover	DAPU5	Dalea purpurea	0–96	–
	Illinois ticktrefoil	DEIL2	Desmodium illinoense	0–96	–
	dotted blazing star	LIPU	Liatris punctata	0–96	–
	silverleaf Indian breadroot	PEAR6	Pediomelum argophyllum	0–96	–
	blackeyed Susan	RUHI2	Rudbeckia hirta	0–96	–
	Missouri goldenrod	SOMI2	Solidago missouriensis	35–96	–
	white heath aster	SYER	Symphyotrichum ericoides	0–96	–
	Baldwin's ironweed	VEBA	Vernonia baldwinii	0–96	–
	hoary verbena	VEST	Verbena stricta	0–96	–
Shrub/Vine
7	Shrubs			0–160
	Shrub (>.5m)	2SHRUB	Shrub (>.5m)	0–160	–
	leadplant	AMCA6	Amorpha canescens	0–160	–
	prairie rose	ROAR3	Rosa arkansana	0–160	–
	western snowberry	SYOC	Symphoricarpos occidentalis	0–160	–
	eastern poison ivy	TORA2	Toxicodendron radicans	0–160	–

Interpretations

Animal community

This site is well adapted to managed grazing by domestic livestock. The predominance of herbaceous plants across all plant community phases best lends these sites to grazing by cattle but browsing livestock such as goats or sheep that will more heavily utilize invasive forbs and brush. Carrying capacity and production estimates are conservative estimates that should be used only as guidelines in initial stages of grazing lands planning.

Often, the plant community does not entirely match any particular plant community (as described in the ecological site description). Because of this, a resource inventory is necessary to document plant composition and production. Proper interpretation of this inventory data will permit the establishment of a safe, initial stocking rate for the type and class of animals and level of grazing management. 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:

- 1.1 Big bluestem-Little bluestem; 3200 lbs/acre production and 0.88 AUM/acre

- 1.2 Sideoats grama-Composite dropseed; 2600 lbs/acre production and 0.71 AUM/acre

- 2.1 Subdominant smooth brome-KY bluegrass; 2500 lbs/acre production and 0.69 AUM/acre

- 2.2 Codominant smooth brome-KY bluegrass; 2350 lbs/ac and 0.64 AUM/acre with 50% or more introduced cool-season component

- 3.1 Smooth brome-KY bluegrass; 2400 lbs/ac and .66 AUM/ac, unfertilized, non-irrigated naturalized community. Refer to Forage Suitability Groups for cool-season pasture under a higher management level.

*Carrying capacity based on continuous season-long grazing by cattle under average growing conditions, 25% harvest efficiency. Air dry forage requirements based on 3% of animal body weight, or 912 lbs/AU/month.

If grazing 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. Utilizing a rotational grazing system that allows for adequate rest and recovery will increase plant vigor and carrying capacity. 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.

Supporting information

Inventory data references

Primary author: Greg Clark (Greg.Clark@usda.gov) Soil Survey Office Leader, USDA-NRCS, Stanton NE

Information presented here has been derived from RANGE-417 archives, Rangeland NRI, and other inventory data. Field observations from range-trained personnel were also used. In addition to the multitude of NRCS field office employees and private landowners that helped with site visits and local knowledge, those involved in developing this site include:

Nebraska NRCS:
Nadine Bishop, State Rangeland Management Specialist
Patrick Cowsert, Resource Soil Scientist
Cassidy Gerdes, Biologist
Dirk Schultz, Soil Conservationist
Dan Shurtliff, Asst State Soil Scientist

South Dakota NRCS:
Stan Boltz, State Rangeland Management Specialist
Shane Deranleau, Area Rangeland Management Specialist
Kevin Luebke, State Biologist

Iowa NRCS:
Jess Jackson, Area Grazing Specialist

Minnesota NRCS:
Lance Smith, Area Grazing Specialist

MLRA Office 10:
Stu McFarland, Ecological Site Inventory Specialist, QC
Stacey Clark, Ecological Site Inventory Specialist, QA
Michael Whited, Soil Data Quality Specialist
Jo Parsley, Soil Scientist/10-3 MSSO Leader

National Soil Survey Center:
Mike Kucera, National Agronomist, Soil Quality & Ecosystems
Steve Peaslee, GIS Specialist, Soil Survey Interpretations

Nebraska Game & Parks Commission:
Gerry Steinauer, Botanist
Scott Wessel, Biologist
Russ Hamer, Biologist
Rebekah Jessen, Biologist

Nebraska Forest Service:
Steve Rasmussen, District Forester

Other references

Bestelmeyer, Brandon, et al. 2010. Practical Guidance for Developing State-and-transition Models. Rangelands 32:6 pp 2-64. Wheat Ridge, CO: Society for Range Management.

Fenneman, Nevin M. 1916. Physiographic Subdivision of the United States. Annals of the Association of American Geographers.

Helzer, Chris. 2010. The Ecology and Management of Prairies in the Central U.S. Iowa City, IA: University of Iowa Press/The Nature Conservancy.

Kaul, Robert B., David Sutherland, and Steven Rolfsmeier. 2006. The Flora of Nebraska. Lincoln, NE: University of Nebraska – Lincoln (Conservation and Survey Division, School of Natural Resources.)

NOAA/UNL – High Plains Regional Climate Center. Historical Data Summaries: http://www.hprcc.unl.edu/data/historical/

Omernik, J.M. 1997. Ecoregions of the Conterminous United States. Annals of the Association of American Geographers, v.77, no. 1, p.118-125.

Steinauer, Gerry and Steve Rolfsmeier. 2010. Terrestrial Ecological Systems and Natural Communities of Nebraska. Lincoln, NE: Nebraska Natural Heritage Program and Nebraska Game and Parks Commission.

USDA/USFS. 2007. Ecological Subregions: Sections and Subsections for the Conterminous United States. Washington, DC: USDA - Forest Service.

USDA/SCS. 1977. Rangeland Resources of Nebraska. Lincoln, NE: Society for Range Management. USDA/NRCS. 2011. ESD User Guide. Fort Worth, TX: Central National Technology Support Center.

USDA/NRCS 2006. Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.

USDA/NRCS. 2012. Field Office Technical Guide (Nebraska, Natural Resources Information, Statewide Soil and Site Information, Rangeland Interpretations, Nebraska Range Site Descriptions – Vegetative Zones 3 and 4), U.S. Department of Agriculture, Natural Resources Conservation Service, Nebraska Ecological Sciences.

Contributors

Greg Clark (Greg.Clark@usda.gov) Soil Survey Office Leader, USDA-NRCS, Stanton NE
Stu McFarland

Approval

Suzanne Mayne-Kinney, 12/10/2024

Rangeland health reference sheet

Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.

Author(s)/participant(s)	Original Authors: Stu McFarland, Nadine Bishop (8/1/2013) Revision Authors: Nadine Bishop, Emily Helms, Jeff Nichols
Contact for lead author	jeffrey.nichols@usda.gov
Date	12/04/2024
Approved by	Suzanne Mayne-Kinney
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
None. Rills are not expected on this site.
Presence of water flow patterns:
None. Water flow patterns are not expected on this site.
Number and height of erosional pedestals or terracettes:
None. Pedestals and terracettes are not expected to occur on this site.
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground is 5 percent or less.

Bare ground is exposed mineral soil that is not covered by vegetation (basal and/or foliar canopy), litter, standing dead vegetation, gravel/rock, and visible biological curst (e.g., lichen, mosses, algae).
Number of gullies and erosion associated with gullies:
None. Gullies are not expected on this site.
Extent of wind scoured, blowouts and/or depositional areas:
None. Wind-scoured and/or depositional areas should not be present.
Amount of litter movement (describe size and distance expected to travel):
Litter of small and medium size classes will move after average to high rainfall events. Litter does not travel far, typically being trapped in small bunches by the extensive vegetative cover. Litter movement may be fairly excessive after major runoff or flooding events. Small woody debris may move up to 6 inches (15 cm). Fine litter may move up to 12 inches (30.5 cm). Numerous debris dams or vegetative barriers may be present.
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil stability ratings will be 5 to 6, typically 6. Surface organic matter adheres to the soil surface. Soil surface fragments will typically retain structure indefinitely when dipped in distilled water.
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
The thickness of the A-horizon is highly variable depending upon soil series and ranges from 6 to 51 inches (15 to 130 cm) thick. Soil surface color ranges from grayish brown, very dark gray to dark gray (hue: 10 YR, value: 3, 4 or 5, chroma: 1 or 2) when dry and black, very dark grayish brown, or very dark brown, (hue: 10 YR, value: 2 or 3, chroma: 1 or 2) when moist.

Soil structure in the A-horizon varies significantly with soil series from weak fine or weak medium fine granular, moderate fine or moderate fine and medium or weak fine subangular blocky, weak fine and medium subangular blocky, weak fine or weak and medium subangular blocky parting to weak fine granular, to moderate fine or moderate medium prismatic structure parting to moderate fine subangular blocky.

See Official Soil Description for more information. The primary soils series assigned to this site include Aowa, Blyburg, Bon, Hobbs, Janude, Kenebec, McPaul, Nodaway, Roxbury, and Shell.
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Plant community composition is approximately 85 to 95 percent grasses or grass-like plants, 5 to 10 percent forbs, and 0-5 percent shrubs and trees which optimizes infiltration on the site. The grass and grass-like component is composed of warm-season (C4), tallgrass, warm-season (C4), midgrass, cool-season (C3) grasses, and grass-likes (5-10%). The functional/structural groups provide a combination of rooting depths and structure which positively influences infiltration.

Invasion of introduced cool-season grasses such as Kentucky bluegrass and smooth brome may have an adverse impact infiltration and runoff. Tree encroachment may also negatively impact infiltration and runoff.
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None. No compaction layers are expected on this site. Some soil have a platy structure in the surface which could be confused with a compaction layer.
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):

Dominant:
Phase 1.1
1. Native, perennial, warm-season tallgrass, 2560-2880, 80-90%(3 species minimum): big bluestem, Indiangrass, switchgrass, composite dropseed.
2. Native, perennial, warm-season, midgrass, 480-960, 15-30%, (2 species minimum): Little bluestem, sideoats grama.

Phase 1.2
1. Native, perennial, warm-season, midgrass (2 species minimum): Little bluestem, sideoats grama.

Sub-dominant:
Phase 1.1
1. Native, perennial, cool-season grass, 160-640 #/ac, 5-20% (2 species minimum): western wheatgrass, Canada wildrye, Scribner’s rosettegrass, prairie Junegrass.

Phase 1.2
1. Native, perennial, cool-season bunchgrass (2 species minimum): Needle and thread, porcupinegrass, green needlegrass, Canada wildrye, Scribner’s rosettegrass, fall rosettegrass, prairie Junegrass.
2. Native, perennial, warm-season, shortgrass (1 species minimum): Blue grama, buffalograss, hairy grama, threeawn.
3. Native, perennial, cool-season, rhizomatous grass (1 species minimum): western wheatgrass.

Other:
Minor - Phase 1.1
1. Grass-likes, 160-320 #/ac, 5-10%: sedges.
2. Forbs, 160-320 #/ac, 5-10%: forbs present will vary from location to location.
3. Shrubs, 0-160 #/ac, 0-5%: shrubs present will vary from location to location.

Minor - Phase 1.2
1. Native, perennial, warm-season tallgrass: big bluestem, Indiangrass, switchgrass, composite dropseed.
2. Forbs: forbs present will vary from location to location.
3. Grass-likes: sedges.
4. Shrubs: shrubs present will vary from location to location.

Additional:
The Big Bluestem-Sideoats Grama or Reference Community (1.1) includes nine F/S groups which include in order of relative abundance, native, perennial, warm-season (C4) tallgrass; native, perennial, warm-season (C4) midgrass; native, perennial, cool-season (C3) grass; grass-likes; native forbs ;shrubs; and native trees.

The Little Bluestem-Sideoats Grama Community (1.2) includes six F/S groups which include in order of relative abundance, native, perennial, warm-season (C4) midgrass; native, perennial, cool-season (C3) grass; native, perennial, warm-season (C4) tallgrass; native forbs; grass-likes; and shrubs.
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Bunchgrasses have strong, healthy centers with few (less than 3 percent) dead centers. Shrubs may show some dead branches (less than 5 percent) as plants age.
Average percent litter cover (%) and depth ( in):
Plant litter cover is evenly distributed throughout the site and is expected to be 75 to 85 percent and at a depth of 0.50 to 1.0 inch (1.3-2.6 cm). Kentucky bluegrass excessive litter can negatively impact the functionality of this site.
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
The representative value (RV) for annual production is 3,200 pounds per acre in a year with normal precipitation and temperatures. Low and High production years should yield 2,655 and 3,745 pounds per acre respectively.
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
No non-native invasive species are present. Annual bromes (cheatgrass and Japanese/field), leafy spurge, Canada thistle, musk thistle, plumeless thistle, spotted and diffuse knapweed, absinth wormwood, sulfur cinquefoil, perennial sow thistle, Kentucky bluegrass, smooth brome, roughleaf dogwood, buckbrush, smooth sumac, eastern redcedar, and autumn olive are known invasives that have the potential to become dominant or co-dominant on the site. Note: species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants.
Perennial plant reproductive capability:
All perennial species exhibit high vigor relative to climatic conditions. Perennial grasses should have vigorous rhizomes or tillers; vegetative and reproductive structures are not stunted. All perennial species should be capable of reproducing annually.

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Ecosystem states

3. Invasive dominant

4. Annual/pioneer

States 1, 5 and 2 (additional transitions)