Habitat Description

Habitat Crosswalk

Sample and Mossman: Idle Warm-season Grasses and Forbs (Sample and Mossman 1997).
Vegetation of Wisconsin: N/A (Curtis 1971).
Wisconsin Department of Natural Resources Natural Communities: Surrogate Grasslands (WDNR 2005).

Introduction

Despite some similarity to prairies, Idle Warm-season Grasses and Forbs habitats are considered surrogate grasslands rather than a native prairie community. They often occur on agricultural lands that are taken out of production and idled for extended periods of time. Examples include retired hayfields and pastures, grasslands planted for wildlife habitat on public lands, and agricultural fields that are retired through the Conservation Reserve Program (CRP) or other set-aside programs (Sample and Mossman 1997, McCoy et al. 2001b, WDNR 2005). These programs encourage landowners to convert highly erodible cropland to long-term vegetative cover, such as warm- or cool-season grasses. Warm-season mixes grow best during the summer and tend to be taller and denser than cool-season mixes. They are composed of native grasses such as switchgrass, big blue-stem, yellow Indian grass, little blue-stem, and side-oats grama. Some stands also have a substantial native forb component and may include purple prairie-clover, black-eyed Susan, and blazing-star. Recently planted fields can have an abundance of annual weeds and bare ground but typically mature to a dense cover of grass with a substantial litter layer if left undisturbed (McCoy et al. 2001a). Idled grasslands are always undisturbed during the nesting season but can remain unmanaged for many years.

Historical and Present-day Context and Distribution

During the nineteenth century, diverse prairie communities in Wisconsin were largely eliminated in favor of small grains, grass hay, and permanent pastures. Although these changes destroyed or significantly altered most native grasslands, the landscape remained largely rural with small farmsteads interspersed with idled or undeveloped lands. Many birds and other wildlife adapted to these changes and used the diverse farmlands as surrogate grassland habitats (Warner 1994). By the mid-twentieth century, however, urban development increased and large farming operations began to displace the more rural land-use patterns (Sample and Mossman 1997, Sample et al. 2003, WDNR 2005). Many pastures were replaced by intensively-managed row crops, hayfields were harvested earlier and more frequently, and housing developments fragmented the landscape and created movement corridors for predators.

Changes in land use have led to a decline in the quality and quantity of grassland habitat and, most likely, fewer idled grasslands. Idled grasslands are difficult to inventory, however, because of their ephemeral nature. Lands idled one year can be back in production the following year and even lands enrolled in conservation programs are not necessarily idled (i.e., managed haying and grazing is often allowed) or protected in perpetuity. CRP contracts typically last 10-15 years with no guarantee of re-enrollment after they expire. Although there are currently 21,319 hectares of CRP fields planted to warm-season grasses in Wisconsin, this figure has declined in recent years (FSA 2006, 2008). Renewed interest in corn ethanol and other market factors have led to high corn prices, creating additional pressure on remaining CRP acres (Murray and Best 2003, Roth et al. 2005, Bies 2006). However, switchgrass may provide a more ecologically-sustainable energy source than corn because it produces more energy per unit of input (Bies 2006). In addition, staggered harvest of switchgrass results in a mixture of harvested and non-harvested fields and thus adds idled grassland habitat to the landscape (Murray and Best 2003, Roth et al. 2005, Herkert 2007).

Natural Disturbances and Threats

Idle Warm-season Grasses and Forbs habitats lack the disturbances inherent to other grassland habitats. Unlike native prairie remnants in Wisconsin, idled grasslands typically are not disturbed by prescribed fire, mowing, or herbicide spray nor are they actively grazed, hayed, or farmed. Lacking any form of disturbance, they can experience substantial changes in their structure and composition over time (Greenfield et al. 2003). For instance, idled grasslands fragmented by woodlots or other human developments are threatened by encroaching woody vegetation (Steinauer and Collins 1996, Briggs 2005). Invasive woody species such as buckthorn, hawthorn, dogwood, box elder, multiflora rose, and sumac can shade out the early-successional grassland plants and cause rapid structural changes that are unacceptable for most grassland birds (Hoffman and Sample 1988, Sample and Mossman 1997). Switchgrass is another aggressive species that can quickly crowd out other planted species if not controlled and form a tall, rank monoculture (McCoy et al. 2001a, Gill et al. 2006). Monotypic stands are devoid of structural diversity and often considered to have low wildlife value (McCoy et al. 2001b; but see Overall Importance of Habitat to Birds). Changes in agricultural practices also pose a significant threat to idled grassland habitats. Intensively-managed row crops with little wildlife value have replaced the idled pastures and hayfields used by many grassland bird species. Also, the recent shift from late-grass to alfalfa hay has reduced the amount of time between harvests and further reduced the amount of idled grasslands on the landscape (Sample and Mossman 1997).

Related WBCI Habitats: Dry-mesic Prairie, Wet-mesic Prairie, Idle Cool-season Grasses and Forbs, Fallow Field.

Overall Importance of Habitat for Birds

Several factors influence bird use of Idle Warm-season Grasses and Forbs habitats. The length of time a field has been idled will affect its suitability for certain species. Recently planted fields often contain bare ground and sparse vegetative cover and thus provide habitat for Upland Sandpiper, Horned Lark, Vesper Sparrow, Grasshopper Sparrow, Western Meadowlark, and other shortgrass species. As the fields age, litter accumulates, height-density of the herbaceous vegetation increases, and conditions become more suitable for mid to tallgrass species. Generalist species such as Sedge Wren, Common Yellowthroat, and Red-winged Blackbird are the dominant breeders in tallgrass warm-season mixes and less common nesting species include Henslow’s Sparrow, Bobolink, Eastern Meadowlark, and Dickcissel (Sample and Mossman 1997, Best et al. 1997). Although Northern Harrier is not a common breeder in any grassland habitat, it preferentially nests in undisturbed grasslands with tall, dense cover such as Idle Warm-season Grasses and Forbs (Herkert et al. 1999). Idled grasslands with scattered shrubs also can support structure-nesting species such as Loggerhead Shrike, Bell’s Vireo, Clay-colored Sparrow, and Field Sparrow.

Landscape context also influences how birds may use idled grassland habitats. Fields of Idle Warm-season Grasses and Forbs adjacent to hayfields or other disturbed lands provide secure areas for second nest attempts after mowing-induced failure (Sample and Mossman 1997). Also, small idled fields located in close proximity to other extensive grassland areas increase the overall size and heterogeneity of the surrounding landscape and thus improve conditions for species requiring large grassland patches. Area-sensitive species such as Northern Harrier, Short-eared Owl, and Greater Prairie-Chicken readily nest, forage, and roost in small patches of idled grassland that are embedded within a high-grassland landscape (Sample and Mossman 1997, Herkert et al. 1999). Other species such as Northern Bobwhite and Ring-necked Pheasant rely on the residual cover of idled grasslands during winter months, emphasizing the importance of these habitats at all times of the annual cycle (Walk 1998, Brennan 1999). The plant composition of idled grasslands is less influential on bird use since both cool-season and warm-season stands can provide suitable structure. Some monotypic warm-season stands can become too tall or too dense for most grassland birds; however, there may be specific cases where monotypic stands are warranted (Walk 1998, Herkert et al. 1999). Priority species such as Sedge Wren and Henslow’s Sparrow prefer the high litter layer and dense cover provided by monotypic grass plantings. Switchgrass, in particular, produces more biomass per area than other native grass species and often dominates warm-season planting mixes (Murray and Best 2003).

Priority Birds

Species	Status	Habitat and/or Special Habitat Features
Mallard	b	If appropriate open water for breeding pairs and broods is available nearby.
Blue-winged Teal	b	If appropriate open water for breeding pairs and broods is available nearby.
Sharp-tailed Grouse	b, w	Occurs in idled grassland habitats within high-grass landscapes.
Greater Prairie-Chicken	b, w	Occurs in idled grassland habitats within high-grass landscapes.
Northern Bobwhite	b, w	Requires brushy areas adjacent to idled grasslands.
Northern Harrier	b, m	May occur in idled grasslands embedded within a large, grassland-dominated area.
Upland Sandpiper	b, m	Occurs in high-grass landscapes with some drier ridges and hummocks.
Barn Owl	f	Very rare resident in southern and central Wisconsin.
Short-eared Owl	b, m, w	May occur in idled grasslands embedded within a large, grassland-dominated area.
Willow Flycatcher	b, m	Requires a shrub component.
Sedge Wren	B, M	Prefers dense herbaceous cover dominated by grasses or sedges and thick litter layer.
Loggerhead Shrike	b, m	Requires a shrub component.
Bell’s Vireo	b, m	Requires a shrub component.
Brown Thrasher	b, m	Requires a shrub component.
Common Yellowthroat	B, M	Prefers tall, dense herbaceous cover and/or a shrub component.
Clay-colored Sparrow	b, m	Requires a shrub component.
Field Sparrow	b, m	Requires a shrub component.
Vesper Sparrow	b, m	Prefers areas with short, sparse vegetation and some bare ground.
Grasshopper Sparrow	b, m	Prefers relatively short, patchy vegetation.
Henslow’s Sparrow	b, m	Prefers tall, dense herbaceous cover that is grass-dominated with a substantial component of residual vegetation.
LeConte’s Sparrow	b, m
Dickcissel	b, m	Prefers sites with a thick-stemmed forb component.
Bobolink	B, M
Eastern Meadowlark	B, M
Western Meadowlark	b, m	Prefers relatively short vegetation and <5% woody cover.

Objectives

• Buffer idled grasslands with other grassland habitats.
• Protect, maintain, and restore 383,000 hectares of grassland habitat in Wisconsin to sustain regional breeding populations of grassland birds (Potter et al. 2007).
• Increase public awareness of the conservation values of surrogate grassland habitats.

Management Recommendations

Landscape-level Recommendations

1. Support state and federal programs that manage, enhance, or restore grassland habitats on private lands. Develop cooperative agreements with private landowners to prevent habitat fragmentation and conversion in areas critical for grassland bird conservation.
2. Determine what scale of landscape management is possible in an area: medium (400-2,000 hectares) or large (>4,000 hectares). Consider developing a grassland Bird Conservation Area in appropriate landscapes (see Fitzgerald and Pashley 2000).
3. Increase inter- and intra-agency coordination to maximize benefits of grassland conservation projects.
4. Develop a digital layer of high-grassland landscapes to focus restoration and conservation efforts. Discourage extensive tree planting within these landscapes to improve the long-term viability of obligate grassland birds.
5. Partner with the agricultural community to ensure rural working landscapes with high amounts of open space suitable for birds and other wildlife.
6. Encourage longer contracts for short-term set-aside programs (>3 years). Enforce guidelines that cover is planted and managed appropriately (Warner et al. 2000).
7. Develop planning maps to guide placement of biomass switchgrass fields to landscapes where they add to the habitat base rather than replace existing habitat. Target areas in the state that were grasslands in presettlement times (Sample and Mossman 1997, Quamen 2007). 

Site-level Recommendations

8. Include grasses of varying heights in seed mixes to promote a variety of height and density among fields, including short native grasses such as little bluestem, side-oats grama, and prairie dropseed (Sample and Mossman 1997).
9. Reduce grass seeding rates by up to 50% (3-5 lb per acre for warm-season grasses) to reduce vegetation density and to encourage forbs (Sample and Mossman 1997).
10. Include enough forb seeds in mixes to result in at least 10% forb cover. In most cases, 10,000-20,000 forb seeds per acre should produce a noticeable forb component (Sample and Mossman 1997).
11. Enroll whole fields into conservation programs to avoid linear-shaped fields with high edge:interior ratios (Sample and Mossman 1997).
12. Remove linear woody features such as hedgerows and woody fencelines as well as woodlots to improve site suitability for obligate grassland birds. Low density, scattered shrubs are acceptable and even required by some grassland birds such as Willow Flycatcher, Bell’s Vireo, and Brown Thrasher (Sample et al. 2003, WDNR 2005, Kost et al. 2007).
13. Develop property-specific plans to control invasive species on idled grasslands, such as common and glossy buckthorn and box elder.

Ecological Opportunities

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Ecological Landscape	Opportunity	Management Recommendations
Central Sand Hills	Major	All
Central Sand Plains	Major	All
Southeast Glacial Plains	Major	All
Southwest Savanna	Major	All
Western Coulee and Ridges	Major	All
Western Prairie	Major	All
Northwest Sands	Important	All
Central Lake Michigan Coastal	Present	All
Forest Transition	Present	All
Northern Lake Michigan Coastal	Present	All
Southern Lake Michigan Coastal	Present	All
Superior Coastal Plain	Present	All

Research Needs

• Investigate how differences in CRP plot size and placement in agricultural-grassland landscapes contribute to differences in nesting productivity (Best et al. 1997, McIntyre and Thompson 2003).
• Compare nesting productivity on CRP lands to native prairie remnants (McIntyre and Thompson 2003).
• Evaluate nest success and long-term population dynamics of species nesting in harvested switchgrass fields to determine whether they can support stable populations of grassland birds (Murray and Best 2003).
• Investigate adverse impacts of toxic chemicals to grassland birds nesting in or adjacent to agricultural fields (Vickery et al. 1999). 

Implementation

Key Sites

• Buena Vista/Leola State Wildlife Areas (Adams, Portage Cos.)
• Crex Meadows State Wildlife Area (Burnett Co.)
• Fish Lake Wetlands and Barrens (Burnett Co.)
• George W. Mead Wildlife Area (Marathon, Portage, Wood Cos.)
• Greenwood State Wildlife Area (Waushara Co.)
• Military Ridge Prairie Heritage Area (Dane, Iowa Cos.)
• Muralt Bluff Prairie State Natural Area (Green Co.)
• Richard Bong State Recreation Area (Kenosha Co.)
• Thomson Memorial Prairie (Dane, Iowa Cos.)
• White River Marsh State Wildlife Management Area (Green Lake Co.)
• Yellowstone Savanna State Natural Area (Lafayette Co.)

Key Partners

• Farm Service Agency: http://www.fsa.usda.gov/
• Invasive Plants Association of Wisconsin: http://www.ipaw.org/
• Natural Resources Conservation Service (NRCS): http://www.nrcs.usda.gov/
• U.S. Fish and Wildlife Service: http://www.fws.gov/
• Wisconsin Department of Natural Resources: http://www.dnr.state.wi.us/ 

Funding Sources

• Farm Bill Programs: http://www.nrcs.usda.gov/programs/
• Knowles-Nelson Stewardship Program: http://dnr.wi.gov/stewardship/
• Landowner Incentive Program: http://dnr.wi.gov/org/land/er/wlip/index.htm
• Partners for Wildlife Program (PFW): http://www.fws.gov/midwest/WisconsinPartners/index.htm 

Information Sources

• Czarpata, E.J. 2005. Invasive plants of the Upper Midwest. University of Wisconsin Press, Madison, WI. 215 pp.
• Effects of management practices on grassland birds: http://www.npwrc.usgs.gov/resource/literatr/grasbird/index.htm
• Grassland Management and Restoration for Breeding Birds: An Annotated Bibliography: http://www.npwrc.usgs.gov/resource/literatr/birdbibl/index.htm
• Habitat Establishment, Enhancement and Management for Forest and Grassland Birds in Illinois: http://www.npwrc.usgs.gov/resource/birds/manbook/index.htm
• Managing Habitat for Grassland Birds: A Guide for Wisconsin: http://www.npwrc.usgs.gov/resource/birds/wiscbird/
• Managing Small Grasslands for Grassland Birds: http://www.massaudubon.org/Birds_&_Beyond/grassland/small.php
• Managing Large Grasslands for Grassland Birds: http://www.massaudubon.org/Birds_&_Beyond/grassland/large.php
• Management of Midwestern Landscapes for the Conservation of Neotropical Migratory Birds: http://ncrs.fs.fed.us/pubs/viewpub.asp?key=251
• NRCS Grassland Bird Leaflet: http://www.mn.nrcs.usda.gov/technical/ecs/wild/gnb.pdf
• Reserve Design for Grasslands - consideration for bird populations: http://www.npwrc.usgs.gov/resource/birds/desgrs/ref.htm
• Restoring and Maintaining Grasslands for Wildlife: http://dnr.wi.gov/org/land/wildlife/publ/homeonrange.pdf
• Wetter, W.A., T.S. Cochrane, M.R. Black, H.H. Iltis, and P.A. Berry. 2001. Checklist of the vascular plants of Wisconsin. Technical Bulletin 192.
• Wisconsin State Herbarium: http://www.botany.wisc.edu/herbarium/ 

References

• Best, L.B., H. Campa, III, K.E. Kemp, R.J. Robel, M.R. Ryan, J.A. Savidge, H.P. Weeks, Jr., and S.R. Winterstein. 1997. Bird abundance and nesting in CRP fields and cropland in the Midwest: a regional approach. Wildlife Society Bulletin 25(4): 864-877.
• Bies, L. 2006. The biofuels explosion: Is green energy good for wildlife? Wildlife Society Bulletin 34(4): 1203–1205.
• Brennan, L.A. 1999. Northern Bobwhite (Colinus virginianus). In the Birds of North America, No. 397 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
• Curtis, J.T. 1971. The vegetation of Wisconsin: an ordination of plant communities. Univ. of Wisconsin Press, Madison, WI.
• Farm Services Agency (FSA). 2006. Conservation Reserve Program: summary and enrollment statistics FY 2006: http://www.fsa.usda.gov/Internet/FSA_File/06rpt.pdf
• Farm Services Agency (FSA). 2008. Conservation Reserve Program monthly summary February 2008: http://www.fsa.usda.gov/Internet/FSA_File/feb2008.pdf
• Fitzgerald, J.A. and D.N. Pashley. 2000. Partners in Flight bird conservation plan for the Dissected Till Plains (physiographic area 32). Jefferson City, MO: Missouri Department of Conservation. 55pp.
• Gill, D.E., P. Blank, J. Parks, J.B. Guerard, B. Lohr, E.Schwartzman, J.G. Gruber, G. Dodge, C.A. Rewa, and H.F. Sears. 2006. Plants and breeding bird response on a managed Conservation Reserve Program grassland in Maryland. Wildlife Society Bulletin 34(4): 944-956.
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• Herkert, J.R. 2007. Conservation Reserve Program benefits on Henslow’s Sparrows within the United States. The Journal of Wildlife Management 71(8): 2749-2751.
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• Kost, M.A., D.A. Albert, J.G. Cohen, B.S. Slaughter, R.K. Schillo, C.R. Weber, and K.A. Chapman. 2007. Natural Communities of Michigan: Classification and Description. Michigan Natural Features Inventory, Report No. 2007-21, Lansing, MI.
• McCoy, T.D., M.R. Ryan, L.W. Burger, and E.W. Kurzejeski. 2001a. Grassland bird conservation: CP1 vs. CP2 plantings in Conservation Reserve Program fields in Missouri. American Midland Naturalist 145: 1–17.
• McCoy, T.D., E.W. Kurzejeski, L.W. Burger, and M.R. Ryan. 2001b. Effects of conservation practice, mowing, and temporal changes on vegetation structure on CRP fields in northern Missouri. Wildlife Society Bulletin 29(3): 979-987.
• McIntyre, N.E. and T.R. Thompson. 2003. A comparison of Conservation Reserve Program habitat plantings with respect to arthropod prey for grassland birds. American Midland Naturalist 150: 291–301.
• Murray, L.D. and L.B. Best. 2003. Short-term bird response to harvesting switchgrass for biomass in Iowa. Journal of Wildlife Management 67(3): 611-621.
• Quamen, F.R. 2007. A landscape approach to grassland bird conservation in the Prairie Pothole Region of the northern Great Plains. Ph.D. Dissertation, University of Montana, Missoula, MT. 150 pp.
• Potter, B.A., G.J. Soulliere, D.N. Ewert, M.G. Knutson, W.E. Thogmartin, J.S. Castrale, and M.J. Roell. 2007. Upper Mississippi River and Great Lakes Region Joint Venture Landbird Habitat Conservation Strategy. U.S. Fish and Wildlife Service, Fort Snelling, MN. 124pp.
• Roth, A.M., D.W. Sample, C.A. Ribic, L. Paine, D.J. Undersander, and G.A. Bartelt. 2005. Grassland bird response to harvesting switchgrass as a biomass energy crop. Biomass and Bioenergy 28: 490-498.
• Sample, D.W. and M.J. Mossman. 1997. Managing habitat for grassland birds: a guide for Wisconsin. Bureau of Integrated Science Services, Department of Natural Resources, Madison, WI.
• Sample, D.W., C.A. Ribic, and R.B. Renfrew. 2003. Linking landscape management with the conservation of grassland birds in Wisconsin In Landscape ecology and resource management: linking theory with practice (J. A. Bissonette and I. Storch, eds.). Island Press, Washington, D.C., pp. 359-385.
• Vickery, P.D., P.L. Tubaro, J.M. Cardosa Da Silva, B.G. Peterjohn, J.R. Herkert, and R.B. Cavalcanti. 1999. Conservation of grassland birds in the Western Hemisphere. Studies in Avian Biology 19: 2-26.
• Walk, J.W. 1998. Winter roost sites of Northern Harriers and Short-eared Owls on Illinois grasslands. Journal of Raptor Research 32(2): 116-119.
• Warner, R.E. 1994. Agricultural land use and grassland habitat in Illinois: Future shock for midwestern birds? Conservation Biology 8(1): 147-156.
• Warner, R.E., S.L. Etter, L.M. David, and P.C. Mankin. 2000. Annual set-aside programs: a long-term perspective of habitat quality in Illinois and the Midwest. Wildlife Society Bulletin 28(2): 347-354.
• Wisconsin Department of Natural Resources (WDNR). 2005. Wisconsin’s Strategy for Wildlife Species of Greatest Conservation Need. Madison, WI. 

Contact Information

• Author: Kim Kreitinger, K.Kreitinger@gmail.com