Habitat Description

Habitat Crosswalk

Sample and Mossman: Row Crops (Sample and Mossman 1997).
Vegetation of Wisconsin: N/A (Curtis 1971).
Wisconsin Department of Natural Resources Natural Communities: Surrogate Grasslands (WDNR 2005).

Introduction

The Row Crop community represents agricultural land planted to corn and soybeans. Conventionally managed row crop fields are highly-specialized, chemical-intensive farming systems designed to maximize crop output (Smith et al. 2005). Throughout the year, farm machinery is used for seed bed preparation, chemical application, tillage operations, and post-harvest discing. Although these activities are designed to increase yield, fields are left barren and susceptible to soil erosion for most of the year. Repeated disturbance by farm machinery also reduces residual vegetation that provides escape cover and food resources for wildlife (Best 1986, Ryan 1986). Large amounts of pesticides and other chemicals are applied to enhance soil fertility for planted crops and prevent establishment of non-crop plants. As a result, dense, vertical plant cover develops with simplified structure, low plant and animal diversity, and limited habitat value (Rodenhouse and Best 1994, Best 2001). Growth patterns of row crop monocultures also reduce their suitability as surrogate grassland habitats. Fields are transformed from bare soil to dense, monotypic plant communities in a few months. Thus, wildlife attracted to the sparsely vegetated fields in early spring may be displaced once the canopy develops (Rodenhouse and Best 1994, Best 2001).

Historical and Present-day Context and Distribution

Since the mid-twentieth century, there have been significant changes in crop management throughout the Midwest. Advances in farm technology created a more intensive farming style designed to increase yield. Synthetic fertilizers enabled crops to be grown at higher densities and negated the need for diversified crop rotations. The development of pesticides and modern farm machinery also reduced the amount of crop diversity per individual farm (Chamberlain et al. 2000). As a result, many farms now contain monocultures of corn and soybeans instead of diversified crops such as small grains, grass hay, alfalfa, pastures, and orchards. According to the 2002 Census of Agriculture, corn and soybean monocultures now cover more than 2 million hectares in Wisconsin and constitute 56% of its harvested cropland (USDA 2002). As farming systems became more specialized, the size of agricultural fields increased and fewer areas were left uncultivated. Non-crop habitat such as grassy corridors, field borders, idled lands, and farm ponds were eliminated in favor of more corn and soybeans (Warner 1994). These changes in agricultural practices have simplified and fragmented the landscape and reduced its capacity to support wildlife populations (Best et al. 1995, Sample and Mossman 1997, Sample et al. 2003, WDNR 2005).

Renewed interest in corn ethanol and other market factors have led to high corn prices in recent years, indicating the future of row crop monocultures is strong (Bies 2006). Since a steep decline in row crop acreage is unlikely, it is important to institute measures that mitigate the adverse effects of these farming operations. Grassed waterways, contour grass strips, herbaceous field borders, filter strips, and riparian buffers are conservation buffer practices that can reduce soil erosion, diminish chemical runoff, and provide wildlife habitat (Best 1983, Smith et al. 2005). Strip intercropping systems alternate row crops, legumes, and small grains in a series of narrow strips to reduce soil erosion, diversify agriculture, improve yields, reduce pests, and potentially enhance wildlife habitat (Stallman and Best 1996). Perennial herbaceous biofuel crops may provide an economically viable and environmentally sound alternative to annual row crops through improved energy gain, improved soil conservation, reduced chemical runoff, and reduced mechanical disturbance (Paine et al. 1996, Murray and Best 2003, Roth et al. 2005).

Natural Disturbances and Threats

Seed bed preparation, mechanical and chemical weed control, tillage operations, and post-harvest discing are disturbances inherent to row crop management. The objectives of individual farms will influence which of these techniques are appropriate and thus determine the amount of disturbance a field receives. Conservation tillage is designed to leave protective amounts of crop residue on the soil surface to combat soil erosion (Best 1986, Ryan 1986). Waste grain also is retained with this practice and thus foraging opportunities for wildlife are enhanced. Conventionally-tilled fields are the most disturbed during the growing season and the least productive for wildlife throughout the year. In addition to planting and harvesting activities, conventional tillage operations require post-harvest discing to bury crop residues and pre-planting discing to prepare soils in the spring. This leaves few food resources for wintering wildlife and little residual cover for early-nesting bird species. Synthetic fertilizers and pesticides can accompany both conventional and conservation tillage operations and further diminish the habitat value of row crop fields by eliminating invertebrate prey and non-crop plants (Best et al. 1995, Pollock 2001, Boatman et al. 2004). Also, increased row crop irrigation within sandy regions (e.g., terraces along the lower Wisconsin River) threatens groundwater levels and the natural communities dependent on this water source (E. Epstein, pers. comm.).

Related WBCI Habitats: Small Grains, Fallow Field.

Overall Importance of Habitat for Birds

In some areas of Wisconsin, croplands often are the only habitats available for grassland bird populations. Row crop fields contain abundant food resources such as sprouting seeds, insect pests, and waste grains and thus are used primarily as foraging sites (Ryan 1986, Best et al. 1995). Blackbirds are major consumers of ripening grains as well as grain left on the soil surface after harvest. Waste grain also is important for staging waterfowl such as MVP Canada Goose, Tundra Swan, and Mallard and wintering game species such as Ring-necked Pheasant, Northern Bobwhite, and Wild Turkey (Sample and Mossman 1997, Krapu et al. 2004). Leftover waste grain also attracts rodents and thereby benefits Northern Harrier, Red-tailed Hawk, Rough-legged Hawk, Short-eared Owl, and other raptors that prey on small mammals. Shallowly flooded agricultural fields with short, sparse vegetation as well as plowed fields may provide alternative seasonal foraging sites for shorebirds, particularly if their traditional foraging areas (i.e. mud flats, lakeshores, and coastal areas) are flooded or otherwise unavailable (Sykes and Hunter 1978, Helmers 1992, Rottenborn 1996). Shallowly flooded soybean fields may be especially beneficial for early spring migrant shorebirds (Twedt et al. 1998). Fewer species use row crop fields as nest sites. Killdeer, Horned Lark, and Vesper Sparrow commonly nest in fields with residual cover or emerging seedlings (Sample and Mossman 1997). As the crop canopy closes, however, conditions become unsuitable for these sparse-cover specialists (Rodenhouse and Best 1983, Best 2001).

Farming operations affect birds in many ways. The amount of cultivation a row crop field receives will impact its habitat suitability. Conservation tillage operations leave surface soil and crop residue undisturbed and thus provide more abundant waste grain than conventional tillage practices (Ryan 1986, Best et al. 1995, Sample and Mossman 1997). Conservation tillage also tends to require fewer equipment passes than conventional tillage and therefore potentially reduces the number of nests destroyed by farm machinery (Ryan 1986, Stallman and Best 1986). Application of chemicals such as herbicides, pesticides, and fertilizers can reduce the availability of seeds and invertebrate prey (Best et al. 1995, Pollock 2001, Boatman et al. 2004) and cause acute or sublethal effects on birds (Koford and Best 1996). Non-chemical fertilizers, such as animal wastes, also are spread onto fields and can attract Wild Turkey and flocks of Horned Lark, Snow Buntings, Lapland Longspur, and Red-winged Blackbird (E. Epstein, pers. comm.).

Intensively farmed landscapes can be enhanced for wildlife by implementing certain conservation practices. Grassy edge communities and other non-crop herbaceous areas provide a greater abundance of food and more complex vegetation structure than adjacent row crops. Adding conservation buffers such as field borders, grassed waterways, terraces, and contour grass strips will create valuable roosting, loafing, thermal, and escape cover for a variety of bird species (Smith et al. 2005). During the winter, these habitats also provide additional seed sources that are vital to sparrows, finches, and other resident species (Rodenhouse and Best 1994, Smith et al. 2005, Conover et al. 2006). Increasing connectivity of non-crop habitats will further enhance their value to wildlife, particularly for species with limited dispersal capabilities such as Northern Bobwhite. Long-term set-aside programs such as the Conservation Reserve Programs (CRP) also provide many benefits to grassland bird populations, especially when blocks of cropland are idled rather than linear tracts and a wide variety of grass and forb species are included in the planting mix (Koford and Best 1996).

Priority Birds

Species	Status	Habitat and/or Special Habitat Features
Canada Goose (Mississippi Valley Population)	F	Forages in row crop fields with abundant waste grain.
Tundra Swan	F	Forages in row crop fields with abundant waste grain.
American Black Duck	f	Forages in row crop fields with abundant waste grain.
Mallard	F	Forages in row crop fields with abundant waste grain.
Northern Pintail	f	Forages in row crop fields with abundant waste grain.
Greater Prairie-Chicken	f	May forage in row crop fields surrounding core protected areas in central Wisconsin.
Sharp-tailed Grouse	f
Northern Bobwhite	F	Forages in row crop fields with abundant waste grain.
Northern Harrier	f	Hunts rodents in row crop fields.
Whooping Crane	f
Migratory Shorebirds	f	Use flooded fields primarily during spring migration.
Barn Owl	f	Hunts rodents in row crop fields.
Short-eared Owl	f	Hunts rodents in row crop fields.
Vesper Sparrow	B	Nests in row crop fields if appropriate crop residue is present.
Grasshopper Sparrow	f
Eastern Meadowlark	f
Western Meadowlark	f

Objectives

• Protect, maintain, and restore 383,000 hectares of grassland habitat in Wisconsin to sustain regional breeding populations of grassland birds (Potter et al. 2007).
• Buffer row crop fields with other grassland habitats within agricultural landscapes.
• Work with agricultural partners to increase the habitat quality of row crop fields.
• 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. Partner with the agricultural community to ensure rural working landscapes with high amounts of open space suitable for birds and other wildlife.
3. 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). 

Site-level Recommendations

4. Identify excess fields, fields with highly erodible soils, and marginal agricultural land to enroll in long-term set-aside programs. Preferably these areas are adjacent to one another to create a single, large refuge area (Undersander et al. 2000, Ochterski 2006).
5. Establish grass conservation buffers along sloped areas, waterways, and field borders to reduce runoff and provide undisturbed wildlife habitat (UWEX 1998).
6. Delay mowing of conservation buffers and set-asides until after the breeding season:
7. For lands managed for conservation, delay mowing until September 1 to protect late-nesting species and fledglings.
8. For lands requiring invasive species control or other priority management actions, weigh the impacts of delayed management versus mowing-induced nest failures. If delayed action threatens the property’s ecological integrity, early mowing may be warranted.
9. Remove linear woody features such as hedgerows and woody fencelines as well as woodlots to improve site suitability for obligate grassland birds (Sample and Mossman 1997, WDNR 2005, Kost et al. 2007).
10. Explore alternative crops and cropping practices such as perennial herbaceous biofuel crops and intercropping practices (NRCS 1999).
11. Use conservation tillage practices to provide residual cover and food resources for wildlife. Minimize the number of equipment passes and allow 35-40 days between passes to improve nesting productivity (NRCS 1999).
12. Reduce pesticide and synthetic fertilizer input. Institute both Integrated Pest Management practices and crop rotations that provide a source of nitrogen such as alfalfa, clover, soybeans (UWEX 1998, NRCS 1999). 

Ecological Opportunities

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

Research Needs

• Continue research on alternative crops and cropping practices that are both beneficial to farmers and birds.
• Evaluate how the density and distribution of waste grain or availability of non-crop cover affects the condition, productivity, and distribution of seed-eating wildlife (Krapu et al. 2004).
• Evaluate the impacts of genetically-modified crops on wildlife populations (Krapu et al. 2004).
• Continue to examine interrelationships of landscape composition, landscape geometry, and farming practices and their effects on the species composition, abundance and productivity of birds in agricultural landscapes (Best et al. 1995).
• Continue research on the overwinter benefits of farmland conservation practices to wildlife (Smith et al. 2005).
• Identify an optimal width threshold of field borders that maintains a working balance between wildlife and producer needs. Evaluate width requirement for edge-sensitive species (Conoly et al. 2007).
• Investigate adverse impacts of toxic chemicals to grassland birds nesting in or adjacent to agricultural fields (Vickery et al. 1999). 

Implementation

Key Partners

• American Farmland Trust: http://www.farmland.org/default.asp
• Farm Service Agency: http://www.fsa.usda.gov/
• Natural Resources Conservation Service (NRCS): http://www.nrcs.usda.gov/
• U.S. Fish and Wildlife Service: http://www.fws.gov/
• University of Wisconsin Cooperative Extension: http://www.uwex.edu/ces/
• Wisconsin Department of Natural Resources: http://www.dnr.state.wi.us/ 

Funding Sources

• Farm Bill Programs: http://www.nrcs.usda.gov/programs/
• 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

• 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/
• 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 

References

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• Best, L.B. 2001. Temporal patterns of bird abundance in cornfield edges during the breeding season. American Midland Naturalist 146: 94–104.
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Contact Information

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