Patch-Burn Grazing with Cattle as a Prairie Management Tool on Missouri Department of Conservation Lands
Executive Summary: Tallgrass prairies, one of North America’s most endangered ecosystems, evolved with fire, drought, and native grazers (bison and elk). In Missouri, over 99% of the original tallgrass prairie has been converted mainly to row-crop fields and tall fescue pastures. Concomitant with these landscape changes have been dramatic declines in the state endangered greater prairie-chicken and other grassland birds. Grassland ecologists in Kansas, Oklahoma, Missouri, and Iowa have been experimenting with a management practice known as patch-burn grazing with either cattle or bison since the late 1980s as a grazing system that benefits wildlife by emulating the presettlement disturbance regime.
Patch-burn grazing uses prescribed fire to manage the grazing behavior and distribution of grazers. A large body of research, including work completed recently by the Missouri Department of Conservation (MDC), demonstrably shows that patch-burn grazing with either cattle or bison results in improved habitat conditions and positive population responses for declining grassland obligate birds. Data also indicate that using patch-burn grazing with cattle (PBGC) with moderate stocking levels does not negatively impact native plant species diversity or floristic quality after 3-5 years of a PBGC rotation. Missouri Department of Conservation prairie wildlife biologists have observed that traditional MDC management of prairies focusing on just burning or haying or hay/burn rotations tended to promote uniform vegetation structure not optimal for the full suite of grassland bird habitat needs. Due to the dire situation with respect to the prairie-chicken, MDC has experimented with and adopted the use of PBGC on a subset of its prairies that are critical for nesting and brood rearing cover of the greater prairie-chicken and other grassland obligate birds.
Patch-burn grazing with cattle has been used on some Missouri prairies since 2001 and a four year replicated experiment has been conducted (2005-2008) involving five MDC prairies. While it is abundantly clear that PBGC benefits native grassland obligate birds, including the endangered greater prairie-chicken and northern bobwhite quail, the impacts of this management practice on individual plant species and insect species, stream water quality, soils, and small mammals are less understood. Little data are available on how PBGC impacts prairie streams. The effects of cattle access to stream health is dependent on several factors including stocking rates, grazing duration and season, vegetative composition, degree of shading in the riparian corridor, topography, and other factors. To date, cattle access to streams on MDC PBGC projects has been primarily limited to first order streams. It is still premature to declare what the long-term (10+) effects of PBGC are on prairie plant, insect, and small mammal communities in Missouri or what the impacts of the practice could be on prairie stream water quality.
MDC manages nearly 13,000 acres of remnant (unplowed) prairie on 64 different conservation areas statewide. In the growing season of 2009, MDC deployed patch-burn grazing with cattle on 11 prairie conservation areas (17% of the prairie conservation areas MDC manages). Current plans by the MDC prairie-chicken recovery team (October 2009) are to have PBGC used on 19 MDC prairies, with the best potential to provide habitat for grassland obligate birds in the near future (30% of the prairie sites MDC manages). For 2010, plans are to utilize patch-burn grazing on part of Taberville Prairie Natural Area, all of Niawathe Prairie Natural Area, and part of Pawnee Prairie Natural Area.
Because PBGC has many positive impacts to the prairie bird community with no apparent negative short-term (four years) impacts to the plant and butterfly communities, it is recommended that the practice is continued as an integral tool for MDC prairie management with specific cautions. Because significant unknowns still exist with respect to the impact of PBGC on streams and the long-term impacts to the plant community a conservative, cautious approach is recommended for using PBGC on MDC prairies. As part of this cautionary approach, stream protection (refer to the MDC Watershed and Riparian Management Guidelines), minimum rest periods, some limitations on deployment, limited long-term vegetation monitoring, and further stream impact studies are recommended for the continued use of PBGC on MDC prairies in the near future.
Fire, grazing, and mowing all have a part in prairie management. The tool-kit available to the prairie manager is broad and includes prescribed fire, haying, mowing, brush-hogging, herbicides, grazing, and seeding or planting. Add to these tools the variables of intensity, duration, season, spatial pattern and size of treatment area, and prairie management becomes extremely complex. All of these tools are needed at some point in the management of a large prairie remnant. Managers need the latitude to use their professional judgment when it comes to implementing and balancing the needs of management objectives.