The Tallgrass Prairie Center Guide to Prairie Restoration in the Upper Midwest

10. Prairie Management [Includes Image Plates]

10 10 daryl฀smith Overview Presettlement prairies were shaped and maintained by wildfire, herbivores, and climatic extremes. Today’s prairies are mostly small, isolated patches that require active management to maintain their diversity. This chapter focuses on the management techniques needed to maintain the integrity and diversity of prairie remnants, restored remnants, and established reconstructions. Natural resource managers use techniques such as prescribed fire, haying, selective mowing, grazing, brush cutting, and strategic application of herbicides to maintain prairie communities. The utilization of these techniques and their advantages and disadvantages will be discussed. The฀Need฀for฀Prairie฀Management Climate, fire, and grazing were the primary processes that originally maintained the tallgrass prairie. After Euro-Americans entered the tallgrass prairie in the 1830s, they converted most of it to intensive agriculture, replaced bison and elk with cattle and other livestock, suppressed fire, dissected the prairie with roads and railways, and covered it with buildings and concrete. The result is a fragmented ecosystem with a few scattered remnants. The remnants either no longer contain elements of the primary processes of the original ecosystem or lack the capability to respond to those that remain. Due to their small size and relatively extensive edge, they are under constant stress from invasive species , sedimentation, reduced genetic vigor, herbicide drift, nutrient overload, air pollutants, and other human disturbances and are thus more likely to lose critical components of the remaining prairie community. Furthermore, lost species cannot be recruited from other nearby prairie sources, because extensive cultivation of the surrounding areas has eliminated them. Obviously, there is a need for managerial intervention to retain high-quality tallgrass prairie remnants. Prairie฀Management Prairie฀Management฀ 135 We now know that remnants need to be managed to maintain the prairie community and prevent degradation. However, when preservation of prairie began in the 1930s and 1940s, most conservationists believed that management was unnecessary, assuming that disturbed remnants would undergo natural secondary succession and return to their presettlement condition. By the late 1960s, it was becoming apparent that some kind of intervention was needed, because many prairie remnants were becoming degraded from invasion by woody species and nonnative weeds and the loss of conservative prairie species. Despite a recognized need, many prairie remnants continue to be inadequately managed due to insufficient funds, limited personnel, incomplete understanding of prairie ecosystems, and/or lack of knowledge of the biology of affected prairie species. In the absence of fire and grazing, gray dogwood, smooth sumac, and buckbrush encroach on prairie remnants, form large thickets , and shade out the prairie vegetation. Eastern red cedar seedlings are quite sensitive to fire and are easily killed when small; however, with heavy grazing and an absence of fire, they become major invaders in many areas of the tallgrass prairie. For example, they invade the steep slopes of the Loess Hills prairies bordering the Missouri River and the hill prairies along the Mississippi River, often forming closed-canopy groves. Management of areas adjacent to remnants is critical to maintaining the components and integrity of the prairie communities. Acquisition and management of buffer lands around prairie remnants will reduce negative impacts from the surrounding altered landscape. Prairie should be reconstructed on these buffer lands with seed from prairie remnants. The buffer lands will also require management, but they protect the biological integrity of the core remnant. Prairie฀Management฀Techniques A well-designed prairie management plan must include specific goals and management objectives to attain these goals. Maintaining a diverse prairie community capable of responding to environmental changes is a desirable primary goal. Other possible goals could be to replicate a particular type of prairie as determined by climate, soil, and hydrology (for example, blacksoil prairie, sand prairie, or wet prairie) or to maintain a hay meadow as an example of a culturally modified prairie (Howe 1994). Management for high diversity in prairie remnants and reconstructions is an attempt to replicate historic, large-scale natural disturbances with carefully planned and timed actions. Management techniques include prescribed fire, 136฀ prairie฀restoration฀and฀management haying, grazing, selective mowing, woody species removal, and strategic application of herbicides. Knowledge of physiological processes and developmental stages of plants is important to determining appropriate seasonal timing and frequency of techniques used to enhance desired species diversity and control undesirable species. A good prairie management system to increase diversity utilizes techniques that vary by intensity, season, and location. Avoid repetition of a technique in the same location at...