Need for Active Management

Sandplain grasslands require active vegetation management by periodic disturbance to arrest secondary succession to shrublands and woodlands and to maintain, promote, or restore particular species of conservation concern. Managers concerned with the persistence of grasslands and biodiversity have two main challenges. One is to preserve and enhance existing grasslands in key places where they can be actively managed. The other is to develop approaches to creating new sandplain grasslands, either from places that supported them in the past, or from other types of ecosystems, such as woodlands or agricultural lands, in places where conditions are similar to those in extant grasslands. Such “new” sandplain grasslands could add to the total regional grassland area or replace previous grasslands lost to residential or other development, shoreline erosion, or succession to woodland in hard-to-manage locations. Both approaches are important, but different, and add to the complexity and challenge of regional sandplain grassland management.

Land managers have a number of potential options for managing for disturbances in existing sandplain grasslands. The main tools in sandplain grassland managers’ collective toolbox are: prescribed fire, mowing, grazing, and vegetation removal (by either mechanical or chemical treatments). Each method has ecological benefits and potential drawbacks. Each also has different challenges for implementation, especially for the frequency at which disturbances are desired. Additionally, each method has a large number of potential associated influential variations that include seasonal timing, frequency, weather and climate conditions, composition and structure of existing vegetation, type of animals, and other factors. For example, prescribed burning can effectively prevent encroachment of woody plants and increase the density of some target, rare sandplain forbs. However, this method can be much less effective in restoring grassland and heathland vegetation to areas where second-growth oak and pine forests are well established, because many woody plants regrow vigorously from rootstocks. Mowing or chemical treatments can be alternatives to prescribed fire and can more predictably be used in cases where adjacent land use or local/regional concerns about fire risk and air pollution make use of fire less feasible. A return to a historic method, the use of grazing animals, could potentially play a greater role in grassland maintenance and management.

Options for creating new sandplain grasslands vary depending on whether exiting land is shrubland or woodland, or open and agricultural. Creating sandplain grasslands from shrublands and woodlands involves tree clearing, establishment of grassland vegetation, and managing aggressive woody regrowth. Creating grasslands from former agricultural land often requires eliminating or greatly reducing the existing predominantly non-native invasive weeds and cool season grasses, and potentially undoing soil conditions such as high pH, created by previous agricultural use that can favor non-native over native species.