Evaluation of Restoration Techniques in Black Belt Prairie Remnants
JoVonn G. Hill, John A. Barone, and Lisa McInnis
Prior to European settlement, the southeastern United States had several regions with abundant grasslands or prairies. One such region, called the “Black Belt”, extends in an arc from McNairy County, Tennessee, southeast to Russell County, Alabama. Instead of being a continuous swath of grasslands, the Black Belt was a heterogeneous landscape of prairies and several types of forest. Surveys conducted by the General Land Office in the 1830’s suggest that in the Black Belt region of Alabama and Mississippi, prairies once covered about 144,000 hectares. Since that time, more than 99% of these prairies have been lost to agricultural and urban development. Remaining prairies are threatened by further development, erosion, and the encroachment of eastern red cedar, Juniperus virginiana L. The Mississippi Natural Heritage Program gives Black Belt Prairie remnants a ranking of S1, meaning they are "critically imperiled" within the state due to extreme rarity or other factors that make their biota vulnerable to extirpation.
The Natchez Trace Parkway intersects the Black Belt in Chickasaw, Lee, and Pontotoc Counties in northeast Mississippi. Along the Parkway, small prairie remnants and scattered populations of prairie plants still occur. A significant threat to these remaining prairies is the spread of eastern red cedar, which has invaded most remaining prairies sites, presumably due to a reduction in natural fires. Parkway managers are considering supplementing a prescribed fire program with other techniques to remove cedars, such as hand-thinning. This procedure should accelerate the restoration process by increasing sunlight and encouraging the regeneration of the prairie flora. However, the financial costs and ecological benefits of hand-thinning, both alone and with prescribed burns, are not yet known.
To evaluate the effectiveness of different management strategies in the restoration of prairie remnants, an experiment will be established along the Natchez Trace Parkway. The experiment will have four treatments: 1) a burn treatment, in which remnant sites will be burned to decrease the density and growth of eastern red cedar; 2) a hand-thinning treatment, in which cedars trees will be cut down and removed; 3) a combination treatment in which the cedars will be cut and left in place and then the remnant burned; and 4) a control, in which there will be no active restoration. There will be multiple replicates of each treatment.
The restoration value of these differing management strategies will be evaluated based on changes in the plant, ant, and grasshopper communities. These three taxa are appropriate for evaluating the efficacy of the restoration experiment for several reasons. First, all three groups are locally diverse and include species that are largely or exclusively found on remnant prairies in this region. Second, the composition of these three communities is quite well-known for Black Belt prairies. Third, the three groups represent different trophic levels and have a variety of ecological roles. By examining these three groups simultaneously, the experiment will be able to assess the effectiveness of the different strategies more broadly.
The reclamation or restoration of these particular prairie remnants is important given the imperiled nature of this habitat and the high visibility and educational opportunities that the Natchez Trace Parkway offers. Currently, there is a roadside pull-off on the Trace called the “Black Belt Overlook”. The view and interpretive sign here indicate the important agricultural aspects of the region. One of the remnants to be treated will be across the road from this pull-off, and will offer a unique opportunity to educate the public on the natural heritage of this region.
2009: Plot set up and pre‑treatment sampling begins.
Winter of 2009/2010: Thinning treatments applied during the. Burning was put off due to prolific rain
2010: Sampling continues
Spring 2011: Burn treatment applied. Sampling ant, grasshopper and plants continue.
Funding Source: Cooperative Ecosystem Studies Units. http://www.cesu.psu.edu/