Tracy Parker
March 3, 1997

Analysis of a Small Mammal Population in a Wetlands Restoration Area

Abstract. In recent years there has been a movement to "fix" damaged ecosystems. This has resulted in the rapid growth of a movement known as restoration ecology. The general goal of restoration ecology is to restore ecosystems to their "natural" state, although that is very difficult to define. Many different methods and techniques of restoration are currently being examined at Pen Branch, located on the Savannah River Site (SRS) near Aiken, South Carolina. At SRS the cooling water from a reactor was directly discharged into the Pen Branch stream corridor. With extreme water temperatures and an order of magnitude increased flow, the Pen Branch ecosystem changed tremendously. Since these extreme conditions persisted for 34 years, it is safe to assume most of the plant and animal life was destroyed. Now that the reactor has been shut-down, SRS is trying to restore Pen Branch. The purpose of this study was to evaluate what effects their restoration efforts are having on the small mammal population. A mark recapture method of trapping was employed and carried out for eighteen consecutive days. The mammal population was surveyed in three different plots at Pen Branch. Each plot contained a transect in control and treated areas. In two of the plots the treatments were intensive (herbicided, burned, planted) and in the third plot the treatment was natural (planted only). Due to the abundance of rodent captures and rarity of captures other mammals, the results were based only on the three species of rodents collected: cotton rat, rice rat, and cotton mouse. Using the Schanbel technique of estimating the population, it was determined that the population estimates on the intensive treatment were significantly lower than their respective controls. It was also found that the natural treatment had a significantly higher population estimate than its control. However, the controls were significantly different which suggests that other factors may be involved in the differences found between treatments.