CERVID PEDITURBATION AS EROSIONAL-DEPOSITIONAL MECHANISM ALONG A SMALL CREEK (MILL RUN, PENNSYLVANIA)

The white-tailed deer (Odocoileus virginianus) is emerging as an increasingly important pediturbation agent along riparian zones of southeastern Pennsylvania. Along a relatively high-traffic reach of Mill Run (Tyler State Park, Bucks County, PA) adult deer track metrics included length (mean: 8.5 cm), width (6.2 cm), and depth (2.6 cm). Bidirectional trackways crossed the creek, rather than followed along the bank. Assessment of erosional-depositional patterns shows that up to 67-75 cm3 of (mean: 73.5 cm3) of sediment are removed by a single hoofprint, which is consistent with values from previous research. Hoofprint casts provided additional information about track volume and porosity of the matrix. Slippage along steep slopes erodes up 230 cm3 of sediment, with most sand-sized fraction redeposited within the stream as small debris fans. Such depositional features may shift the water flow toward the cutbank, thereby accelerating total erosion. Zoogeomorphological research of ungulate populations in small riparian ecotones is in need of frequent monitoring in order to quantify their impact as geological and ecological agents.