Off road vehicle impact in Cape Cod national seashore: Disruption and recovery of dune vegetation

Abstract

An on-going investigation of the rates of vegetation breakdown and natural recovery under controlled conditions has been established at Cape Cod National Seashore, Massachusetts, U.S.A. In this study, the effects of controlled impacts on a variety of coastal habitats were measured in terms of above and below ground biomass. Dune sites, ranging from unstabilized to moderately stabilized, were driven on at varying levels of intensity and along different exposures relative to slope and prevailing wind direction. Preliminary evidence suggests that a single summer season of driving (300–700 passes) on a confined track through dense stands ofAmmophila vreviligulata, Arctostaphylos uva-ursi, andDeschampsia flexuosa, can completely destroy the above-ground portions but leave adequate underground roots and thizomes for a small amount of vegetative regrowth after cessation of impact in the late summer and fall. Large differences in wind speed at ground level have been noted in driving tracks with different alignments relative to wind direction. Deflation rates may be excessive in tracks devoid of above ground cover and aligned parallel to strong prevailing winter winds.