Assessment of beach access paths on dune vegetation and implications for dune path planning and management

Background/Question/Methods

Expanding coastal urbanization is putting increasing pressure on remnant natural habitat areas, such as coastal dune ecosystems. Dune systems are highly disturbed, shifting systems which experience salt spray, high winds, blowing sand and full sun. Studies of other remnant habitat types are not necessarily good predictors of the impacts of nonnative species and disturbance in coastal dune systems because of the unique abiotic factors in these environments. This study asks 1) Is there a difference in ground cover and species richness, a measure of biodiversity, between plots adjacent to beach access paths and those farther away? 2) Does the type of path influence the plant ecology? and 3) Are species of conservation or invasion concern found in greater abundance close to or far from pathways?

Employing a stratified random sampling procedure 60 survey blocks of three path types (public sand paths, private sand paths and private wooden paths) were selected from existing access paths on the Isle of Palms, SC. Each block contained three transects, spanning back, mid and fore dune areas, with five plots 0m, 1.5m, 5m, 10m, and 20m from the path. I collected species richness, stem number and percent cover data in each plot.

Results/Conclusions

We found that species richness varies with distance from the path. As distance from the path increases, the average number of species per plot increases from 3 sp at 0m to 5 sp at 20 m. Paths that are closely spaced have a significantly larger influence on percent sand cover at 5m from the path. The density of vegetative cover is also influenced by proximity to the paths. For the percent sand cover category, as distance from the path increases the percent of sand cover decreases. The type of path also has an influence on the density of vegetation and sand cover directly adjacent to the path. Percent sand cover is significantly lower adjacent to wooden paths than adjacent to both private and public sand paths. Further, raised wooden paths have less influence on vegetation density near the path. Of the total 726 plots, 15 plots contained threatened species, 1 plot contained an introduced species, 3 plots contained an invasive species, and 24 plots contained species on the USDA noxious weed list. Recommendations for planning regulations for path placement and material will be suggested from these findings.