Understanding the effects of sand fence usage and the resulting landscape, landforms and vegetation patterns: a New Jersey example

Sand fences are important human adjustments modifying the morphology of developed shores because they are inexpensive, easy to build and permitted seaward of dunes. The effects of sand fences on sediment transport and deposition in the early stage of their use are well known, but little is known about the significance of sand fences as instruments of landscape change and the effect of their late stages when they have deteriorated into weathered remnants and potential low scale barriers benefiting dune vegetation growth. This study identifies the role of sand fences in modifying coastal dunes. Effects of fence usage were evaluated in 29 municipalities of the developed coast of New Jersey over a 6-year period through a video inventory, interviews with municipal officers and field reconnaissance. Data on vegetation, topography and fence characteristics were gathered at four dune sites within Stone Harbor and Ocean City, New Jersey during September 2007 and March 2008. Variables include: vegetation diversity and density, distance of vegetation quadrat landward of dune toe, degree of sheltering, sediment deposition and erosion, presence of remnant fence, and distance of vegetation quadrat landward and seaward of fence. Results reveal that sand fence characteristics define the coastal landscape and communicate management goals which presently are not based on restoring landforms and habitats; use of fences can be made more compatible with natural processes and biota if careful consideration is given to their initial placement, sand fences remain visible when deployed at locations of low sediment transport; vegetation diversity does not increase near remnant fences but accretion caused by fences in the past may result in topographic diversity which benefits the development of specific vegetation communities.Ph.D.Includes bibliographical referencesIncludes vitaby Rosana Grafals-Sot