Honors College Theses

Date

2022

Major

Biology (B.A.)

Document Type and Release Option

Thesis (open access)

Faculty Mentor

Dr. Lissa Leege

Abstract

Sand dunes play a valuable role on the coastline supporting unique native species and protecting beach communities. The City of Tybee Island, Georgia, USA has undergone extensive dune restoration to expand and rehabilitate its shoreline to better defend the town against the increasing frequency of hurricanes and storm surge. The project included the recovery of existing dune structures and construction of new dunes filled with sand pumped from offshore and vegetated with a variety of native species. To analyze the impact of human trampling on dune vegetation occurring adjacent to footpaths and crossovers in new and established dunes, we measured plant data, sand accumulation, path width, and colonization of previously trampled regions. A greenhouse study was also conducted on the species Uniola paniculata to examine the impacts of trampling at various levels under controlled conditions. Vegetation in sites adjacent to the footpaths had lower chlorophyll content and decreased growth in comparison to the sites adjacent to crossovers. The footpaths experienced erosion rather than sand accumulation and widened further into the dunes throughout the study. In the greenhouse, trampled plants had lower chlorophyll content, slower growth, and a loss of stems. Human trampling is detrimental to dune vegetation and their function in supporting the dune structure. These impacts are present around footpaths on the dunes but less so around the crossovers, and are more profound in the younger, newly constructed dunes. These results encourage limiting allowance of trampling on dune, particularly in restoration areas.

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