Pre-nourishment Beach Benthic Invertebrate Monitoring
Barrier island beaches are the first line of defense against tropical systems along the Gulf of Mexico shoreline. Coastal development, even with restrictions, is vulnerable to shoreline erosion and flooding and owners/developers face significant economic and property losses (Peterson and Bishop 2005). Coastal erosion and shoreline retreat are also deleterious to the value of the habitat to fish and other wildlife, including endangered and threatened species such as sea turtles, Piping Plover, and Red Knot. Engineered solutions to coastal erosion, such as beach nourishment, are in ever greater demand, and are being used more often as the rate of sea level rise and the frequency and intensity of tropical systems increases. Beach nourishment can be effective in maintaining beach/barrier island integrity over short (<decadal) time scales by reducing erosion from waves and/or flooding and by supplying sediment in areas where sediment supply is insufficient. Ecological disturbance during beach nourishment activities may be of short duration but functional degradation can result and may persist. Disturbance effects include reduced prey density for shorebirds, fish, and crabs as well as depressed nesting by sea turtles. Benthic invertebrates are the most frequently targeted organisms for impact assessments because of their suitability as ecological indicators and because they are relatively sessile and provide ecologically meaningful patterns that can be used to infer causation.
The goal of this project is to design and conduct beach benthic macrofaunal monitoring to assess time for the benthic invertebrate community to recover following a beach nourishment event. The design, implementation, and interpretation of this study will address the flaws identified by Peterson and Bishop (2005) regarding studies that examine benthic response to beach nourishment. TAMUCC will use Coastal Management Program Cycle 26 §309 funding to conduct the first phase of this work, which will involve 10-12 months of pre-nourishment sampling at two beaches with planned nourishment events (to be later defined by the Texas General Land Office, or GLO), two nearby control beaches, and one pristine beach (never nourished or close to nourishment). Work will later be continued under a separate contract and funding source to collect post-nourishment data. The full before-aftercontrol- impact analysis will be used to estimate time required for recovery of the benthic community. Results will be used by the GLO to provide support for an allowable frequency of beach nourishment under a U.S. Army Corps of Engineers (USACE) Regional General Permit.