Speed Presentation 2024 Australian Marine Sciences Association Annual Meeting combined with NZMSS

Beach Environments and Infauna Community Structure are Interlinked Along Coastlines with Ongoing Beach Replenishment (#448)

Jasper Willoughby 1 , Graziela Miot da Silva 1 , Ryan Baring 1
  1. College of Science and Engineering , Flinders University, Bedford Park, South Australia, Australia

The natural cycle of sand movement and deposition is interrupted on highly modified coastlines. In these sandy beach ecosystems, there is little or no natural dune system, and hard structures installed for shoreline stabilisation and protection tend to interrupt the natural longshore movement of sand, causing erosion of sandy beaches. Sand replenishment or nourishment as the mechanical movement of sand to areas of erosion, is becoming a more popular solution to combat against coastal erosion. Studies globally have identified overall negative impacts of beach nourishment on the abundance and diversity of infauna communities, however species-specific responses are variable, and focussed on macroinvertebrates only. Our study aimed to identify the links of shifts in macroinvertebrate and meiofauna communities to the changing beach environment after beach nourishment. We achieved this by conducting seasonal surveys, before, during, and after replenishment for infauna, beach morphology, and environmental parameters. Infauna communities respond predominately to shifts in environmental conditions (e.g. grain size and beach slope) rather than pulse disturbances from small scale replenishments. Results from this study will inform coastal managers of potential impacts of sand replenishment programs on sandy beach ecology, and the interlinked environmental and ecological factors to consider when designing replenishment programs.