Poster Australian Marine Sciences Association 2022

How does shoreline management impact seagrass function? (#483)

Orla McKibbin 1
  1. University of New South Wales, Sydney, NSW, Australia

Nature-based solutions are being increasingly used as management strategies to combat erosion and rising sea-levels. Despite generally being considered better than hard-engineering solutions (e.g. seawalls), which have known impacts to marine habitats, there is an overall lack of information on how these strategies compare regarding their effects on ecosystem function. The impact of such interventions is even less established for the habitats adjacent to them. This is despite the likely impact of management strategies on them, due to changes in system connectivity and water dynamics.

Lake Macquarie, Australia’s largest coastal lake has utilised several different strategies to manage erosion, including the construction of seawalls and the addition of artificial cobbles to mimic the natural shoreline. I will assess how these two strategies impact adjacent seagrass beds, compared to unmodified shorelines in the Lake. Specifically, I will compare total area of seagrass, growth rate of plants, above and below ground biomass, and invertebrate biodiversity in beds adjacent to seawalls, artificial cobble beaches and unmodified shorelines. I will also compare the productivity and community metabolism of seagrass using benthic chamber incubations. Understanding how different shoreline modifications alter seagrass beds and their functioning is critical in maintaining the important services these habitats provide.