A trophic-ecology based tool to assess and manage HAB impacts on marine ecosystems

Commonwealth and state agencies identified the need for tools that assess and track food-web condition beyond traditional species counts and biomass estimations.

This project will analyse a combination of biodiversity datasets and influencing factors to provide a clear, science-based assessment of subtidal reef condition in areas of South Australia.

A decision-support tool will be developed to assess, track and predict the impact of events such as the 2025 HAB and marine heatwave, and visualise management actions such as spatial protection, habitat restoration and fishing closures.

Approach

Trophic integrity framework

A framework will be developed to enable development of a Normalized Reef Status Index (NRSI). The NRSI is based on calculating the relative biomass at different levels of the marine food web (trophic integrity). It will underpin the assessment of sub-tidal reef condition within South Australia’s marine estate.

Biodiversity data for the NRSI will be drawn from:

• Reef Life Survey;
• the Australian Temperate Reef Collaboration;
• baited remote underwater stereo-video surveys (South Australian Department for Environment and Water (SA DEW) and Flinders University); and
• long-term data series on habitat condition, plankton and water quality (South Australian Environment Protection Authority (SA EPA)).

Assessment models

Models will be developed that link the NRSI to environmental, disturbance, and management drivers of trophic integrity. This will enable the mapping of 2025 HAB impacts and recovery and predict areas most vulnerable to future events.

Interactive decision-support tool

A customised, web-based dashboard will be developed to visualise marine ecosystem condition, disturbance impacts, and recovery trajectories in South Australia’s Marine Estate. The approach will allow for integration with existing government dashboards and allow the evaluation of potential management actions such as fishing closures, restoration interventions and rezoning.

Communication and engagement

A project technical report will outline ecological impacts of the 2025 HAB and provide management recommendations. Communication products will be developed to communicate to a broader group of stakeholders and communities about marine ecosystem condition and recovery.

Expected outcomes

Science-based assessment, tracking and prediction of subtidal reef condition in South Australia will be available to research users including the:

• SA DEW;
• SA EPA;
• Commonwealth Department of Climate Change, Energy the Environment and Water;
• HAB Science Program;
• South Australian Research and Development Institute/South Australian Department of Primary Industries and Regions HAB task force; and
• Green Adelaide.

Information on reef condition and recovery progress will be broadly communicated.

Project location

South Australia