A lifecycle model approach for predicting mangrove extent

Area of Science:

• Ecology
• Marine Biology
• Environmental Science

Background:

• Traditional mangrove distribution models rely on tidal parameters but overlook species-specific survivability thresholds and lifecycle stages.
• This lack of understanding contributes to poor outcomes in mangrove restoration and creation projects globally.
• Avicennia marina viability is influenced by complex interactions between tidal dynamics, estuarine typology, and physiological thresholds.

Purpose of the Study:

• To propose and validate a novel mangrove lifecycle model using a multi-forcing threshold approach for simulating Avicennia marina viability.
• To provide physiological reasoning for mangrove establishment and development across different life phases.
• To accurately predict mangrove extent by integrating lifecycle stages, environmental conditions, and estuarine characteristics.

Main Methods:

• Developed a mangrove lifecycle model incorporating critical thresholds for reproduction, seed dispersal, seedling establishment, and mature tree survival.
• Validated the model at 37 sites across eastern Australia, considering diverse estuary types and tidal dynamics.
• Employed statistical analysis, including RMSE and R-squared, to assess the accuracy of predicted mangrove surface elevations.

Main Results:

• The model accurately predicted upper (RMSE = 0.0676, R² = 0.8932) and lower (RMSE = 0.0899, R² = 0.7417) mangrove surface elevations.
• Mangrove establishment stressors were identified as the primary drivers of extent, with estuarine typology influencing threshold limits.
• Estuaries with limited tidal decay offered greater establishment opportunities, and mature Avicennia forests demonstrated resilience to hydrologic changes.

Conclusions:

• The proposed causal lifecycle model offers a more accurate method for estimating mangrove extent across various stages and locations.
• Understanding lifecycle-specific thresholds and establishment stressors is crucial for successful mangrove restoration and conservation.
• Mature Avicennia forests exhibit resilience, but predicting their response to escalating climatic and hydrologic pressures requires further investigation.