Adaptive Botany: Case Study of Mangrove Restoration in the Singapore Port Authority's Coastal Zones

Thesis Abstract

Mangrove ecosystems in coastal urban interfaces experience pressures from industrial activity, shoreline modification, and climate-induced stresses, necessitating evidence-based restoration strategies that align with port operations and biodiversity goals. This study addresses the gap between practical mangrove rehabilitation within commercial port landscapes and the ecological outcomes required for resilient coastal ecosystems, focusing on the Singapore Port Authority’s (SPA) coastal zones. The aim is to evaluate adaptive restoration approaches that integrate habitat restoration with port service demands, with specific objectives (1) to assess baseline ecological conditions and post-restoration trajectories of mangrove structure and function in selected SPA sites; (2) to identify site-specific drivers of restoration success including hydrological regime, sediment characteristics, and anthropogenic disturbance; (3) to evaluate the resilience of restored mangrove stands to oil spill risk, flood events, and sea-level rise through scenario modelling; (4) to develop an adaptive management framework incorporating stakeholder inputs and operational constraints of port logistics; and (5) to formulate actionable guidelines for scalable restoration within industrial coastal zones. The methodology employs a convergent mixed-methods design (sequential explanatory) implemented across three SPA-managed sites representing varied hydrodynamics and disturbance histories. The population comprises avicennia alba and sonneratia alba transplant cohorts, local mangrove saplings, sediment cores, and associated faunal indicators. A stratified random sample of 120 plots (40 per site) is used for quantitative assessments, complemented by 25 semi-structured interviews with SPA managers, buffer zone residents, and environmental consultants. Data collection instruments include transect-based vegetation surveys, dendrometric measurements, soil salinity and redox potential probes, sediment granulometry, chlorophyll fluorescence indices, and remote sensing-derived canopy cover. Ecological data are analyzed using generalized linear mixed models to relate vegetation metrics to hydrological and sediment variables, ANOVA for site comparisons, and time-series analyses for restoration trajectory assessment. Biodiversity indices (Shannon, Pielou) and functional trait analyses (root porosity, pneumatophore density) illuminate ecosystem function. Stability and resilience are examined via scenario-based modelling using hydrodynamic and carbon sequestration simulations, and a Bayesian updating framework to refine management decisions with ongoing monitoring data. The qualitative strand employs thematic analysis of interview transcripts, triangulated with management documents to capture governance and stakeholder perceptions. Expected findings include (i) improved mangrove stand structure in restored areas with higher canopy cover, stem density, and aboveground biomass relative to degraded controls; (ii) significant associations between hydrological connectivity, sediment granulometry, and nutrient availability with mangrove growth rates and species composition; (iii) enhanced carbon sequestration potential and habitat complexity contributing to increased faunal richness; (iv) demonstrable resilience of restored patches to episodic salinity spikes and moderate storm events, and (v) a robust adaptive management framework with decision-support tools reflecting SPA operational constraints. The study will contribute to knowledge by advancing understanding of adaptive restoration in anthropogenic coastal zones, integrating ecological data with maritime management objectives, and offering transferable models for port-adjacent mangrove rehabilitation. The study’s practical contributions include a prioritized restoration protocol for the SPA, including selection criteria for planting sites, species mix, monitoring indicators, and contingency measures for climate-related disturbances. The theoretical contribution centers on integrating adaptive management theory with ecosystem-based restoration in a high-disturbance setting, drawing on the theoretical frameworks of resilience theory, ecosystem-based management, and social-ecological systems. The research is expected to inform policy development on green-grey infrastructure integration, environmental risk mitigation, and urban coastal resilience. The main conclusion anticipates that adaptive restoration within SPA coastal zones yields higher ecological return on investment when restoration design is coupled with continuous monitoring, stakeholder involvement, and iterative management adjustments. Recommendations include scalable reproduction and transplantation protocols, incorporation of real-time hydrological sensors, establishment of a continuous learning platform for SPA personnel, and policy alignment to incentivize private-public collaboration for coastal green infrastructure projects.