Mangrove lifecycle dynamics for designing nature-based solutions

Nature-based Solutions (NbS) are becoming increasingly popular worldwide for their capacity to provide a range of ecosystem services, including climate change mitigation and adaptation, habitat provision, coastal protection, and support for social and economic livelihoods. However, on-ground implementation of NbS is fraught with design and uptake concerns, which have limited their applicability and effectiveness. A global review of NbS research suggested that NbS design guidelines should aim to integrate quantitative ecological sciences with engineering principles across the project lifecycle. Further, current NbS research has placed limited importance on socio-economic benefits and a holistic approach is required to better integrate societal, economic, and environmental needs in NbS design. As such, new methodologies and design tools are needed to improve NbS design and evaluate the diverse benefits of NbS. Following this NbS knowledge review, this thesis aimed to quantify the lifecycle dynamics of mangrove ecosystems to support design guidance for the use of mangroves as NbS. This was achieved via the development of a mangrove Lifecycle Ecosystem Analysis and Forecasting (LEAF) model, where individual mangrove size, forest density, response to extreme events, biomass, and ecosystem services can be calculated across the lifecycle of a mangrove forest. This model was supported by field data across four estuary typologies, with mangrove attributes quantified via Terrestrial Laser Scanning (TLS) techniques. Allometric relationships were derived between mangrove stem diameters, tree heights, and projected surface areas to accurately inform ecosystem services and underpin the mangrove LEAF model. To provide quantifiable advice to restoration practitioners, an updated LEAF model was used to evaluate the lifecycle responses of typical mangrove restoration strategies under climatic forcing. Finally, the temporal response of mangroves to sea level rise was simulated using the LEAF model to assess potential changes to societal benefits across diverse social contexts. The findings of this research emphasise the importance of utilising a mangrove lifecycle approach to provide causal linkages in NbS design, which will hopefully ensure a broader uptake and social benefits worldwide.