Résumé
The geomorphology of mangrove ecosystems is strongly influenced by hydrodynamic factors. Mangrove growth is conditional on water and sediment budgets at the coastal interface. This basic ecological principle has been ignored in many mangrove restoration or rehabilitation programs, leading to failures in the design of successful and cost-effective ecosystem restoration and rehabilitation. This chapter highlights how restoring tidal flows can adequately supply sediments to the mangrove system and stimulate its recovery in abandoned aquaculture ponds, where hydrology was previously constrained by pond walls. Tidal flows transport sediments that accumulate in the pond, causing an increase in soil surface elevation; a key factor in both helping minerogenic mangroves maintain their elevation in the face of sea level rise and improving the local blue carbon balance through carbon accumulation. In a number of cases, tidal flow also facilitates the dispersal of mangrove propagules over the site, contributing to subsequent mangrove development. As restoring the hydrological regime is most likely to have positive contributions to the early development of mangroves in abandoned ponds, it should be considered as a “nature-inspired” alternative to plantation programs. Our work suggests that such “passive” mangrove restoration strategies are to be preferred as they provide better opportunities for blue carbon abatement and increase resilience of coasts to rising sea levels and biodiversity loss.