Testing a biodegradable engineering product for mangrove restoration along a high wave-energy coastline
Human development, extreme weather events and rising sea levels are driving the loss anddegradation of many of the world’s mangrove ecosystems. Mangrove forests are natural coastalbarriers that provide protection from erosion and storms while also supplying material andbiodiversity services tohuman andnon-humancommunities worldwide. In recent years innovativeand novel products of ecological engineering have emerged to safeguard and restore coastalecosystems. Biodegradable Ecosystem EngineeringElements(BESE) are one such innovation thathave been shown to stabilize sediment, attenuate waves, and mimic dense root mats to facilitatethe establishment of coastal vegetation. This studyinvestigatesthe effect of a built BESE structureon abiotic factors andRhizophora mangletransplant responsesalong a high-wave energy coastlineon the island of Bonaire, Dutch Caribbean. Results reveal that BESEelementsdo not significantlyalter wave-energy and sediment mobility, or increase transplant survival, shoot growth rate andbiomass allocation. Survival rate of transplants was significantly higher when secured by rockscompared to BESE structures and bare sediment, highlighting simple, local, and low-cost methodsfor restoration. Despite not being significant, there were indications of the potential for BESEstructures toattenuate a minimal amount of waves and stabilize propagules for greater investmentin above-ground biomass during establishment. Yet, longer monitoring is needed to validate this.Limitations ofthe BESE structuressuggest thattheymay be more optimally used below-ground onsediment substrate, in larger clustered structures, or within interconnected foreshore ecosystemsfor landscape-level coastal protection and resilience.