Coastal wetlands mainly include ecosystems of mangroves, coral reefs, salt
marsh, and sea grass beds. As the buffer zone between land and sea, they are frequently
threatened from both sides. The world coastal wetland lost more than 50% of its area in
the 20th century, largely before their great value, such as wave attenuation, erosion control,
biodiversity support, and carbon sequestration, was fully recognized. World wetland loss
and degradation was accelerated in the last three decades, caused by both anthropogenic
and natural factors, such as land reclamation, aquaculture, urbanization, harbor and navigation
channel construction, decreased sediment input from the catchments, sea level rise,
and erosion. Aquaculture is one of the key destinations of coastal wetland transformation.
Profound consequences have been caused by coastal wetland loss, such as habitat loss for
wild species, CO2 and N2O emission from land reclamation and aquaculture, and flooding.
Great efforts have been made to restore coastal wetlands, but challenges remain due to lack
of knowledge about interactions between vegetation and morphological dynamics.
Compromise among the different functionalities remains a challenge during restoration
of coastal wetlands, especially when faced with highly profitable coastal land use. To solve
the problem, multi-disciplinary efforts are needed from physio-chemical–biological monitoring
to modelling, designing, and restoring practices with site-specific knowledge.