Direct plant–plant facilitation in coastal wetlands: A review

Coastal wetlands provide important ecosystem services to humanity, but human activity and climate change are rapidly degrading these ecosystems. Thus the conservation and restoration of coastal wetlands becomes an urgent issue. Species facilitation among plants has regained attention of ecologists recently. Many studies in coastal wetlands have revealed direct plant–plant facilitation influencing community structure and ecosystem function, thus improving our understanding of community organization and giving new directions for the restoration of degraded coastal wetlands. Our paper examines studies of direct plant–plant facilitation in coastal wetlands with an emphasis on tests of the stress gradient hypothesis and influences of species facilitation on species zonation, species diversity patterns, phylogenetic diversity and ecosystem function. Investigating how plant–plant facilitation affects ecosystem function is an important future direction, which can provide basic knowledge applicable to the preservation and recovery of coastal wetlands in these times of rapid global change.