Ecological engineering approaches in coral reef restoration

The combined accelerated footprint of climate change and enhanced anthropogenic pressures and the poor outcomes of many traditional management activities raise the needs for active reef restoration tactics (targeting coral mariculture/transplantation), backed by ecological engineering approaches. These approaches include, among others, the use of ecosystem engineer species, which, through modifications in their physical or biological properties, they create new habitats characterized by novel biodiversity (through either autogeny or allogeny engineering acts). Only a small number of studies on coral reef restoration have discussed/mentioned "ecological engineering"or "coral reef engineering". Examining reef restoration publications (2016-2019; 145 publications) reveals only 39 (26.9%) dealing with ecological engineering aspects, with 10 classes of "applications"(26 publications) and 4 classes of "properties"(n = 13). Ecological engineering "applications"incorporate all aspects of reef restoration, while the ecological engineering "properties"deal with assisted genetics, coral chimerism, aqua-culturing reef-dwelling organisms, and the consideration of life history parameters of maricultured/transplanted key species. Yet, many ecological engineering applications focus on particular coral species, addressing their specific community issues, while only few address the needs of the entire ecosystem/landscape restoration. It is concluded that rather than trying to return ecosystems to historic states, ecological engineering should shift towards creating novel ecosystems not existed before.