Functional developmental states of the Greater Caribbean coral reefs

Trophic networks are the way by which energy is distributed through the ecosystem and out of it. Each ecosystem at a particular functional developmental state (FDS) has attributes that can be measured and understood through the food web. Trophic interactions can further our understanding of the FDS of coral reefs that can be associated with their geomorphological structure; however, the number of the states is presently unknown. Thus, we investigated the geomorphology of a set of the Greater Caribbean coral reefs, describing gradients of coral reef FDS. Eleven coral reefs in the Gulf of Mexico and 17 reefs in the Caribbean Sea were examined, including fringing reefs and platform reefs (submerged and emergent with and without sandy-island cay). For each coral reef, nine ecosystem developmental attributes and five topological indices were estimated from trophic models. Using non-metric multidimensional scaling and analysis of similarities, we found a gradient of maturity consisting of eight FDS. Early states correspond to fringing reefs (Punta Nizuc, Mahahual) in the Mexican Caribbean, and later states correspond to emerging platform reefs without (Palo Seco, Blanquilla) and with sandy-island cay (Cayo Cochinos, Media Luna). Using topological indices as variables and the eight FDS as nominal variables in a partial redundancy analysis, we confirmed that energy flow control increases with maturity and degree of geomorphological and physical structural complexity. On the contrary, betweenness centrality, the number of connections, and the number of predator–prey interactions decrease with functional maturity.