The role of geomorphic zonation in long-term changes in coral-community structure on a Caribbean fringing reef

PeerJ. 2020 Oct 22:8:e10103. doi: 10.7717/peerj.10103. eCollection 2020.


Ecological processes on coral reefs commonly have limited spatial and temporal scales and may not be recorded in their long-term geological history. The widespread degradation of Caribbean coral reefs over the last 40 years therefore provides an opportunity to assess the impact of more significant ecological changes on the geological and geomorphic structure of reefs. Here, we document the changing ecology of communities in a coral reef seascape within the context of its geomorphic zonation. By comparing basic ecological indices between historical and modern data we show that in 35 years the reef-front zone was transformed from a complex coral assemblage with a three-dimensional structure, to a size-homogenized and flattened one that is quasi indistinguishable from the adjacent non-accretional coral-ground zone. Today coral assemblages at Punta Maroma are characterized by the dominance of opportunistic species which are either tolerant to adverse environmental conditions, including sedimentation, or are known to be the first scleractinian species to recruit on disturbed reefs, implying they reflect a post-hurricane stage of adjustment. Despite an increase in similarity in ecological indices, the reef-front and coral-ground geomorphic zones still retain significant differences in coral assemblages and benthic habitat and are not homogeneous. The partial convergence of coral assemblages certainly has important consequences for the ecology and geological viability of the reef and its role in coastal protection, but environmental physical drivers continue to exert a fundamental role in the character and zonation of benthic communities of this reef seascape.

Keywords: Biotic homogenization; Climate change; Coral reef; Reef accretion; Reef-building corals.

Grants and funding

Alexis E. Medina-Valmaseda was supported by a PhD scholarship (No. 666383) from CONACyT. Paul Blanchon was funded by the Mexican Council of Science and Technology (CONACyT, A1-S-18879) and the Universidad Nacional Autónoma de México (DGAPA/PAPIIT RN214819). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.