A framework for measuring coral species-specific contribution to reef functioning in the Caribbean

Social–environmental drivers inform strategic management of coral reefs in the Anthropocene

“…It is striking that the majority of Indo-Pacific reefs remain dominated by structurally-important corals even following the impacts of the 1998 mass coral bleaching event and subsequent bleaching events, and given expectations of different trajectories of regime shifts and recovery following bleaching impacts or human activities 6,21,22 . Notably, these findings are in contrast to contemporary Caribbean reefs where very few reefs remain dominated by key reef-building species and instead comprised of weedy taxa with limited functional significance 8,23 . However, Indo-Pacific reefs varied in their absolute abundance of the four types ( Figure 1), also suggesting the potential for dramatic structural and functional shifts away from expected historical baselines of highly abundant branching and plating corals 24 , a warning sign considering recent community shifts in the Caribbean 23 .…”

“…Given such concerns about the long-term functional erosion of coral communities, one conservation strategy is to prioritize the protection of reefs that currently maintain key ecological functions, i.e., reefs with abundant fast-growing and structurally-complex corals that can maintain vertical reef growth and net carbonate production 5,6 . However, efforts to identify potentially functioning reefs across large spatial scales are often hindered by a focus on total coral cover, an aggregate metric that can overlook taxonspecific differences in structural complexity and carbonate production 7,8 . To date, global empirical studies of scleractinian coral communitiesand their environmental and socioeconomic driversare rare, in part due to the absence of large-scale assemblage datasetsa key challenge that must be overcome in modern ecology.…”

“…On each reef, we evaluated total coral cover and the abundance of different coral life history types previously developed from a trait-based approach with species characteristics of colony morphology, growth, calcification, and reproduction 9 (https://coraltraits.org). The abundance of different coral taxa can affect key ecological processes for future reef persistence, including the provision of reef structural complexity, carbonate production (the process by which corals and some other organisms lay down carbonate on the reef), and ultimately reef growth (the vertical growth of the reef system resulting from the processes of carbonate production and erosion) 5,7,8,10 . Fast-growing branching, plating and densely calcifying massive coral taxa that can contribute to these processes are expected to be functionally important, not only by maintaining critical geo-ecological functions that coral reefs provide 10 , but might also help reefs track sea level rise 5 , recover from climate disturbances 11 , and sustain critical habitat for reef fish and fisheries 12,13 .…”

“…Specifically, we consider four coral life histories 9 (Supplementary Table 2): a 'competitive' life history describes fast-growing branching and plating corals that can accrete structurally-complex carbonate reef architectures but are disproportionately vulnerable to multiple stressors; a 'stress-tolerant' life history describes large, slow-growing and long-lived massive and encrusting corals that can build complex high-carbonate reef structures to maintain coral-dominated, healthy and productive reefs, and often persist on chronically disturbed reefs; by contrast, 'generalist' plating or laminar corals may represent a subdominant group of deeper water taxa, while smaller brooding 'weedy' corals typically have more fragile, lower-profile colonies that provide less structural complexity and contribute marginally to carbonate production and vertical growth 10,12,14 . We therefore consider competitive and stress-tolerant life histories as key framework-building species given their ability to build large and structurally complex coral colonies 8,10,12 . We hypothesize that the abundance of different life histories within a coral assemblage provides a signal of past disturbance histories or environmental conditions [15][16][17] that may affect resilience and persistence to future climate impacts 18 .…”

Changing geo‐ecological functions of coral reefs in the Anthropocene

“…An emerging challenge in coral reef ecology is therefore to understand the functional consequences of shifts in coral abundance and composition. Ecological assemblage phase shifts have direct relevance to the issues of changing carbonate budgets discussed above because different morphological groups of corals are generally defined by different calcification and linear extension rates (González‐Barrios & Álvarez‐Filip, ). Coral reef habitats dominated by stress‐tolerant taxa may thus become defined by persistent low (relative to regional optimal) budget states (Manzello et al., ).…”