Why more comparative approaches are required in time-series analyses of coral reef ecosystems

Abstract

In the Anthropocene, the negative effects of environmental change on coral reefs are outpacing their capacity for continued growth. However, a few reefs have shown resilience to recent disturbances, and here we suggest that more comprehensive attention to comparative approaches could lead to a deeper understanding of the processes causing declining coral cover and impaired ecological resilience. Using sites in Mo'orea, French Polynesia, and Panama, Eastern Tropical Pacific, as examples of resilient reefs that have been studied for over 35 yr, we demonstrate the potential of the comparative approach by exploring different ecological drivers of community resilience at each location. In both cases, coral reef community resilience is associated with strong herbivory, but in Mo'orea, resilience is a product of rapid coral community recovery through sexual recruitment in response to a largely indiscriminate disturbance (crown-of-thorns seastars), while in Panama, resilience appears to be a product of corals acquiring resistance to a repetitive selective disturbance (bleaching). Based on these trends, we propose a hypothesisdriven conceptual framework to test for mechanisms driving community resilience. The recent decade of coral reef degradation has brought time-series analyses to the forefront of research on these systems, where they are detecting disturbances that are unique to modern ecological science. Without explicit comparison among systems, the research potential of these projects will not be fully realized.