When coral reefs are damaged, their ecosystems rapidly change to achieve a new stable state. This process, known as a regime shift, is happening on a global scale: corals that were previously hyperdiverse are now being dominated by macroalgae (rather than corals), losing animal diversity, and potentially losing it as a result. ecosystem services. System shifts are not universal, however, and disturbed reefs can revert to their coral-dominated state.
Nicholas Graham and colleagues used long-term data from 21 disturbed reefs in the Indo-Pacific region to study the factors that determine whether a reef will recover or undergo a systemic transformation. Through this natural experiment, they identified thresholds for features such as structural complexity, water depth and fish density that determine the reef's response to an extreme weather event. These results deepen our understanding of one of the greatest threats to marine biodiversity, and may also lead to preemptive action to mitigate the impacts of climate change on tropical coral reefs.
Source: "Nature"