Anthropogenic disturbances and ecological memory modulate dynamics in the world’s coral reefs

Abstract

Rapidly changing conditions alter disturbance patterns, highlighting the need to better understand how the transition from pulse disturbances to more persistent stress will impact ecosystem dynamics. We conducted a global analysis of the impacts of eleven acute disturbances on reef integrity using the rate of change of coral cover as a measure of damage. Then, we evaluated how the magnitude of the damage due to thermal stress, cyclones, and diseases varied among tropical Atlantic and Indo-Pacific reefs and whether the cumulative impact of thermal stress and cyclones was able to modulate the responses of reefs to future events. We found that reef damage largely depends on the condition of a reef before a disturbance, disturbance intensity, and biogeographic region, regardless of the type of disturbance. Changes in coral cover after bleaching events were largely influenced by the cumulative stress of past disturbances and did not depend on disturbance intensity or initial coral cover, which suggests that an ecological memory is present within coral communities. In contrast, the effect of cyclones (and likely other physical impacts) was primarily modulated by the initial reef condition and did not appear to be influenced by previous impacts. Our findings also underscore that coral reefs can recover if stressful conditions decrease, yet the lack of action to reduce anthropogenic impacts and greenhouse gas emissions continues to trigger reef degradation. We uphold that evidence-based strategies can guide managers to make better decisions to prepare for future disturbances.

Legacy effects of anthropogenic disturbances modulate dynamics in the world's coral reefs

“…In 90% of risk‐sets, 3 years or less had elapsed between the starting and end points of a disturbance. The data set is publicly available in a DRYAD repository (González‐Barrios et al, 2023).…”

Universality of ecological memory for local and global net ecosystem exchange, atmospheric CO2, and sea surface temperature

“…The use of this ecological parameter has allowed many to probe the underlying mechanisms of ecosystem interactions and of interrelated environmental systems' responses and feedback to both natural and anthropogenic disturbances ? . For example, the potential effect of ecological memory has been elucidated in benthic-herbivore interactions 7 , on identifying the key transcriptor to maintain cell-type memory for gene expressions 8 , ecological effects in invasion biology 9 , cumulative stress in coral communities 10,33,12,13 , interrelated climate dynamics such as global carbon exchanges 14 , and other environment-ecosystem interactions 15,16 .…”

“…Ecological memory in complex systems, such as those observed in ecosystem models, operates as a response to external influences. For example, biological mechanisms such as acclimatization, adaptation, and shifts in community composition are an ecosystem's response to the cumulative stress of past disturbances 13,17 . In a similar manner, these external influences, such as climate disturbances, may also be operating with underlying memory, called climate memory 18 .…”