Data from: Marine protected areas enhance structural complexity but do not buffer the consequences of ocean warming for an overexploited precious coral

1. Global warming and overexploitation both threaten the integrity and
resilience of marine ecosystems. Many calls have been made to at least
partially offset climate change impacts through local conservation
management. However, a mechanistic understanding of the interactions of
multiple stressors is generally lacking for habitat-forming species;
preventing the development of sound conservation strategies. 2. We
examined the effectiveness of no-take marine protected areas (MPAs) at
enhancing structural complexity and resilience to climate change on
populations of an overexploited and long-lived octocoral. We used
long-term data over eight populations, subjected to varying levels of
disturbances, and Integral Projection Models to understand how the
interaction between overfishing and mass-mortality events shapes the
stochastic dynamics of the Mediterranean red coral Corallium rubrum. 3.
MPAs largely reduced colony partial mortality (i.e. shrinkage), enhancing
the structural complexity of coral populations. However, there were no
significant differences in individual mortality or population growth rates
between protected and exploited populations. In contrast, warming had
detrimental consequences for the long-term viability of red coral
populations, driving steady declines and potential local extinctions due
to sharp effects in survival rates. Stochastic demographic models revealed
only a weak compensatory effect of MPAs on the impacts of warming. 4.
Policy implications. Our results suggest that marine protected areas
(MPAs) are an effective local conservation tool for enhancing the
structural complexity of red coral populations. However, MPAs may not be
enough to ensure red coral’s persistence under future increases in thermal
stress. Accordingly, conservation strategies aiming to ensure the
persistence and functional role of red coral populations should include
management actions at both local (well-enforced MPAs) and global scales
(reductions in greenhouse gas emissions). Finally, this study unravels the
divergent demographic consequences that can arise from multiple stressors
and highlights the key role of demography in better understanding and
predicting the consequences of combined impacts for vulnerable ecosystems.