Resumen de Resilience of long-lived mediterranean gorgonians in a changing world: insights from life history theory and quantitative ecology
In this thesis, we combined long-term demographic surveys and large-scale distribution datasets with innovative population and spatial modeling approaches, and meta-analyses to unravel how local management and ocean warming affect the dynamics and resilience of dominant habitat-forming species. A comparative analysis across marine sessile species revealed strong linkages between depth occurrence, longevity and demographic stability. These results demonstrated a fundamental role of environmental gradients in shaping the evolution of life-history strategies and suggest that deep-sea benthic communities tend to be dominated by long-lived species that are very vulnerable to external sources of mortality. In addition, we demonstrate that life-history strategies play a role in important conservation issues such as recovery times after fishing or restoration actions.
Focusing on the Mediterranean red coral Corallium rubrum, an overharvested precious coral emblematic of coralligenous assemblages, we revealed an extremely slow life-history strategy characterized by low reproduction success, high natural survival, and extended longevity. Local and global stressors such as overfishing and warming have strong impacts on different demographic processes of red coral populations. Harvesting drives strong shifts in size-class distribution towards populations dominated by small colonies. MPAs can enhance structural complexity of red coral populations but, contrary to prior expectations, have little effect on their long-term viability and associated extinction risk. On the other hand, recurrent warming-driven mass mortality events had detrimental effects on affected populations, causing long-term declines and potential local extinction. While MPAs have been proposed to enhance the resilience of marine ecosystems to climate change, our simulations suggested that MPAs only have a weak buffering effect to climatic impacts.
Finally, spatial analyses revealed that future climate change may cause extensive impacts on gorgonian populations across the Mediterranean Sea. Importantly, we found that the extent and severity of warming impacts will be strongly dependent on depth and the global emissions scenarios.
