Candela Marco-Méndez1, Mario Minguito-Frutos2, Sofía Monte-Palomo1, Jordi Boada1, Laura Tamburello3,4, Simone Farina3,5, Giullia Ceccherelli6, Bernat Hereu7, Antonio Di Franco3,4, Antonio Calo8, Manfredi Di Lorenzo3,4, Alcoverro Teresa1
1Centre d’Estudis Avançats de Blanes (CEAB-CSIC), Spain - 2Ifremer, France - 3Stazione Zoologica Anton Dohrn, Italy - 4NBFC, National Biodiversity Future Center, Italy - 5National Research Council, Italy - 6University of Sassari, Italy - 7Universitat de Barcelona, Spain - 8University of Palermo, Italy
Mediterranean marine forests face increasing threats from overgrazing, climate change, and anthropogenic pressures, resulting in transitions to states dominated by turf or bare rock and encrusting algae. This study investigates the differential roles of Arbacia lixula and Paracentrotus lividus in driving these phase shifts, with a focus on species-specific sea urchin biomass thresholds associated to two regions: Catalonia and Sicily). In Catalonia, A. lixula exerts a dominant influence, with a critical biomass threshold of approximately 200 g/m² sufficient to reduce canopy-forming algae. P. lividus impacts algal communities at higher thresholds ( 300 g/m²), contributing to transitions in macroalgae habitats with less pronounced effects compared to A. lixula. In contrast, Sicily’s oligotrophic environments exhibit lower thresholds for phase shifts for both species and an inverted species tendency. A. lixula drives significant reductions in algal complexity at just 127 g/m², while P. lividus thresholds are even lower, around 94 g/m². These differential species-specific thresholds reflect the differential impact that both species can have depending on the region. These findings underscore the importance of context-specific management strategies where knowing the identity of the sea urchin becomes crucial. Maintaining urchin populations below critical biomass thresholds is essential to preserving algal biodiversity and preventing habitat desertification. This study provides a Mediterranean-scale framework for understanding the species-specific drivers of benthic habitat resilience and informs adaptive management efforts under increasing environmental and anthropogenic stressors.
Biography
Dr Marco-Méndez has dedicated her scientific career to investigating the environmental impacts on marine ecosystems, with a particular emphasis on the resilience of seagrass meadows and other benthic habitats under the pressures of climate change. To date, she has authored 31 peer-reviewed articles, including 40% as first author and 25% as senior author, as well as 5 book chapters and over 30 technical reports. Her research, published in leading journals such as Nature Ecology & Evolution and Sc