Spatio-temporal change of indicators of marine communities along a latitudinal gradient in the Western Mediterranean Sea

VII International Symposium on Marine Sciences (ISMS 2020), 1-3 July 2020 (Barcelona).-- 2 pages

The Mediterranean Sea is a marine ecosystem with high heterogeneity in its physical, chemical, biological and ecological characteristics, with clear north-south and east-west gradients. It is also an important area in terms of biodiversity and conservation of vulnerable species, as it suffers several human impacts, like fishing and climate change. Previous studies have characterized spatial and temporal patterns of species distribution and biodiversity indicators. However, a community-based analysis combining specific indicators sensitive to fishing impact and climate variability that help to identify which areas and taxa are most sensitive to specific drivers is still missing. In this study, we examined spatio-temporal changes of marine communities along a latitudinal gradient off Spain’s mainland in the Western Mediterranean Sea using data from the MEDITS surveys from 1994 to 2017. Several ecological indicators measuring α (richness, Shannon index and Pielou's evenness index) and β diversity (assessing both turnover and nestedness) were selected, as well as indicators linked with changes in communities due to fishing impact or climate change, like community biomass and functional groups, relative predator weight and trophic level metrics. We used correlation analyses between these indicators and other variables (among them year, location and subarea) and spatial-temporal statistical models to assess variations in the indicators and spatial-temporal gradients. Our results clearly show a heterogeneous response between taxa and area, with a remarkable increase in several indicators when focusing on cephalopods. Our study shows a contrasting response between taxonomic groups suggesting a change in the ecosystem functioning over time in the Western Mediterranean Sea. This in depth analysis of the ecosystem serves as a case study for the use of selected indicators that combine the capacity to detect changes both at regional and local scales

This study has beenfunded by the European project TRIATLAS (BG-08-2018-2019-RIA-SEP-210482854), predoctorals cholarships of the Spanish Ministry of Science and Universities (FPU18/05594) and the European Maritime and Fisheries Fund (EMFF) within the National Program of collection, management and use of data in the fisheries sector and support for scientific advice regarding the Common Fisheries Policy, that support the MEDITS program

Peer reviewed