Erratum: CORRIGENDUM: Coralligenous and maërl habitats: predictive modelling to identify their spatial distributions across the Mediterranean Sea

Variations in coralligenous assemblages from local to biogeographic spatial scale

The present study aims at contributing to the knowledge of the spatial variability of coralligenous reefs through the evaluation of patterns ranging from local to biogeographic scale around the island of Sardinia. The coralligenous reef assemblages of six areas were studied through a hierarchical sampling design: three sites per area were selected, in each site three plots were sampled and in each plot ten photographic samples were collected. The structure of coralligenous reefs across closed biogeographic regions is described, highlighting that nearly pristine assemblages, although characterized by similar high diversity, can be either dominated by animals, such as gorgonians and bryozoans, or macroalgae. The observed variations seem largely related to biogeographic patterns rather than spatial distance, supporting the need to identify specific reference conditions to assess the ecological quality of this habitat depending on the biogeographic area to be monitored.

Extreme events and conservation of subtidal habitats: Effects of a rainfall flood on coralligenous reefs

The increase of the intensity and frequency of rainfall-dominated flood is considered a main effect of climate change. The present study evaluated the effect of a rainfall flood event on coralligenous reefs. The flooded site was compared to three control sites using a Before/After-Control/Impact (BACI) design. Sites were sampled using the STAR (STAndaRdized coralligenous evaluation procedure) approach and three ecological indices (ESCA, COARSE and ISLA) were calculated. At the disturbed site the number of species per sample, beta diversity, sensitivity levels of assemblages and the values of the three indices were lower after the flooding event, while the same variables did not decrease at the control sites. Algal turf and Dictyotales increased at the disturbed sites after the flood event, while Udoteaceae, erect sponges, bryozoans and Corallium rubrum decreased. This study provides evidence for identifying floods as a further cause of degradation for the coralligenous reef assemblages.

Testing methods to support management decisions in coralligenous and cave environments. A case study at Portofino MPA

Baseline data on the distribution, condition and extent of coralligenous and cave bioconcretions is one of the main requirements of the European Marine Strategy Framework Directive (MSFD) necessary to assess the achievement of a Good Environmental Status (GES) by 2020. In this study the potential of remote sensing and distribution modelling techniques to map, measure descriptors and choose indicators were tested, that could provide standard methods for the assessment of the health status and assist in monitoring activities. It is demonstrated how, by combining different methodologies, it is possible to map the distribution of the bioconcretions with acceptable accuracy and to discriminate the main habitat types and facies. In addition, zonal statistical analysis revealed that fishing activities primarily coincide with areas of high coverage of the bioconcretions. Results demonstrate that the presented methodology is a valuable simple tool to assess several MSFD descriptors and indicators, and could strengthen management efficiency when making informed, ecologically relevant decisions.

Fine-Scale Cartography of Human Impacts along French Mediterranean Coasts: A Relevant Map for the Management of Marine Ecosystems

Ecosystem services provided by oceans and seas support most human needs but are threatened by human activities. Despite existing maps illustrating human impacts on marine ecosystems, information remains either large-scale but rough and insufficient for stakeholders (1 km² grid, lack of data along the coast) or fine-scale but fragmentary and heterogeneous in methodology. The objectives of this study are to map and quantify the main pressures exerted on near-coast marine ecosystems, at a large spatial scale though in fine and relevant resolution for managers (one pixel = 20 x 20 m). It focuses on the French Mediterranean coast (1,700 km of coastline including Corsica) at a depth of 0 to 80 m. After completing and homogenizing data presently available under GIS on the bathymetry and anthropogenic pressures but also on the seabed nature and ecosystem vulnerability, we provide a fine modeling of the extent and impacts of 10 anthropogenic pressures on marine habitats. The considered pressures are man-made coastline, boat anchoring, aquaculture, urban effluents, industrial effluents, urbanization, agriculture, coastline erosion, coastal population and fishing. A 1:10 000 continuous habitat map is provided considering 11 habitat classes. The marine bottom is mostly covered by three habitats: infralittoral soft bottom, Posidonia oceanica meadows and circalittoral soft bottom. Around two thirds of the bottoms are found within medium and medium high cumulative impact categories. Seagrass meadows are the most impacted habitats. The most important pressures (in area and intensity) are urbanization, coastal population, coastal erosion and man-made coastline. We also identified areas in need of a special management interest. This work should contribute to prioritize environmental needs, as well as enhance the development of indicators for the assessment of the ecological status of coastal systems. It could also help better apply and coordinate management measures at a relevant scale for biodiversity conservation.