Combining literature review, acoustic mapping and in situ observations: an overview of coralligenous assemblages in Liguria (NW Mediterranean Sea)

Abstract

Summary:A review and update of the existing knowledge on the coralligenous assemblages of Liguria (NW Italy) was conducted as an essential step towards management measures for their conservation according to the EU Marine Strategy Framework Directive. By combining a literature review, acoustic mapping and in situ observations on a geographic information systems platform, we were able to assess the distribution and heterogeneity of coralligenous assemblages and the main pressures affecting them. The reliability of the literature was previously estimated using a dependability index. The coralligenous assemblages cover an area of 130.9 ha and range from 10 to 113 m depth. Twelve different biological facies (five of them not included in the EUNIS list) were identified and four main geomorphotypes (plungingcliffs, paleocliffs, rockfalls and shoals) were recognized. Incident light values influenced the distribution of four facies in Portofino promontory. Pressures were found on 33% of the coralligenous assemblages investigated, mainly due to fishing activities, mass mortality events, invasive species and occasional mucilaginous events. Our results showed a high spatial, geomorphological and biological heterogeneity of coralligenous assemblages in Liguria.Keywords: mapping; literature review; heterogeneity; coralligenous assemblages; NW Mediterranean Sea.Combinando revisión bibliográfica, mapas acústicos y observaciones in situ: sinopsis de las formaciones coralígenas en Liguria (NO del mar Mediterráneo) Resumen: Una revisión y actualización del conocimiento existente sobre las formaciones coralígenas en Liguria (NO de Italia) ha sido implementado como paso esencial con vistas a las medidas de gestión para su conservación de acuerdo con la Directiva Marco sobre la Estrategia Marina. Combinando en plataforma SIG revisión bibliográfica, mapas acústicos y observaciones in situ hemos sido capaces de determinar la distribución de las formaciones coralígenas, su heterogeneidad y sus principales presiones. La fiabilidad de la bibliografía fue estimada a través del índice de confianza (DI). Las formaciones coralígenas cubren un área de 130.9 ha en un rango de profundidad que va desde los 10 m a los 113 m. 12 facies biológicas diferentes (5 de ellas no incluidas en la lista EUNIS) fueron identificadas y 4 geomorfotipos principales (acantilado actual, paleoacantilado, cúmulo de rocas y bajos) fueron reconocidos. Los valores de luz incidente influenciaron la distribución de 4 facies en el promontorio de Portofino. Fueron encontradas presiones en el 33% de las formaciones coralígenas investigadas, principalmente debidas a actividades de pesca, episodios de muerte masiva, especies invasoras y proliferación de algas mucilaginosas. Nuestros resultados mostraron una elevada heterogeneidad espacial, geomorfológica y biológica de las formaciones coralígenas en Liguria.

The park never born: Outcome of a quarter of a century of inaction on the sea‐floor integrity of a proposed but not established Marine Protected Area

“…It was characterized by the abundance of large, massive, or erect sponges, including Axinella polypoides , Sarcotragus foetidus , Spongia lamella , Dysidea avara , and Scalarispongia scalaris . Similar epibenthic communities have been described for coralligenous reefs in other Mediterranean regions (Bedulli, Bianchi, Morri, & Zurlini, ; Ben Mustapha et al, ; Cánovas Molina et al, ; Garrabou et al, ), but have not yet been recognized either by EUNIS or by the handbook for the classification of Mediterranean habitats (Pergent, Bellan‐Santini, Bellan, Bitar, & Harmelin, ). We propose, therefore, that a ‘Facies with Axinella polypoides ’ category be included in the next revision of EUNIS.…”

“…The first concern of the management plan for the Gallinara sea floor should be the reduction of sea‐based human pressures. Early studies suggested that boat anchoring represented the most serious threat to seafloor integrity (Balduzzi et al, ), which has been confirmed by later assessments (Cánovas Molina et al, ; Tunesi et al, ). Anchoring must therefore be banned, and recreational boating regulated (Venturini et al, ).…”

“…The tidal range does not exceed 0.3 m (Vacchi et al, ). The perimeter of the island measures approximately 1.4 km and features steep plunging cliffs (Cánovas Molina et al, ), notably in the south‐east portion (Figure b). Here, the base of the cliffs can reach down to 15 m depth, lying on a gravelly sea floor the origin of which is most likely related to the progressive collapse of the cliff face.…”

STAR: An integrated and standardized procedure to evaluate the ecological status of coralligenous reefs

“…vertical or near‐vertical walls from a steep littoral rock face) and banks (according to the original substratum: rock or sediment) (Ballesteros, ). Although both forms may be relatively shallow depending on the environmental conditions, rims characterize mostly coastal rocky systems, whereas banks mainly occur on deeper continental shelfs (Cánovas‐Molina et al, ).…”

Integración de el índice ESCA por medio de los macro-invertebrados sésiles

“…It is one of the most important coastal ecosystems of the Mediterranean Sea for distribution, biodiversity, productivity and role in the CO 2 cycle (Bertolino et al 2013, Martin et al 2014, Casas-Guell et al 2015. Coralligenous habitat is considered sensitive to human activities (Piazzi et al 2012, Cánovas Molina et al 2016) and has been included in the protection programme of European legislation (e.g. the Habitats Directive 92/43/EEC; the Marine Strategy Framework Directive 2008/56/EEC) as a habitat of high scientific interest and biodiversity ("special habitat type" sensu MSFD 2008/56/EEC) (EC 2008).…”