Database of sea fans spatial distribution in the northwestern Mediterranean sea

sea fans (order : alcyonacea) are the most remarkable and easily identifiable species of the subtidal hard substrate communities (gili and ros, 1985). from an ecological point of view, sea fans play an essential role (gili and coma, 1998) by increasing the biomass and the diversity of hard substrates (mitchell et al, 1992; ballesteros, 2006) via an umbrella species role providing habitat for small epifauna and a refuge for many fish (ross and quatrini, 2007). when their density is high enough, they form animal forests (sensu rossi et al 2017) and become engineering species by modifying the level of turbulence and therefore of sedimentation of propagules in the benthic boundary layer (chamberlain and graus, 1975). in the shallow rocky habitats of the mediterranean, five species of sea fans dominate: the white gorgonian eunicella singularis (esper, 1791), the orange gorgonian leptogorgia sarmentosa (esper, 1789), the yellow gorgonian eunicella cavolinii (koch, 1887), the red gorgonian paramuricea clavata (risso, 1826), and the red coral corallium rubrum (linnaeus, 1758). some of these species, characterized by long life span, have been included in the management plans of the gulf of lion marine protected areas, with surveys for the monitoring of the demographic structure of e. singularis (réserve naturelle marine de cerbère-banyuls, aire marine protégée agathoise) and c. rubrum (réserve naturelle marine de cerbère-banyuls, parc marin de la côte bleue). in parallel with these management-related surveys, some scientific studies on the demographic structure and ecology of p. clavata, e. singularis and c. rubrum, with the aim of documenting mass mortality events (cerrano et al. al., 2000, garrabou et al., 2001) have been undertaken in the parc marin de la côte bleue, in the parc national de port-cros, along the côte vermeille and cap de creus coast and in the cinque terre national park (garrabou and harmelin, 2002, torrents et al., 2005 ; linares et al. 2008 linares et al., 2010 ; santangelo et al., 2011; gori et al., 2011a ; gori et al. 2011b; rossi et al., 2008). the present database gathers two extensive inventory of sea fans populations performed between 2013 and 2015 in the gulf of lion and between 2018 and 2019 in the ligurian sea.the same protocol was applied to estimate the population density of the five species in 585 stations. the 585 stations were defined a priori on a regular mesh mapping the main hard-bottom substrate units of the gulf of lion (côte bleue, plateau des aresquiers, plateau du cap d'agde, cap leucate, côte vermeille), and surrounding the ports of toulon, la spezia and bastia (figure 1). the spacing between stations was varied from 100m to 800 m according to bathymetry steepness. each station was geo-referenced from the surface and located on the sea bed with a mooring. counts of individuals of the five species were made by scuba divers trained to species identification in four quadrats (1m x 1m), positionned at 5 m from the mooring along the sea bed, in the four cardinal directions. in total, the sampling required 1500 dives.referencesballesteros e. 2006. mediterranean coralligenous assemblages: a synthesis of present knowledge oceanography and marine biology: an annual review 44, 123-195carpine c, grasshoff m. 1975. les gorgonaires de la mediterranee. bull inst oceanogr monaco 71:1–140cerrano, c., bavestrello g., bianchi c.n., cattaneo r. vietti, s. bava, c. morganti, c. morri, p. picco, g. sara s. schiaparelli s. siccardi a. & sponga, f. 2000. a catastrophic mass-mortality episode of gorgonians and other organisms in the ligurian sea (northwestern mediterranean), summer 1999. ecology letters 3: 284–293.chamberlain j.j. a., graus, r.r. 1975. water flow and hydromechanical adaptations of branched reef corals. : bulletin of marine science 25 (1): 112-125garrabou j., perez t., sartoretto s., harmelin j.g., 2001. mass mortality event in red coral corallium rubrum populations in the provence region (france, nw mediterranean). mar ecol prog ser 217:263–272garrabou j., harmelin g. 2002. a 20-year study on life-history traits of a harvested long-lived temperate coral in the nw mediterranean: insights into conservation and management needs. j anim ecol 71:966–978gili, j.m., & ros, j. 1985. study and cartography of the benthic communities of the medes islands (ne spain). marine ecology 6, 219–238.gili j.m. and coma r. 1998. benthic suspension feeders: their paramount role in littoral marine substrates. tree 13 (8): 316-321gori, a., rossi, s., linares, c., berganzo, e., orejas, c., dale, m. & gili, j.m. 2011a. size and spatial structure in deep versus shallow populations of the mediterranean gorgonian eunicella singularis (cap de creus, northwestern mediterranean sea)” marine biology, doi: 10.1007/s00227-011-1686-7gori a., rossi s., berganzo e., pretus j.l., dale m.r.t., gili j.m. 2011b. spatial[...]

海葵（目：海葵目）是潮下硬质底质群落（Gili 和 Ros，1985年）中最显著且易于识别的物种。从生态学的角度来看，海葵通过伞形物种的角色，为小型附着生物提供栖息地，并为众多鱼类提供庇护所，从而在增加硬质底质的生物量和多样性方面发挥着至关重要的作用（Gili 和 Coma，1998年；Mitchell 等人，1992年；Ballesteros，2006年）。当其密度足够高时，它们会形成动物森林（如 Rossi 等人，2017年所述），并通过改变水底边界层中种子的沉积水平，从而改变湍流水平，成为工程物种（Chamberlain 和 Graus，1975年）。在地中海的浅水岩石栖息地中，有五种海葵物种占主导地位：白色海葵 Eunicella singularis（Esper，1791年），橙色海葵 Leptogorgia sarmentosa（Esper，1789年），黄色海葵 Eunicella cavolinii（Koch，1887年），红色海葵 Paramuricea clavata（Risso，1826年）和红色珊瑚 Corallium rubrum（Linnaeus，1758年）。其中一些物种因其长寿而被纳入狮子湾海洋保护区（Réserve naturelle marine de Cerbère-Banyuls，Aire marine protégée Agathoise）和 C. rubrum（Réserve naturelle marine de Cerbère-Banyuls，Parc marin de la Côte Bleue）的管理计划中，并对 E. singularis（Réserve naturelle marine de Cerbère-Banyuls，Aire marine protégée Agathoise）和 C. rubrum（Réserve naturelle marine de Cerbère-Banyuls，Parc marin de la Côte Bleue）的种群结构进行监测调查。与此相关的管理调查并行，一些关于 P. clavata、E. singularis 和 C. rubrum 的种群结构和生态学研究，旨在记录大规模死亡事件（Cerrano 等人，2000年，Garrabou 等人，2001年），已在 Côte Bleue 海洋公园、Port-Cros 国家公园、Côte Vermeille 和 Cap de Creus 海岸以及五渔村国家公园进行（Garrabou 和 Harmelin，2002年，Torrents 等人，2005年；Linares 等人，2008年；Linares 等人，2010年；Santangelo 等人，2011年；Gori 等人，2011a；Gori 等人，2011b；Rossi 等人，2008年）。当前数据库汇集了在 2013 年至 2015 年间在狮子湾以及 2018 年至 2019 年间在利古里亚海进行的两次广泛的海葵种群普查。对五种物种的种群密度进行了估计，共在 585 个站点进行。这些站点预先定义在了一个规则的网格中，映射了狮子湾主要的硬质底质单元（Côte Bleue，Platou des Aresquiers，Platou du Cap d'Agde，Cap Leucate，Côte Vermeille），并环绕着土伦、拉斯佩齐亚和巴斯蒂亚港口（图 1）。站点之间的间距根据水深陡峭程度从 100 米到 800 米不等。每个站点从水面进行地理定位，并通过锚定定位在海底。潜水员在海底四条正方向上，距离锚定点 5 米的四个 1 米 x 1 米的四边形中，对五种物种的个体数量进行计数。这些潜水员经过培训，能够对物种进行识别。总共需要 1500 次潜水。参考文献：Ballesteros E. 2006. Mediterranean coralligenous assemblages: a synthesis of present knowledge. Oceanography and Marine Biology: An Annual Review 44, 123-195；Carpine C, Grasshoff M. 1975. Les gorgonaires de la Méditerranée. Bull Inst Oceanogr Monaco 71:1–140；Cerrano, C., Bavestrello G., Bianchi C.N., Cattaneo R. Vietti, S. Bava, C. Morganti, C. Morri, P. Picco, G. Sara S. Siccardi A. & Sponga, F. 2000. A catastrophic mass-mortality episode of gorgonians and other organisms in the Ligurian Sea (northwestern Mediterranean), summer 1999. Ecology Letters 3: 284–293；Chamberlain J.J. A., Graus, R.R. 1975. Water flow and hydromechanical adaptations of branched reef corals. : Bulletin of Marine Science 25 (1): 112-125；Garrabou J., Perez T., Sartoretto S., Harmelin J.G., 2001. Mass mortality event in red coral Corallium rubrum populations in the Provence region (France, northwestern Mediterranean). Mar Ecol Prog Ser 217: 263–272；Garrabou J., Harmelin G. 2002. A 20-year study on life-history traits of a harvested long-lived temperate coral in the northwestern Mediterranean: Insights into conservation and management needs. J Anim Ecol 71: 966–978；Gili J.M., Ros J. 1985. Study and cartography of the benthic communities of the Medes islands (northeast Spain). Marine Ecology 6, 219–238；Gili J.M. and Coma R. 1998. Benthic suspension feeders: their paramount role in littoral marine substrates. Tree 13 (8): 316-321；Gori A., Rossi S., Linares C., Berganzo E., Orejas C., Dale M. & Gili J.M. 2011a. Size and spatial structure in deep versus shallow populations of the Mediterranean gorgonian Eunicella singularis (Cap de Creus, northwestern Mediterranean Sea). Marine Biology, doi: 10.1007/s00227-011-1686-7；Gori A., Rossi S., Berganzo E., Pretus J.L., Dale M.R.T., Gili J.M. 2011b. Spatial[...]