Biodiversity and habitat mapping of Menorca Channel (western Mediterranean): implications for conservation

Abstract

Menorca Channel (Balearic Islands, western Mediterranean) comprises 98,700 Ha of continental shelf. It has been proposed to include this area in the Natura 2000 network due to the wide range of species and habitats of high conservation value found here, such as Posidonia oceanica meadows and maërl and coralligenous beds. This study aimed to establish a scientific basis for managing and protecting the continental shelf bottoms in Menorca Channel. Sampling was carried out with side-scan sonar, beam trawls, box corers, a remote-operated vehicle and an underwater drop camera. The information collected was used to map the habitat distribution between 50 and 100 m depth, as well as make an inventory and describe the spatial patterns of both the specific and functional diversity. A total of 636 species was recorded in a mosaic of habitats in which Corallinacea calcareous algae and other soft red algae (Osmundaria volubilis and Peyssonnelia spp.) were the most abundant groups. Hotspots of specific and functional diversity were located in areas with high habitat heterogeneity and complexity. Protection of Menorca Channel should not only include the habitats and species in the European directives, but also the habitats that are not currently protected, such as O. volubilis and Peyssonnelia beds, due to Electronic supplementary material The online version of this article (

Contribution to the study of deep coastal detritic bottoms: the algal communities of the continental shelf off the Balearic Islands, Western Mediterranean

“…see Dieuzede, 1940;Huvé, 1956;Costa, 1960;Bourcier, 1968;Blunden et al, 1977;Bordehore et al, 2003;Peña, 2010) and beam trawls (Barberá et al, 2012;Ellis et al, 2013). Images obtained by ROV, together with previous results (Joher et al, 2012), showed that the community dominated by S. fruticulosus was very homogeneous, and composed mainly of small maërl-forming species (S. fruticulosus and Phymatolithon calcareum).…”

“…Several ROV dives were performed in 2009 in the Menorca channel and along the Southern coast of Menorca (Barberá et al, 2009(Barberá et al, , 2012 in order to locate certain homogeneous areas harbouring the communities that characterized the seascapes found by Joher et al (2012). Three of these areas were located: one with maërl beds of S. fruticulosus, another with forests of L. rodriguezii, and a last one with P. inamoena beds.…”

“…Maërl beds dominated by S. fruticulosus have seldom been reported from the Balearic Islands (Barberá et al, 2012), and their composition and structure have only been studied from Tossa de Mar (Northwestern Mediterranean, Spain) (Ballesteros, 1988), where the maërl bed grows in reduced light levels (around 0.3 % of surface PAR irradiance) and moderate temperature range conditions (12.5 to 21.5ºC). Forests of L. rodriguezii develop under low light intensities (usually at depths between 50 and 120 m, being more abundant below 70 m), low temperature (less than 14ºC), and unidirectional current conditions (Feldmann, 1934;Huvé, 1955;Molinier, 1960;Pérès & Picard, 1964;Giaccone, 1967Giaccone, , 1971Lüning, 1990;Giaccone & Di Martino, 1997).…”

First record of the Reticulated dragonet, Callionymus reticulatus Valenciennes, 1837 (Actinopterygii: Callionymiformes: Callionymidae), from the Balearic Islands, western Mediterranean.

“…Callionymus reticulatus inhabits coarse sand bottom, with a grain size similar to the size of the spots on the back and sides of the specimens; the species was found near Mallorca at depths of 46-68 m, significantly deeper than in the north-eastern Atlantic; Atlantic depth records based on SMNS materials range from 11-57 m. A reason for this deeper occurrence may be due to a slightly higher water temperature in the Mediterranean compared to the same depths in the north-eastern Atlantic and the presence of red algae communities such as maërl and Peyssonnelia beds which dominate the coarse sand circalittoral bottoms of the Balearic Islands down to 80 m depth (Ballesteros 1994, Ordines and Massutí 2009, Barberá et al 2012. In this sense, there seems to be a clear habitat partitioning between C. reticulatus and C. maculatus in the area sampled during the DRAGONSAL0914 survey.…”

Submarine Mass Movements Along a Sediment Starved Margin: The Menorca Channel (Balearic Islands – Western Mediterranean)

“…Sediments composing the seafloor mainly originate from 69 local coastal erosion processes and by a variable carbonate production of bioherms 70 (Barberà et al 2012). …”