Chapter Mapping of benthic rocky shore habitats of the algerian coast (south-western mediterranean)

Abstract

This study is the first large-scale mapping of supralittoral, mediolittoral and upper infralittoral benthic rocky substrate habitats of the Algerian coast. It is a first step to fix the lack of cartographic information and general knowledge of coastal marine habitats in Algeria. 2D digital habitat mapping was carried out along 450 km of coastline using CAT-LIT methodology. We also provide a reference database of the coastal marine habitats of the Algerian coast, named "List of ALGerian MARin HABitats". Natural rocky coastlines are the dominant typological category in the area. The coastline studied is highly diverse in terms of habitats, since 35 benthic habitats were identified. Supralittoral benthic communities are dominated by barnacle Euraphia depressa and the lichen Verrucaria amphibia. Barnacles (Chthamalus spp.) and the red alga Rissoella verruculosa occupy the upper mediolittoral zone, while habitats dominated by the red algae Ellisolandia elongata and Lithophyllum byssoides characterize the lower mediolittoral zone. The upper infralittoral fringe is dominated by Ellisolandia elongata and rockweed Ericaria selaginoides in exposed shores or by Gongolaria barbata in sheltered areas. These habitats represent the core habitats of the littoral zone of Algeria. Anthozoans Astroides calycularis and Actinia equina are common in the infralittoral zone. Ulvales are abundant in Algiers Bay indicating polluted waters.