Data collected related to spatial distribution of six coastal habitats of red algae on the Catalan coast, significantly influenced by environmental variables. The red algae mentioned in the database are: Rissoella verruculosa, Lithophyllum byssoides /Lithophyllum byssoides rims ("Trottoir"), Neogoniolithon brassica-florida, Hildenbrandia rubra /Phymatolithon lenormandi and Cystoseira mediterranea. Data on littoral habitat distribution and environmental variables were collected along the whole coast of Catalonia (North-Western Mediterranean between 3º 10' 28.072" E, 42º 26' 17.619" N and 0º 30' 57.001" E, 40º 31' 26.302" N)

The file called 'Full data base' for each identifier point, collect the followimg information: the projected coordinates (European Datum 1950 UTMZone 31N), the environmental variables and the presence/absence (1/0) of each habitat. Slope code: 1 = 0º-10.8º; 2 = 10.8º-22.8º; 3 = 22.8º-45.1º; 4 = 45.1º-68.2º; 5 = 68.2º-87.8º. Habitats code: Riv = Rissoella verruculosa; Lby = Lithophyllum byssoides; Tro = Lithophyllum byssoides rims ("Trottoir”); Neo = Neogoniolithon brassica-florida; Hph = Hildenbrandia rubra/ Phymatolithon lenormandi.

Tables A-F contain results of logistic regression models. Results of logistic regression models for all sampling strategy designs are presented for each habitat and for all sample sizes. For training data, the number (N) and frequency (F) of the habitat occurrence are presented. Results of null models are shown with the mead and standard deviation of the 10 models calculated. The D2 is the Deviance of the model in the training data; AUC is the area under the receiver operating characteristic (ROC) curve, se and spe are the sensitivity and specificity respectively, for the predictive model in the test data