Cliffs, together with vegetated crevices, ledges and cliff-tops along the coasts of the Mediterranean Sea and the Atlantic Ocean in southern Portugal, and more locally, the Black Sea. Exposed bedrock dominates the habitat, and its variable composition and structure determine the character of available surfaces, the height and slope of the cliffs influencing the input of salt spray which, on exposed coasts, can be very high close to the sea. This combination of local climatic and topographic conditions determines the often strong zonation of crevice vegetation and grasslands found on the cliffs, with regional climate also affecting the flora, with many Mediterranean endemics.