Almost bare rock pavements, including limestone pavements

More or less level surfaces of rock exposed by glacial erosion, by weathering processes, or by aeolian scouring, bare or colonized by mosses, algae or lichens. The hard rock surface may be exposed or partially covered by erosional rock debris, in particular, those produced by frost weathering, heaving, thrusting or cracking. Included are rock surfaces in karst landscapes, rock dome tops, whaleback, roche moutonné, flyggberg and rock basin formations of periglacial areas, golec and felsenmeer formations, level surfaces of dykes and old lava flows. Vascular plant communities may colonize cracks and weathered surfaces.