Limestone Pavement
Limestone pavement is a unique and rare habitat in Britain with the majority of the area occurring in western North Yorkshire and south and east Cumbria. The Yorkshire Dales National Park contains approximately half of the limestone pavement area in Britain and is therefore an extremely important area for this internationally recognised habitat.
Limestone pavements consist of a near horizontal surface of Carboniferous limestone, irregularly corrugated and furrowed by chemical weathering, with deeper fissures or 'grikes' corresponding to natural joints within the rock, resulting in the formation of discrete separated blocks or 'clints'. The biodiversity of limestone pavements depends primarily on the depth of grikes and the level of grazing by livestock and rabbits. The majority of limestone pavements in the Limestone Country Project area are heavily affected by grazing with vegetation growth confined to the deeper and less accessible grikes. Ferns are the most characteristic plant species of limestone pavements. Some of these, like rigid buckler fern and baneberry, are extremely rare and confined exclusively to limestone pavements. Other plants associated with the limestone Pavements are woodland species such as dog's mercury, wood sorrel and ramsoms. More rarely herb Paris and lily-of-the-valley occur.
Pavements with only light grazing can develop vegetation on the surface of the clints, including blue moor-grass, rock-rose and bloody crane's-bill. Where grazing pressure is absent tree and shrub species colonise the pavements, including hazel, ash, rowan and hawthorn.
