Rock climbing alters the vegetation of limestone cliffs in the northern Swiss Jura mountains

Betr. Auswirkungen des Klettersports auf die Pflanzenwelt im Baselbieter Jura Exposed cliffs in the northern Swiss Jura Mountains harbour a highly diverse flora with numerous endangered and relic plant species. On these cliffs, sport climbing is enjoying increasing popularity. We examined the ecological effects of sport climbing on vascular plants at the cliff base and on the cliff face by assessing plant cover and species density at various distances from frequently used climbing routes. Plant cover was significantly reduced at the base of climbing routes. Furthermore, species density (number of species per square metre) at the cliff base, as well as plant cover and species density at the cliff face, tended to increase with distance from the route. We also compared the vegetation of five frequently climbed cliffs with that of seven unclimbed cliffs. Climbing significantly altered the plant composition. Specialized rock species occurred less frequently on climbed cliffs than on unclimbed cliffs. Management plans and conservation actions are needed to preserve the threatened plant species on frequently climbed cliffs. Such plans should include the establishment of climbing-free protection areas on cliffs with a high number of specialized, relic plants and the protection of entire cliffs that are not yet climbed.