Effects of rock climbing on cliff plant communities at Joshua Tree National Park, California

We compared the plant communities on cliffs used for rock climbing with cli ffs not used for climbing. Eighteen cliffs in Joshua Tree National Park, Ca lifornia (six each with no climbing, moderate climbing, and intensive climb ing) were sampled for plant diversity and community structure. Plants were sampled on cliff faces and at the base of cliffs The dominant ta;ra were Qu ercus cornelius-mulleri, Ericameria cuneata var. cuneata, and Bromus madrit ensis ssp, rubens. Plant species richness on cliff faces and at the base of cliffs was greater for cliffs with no evidence of climbing and lowest for cliffs with intensive use. Numbers of individual plants decreased with incr eased climbing use. Trees, shrubs, forbs, and cacti had greater relative ab undances on cliffs without climbing than on cliffs with climbing. Plant cov er on cliff faces decreased with increased climbing use. Adaptive managemen t will be necessary to minimize the deleterious effects of rock climbing on plant communities associated with cliffs.