CLIFF-BIRD AND PLANT-COMMUNITIES IN JOSHUA-TREE-NATIONAL-PARK, CALIFORNIA, USA

During spring and summer 1993, we measured bird and plant communities at cliff and noncliff sites in the Mojave Desert, California. Six site s (each with cliff and noncliff plots) were sampled in Joshua Tree Nat ional Park. Bird species diversity was 60% greater at cliff sites than at noncliff sites. Five bird species accounted for 56% of the relativ e abundance at cliff sites, whereas two species accounted for 66% of t he relative abundance at noncliff sites. Cliff plant diversity was 2.9 times the diversity of noncliff sites. Grasses were the dominant plan ts at noncliff sites, whereas grasses, shrubs, and trees shared domina nce at cliff sites. Cliffs support enhanced floral and avian diversity .