Abstract: Climate change promote strong controlling forces simultaneous with microhabitat types on biodiversity patterns in stressful ecosystems. Extensive studies on the role of rock outcrops as a suitable microhabitat to determine biodiversity patterns have not been performed so far. Therefore, in this study, biodiversity patterns were investigated in rock outcrops and adjacent rangelands in a climatic gradient of annual precipitation (160 to 910 mm) from Shahroud to Gorgan. In this regard, 90 plots of 25 m2 in 12 pairs of sites (rangeland or outcrop) and Taxonomic diversity was measured using Hill numbers (N0, N1 and N2) and functional diversity was measured using Fdis‌ index. We found similar taxonomic patterns (under N0 and N1 indices) between outcrop and rangeland communities across precipitation gradient. While, taxonomic diversity under N2 index showed a significant increase in rangeland simultaneously with non-significant changes for the outcrop across precipitation gradient. Functional diversity represent opposite trends across precipitation in rangeland vs outcrop. Such trends exhibited a significant decrease and increase in functional diversity across precipitation gradient for outcrop and rangeland, respectively. These results indicated that impacts of rock outcrops on taxonomic diversity were similar to mechanisms shaping taxonomic diversity in

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