Influence of slope aspect on Mediterranean woody formations: Comparison ofa semiarid and an arid site in Israel

This study investigates the effects of slope aspect on plant community char acteristics such as plant cover, species composition and above-ground bioma ss production in Mediterranean trees and shrubs in two climatological regio ns. Two experimental sites were selected in a climatic gradient that runs f rom the foothills of the Judean Hills to the northern Negev desert in Israe l. In each site, 16 quadrats of 10 m x 10 m (eight south-facing and eight n orth-facing slopes) were established and the vegetation was recorded. Domin ant tree and shrub species were measured using allometric parameters of are a and volume, and representative branches were cut and weighed. Species stu died were Quercus calliprinos, Phillyrea latifolia, Pistacia lentiscus, Cis tus creticus, Coridothymus capitatus, and Sarcopoterium spinosum. The resul ts showed that slope aspect had significant effects on the composition, str ucture and density of the plant communities developing in both sites. Veget ation structure within a site changed significantly in the short distance s eparating the north and south-facing slopes, and that pattern remained gene rally constant when comparing the two sites along the rainfall gradient. Th e data collected here provides new insight into the slope aspect effects on biomass allocation of different woody life forms of eastern Mediterranean plant communities.