Biodiversity interslope divergence of oribatid mites at "evolution canyon", Mount Carmel, Israel

We studied the local distribution of oribatid mites at "Evolution Canyon", lower Nahal Oren, Mt. Carmel, Israel. Altogether, 135 species of oribatid mites from 54 families and 88 genera were collected in two years. Species richness and abundance were significantly lower on the "African-savannoid"-like south-facing slope than on the more humid, cooler, "European" north-facing slope covered by a dense Mediterranean garrigue and were positively correlated. The majority of species were widely distributed, i.e., cosmopolitan, Holarctic, Palaearctic, and Euro-East Mediterranean. A similarity of the mites' interslope differentiation pattern to the "water-dependent" groups, such as Collembola, mosses, and fungi, indicates that water availability might be the most important underlying differentiating slope factor in spite of the fact that mite species richness increased upslope and water increased downslope on both slopes. This conclusion supports the idea that water, energy, and water-energy balance might be good predictors for local as well as global distribution patterns of species richness in many organismal groups.