RODENT SPECIES-DIVERSITY AND MICROHABITAT USE ALONG OPPOSING SLOPES OF LOWER NAHAL OREN, MOUNT-CARMEL, ISRAEL

We assessed species diversity, microhabitat distribution, and mobility of rodent species along the north-facing slope (NF) and south-facing slope (SF) of an environmentally heterogeneous canyon: Lower Nahal Ore n, Mount Carmel, Israel. During February, May, and September 1992, liv e traps were used along seven transect Lines at lower, middle, and upp er altitudes (30, 60, and 90 m from the valley floor, respectively) on each slope and the valley floor. Species richness was greater on NF t han on SF, with very low interslope community overlap. Trapped animals on SF were almost exclusively Acomys cahirinus. On NF, the vast major ity of rodents were Apodemus mystacinus or Apodemus flavicollis, with few A. cahirinus and even fewer Mus macedonicus and Rattus rattus. Wit hin slopes, activity density depended on elevation and species. On SF during the winter, A. cahirinus densities decreased with decreasing el evation. This pattern disappeared by fall. On NF, Acomys activity dens ities decreased from top to bottom. A. mystacinus was widely distribut ed and most abundant in the middle elevation. A. flavicollis decreased with increasing elevation. In a station-by-station analysis, there wa s no statistically significant association between the two Apodemus sp ecies. Rodents were rarely caught on the valley floor. Recapture data indicate that individuals tended to remain within the same or adjacent elevational transects within the same slope. Not a single marked anim al was recovered on the opposite slope. The interslope rodent communit y dissimilarity is attributed to the different microclimates and plant communities on the opposing slopes.