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

ABSTRACT

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 Oren, Mount Carmel, Israel. During February, May, and September 1992, live traps were used along seven transect lines at lower, middle, and upper altitudes (30, 60, and 90 m from the valley floor, respectively) on each slope and the valley floor. Species richness was greater on NF than on SF, with very low interslope community overlap. Trapped animals on SF were almost exclusively Acomys cahirinus. On NF, the vast majority of rodents were Apodemus mystacinus or Apodemus flavicollis, with few A. cahirinus and even fewer Mus macedonicus and Rattus rattus. Within slopes, activity density depended on elevation and species. On SF during the winter, A. cahirinus densities decreased with decreasing elevation. This pattern disappeared by fall. On NF, Acomys activity densities decreased from top to bottom. A. mystacinus was widely distributed and most abundant in the middle elevation. A. flavicollis decreased with increasing elevation. In a station-by-station analysis, there was no statistically significant association between the two Apodemus species. 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 animal was recovered on the opposite slope. The interslope rodent community dissimilarity is attributed to the different microclimates and plant communities on the opposing slopes.