Impacts of Ecological factors on the distribution of Wild Sheep in Khojir and Sorkhe Hessar National Parks



Habitat associations of wild sheep, Alborz red sheep (Ovis orientalis gemelini X Ovis orientalis arkali ), in Khojir and Sorkheh Hesar National Parks were studied over three seasons (Spring, autumn and winter) in 2000. The position of observed maternal groups (including ewe with lamb) and male groups (including rams, barren ewes and juveniles) were determined on topographical maps during the field work. Then, the prepared maps were digitized. Maps of slope, aspect, altitude, soil types, vegetation density, vegetation density of higher than 50 cm, density of forbs, distance to escape terrains, distance to water source and position of asphalted roads, tracks, paths and rural areas were digitized. The frequency of occurrence and density of different observed groups were compared among the classes of each information layer via Geographical Information Systems (GIS). Habitat suitability maps were subsequently prepared. The assessment of prepared maps indicates a logical relation between habitat suitability maps and filed observation Results suggest that wild sheep frequency has a relationship with slope and aspect. Notable aspect of preference of wild sheep is often eastern. In spring, male groups prefer the eastern aspect. Distribution was higher in soils with abundant gravels and high permeability. Abundance and density of wild sheep increase with density of total vegetation and forbs, and also vegetation taller than 0.5 meter, although the latter is not related to the increase of the ewes with lambs' Distance. Analysis shows a decrease in wild sheep abundance when the area is far from water sources and escape terrain and wild sheep are rarely seen to 500 meters from roads and 1000 meters from rural areas.