四川石渠县夏季藏原羚的分布和栖息地特征

Characteristics of the Summer Tibetan Gazelle's Distribution and Habitat in Shiqu County of Sichuan Province

The distribution, size and habitat of Tibetan gazelle （Procapra picticaudata）population have been investigated in Shiqu County of Sichuan Province from June to August of 1999 and July to August of 2003. 195 sampling belts （3 km×3 km） were made in total, which covered 10.8% of the whole grassland. The results showed that average density of Tibetan gazelles was 0.117 individuals/km(2a in Shiqu County, and their population size was about 1 901 individuals.They mainly occurred from （4 200） to （4 700） m altitude （88.3%）.Aggregation characterized distribution pattern of Tibetan gazelles that can be divided into three types:male-only groups（42.1%）, female-only groups（21.1%）and mother-offspring groups（36.8%）, with main group size varied from 2 to 8 individuals （83%） and mean group size 4.8 individuals. 42 sampling plots （20 m ×20 m） were set at least every 100 m apart. Factor analysis indicated that more away from residence （69%） and closer to water source （93%） were characteristic of Tibetan gazelle habitat. It was usually located in sunny （79%）, drafty（83%） and smooth grassland slope （95%） with favorable concealing condition （52%）, where vegetation was mainly 5-8 cm in height （62%）and 75%- 90% in canopy （64%）.