春季岩羊种群生态学特征的初步研究

A PRELIMINARY STUDY OF SOME CHARACTERS OF BLUE SHEEP POPULATION ECOLOGY IN SPRING

本文通过对贺兰山春季岩羊的研究得出，贺兰山的岩羊为晨昏性活动动物，两个活动高峰分别在５００～９００和１７００～２０００。在春季，岩羊群主要以小群为主，且主要是混合群，平均群大小为５．６头；整个贺兰山的岩羊密度为３．６头／ｋｍ２；岩羊的雌雄性比为１１．３６，并指出目前偷猎仍然影响着种群的性比；雄性岩羊的自然死亡年龄在６．５～１０．５岁，其中以９．５岁是其自然死亡的高峰时期。

? The population of blue sheep(Pseudors nayaur) was studied in Helan mountain, China between April and May 1996.808 blue sheep were observed during the study period. The blue sheep was mainly crepuscular animal in spring, two activity peaks were from 05∶00 to 09∶00 and from 17∶00 to 20∶00, respectively. The average herd size of blue sheep was 56 individuals. The largest herd we saw was 30 individuals,and the smallest was 2 individuals. The blue sheep herds can be divided into three types: male herds, femal herds and mixed herds.The population density of blue sheep was 36 individuals/km2,the 656 blue sheep classified for sex and age, the ratio of adult males to females was 1∶136, and the ratio of adult females to youngs was 1∶043. We collected 52 male skulls with forns in the field and determined the age by growth ring of horns. According to these skulls, the major natural death for the male blue sheep was found between 65～105 years old,and 95 years old was a peak. Hunting pressure was one of major threat to the blue sheep surrival.