宁夏贺兰山国家级自然保护区岩羊(Pseudois nayaur)种群数量及结构

为了解宁夏贺兰山岩羊的种群现状，2020-2021年的8月和12-1月，在宁夏贺兰山国家级自然保护区运用样线法对岩羊（Pseudois nayaur）进行种群数量调查，利用R 4.0.1中的Distance 1.0.2对样线观测数据进行分析，估测保护区内岩羊的种群数量及密度，分析其种群结构。结果显示，夏季岩羊种群数量为5176（2554-10490）只，种群密度为2.674（1.320-5.420）只/km²；冬季岩羊种群数量为15752（7294-34017）只，种群密度为8.139（3.769-17.58）只/km²；多数观测距离样线垂直距离在0-200 m之内。岩羊主要集群形式：夏季为雌幼群（52.17%）；冬季为混合群（26.60%）。岩羊平均群大小：夏季为（6.261±8.023）只，冬季为（4.064±4.229）只，群大小在不同季节的差异显著（P=0.010），集群大小多集中于1-5只之间，最大为47只。夏季调查中，雄性个体占比11.27%，雌性个体占比56.74%，幼体/亚成体占比31.99%；冬季调查中，雄性个体占比29.61%，雌性个体占比50.15%，幼体/亚成体占比20.24%；夏季和冬季岩羊组成成分之间差异极显著（P<0.001）。

Population size and structure of blue sheep in Helan Mountains National Nature Reserves, Ningxia

In order to understand blue sheep (Pseudois nayaur) population in the Helan Mountains, Ningxia Hui Autonomous Region, we carried a blue sheep population survey using line transect method from August and December, 2020 to January 2021. We estimated the sheep population size and density, and analyzed its population structure by the Distance 1.0.2 in R 4.0.1. The results showed that the population size of blue sheep in summer was 5176 (2554-10490) and the population density was 2.674 (1.320-5.420) individual/km²; the population size in winter was 15752 (7294-34017) and the population density was 8.139 (3.769-17.58) individual/km². Blue sheep were mostly observed within 0-200 m of the vertical distance from the transect line. In summer, the main group form of the sheep was female and juvenile group (52.17%); In winter, it was mixed group (26.60%). The average group size of blue sheep was (6.261±8.023) in summer and (4.064±4.229) in winter. The difference of group size was significant between two seasons (P=0.010), ranging between 1 to 5, with a maximum of 47. In summer, male, female and juvenile accounted for 11.27%, 56.74% and 31.99%, respectively; In winter survey, male and female accounted for 29.61%, 50.15%, and juvenile accounted for 20.24%. There was significant difference in composition between summer and winter (P<0.001).