A Preliminary Study on the Population Abundance and Distribution of Blue Sheep in Wanglang National Nature Reserve, Sichuan Province, China

Blue sheep (Pseudois nayaur) are widely distributed across the Tibetan Plateau. Wanglang National Nature Reserve is located in the eastern margin of its distribution area, but the population quantity and distribution of blue sheep in Wanglang area are less known. From May 2020 to August 2021, the abundance and distribution of blue sheep in Wanglang National Nature Reserve were investigated. A total of 1 012 blue sheep were recorded, among which 117 were single sheep and another 895 were integrated into 142 groups, with a mean group size of 6.31±1.52(2-36). Small herd size of 2 blue sheep was the most common group size, accounting for 11.86% of the total population. Among the 142 groups, the mixed groups were the most frequently observed, accounting for 65.49% of the total number. The analysis results of Distance 6.0 showed that the number of blue sheep in Wanglang National Nature Reserve was about 3 144 (1 989-4 970). In Wanglang area, the blue sheep were distributed in five areas, namely, the first branch ditch of Dawodang, the first branch ditch of Zhugencha, the second branch ditch of Zhugencha, the Tiebanfang, and the Great Lawn. The altitude distribution range was 2 000-3 679 m, and the main altitude distribution was above 3 000 m. The MaxEnt model analysis results showed the grazing, vegetation type, elevation and distance from settlement were the main environmental factors related to the distribution of blue sheep in this area. The MaxEnt model and ArcMap calculation showed that there were 181.25 km² suitable habitat area, 56.42 km² sub-suitable habitat area, and the total area of the two parts was 237.67 km², accounting for 73.59% of the nature reserve. The content of this study enriched the basic data of blue sheep population in Wanglang National Nature Reserve, and put forward suggestions for the management of the reserve, which is of great significance for the protection of blue sheep and its habitat.