JOURNAL OF NATURAL RESOURCES ›› 2019, Vol. 34 ›› Issue (5): 1054-1065.

### Using UAV remote sensing for a population census of blue sheep (Pseudois nayaur) in Maduo county, source region of the Yellow River

Xing-jian GUO1,2(), Quan-qin SHAO1,2, Fan YANG1,2, Yu-zhe LI1, Yang-chun WANG3, Dong-liang WANG1

1. 1. Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
2. University of Chinese Academy of Sciences, Beijing 101407, China
3. Institute of Mountain Hazards and Environment, CAS, Chengdu 610041, China
• Received:2018-11-06 Revised:2019-01-30 Online:2019-05-28 Published:2019-05-28

Abstract:

In this study, Maduo county, the source region of the Yellow River, was selected as the research area. In 2017, UAV aerial survey was used to estimate the population of the blue sheep (Pseudois nayaur) and its distribution. The effective area of aerial surveys was 326.6 km2, and 23784 images were acquired. The population in the survey transect was 203, which was identified visually on computer monitors by human observers, and the density was 0.6215/ km2. A total of 12 groups of blue sheep were found in the transects, of which 6 groups had a cluster size of 2-10, accounting for 50% of the total. Estimation of population of blue sheep in Maduo county was 8968, which was based on the relationship of different types of grassland area between transects and the whole county. In this way, the area of non-vegetation types (such as bare stone gravel, water bodies, glaciers, towns, high-speed and national roads) is deducted, and the influence of human disturbance is considered. This avoided overestimation of the blue sheep population. The relationship between the distribution density of blue sheep and ecological factors of habitat was analyzed. Results show that blue sheep preferred an area within 1 km from rural settlements, 3 km away from roads, 1-3 km from water sources, within 200 m from the cliff and with an elevation of 4100-4200 m, vegetation coverage of 0-0.4, slope over 5°, vegetation type of Stipa purpurea + Subordinate grass and Kobresia pygmaea. The environmental factors of the blue sheep habitat may have a correlation with each other, in order to identify the environmental factors that have a major impact on the choice of habitat, and describe the preference more accurately, principal component analysis was carried out. The results showed that altitude, distance from the road and distance from the cliff were the main environmental factors affecting the choice of habitat of blue sheep. In this study, a UAV aerial sampling survey was conducted to estimate the population and density of the blue sheep in the study county. Aided by ArcGIS, the habitat was analyzed. The combination of 3S technology and wildlife surveys provides a new idea for the research on wildlife in the Tibetan Plateau.