Feeding habitats of blue sheep(Pseudois nayaur)during winter and spring in Helan Mountains,China

摘要

The feeding habitat selection of blue sheep(Pseudois nayaur)was studied by direct observation method in the Helan Mountains,China during winter(from Novembe r to December)and spring(from April to June)from 2003 to 2004.We established 25 line transects to collect information on feeding habitats used by blue sheep.Blue sheep in the study area preferred mountain savanna forests,a habitat dominated by Ulmus glaucescens,with medium tree density(5 individuals/100 m^(2)),higher shrub(>1.3 m),higher food abundance(>50 g),moderate distance to human disturbance(100 g),moderate altitude(<2000 m),moderate distance to water resource(<500 m),and medium hiding cover(50%-75%)during spring.Selection of the feeding habitats by sheep showed a significant difference in vegetation type,landform feature,dominant tree,tree height,shrub density,distance to the nearest shrub,food abundance,slope direc-tion,slope degree,distance to water resource,and hiding cover between winter and spring.Results of principal com-ponents analysis indicated that the first principal component accounted for 24.493%of the total variance among feeding habitat variance during winter,with higher loadings for vegetation type,dominant tree,tree height,distance to the nearest tree,shrub density,shrub height,altitude,distance to water resource,and distance to human disturbance.In spring,the first principal components explained 28.777%of the vari-ance,with higher loadings for vegetation type,distance to the nearest tree,shrub height,distance to the nearest shrub,food abundance,altitude,and distance to human disturbance.