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

Abstract

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 (<4 individuals / 400 m 2 ), moderate tree height (4-6 m), higher shrub density (>5 individuals / 100 m 2 ), higher shrub (>1.3 m), higher food abundance (>50 g), moderate distance to human disturbance (<500 m), and mild distance to bare rock (<2 m). Such habitats characterized by 12 ecological factors were preferred as feeding areas by blue sheep during winter. Similar to habitat selection by the species during winter, blue sheep also showed a preference for mountain savanna with tree dominated by Ulmus glaucescens and medium tree density (<4 individuals / 400 m 2 ) during spring. Nevertheless, blue sheep preferred medium tree height (<6 m), moderate tree density (5-10 individuals / 100 m 2 ), medium shrub height (1.3-1.7 m), higher food abundance (>100 g), moderate altitude (<2 000 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 direction, slope degree, distance to water resource, and hiding cover between winter and spring. Results of principal components 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 variance, 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.

Age-gender feeding differences in dwarf blue sheep, Pseudois schaeferi (Cetartiodactyla, Bovidae) magnified by the expansion of an invasive plant species

“…Pseudois nayaur show a similarly narrow feeding breadth across its range, e.g., in Ninxia Hui Autonomous Region, Inner Mongolia (Liu et al 2007a (Harris and Miller 1995, Miller and Schaller 1998, Schaller 1998, Mishra et al 2004, Shrestha et al 2005, Liu et al 2007a, Suryawanshi et al 2009 ). This shift is particularly pronounced in winter when graminoid resources become limited or where competition with domestic livestock or other wild ungulates occurs (Mishra et al 2004, Liu et al 2007a, Suryawanshi et al 2009 ). Ultimately, the local plant composition determines the availability; for example, a complete lack of woody species in some areas totally precludes that component from entering the diet Miller 1995 , Miller andSchaller 1998 ).…”

“…Wang et al (2000) and Wu et al (1990) each observed the dwarf blue sheep to have mixed diets, though specific proportions of the foraging classes were not given. Many specialist herbivores show considerable temporal variation in the contribution of foraging classes to their diets in response to environmental factors (Bodmer 1990, Brown and Doucet 1991, Liu et al 2007a. Pseudois nayaur is, in its natural habitat, predominantly a grazer, preferring graminoids, though shifts its diet along the grazer-browser continuum as a result of seasonal availability, competitive exclusion by sympatric grazers, and local plant com position dwarf blue sheep fed unevenly on the most common species (Pearson's χ 2 = 90.996, df = 16, p < 0.001).…”

“…As a consequence, the persistence of many species hinges on their ability to adapt their diets to modified and changing habitats, and for many species, successful conservation management will depend on having at least a baseline knowledge of feeding ecology (Korschgen 1980, Bagchi et al 2004, Mishra et al 2004, Liu et al 2007a ). The dwarf blue sheep ( Pseudois schaeferi , Haltenorth 1963), a Caprinae, is confined to a narrow distribution along the steep rocky slopes of the upper Yangtze River gorge between c. 28 ° 15 ′ N and 31 ° 0 ′ N in Sichuan, Yunnan, and Tibet, China (Wang and Hoffman 1987, Wang et al 2000, Harris 2008a ).…”

“…These observations are congruent with those made of the bharal Pseudois nayaur (Hodgson, 1833), the only close relative of P. schaeferi , but which occupies a wide range of mostly treeless mountain habitats across the high ranges of the Himalayas from Pakistan to Inner Mongolia (Harris 2008b ). Pseudois nayaur preferentially select habitats near cliffs (Mishra et al 2004 ), where they preferentially graze on graminoids, and to a lesser degree on shrubs, trees, forbs, and lichens where graminoid availability is low or has been reduced (Harris and Miller 1995, Shrestha et al 2005, Liu et al 2007a, Suryawanshi et al 2009 ). For P. schaeferi , no quantitative estimate of diet for the species has ever been completed, and nothing has been reported on the population at Rini Mountain, Yunnan.…”

Establishing baseline estimates of blue sheep (Pseudois nayaur) abundance and density to sustain populations of the vulnerable snow leopard (Panthera uncia) in Western Bhutan

“…Alternately, smaller herds could possibly be more common in winter when forage is poor (Liu et al 2007).…”