Microhabitat Selection And Spatial Niche Segregation Of Three Sympatric Mammals During Summer In Altun Mountain National Nature Reserve

The plateau pika(Ochotona curzoniae), the woolly hare(Lepus oiostolus) and the Blyth’s vole(Phaiomys leucurus) are endemic small mammal species of Qinghai-Xizang Plateau. A number of studies on microhabitat of plateau pika had reported, but little has been known about microhabitat of the woolly hare and the Blyth’s vole. Difference of microhabitat among these sympatric mammals has not been reported yet. We investigated the habitat use of three specie s with the trace test and direct observation in the Altun Mountains National Nature Reserve during summer. Results of our study are most significant in maitaining the stability of this area and the maintenance of the biodiversity.Results:(1) A total of 69 samples in active burrowing clones and 53 control samples in nearby similar habitat without burrow. There is very significant difference on elevation, vegetation cover, vegetation height, slope, habitat type and soil hardness(P<0.01). Principal component analysis showed that the factors affected the habitat choice of plateau pika w as elevation, vegetation cover, numbers of the plant species and road distance. The Vanderloeg and Scavia Election Index indicated that the Plateau pika prefers to burrow into areas with softer soil(3-4 kg/m2), areas whose vegetative microhabitat stands at a height of less than 8 cm, and areas with a section of low-lying canopy which provides hiding cover whose height is also less than 8 cm.The plateau pika preferred habitat with higher elevation, steeper slope, higher vegetation density, shorter vegetation, and softer soil.(2) A total of 32 samples in resting sites and 33 control samples in nearby similar habitat of woolly hare were set. The results showed that there is very significant difference on canopy cover, vegetation height and vegetation density(P ?0.01) and a significant difference in numbers of the plant species and soil hardness(P ?0.05). Then we analyzed selection of the woolly hare with Vanderloeg and Scavia Election Index. woolly hare like choice under three kinds of more than 30 cm high, coverage and density between 30-60% in 80 plant/ m2 vegetation, canopy cover in more than 10 cm, soft soil( 6-9 kg/cm2) of microhabitat. According the factor loading of principal component analysis(PCA), the main factors affected the resting sites use of the woolly hare were vegetation density, vegetation cover, and canopy cover. The woolly hare preferred the habitat with higher vegetation and canopy cover, lower vegetation density and softer soil on alpine meadow and alpine desert.(3) A total of 261 sample areas, of these 40 sample areas contained a vole nesting site.The results showed that there were very significant differences in vegetation height and density, the numbers of the plant species and soil hardness(P ?0.01) when comparing the nest sites and random sites. According to Principal Component Analysis(PCA), the main factors affecting the nest site choice of the Blyth’s vole were canopy cover, vegetation height, distance to the nearest road, vegetation density, the numbers of differing plant species, and soil hardness. The Vanderloeg and Scavia Election Index indicated that the Blyth’s vole prefers to burrow into areas with softer soil(3-4 kg/m2), areas whose vegetative microhabitat stands at a height of less than 8 cm, and areas with a section of low-lying canopy which provides hiding cover whose height is also less than 8 cm.(4) Our results showed that during the summer, three species segregate their habitat. The results showed that the main factors affecting three small mammal habitat uses include plant height, soil hardness, covert level, plant species, plant density and biomass. Niches on plant height, soil hardness and plant density showed a significant ecologi cal differentiation among three small mammals.