Abstract
In the alpine grazing rangeland of the Tibetan Plateau, where three major rivers originate in China, ten sites (Plot 1 to
10, 20 m × 20 m each) were selected in the habitats of plateau pikas (Ochotona curzoniae) in August 2012 for investigating
the relationship among population density of pleateau pikas, vegetation and soil physical and chemical properties. The
population density was estimated by counting the active (opened) burrows with a filling-burrow method after counting the
number of burrow openings in each plot. A vegetational survey was conducted with quadrat methods in those plots. Soil
samples were collected from 0 to 5 cm depth and physical and chemical properties were determined. The burrow opening
density (BD) ranged from 0 to 133/400 m2 and the available burrow opening density (ABD) ranged from 5 to 63/400 m2
except 0 in Plot 1, 2 and 3. BD was negatively correlated with plant height (r = -0.652, P < 0.05) and tended to be done
with coverage (r = -0.600, P < 0.1) in vegetation and positively with bulk density (r = 0.607, P < 0.1) and negatively with
SO4
2- content (r = -0.572, P < 0.1) in soil. ABD tended to be correlated with plant height (r = -0.562, P < 0.1) and bulk
density (r = 0.593, P < 0.1). Generalized liner model analyses showed that BD and ABD were affected positively by soil
hardness and TN and negatively by plant height (P < 0.001). BD only was negatively affected by TC in soil (P < 0.001).
With cation and anion contents in soil, BD and ABD were negatively affected by Ca2+, NH4
+ and SO4
2- (P < 0.001), and also
only BD was affected by Mg2+ (P < 0.001). It was suggested that the increase of population density of plateau pikas might
be related with the lowered plant height, increases of soil hardness and the TN content and decrease of the TC content
where domestic herbivores have grazed intensively.
