Root voles in the study area
Our study was conducted at Haibei Alpine Meadow Ecosystem Research
Station, Menyuan County, approximately 155 km north of Xining, the
capital city of Qinghai province, People’s Republic of China (37°370´N,
101°120´E). The area is a secondary vegetation type meadow with a dense
leaf layer. The major plant species include Elymus nutans, Poasp., Kobresia humilis, and Potentila fruticosa . The root
vole is the most common rodent in the study area. Root-vole populations
in this area fluctuate only seasonally, with the lowest levels occurring
in early spring; multiyear cycles are weak or absent (Jiang et al.,
1991). Root voles have a preference for dense vegetation (mainlyE. nutan s) (Liu et al., 1991; Bian et al., 1994). The average
population size in the habitat ranges from 217 to 280 voles
ha-1 in autumn (Bian et al., 1994), where grazing
activities had a limited population density of approximately 400 voles
ha-1 in autumn (Sun et al., 2002). The breeding season
typically lasts from April to late October. Females have exclusive
territoriality during the breeding season; males, conversely, have large
area ranges that extensively overlap with those of other males (Sun et
al., 1982). The lifetime of free-ranging individuals is < 1
year. Spring-born individuals attain sexual maturity in the year they
are born; fall-born voles remain reproductively inactive during winter
(Bian et al., 2015).