Effects of Grazing on the Northern Three-Toed Jerboa Pre- and Post-Hibernation

Resource availability pre-hibernation and post-hibernation may be crucial phases for the survival of hibernators. However, the effects of grazing on food availability in pre-hibernation and on the winter survival of hibernating rodents remains unstudied. The objective of this study was to investigate the effects of domestic sheep grazing on northern three-toed jerboa (Dipus sagitta) populations pre-, post-, and during hibernation. We conducted a grazing exclusion experiment with randomized complete block design in the Alxa Desert, Inner Mongolia, China, from April to October 2006 to 2011. We live-trapped jerboas in 3 grazed plots and 3 ungrazed plots. We measured the quantity of vegetation in grazed and ungrazed plots to determine the relationship between jerboas and plant food resources. We observed higher jerboa densities both pre- and post-hibernation, and heavier individual body mass pre-hibernation, in ungrazed sites. More food availability contributed to higher jerboa body mass in ungrazed areas during pre-hibernation, and attracted more jerboas immigrating to ungrazed areas during the post-hibernation period. These results demonstrate that grazing negatively affects the northern three-toed jerboa population by adjusting food availability pre- and post-hibernation; survival rates were not affected by grazing.