Effect of plateau zokor on soil carbon and nitrogen concentrations of alpine meadows

Small subterranean mammals cause extensive disturbance of grasslands by producing many mounds in the grasslands. This study aimed to evaluate the effect of a small subterranean mammal, plateau zokor (Myospalax fontanierii), on soil carbon and nitrogen concentrations in alpine meadows. In this study, the disturbance effect by plateau zokor on alpine meadow was classified into mound, edge vegetation zone and undisturbed vegetation areas, and a random stratified paired sampling design was used to collect soil samples at mound, edge vegetation zone and undisturbed vegetation area. The results of the present study found that the soil total carbon, organic carbon and total nitrogen concentrations in undisturbed soil were higher than those in mound soil and lower than those in edge soil; the nitrate nitrogen (NO3--N) concentration in edge soil was higher than that in undisturbed soil and lower than that in mound soil. However, the soil inorganic carbon and ammonium nitrogen (NH4+-N) concentrations were site dependent. The results of the present study also found that ratios of soil organic carbon to soil total nitrogen (C: N) were lower in mound soil than in edge soil and undisturbed soil, and the ratios of NH4+-N to NO3--N (ANR) were higher in mound soil than in edge soil and undisturbed soil across the three sites and at individual site, which imply that the lower C: N and higher ANR in mounds are a possible mechanism by which bare mound caused by small subterranean mammals can naturally recover. The findings of this study reveal the general patterns of soil total carbon, soil organic carbon, soil total nitrogen, NO3--N, C: N, and ANR in relation to disturbance effects, and present a possible approach for estimating how the presence of a small subterranean mammals influences grassland soil carbon and soil nitrogen.