Soil disturbance and disturbance intensity: Response of soil nutrient concentrations of alpine meadow to plateau pika bioturbation in the Qinghai-Tibetan Plateau, China

Abstract Plateau pikas ( Ochotona curzoniae ) bioturbation affects the soil nutrient concentrations of the alpine meadow in the Qinghai-Tibetan Plateau (QTP) by the arrangement of bare land. This study investigated the effect of the disturbance produced by plateau pika bioturbation on primary soil nutrient concentrations of the Kobresia pygmaea meadow in view of overall and site scale and further analyzed the effect of the disturbance intensity of plateau pika on the soil nutrient concentrations of vegetated land and bare land. Our results showed that the disturbance by plateau pika bioturbation significantly decreased the soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP), and increased the available phosphorus (AP), NO 3 − -N and NH 4 + -N of bare land. Moderate disturbance intensities increased the SOC, TN and TP of both vegetated land and bare land and reduced the NO 3 − -N, NH 4 + -N and AP of vegetated land while increasing those of bare land. Disturbance within the threshold disturbance intensities of plateau pika is beneficial to the soil C and N, accumulating higher available nutrient concentrations in the topsoil, which would provide good habitats for certain rare plants and supply nutrients for the nitrophilous graminoid plants to grow well in the QTP. These results suggest that the understanding of the responses of the soil nutrient concentrations to plateau pika bioturbation should consider the bare land under disturbance intensities of plateau pika and alpine meadow type.