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Herbivores can influence plant species richness and plant aboveground biomass. However, only a few studies have examined their impact on the relationship between plant aboveground biomass and plant species richness, focusing on large herbivores. This study examined the influence of a small burrowing herbivore, the plateau pika (Ochotona curzoniae) with averaging 150 g, on the plant aboveground biomass, plant species richness, and their relationship in the alpine meadows on the Qinghai–Tibet Plateau. The study used a random stratified paired sampling design to collect data on plant species richness and plant aboveground biomass across five sites. Each site contained 10 pairs of plots. Each pair consisted of an undisturbed plot and a disturbed plot. Plant species richness was higher in the disturbed plots; whereas, plant aboveground biomass did not differ in relation to plateau pika disturbance. In the undisturbed plots, the plant species richness increased positively with plant aboveground biomass. In the disturbed plots, the plant species richness peaked at intermediate plant aboveground biomass levels. The findings suggest that small herbivores could alter the relationship between plant aboveground biomass and plant species richness by inducing an increase in plant species diversity, and they should be considered for assessing the management and conservation measures of alpine meadow. [ABSTRACT FROM AUTHOR]

Small burrowing herbivores create extensive disturbances to grassland soil, which may change carbon cycling. We focused on the plateau pika (Ochotona curzoniae) to simultaneously investigate the responses of the soil organic carbon (SOC) and soil inorganic carbon (SIC) stocks of alpine meadows to the disturbance caused by this small burrowing herbivore and its disturbance intensity at the plot scale across five sites on the Qinghai‐Tibetan Plateau. The percentage of bare soil area in a disturbed plot was used as a proxy for the disturbance intensity of plateau pikas. Our study found that the disturbance by plateau pikas reduced the SIC stock and increased the SOC stock, whereas it had no effect on the soil total carbon (STC) stock. Our study also found that the SOC and STC stocks were higher at intermediate disturbance intensities of plateau pikas, whereas the SIC stock showed a decreasing trend as the disturbance intensity of plateau pikas increased. Our findings suggest that intermediate disturbance intensities of a small burrowing herbivore (plateau pika) improve soil quality by increasing the SOC stock and benefit soil carbon sequestration by increasing the STC stock. Highlights: Explored the SIC and SOC stocks simultaneously in relation to the disturbance by a small burrowing herbivore.Soil carbon stocks were evaluated at plot scale across five sites.SIC and SOC stocks responded differently to the disturbance by plateau pika and its disturbance intensity.The intermediate disturbance intensities were good for the soil quality and soil carbon sequestration. [ABSTRACT FROM AUTHOR]