Effects of disturbances by plateau pikas on soil microbial communities in an alpine ecosystem of the southeast Qinghai-Tibetan plateau, China

Abstract

Small burrowing herbivores often disturb the grassland soil. Although the plateau pika (Ochotona curzoniae) is widespread in alpine meadows in the Qinghai–Tibet Plateau, their detailed effects on ecosystem properties are not well-established. In this study, we investigated the effects of the densities of plateau pikas on plant characteristics, soil properties, and the composition and diversity of soil microbial communities. Plant coverage, height, aboveground biomass, and belowground biomass decreased with an increase in the densities of active plateau pika burrows. Additionally, pika disturbances led to distinct changes in soil moisture, soil bulk density (SBD), total phosphorus (TP), NH4+-N, available phosphorus (AP), and available potassium (AK) contents. Soil moisture, TP and AK contents were highest under moderate plateau pika disturbance levels, whereas the SBD and AP content were highest under the highest active burrow density. However, soil microbial diversity, as determined by high-throughput sequencing, did not differ significantly among pika disturbance levels. Linear discriminant analysis Effect Size revealed that biomarker bacteria for various levels of disturbances belong to Proteobacteria, Bacteroidetes, and Firmicutes, and most biomarker bacteria were found at moderate disturbance level (D2), while biomarker fungi belong to Ascomycota and Basidiomycota, and most biomarker fungi were found in the highest plateau pika disturbance level (D4). Pika disturbances significantly influenced the microbial community, possibly via alterations in the belowground biomass, SBD, AK and TP contents. Thus, plateau pika disturbances significantly influenced the plant and soil properties and microbial community structure.