Plant Functional Groups Mediated the Effects of Plateau Pika Disturbance and Mowing on the Community Stability of Alpine Meadow Plants

ABSTRACT

The composition of plant functional groups is a primary factor influencing grassland ecosystem stability. Currently, it remains unclear how plant functional groups mediate the effects of external disturbances on the stability of alpine meadow ecosystems. This study aims to fill this knowledge gap via a six‐year controlled experiment involving three levels of mowing intensity (unmown, moderate, and heavy) and three levels of plateau pika ( Ochotona curzoniae ) density (0, 93.3, and 186.7 individuals·ha ⁻¹ ). Also explored is how they affected plant community composition, biomass by plant functional groups (grasses, sedges, and forbs) and their community stability, and soil properties, either individually or jointly. It is found that both types of disturbance significantly affected the importance value (IV) of plant functional groups. The medium‐density plateau pika and heavy mowing treatment reduced grass IV but increased forb IV. Both disturbances significantly affected plant functional groups' biomass and community stability, and their interaction significantly influenced the aboveground biomass (AGB) of grasses and sedges, as well as soil nutrients. Grass biomass decreased significantly following the disturbances, but forb biomass increased significantly. AGB of grasses and sedges exhibited a highly significant negative correlation with community stability. Conversely, AGB of forbs showed a positive correlation with community stability. Structural equation modeling (SEM) revealed that plant functional groups' biomass played a crucial mediating role in regulating the influence of plateau pika and mowing disturbances on plant community stability.