Thresholds and Driving Mechanisms of Plateau Pika Burrowing on Ecosystem Multifunctionality in Alpine Meadows

The activities of plateau pika (Ochotona curzoniae) significantly influence ecosystem functions and services in alpine meadow, yet further investigation is required to explore how pika burrowing impacts the ecosystem multifunctionality and its underlying drivers. Here, we evaluated the response of ecosystem multifunctionality to carrying levels of pika burrowing activity using various methodologies, including field surveys, laboratory analyses, and model approaches. Our study demonstrated that the criticality and reliability of ecosystem multifunctionality assessment in determining optimal pika burrowing thresholds surpass the utility of individual indicators. Specifically, maintaining low levels of pika burrowing disturbance emerges as essential for preserving multiple ecosystem functions. We observed that ecosystem multifunctionality and species richness peaked when pika burrowing densities were approximately 780 and 730 burrows per hectare, respectively. The critical threshold of pika burrowing density impacting ecosystem multifunctionality (transitioning from positive to negative) was identified at around 1 500 burrows per hectare. Structural equation models revealed that under low pika burrowing conditions, belowground ecosystem functions predominantly shaped ecosystem multifunctionality. Conversely, under high pika burrowing conditions, ecosystem multifunctionality was regulated by altering species richness and soil temperature. These findings put forward a broader insight into evaluating the relationship between ecosystem functions and plateau pika burrowing activities, offering a basis for developing reasonable ecological management strategies for rodent control in alpine meadow ecosystems.