Characterization of the spatial distribution of plateau pika burrows along an alpine grassland degradation gradient on the Qinghai-Tibet Plateau.

Dawen Qian,Qian Li,Yuting Lan,Bo Fan,Guangmin Cao

doi:10.1002/ece3.8176

Abstract

Plateau pika burrows are common feature of degraded grassland in the Qinghai–Tibet Plateau (QTP) and serve as an important indicator of pika activity and grassland degradation. However, the current understanding of the spatial pattern changes of pika burrows and their critical thresholds across a degradation gradient in alpine grassland is deficient. In this study, we investigated and quantified changes in the spatial pattern of plateau pika burrows under typical degraded alpine shrub meadows in the northeastern QTP using an unmanned aerial vehicle and landscape pattern metrics. The degradation of the alpine shrub meadow leads to a change in landscape pattern from a two‐layered structure of alpine shrub and alpine meadow to a mosaic of alpine meadow and bare soil, with plateau pika burrows scattered throughout. Moderate degradation is the tipping point for changes in surface landscape patterns, followed by the disappearance of alpine shrub, the retreat of alpine meadows and the encroachment of bare soil, and the increasing density and size of pika burrows. The area characteristics of alpine meadows have influenced changes in the spatial pattern of pika burrow, and maintaining its proportional area is a vital measure to control the threat of pika burrows to pastures. The results of this paper provide a methodological reference and guidance for the sustainable utilization of grassland on the QTP.

Highlights

The Qinghai–Tibet Plateau, known as the “roof of the world” due to its high altitude, has a unique climate and ecosystem that are profoundly affected by climate change and impact on water resources and biodiversity conservation in the region and beyond
The results of this study showed a density of 5500 pika burrows/ha in degraded alpine shrub meadow, whereas surveys conducted in the western part of the southern Qilian Mountains have shown that the average number of pika burrows in normal grassland is 300–800 burrows/ha (Qin, Sun, et al, 2020; Qin et al, 2019; Yi et al, 2016)
We found that the average area of a pika burrow opening was 0.003 m2, which is smaller compared with other studies (Ma et al, 2011; Pech et al, 2007)

Summary

Introduction

The Qinghai–Tibet Plateau, known as the “roof of the world” due to its high altitude, has a unique climate and ecosystem that are profoundly affected by climate change and impact on water resources and biodiversity conservation in the region and beyond. Half of the alpine grassland has been experiencing degradation for several decades on QTP (Dong & Sherman, 2015), resulting in decreased plant diversity and productivity, accelerated soil erosion (Liu et al, 2018), and an increase in greenhouse gases released into the atmosphere (Su et al, 2015). The plateau pika (Ochotona curzoniae) has long been considered to be responsible for the degradation of alpine grassland due to their foraging, which can reduce vegetation height and alter plant community structure and biomass, and due to their burrowing behavior, which can destroy surface vegetation and increase the risk of soil erosion (Yi et al, 2016; Yu et al, 2017; Zhang et al, 2020). Plateau pikas provide many benefits for grassland ecosystems; for example, their burrows can provide shelter for other animals and their behavior serves to increase vegetation species richness, and they are the prime prey for predator species on QTP (Dobson et al, 2019; Smith et al, 2019)

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Discussion

Conclusion