Work

Bioturbation–elevation interactions mediate alpine soil carbon stability: Microbial necromass compensation and network robustness under plateau pika bioturbation

Year: 2026

Type: article

Abstract: Alpine meadows harbor abundant soil organic carbon (SOC) but face pressures from climate change and biological disturbances. Although the plateau pika ( Ochotona curzoniae ) is recognized as an ecosystem engineer, how its disturbance-associated differences vary along elevational gradients and modulate SOC through belowground processes remains unresolved. We established paired high- and low-density pika-burrow plots across an elevational gradient (2869–4712 m) on the Qinghai-Tibet Plateau. We assessed plant diversity, SOC fractions, microbial necromass, microbial community structure, and co-occurrence networks. Continuous analysis detected no significant relationship between elevation and SOC ( p > 0.05). Regional comparisons showed that surface-soil SOC was 46% and 40% lower in high-density than in low-density plots in the low- and mid-elevation zones, respectively (both p < 0.001). At high elevations, SOC was 31% lower in high-density plots, but the difference was not significant ( p > 0.05). Pika bioturbation was also associated with altered microbial necromass accumulation. Bacterial necromass carbon (BNC) and total necromass carbon (TNC) showed significant disturbance × elevation 2 interactions ( p = 0.023 and p = 0.044, respectively), whereas the corresponding interaction for fungal necromass carbon was not significant ( p = 0.056). Intense disturbance was associated with a shift in necromass dominance from fungal to bacterial pathways. Structural equation modeling suggested a potential indirect pathway linking pika bioturbation to SOC through increased microbial necromass. However, this potential compensation did not offset disturbance-associated lower SOC content. These findings inform the management of pika outbreaks and belowground carbon-related functions in alpine meadows.

Source: CATENA

DOI: 10.1016/j.catena.2026.110695