Impacts of Climate Change on CO ₂ and CH ₄ Fluxes in Alpine Meadow Ecosystems in the Permafrost Zone

ABSTRACT Background Under climate change conditions, alpine meadows have been severely affected, but the response of carbon flux in alpine meadow ecosystems to climate change remains unclear. Methods In this study, we focused on alpine meadows on the Qinghai–Tibet Plateau and established six treatments: Control (CK), warming (W), 30% reduced precipitation (P−), 30% increased precipitation (P+), warming and reduced precipitation (WP−), and warming and increased precipitation (WP+). Results By monitoring and analyzing ecosystem fluxes under different treatments, we found that warming and changes in precipitation patterns significantly affected the net ecosystem carbon dioxide exchange (NEE). Specifically, P− increased NEE by suppressing ecosystem respiration (ER) and gross primary productivity (GPP) to different extents, while other treatments increased NEE by enhancing plant photosynthesis. In addition, warming enhanced the effects of P+ on RE and GPP. However, our treatments had a minor effect on methane (CH 4 ) flux, but we found that methane flux under light conditions was significantly higher than under dark conditions, which may be related to methane oxidation promoted by plant roots. Environmental factor analysis indicated that soil temperature, precipitation, and photosynthetically active radiation were the main factors influencing CO 2 and CH 4 fluxes. Conclusions These findings emphasize the significant impact of temperature and moisture regulation on carbon and methane fluxes in alpine meadows and provide a deeper understanding of the response mechanisms of these ecosystems to global change.