Responses of soil respiration to experimental warming in an alpine steppe on the Tibetan Plateau

Abstract

High-latitude and high-altitude ecosystems store large amounts of carbon (C) and play a vital role in the global C cycle. Soil respiration ( R _S ) in these ecosystems is believed to be extremely sensitive to climate warming and could potentially trigger positive C-climate feedback. However, this evidence is largely derived from wet ecosystems, with limited observations from dry ecosystems. Here, we explored the responses of R _S , autotrophic ( R _A ), and heterotrophic ( R _H ) respiration under experimental warming in a dry ecosystem, an alpine steppe on the Tibetan Plateau. We assessed the effects of soil temperature and moisture dynamics on R _S , R _A, and R _H and performed a meta-analysis to examine whether the warming effects observed were similar to those reported in wet ecosystems, including Tibetan alpine meadow and arctic ecosystem. Experimental warming did not alter R _S , R _A, and R _H in this alpine steppe, likely because decreased soil moisture constrained positive warming effects. In contrast, the meta-analysis revealed that R _S exhibited a significant increase under experimental warming in both the Tibetan alpine meadow and arctic wet tundra. These results demonstrate that R _S exhibits different responses to climate warming between dry and wet ecosystems, suggesting potential more complex C-climate feedback in cold regions.

Keywords

• climate warming
• meta-analysis
• carbon cycle
• carbon-climate feedback
• alpine ecosystem
• arctic ecosystem