Warming affects herbaceous germination, early survival, and growth by shifting plant-soil microbe interactions in an alpine ecosystem

Background and aims Plant interactions with soil microbes are important drivers of biodiversity and dynamics of alpine plant communities. However, little is known about the effects of these interactions on seed germination and plant establishment of alpine plants under global climate change. We investigated the individual and interactive effects of warming, soil microbes and shrubs on seed germination, survival, and growth of herbaceous species. Methods We simulated warming and manipulated live and sterile soil microbes and microhabitat in the alpine meadow ecosystem dominated by the shrub ( Dasiphora fruticosa ) on the Qinghai-Tibet Plateau. We tested the interactive effects of warming, soil microbes, and shrubs on the germination, early life survival, and growth of herbaceous species. Soil microbial communities were determined by high-throughput sequencing. Results Our results showed that seed germination was significantly reduced under warming; seed germination was higher in live soils than in sterile soils; early life survival was lower under shrub canopies. Additionally, in the warming treatment, the positive effect of soil microbes on seed germination shifted to negative on the early survival of herbaceous species. Furthermore, in the warming treatment, shrubs enhanced the positive effects of soil microbes on seed germination and reduced the negative effects of soil microbes on early survival. The effects of these individual and interactive factors on herbaceous species also depended on species identity and life stages. Conclusion Overall, our work demonstrates that soil microbes were particularly critical at seed germination stage and plant interactions with soil microbes were significantly altered with experimental warming.