Climate change is one of the most serious challenges facing mankind. Sphagnum moss plays an important role in the carbon sink of peatland. Understanding the potential distribution of Sphagnum moss under climate change scenarios is critical for the conservation and rational exploitation of it. In this study, we divided the Hengduan Mountains (HDM) into east (EHDM) and west (WHDM) parts to see the difference between the whole and the parts, and understand the effects of integrity and connectivity of the landscape on species distribution. Since no enough occurrence data in EHDM, we applied the occurrence data in WHDM. Then, MaxEnt model was employed to predict the potential distribution of Sphagnum moss and computed the migratory paths of the distribution center points. We found precipitation in the coldest quarter, daily range of average temperature, isothermality and slope were the main factors affecting the suitable habitat for Sphagnum moss in HDM and WHDM. In HDM, the current potential suitable habitat is 2.6×104 km2, and will increase over 8 times and tend to shift northeastward and higher elevations in the future. In WHDM, the suitable area is 1.06×104 km2, but will decline exceeds 70% under most future climate scenarios, and tend to shift southward and lower elevations. Landscape integrity and connectivity have a great impact on the distribution of HDM Sphagnum moss species. Overall, our findings provide a reference for the conservation and management of Sphagnum moss.

Nitrogen (N) deficiency has been recorded in the top surface of Tibetan Plateau. However, the variation of soil N availability across the elevational gradient in alpine forests remains poorly understood. Here, the elevational patterns and determinants of soil N composition, key N transformation processes and functional microbes across three typical mountains on the southeastern Tibetan Plateau were characterized by multiple techniques. Our results showed that soil total N and ammonium were markedly enriched in high elevation zones where a stable N release via mineralization and extremely low net nitrification were observed. Further, the increasing biological N fixation rates along the elevation driven by abiotic (i.e., high organic carbon) and biotic (i.e., key diazotrophic taxa like Bradyrhizobium, Herbaspirillum and Klebsiella) factors greatly benefited N accumulation at high elevations. Our study offers new insights into the N dynamics in alpine forests on the Tibetan Plateau under scenarios of future climate change.