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There is growing evidence that land‐use management practices such as livestock grazing can strongly impact the local diversity, functioning, and stability of grassland communities. However, whether these impacts depend on environmental condition and propagate to larger spatial scales remains unclear. Using an 8‐year grassland exclosure experiment conducted at nine sites in the Tibetan Plateau covering a large precipitation gradient, we found that herbivore exclusion increased the temporal stability of alpine grassland biomass production at both the local and larger (site) spatial scales. Higher local community stability was attributed to greater stability of dominant species, whereas higher stability at the larger scale was linked to higher spatial asynchrony of productivity among local communities. Additionally, sites with higher mean annual precipitation had lower dominant species stability and lower grassland stability at both the spatial scales considered. Our study provides novel evidence that livestock grazing can impair grassland stability across spatial scales and climatic gradients. [ABSTRACT FROM AUTHOR]

• Elevated CO 2 significantly advanced spring phenology in kobresia pygmaea. • Alpine plants on the tibetan plateau are more sensitive to elevated CO 2. • Elevated CO 2 reduced overlapping flowering between species. • Advancement in K. pygmaea's phenology was linked to higher water-use efficiency. Phenological changes in global vegetation are often attributed to climate warming. However, climate warming and elevated atmospheric CO 2 concentration (e CO 2) are two co-occurring global change factors, and how e CO 2 would affect vegetation phenology has received less attention. The partial pressure of atmospheric CO 2 on the Tibetan Plateau (TP) is lower than that in regions of lower altitudes. Consequently, the growth and phenology of alpine plants in this region could be more sensitive to e CO 2 , but this hypothesis is not yet supported by empirical evidence. Here we explored the effect of e CO 2 on plant phenology (including phenophases of green-up, budding, and flowering) through a 5-year field manipulation experiment in a high-altitude (4600 m above sea level) alpine grassland on the TP. Our results showed that e CO 2 significantly advanced the spring phenology of an early-flowering species (Kobresia pygmaea), while it had no impact on the phenology of two mid-flowering species (Potentilla saundersiana and Potentilla cuneata). Compared to other low-altitude regions, plant phenology on the TP underwent greater alterations under e CO 2 , which supports our hypothesis that the growth of high-altitude plants is more sensitive to e CO 2. Furthermore, we found that e CO 2 significantly reduced the overlapping of flowering between contrasting plant species, mainly due to the phenological advancement of the K. pygmaea induced by e CO 2. The observed advancement of the spring phenology in K. pygmaea under e CO 2 was associated with increasing ecosystem water-use efficiency (WUE), thereby advancing its subsequent phenological development, such as budding and flowering. Our findings provide experimental evidence that atmospheric CO 2 enrichment can accelerate plant growth processes in high-altitude regions, and suggest that large-scale model simulations should consider the effects of elevated atmospheric CO 2 concentration on plant growth and phenology. [Display omitted] [ABSTRACT FROM AUTHOR]

• A warming and wetting trend in Chinese drylands resulted in an increased CUEe. • The slight inhibiting effect of warming on CUEe is overridden by the strong promotion effect by increased precipitation. • The response pattern of CUEe to warming or wetting is nonlinear and unimodal. Co-limited by environmental constraints, ecosystems in arid and semi-arid regions (ASARs) are extremely sensitive to climate change. A warmer and wetter climate trend has been observed extensively in ASARs of China, but whether and how the changing climate has influenced ecosystem carbon allocation and balance remains largely unclear. To bridge this knowledge gap, we conducted a comprehensive study integrating manipulative experiments, flux observations, and model simulations and our research findings reveal that the changing climate exerts a significant influence on ecosystem carbon use efficiency (CUEe) in ASARs. Specifically, the effect of increased precipitation has outweighed the warming effect, resulting in a widespread rise in CUEe across most parts of ASARs. In regions with alpine vegetation, the stimulated effects of increased temperature and precipitation play a dominant role in shaping the pattern of CUEe changes. However, with intensified warming, its stimulated effect on CUEe gradually diminishes or even reverses in ASARs. These findings can improve our understanding of ecosystem carbon sequestration regarding the response of resource-constrained ecosystems to climate change, thereby guiding ecosystem management. [ABSTRACT FROM AUTHOR]

• Precipitation mainly drives biomass allocation (R/S) in temperate grasslands. • Both precipitation and temperature drive R/S in alpine grasslands. • Plant functional group compositions affect R/S more than soil nutrition. • Effects of forbs on R/S is larger than those other dominant plant groups. Elucidating biomass partitioning between above- and belowground parts in plant communities is vital to better assessing the ecological services of terrestrial ecosystems. However, the knowledge of biomass allocation in grasslands is scant, especially for the divergent mechanisms under both contrasting conditions. On two large geographic transects, Tibetan Plateau and Inner Mongolian Plateau, we analyzed the general and differential mechanisms of biomass allocation (plant biomass ratio of root to shoot, R/S) in temperate vs. alpine grasslands. We found that the R/S exhibited large variations, ranging from 3.89 to 45.10 in temperate grasslands and from 4.74 to 80.72 in alpine grasslands. The R/S decreased with increasing precipitation in both grasslands, whereas it weakly related to temperature. Plant functional group had highest importance on R/S than mean annual precipitation, mean annual temperature, soil nitrogen and phosphorus availabilities, and plant richness and diversity index. Climate factors indirectly but strongly drove R/S by mainly changing plant functional group compositions. Particularly, forbs affected R/S more than other dominant plant functional types. This information can provide a profound insight into the biomass allocation dynamics in grasslands at regional level under climate change scenarios. [ABSTRACT FROM AUTHOR]