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The ongoing climate change on the Tibetan Plateau, leading to warming and precipitation anomalies, modifies phosphorus (P) cycling in alpine meadow soils. However, the interactions and cascading effects of warming and precipitation changes on the key "extracellular" and "intracellular" P cycling genes (PCGs) of bacteria are largely unknown for these P‐limited ecosystems. We used metagenomics to analyze the individual and combined effects of warming and altered precipitation on soil PCGs and P transformation in a manipulation experiment. Warming and increased precipitation raised Olsen‐P (bioavailable P, AP) by 13% and 20%, respectively, mainly caused by augmented hydrolysis of organic P compounds (NaOH‐Po). The decreased precipitation reduced soil AP by 5.3%. The richness and abundance of the PCGs' community in soils on the cold Tibetan plateau were more sensitive to warming than altered precipitation. The abundance of PCGs and P cycling processes decreased under the influence of individual climate change factors (i.e., warming and altered precipitation alone), except for the warming combined with increased precipitation. Pyruvate metabolism, phosphotransferase system, oxidative phosphorylation, and purine metabolism (all "intracellular" PCG) were closely correlated with P pools under climate change conditions. Specifically, warming recruited bacteria with the phoD and phoX genes, which encode enzymes responsible for phosphoester hydrolysis (extracellular P cycling), strongly accelerated organic P mineralization and so, directly impacted P bioavailability in alpine soil. The interactions between warming and altered precipitation profoundly influenced the PCGs' community and facilitated microbial adaptation to these environmental changes. Warming combined with increased precipitation compensated for the detrimental impacts of the individual climate change factors on PCGs. In conclusion, warming combined with rising precipitation has boosting effect on most P‐related functions, leading to the acceleration of P cycling within microbial cells and extracellularly, including mineralization and more available P release for microorganisms and plants in alpine soils. [ABSTRACT FROM AUTHOR]

Assessment of spring snow cover fraction (SCF) can be valuable for understanding the efficacy of certain Earth system models (ESMs) in simulating the energy exchange between land and atmosphere system, global hydrological cycle and future climate impacts. Here, we provide a comprehensive evaluation of simulated spring SCF from 23 and 20 ESMs participating CMIP5 and CMIP6, against satellite data from National Oceanic and Atmospheric Administration and National Climatic Data Center (NOAA/NCDC) and a long‐term Northern Hemisphere daily 5‐km snow cover extent product (JASMES) over the Northern Hemisphere (NH) and its 13 subregions during the period of 1982–2005 and 2072–2095. Our results show that (a) no model performs consistently better in simulating spring SCF from all aspects (mean annual, long‐term trend and climatological monthly of spring SCF); (b) the mean annual of spring SCF that was simulated by CMIP5 and CMIP6 model simulations was underestimated in most of the NH and overestimated over the Tibetan Plateau and eastern Asia; (c) most of the model simulations showed a stronger reduction trend for mean annual of spring SCF; (d) the climatological monthly variation of spring SCF is reasonably captured by all model simulations, except for overestimation over the TIB and EAS regions, and there is underestimation in other regions; (e) compared to CMIP5, most of the model simulations in CMIP6 exhibit an improved ability to simulate spring SCF across all aspects; (f) we confirm that the multi‐model ensemble mean (MME) is a better way to represent the three aspects of spring SCF than most individual model simulations. Finally, the spring SCF values predicted by models with better simulation abilities over the NH and its 13 subregions under different scenarios show decreasing trends. Specifically, the highest decreasing trend of spring SCF was found under high emission scenarios (RCP8.5 and SSP5‐8.5). [ABSTRACT FROM AUTHOR]

In terrestrial ecosystems, atmospheric nitrogen (N) deposition has greatly increased N availability relative to other elements, particularly phosphorus (P). Alterations in the availability of N relative to P can affect plant growth rate and functional traits, as well as resource allocation to above- versus belowground biomass ( MA and MB). Biomass allocation among individual plants is broadly size-dependent, and this can often be described as an allometric relationship between MA and MB, as represented by the equation [ABSTRACT FROM AUTHOR]

To predict the consequences of environmental change on the structure and composition of communities, it is necessary to also understand the regional drivers underlying the structuring of these communities. Here, we have taken a hypothesis-based approach to test the relative importance of niche versus neutral processes using niche overlap, species traits and population asynchrony in two crossed treatments of fertilization and grazing in an alpine meadow community. Our results suggested that the observed species biomass overlap was not significantly different between treatments of grazing, grazing × fertilization and grazer exclusion. In contrast, the species biomass overlap was higher than expected in fertilization treatments when grazers were excluded. On the one hand, we found no relationship between species traits and relative abundance in grazing, grazing × fertilization and grazer-exclusion treatments; on the other hand, mechanistic trait-based theory could be used to predict species relative abundance patterns in fertilization treatments when grazers were excluded. From grazing to fertilization, when grazers were excluded, there was a slight increase in species synchrony, which indicated that the complementary dynamic of species gradually changed from complete independence into synchronously fluctuating with increasing fertilization. Based on the above results, we concluded that stochastic and deterministic processes formed ends of a continuum from grazing to fertilization when grazers were excluded in an alpine meadow plant community, and the importance of niche differences between species in structuring grassland communities increased with increasing fertilization and decreased with grazing. [ABSTRACT FROM AUTHOR]

Light is a fundamental heterogeneous environmental factor for plants and often varies at both spatial and temporal scales. In the present study, we carried out a shading experiment to investigate the effect of variable light availability at the rosette stage of the first year in the strict biennial species Pedicularis torta (an endemic species of the Qinghai-Tibet Plateau) on reproductive traits (i.e. total number of flowers per plant, total number of fruits per plant/total number of flowers per plant, the number of seeds per fruit, mean individual seed mass and estimation of the total number of seeds per plant, plant size at maturity in the second year and on the relationships between reproductive traits and plant size at this stage). We found that light availability affected most of the reproductive traits (except for mean individual seed mass), plant size at maturity in the second year, and the relationship between the total number of flowers per plant and plant size at this stage. Our results indicate that reproductive traits respond to changes in light availability during the rosette plant stage. [ABSTRACT FROM AUTHOR]

Livestock grazing can affect both above- and below-ground communities, however, the effects of grazing intensity on vertical distribution of root traits and their associations with belowground food webs are still unclear. Based on a 5-year grazing intensity experiment (i.e., no grazing, moderate grazing and heavy grazing) in a Tibetan plateau meadow, we investigated how grazing-induced changes in root traits affected soil biota (microbes and nematodes) from the surface (0–10 cm) and subsurface soils (10–20 cm). Our results showed that moderate grazing increased nematode abundance and structure complexity of the soil micro-food webs compared to no and heavy grazing, and predominantly increased herbivores and fungivores regardless of soil layers. Shifts in herbivores and fungivores were mainly driven by root quantity and quality, emphasizing the stronger bottom-up effects on the lower trophic levels of nematodes. Grazing decreased the number of omnivores-predators in the surface soil compared to no grazing, which therefore weakened predation pressure on soil nematodes lower in the trophic structure, including root herbivores, while that effect was far less pronounced in the subsurface soil. Our study demonstrated that changes in root quantity and quality were highly associated with the complexity of the soil micro-food webs under grazing scenarios. These findings warranted the ideas that combined aboveground herbivore-root-soil micro-food webs as an ecological holo is essential for sustainable management of grassland. [Display omitted] • Structure complexity of soil micro-food webs showed hump-shaped responses to grazing intensity. • The carbon\nitrogen ratio of plant root was decreased by grazing compared to no grazing scenarios. • Moderate grazing strengthened the herbivory and fungal pathways of nematode community. • The abundance of herbivores and fungivores were positively correlated with plant root quantity and quality. [ABSTRACT FROM AUTHOR]