Dominant species may strongly influence biotic conditions and interact with other species, and thus are important drivers of community dynamics and ecosystem functioning, particularly in the stressed environment of alpine grasslands. However, the effects of dominant species on the community stability of different ecosystems remain poorly understood. We examined the temporal stability (2014-2020 year) of above-ground productivity and community stability mechanisms in the northern Tibetan four alpine grasslands (alpine meadow, alpine meadow steppe, alpine steppe, and alpine desert steppe) with changing species composition and dominance. Our results showed that community stability was significantly higher in the alpine meadow than in the other three types of grasslands. This difference was mainly attributed to the higher compensatory effect and selection effect in the alpine meadows. Furthermore, dominant species strongly affected community stability through increasing dominant species stability and species asynchrony. However, species richness had almost little effect. Our findings demonstrate that dominant species, as foundation species, may play leading roles in shaping community stability in the alpine grasslands, highlighting the importance of conserving dominant species for stable ecosystem functioning in these fragile ecosystems under increasing environmental fluctuations.

Although decoupling tourism growth from carbon emissions is vital for sustainable tourism development, the driving forces of tourism carbon decoupling in the Yangtze River Economic Belt (YREB) are little known. Herein, our study applies the geo-detector model and the Tapio decoupling index to investigate the decoupling trend and driving mechanism of the tourism economy in the YREB from carbon emissions from 2009 to 2019. Our results show that (1) the tourism carbon decoupling status has gradually evolved from connection to decoupling, and the average decoupling index was optimized from 1.36 in 2011 to 0.34 in 2019; (2) the dominant factors promoting the evolution of decoupling are the industrial structure (with an average q of 0.64 (2009–2019)) and the urbanization index (with an average q of 0.61 (2009–2019)), with government policy, technological innovation capability and consumption, and regional GDP also being important drivers; and (3) the double and nonlinear enhancement between the driving factors imply that regions in poor decoupling areas, such as Shanghai and Chongqing, can promote the evolution of decoupling through multi-factor interactions to realize the sustainability of the tourism industry. Finally, an integrative and proactive policy framework that has important theoretical, methodological, and management implications for the construction of green demonstration areas in the YREB is proposed.

In the context of “Carbon Emissions Peak” and “Carbon Neutrality”, grazing exclusion (GE) has been applied widely to rehabilitate degraded grasslands and increase carbon sequestration. However, on the Qingzang Plateau (QP), the impacts of GE on carbon dynamics of alpine grasslands are poorly understood, particularly at regional scale. Here, we evaluated the responses of carbon sequestration to GE in different alpine grasslands across QP to fill this knowledge gap by using meta-analysis. Overall, the effects of GE on ecosystem carbon fractions were dependent on GE duration, grassland types and climate factors. GE had more obviously positive effects on carbon stock across alpine meadow than alpine steppe. Longer duration of GE was more effective for ecosystem carbon sequestration in alpine steppe. Annual mean precipitation (AMP) and temperature (AMT) began to dominate ecosystem carbon sequestration after three years of GE duration across alpine meadow; and AMP was important climate factor limiting ecosystem carbon sequestration in the alpine steppe. In terms of plant carbon fraction, GE generated continuous positive effects on aboveground biomass (AGB) with increased GE duration in alpine meadow, while the continuous beneficial effects for AGB of alpine steppe disappeared at the 8th year of GE duration. And no positive effects were found on belowground biomass at the 11th year in both alpine meadow and alpine steppe. For soil organic carbon and microbial biomass carbon, there were no obvious trends in response to GE duration. In general, we highlighted that the responses of different carbon fractions (plant -soil - microbe) to GE were nonuniform at spatial and temporal scales, thereby we should adopt different carbon management practices for sustainable development of different grasslands.

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