Ying Pan

Alpine grasslands are crucial carbon (C) reservoirs, facing strong disruptions from intensified grazing. However, how grazing intensity regulates the allocation of recently assimilated C belowground and its utilization by soil microorganisms remains uncertain. Using in-situ 13CO2 pulse labeling in an alpine steppe, we compared the effects of non-grazing (NG), moderate grazing (MG), and heavy grazing (HG) on the allocation and cycling of recently assimilated C in shoots, roots, soil, and soil microorganisms. The initially assimilated 13C in shoots were highest under MG (245 mg C m–2). Root δ13C peaks were also highest under MG (28.5 mg C m–2), yet their mean residence time (MRT) was shortest (3.1 days), indicating rapid uptake and downward transport of newly fixed C through roots under MG. In contrast, HG delayed shoot δ13C peaks (to day 14) and produced the only pronounced soil δ13C peak (4‰), followed by a rapid decline, suggesting accelerated but short-lived belowground C allocation after severe defoliation. Despite phospholipid fatty acid (PLFA) profiles remaining stable, the share of 13C-PLFA held by Gram-positive bacteria increased from 30% to 40% under HG, indicating they became the dominant consumers of rhizodeposits. Besides, increasing grazing intensity exponentially shortened MRT across plant, soil, and microbial C pools. These results demonstrate that MG optimizes C allocation belowground and the microbial fate of plant-derived C, but HG accelerates plant–soil C fluxes and alters microbial consumer of rhizodeposits. Our study emphasizes the need to track where C flows and how long it resides in grazing grasslands.

Unbalanced regional development remains a major obstacle to sustainable development. In recent years, China has experienced slower GDP growth, shifting population trends, rural revitalization, and nationwide poverty reduction. It is unclear if China's core pattern of uneven regional development has changed as a result. This study analyzes county-level data from 2010 to 2020 using five regional categories: poverty-stricken vs. non-poverty-stricken counties, urban-dominant vs. rural-dominant areas, population growth vs. population decline, GDP growth vs. decline, and Eastern, Central, Western, and Northeast China regions. Using the Sustainable Development Index and Theil Index, we calculated 21 county-level sustainability indicators to measure regional gaps across economy, environment, and social services. Results show that as of 2020, the overall sustainable development in China steadily improved. While the disparity between poverty- and non-poverty-stricken counties has largely narrowed, disparities between urban-rural-dominant areas and between Eastern and Western China remain the main challenges. Differences linked to population or GDP changes were not significant. However, many Northeast China regions pose sustainability concerns due to simultaneous population and GDP decline.

Understanding how plant physiological traits respond to environmental variation is essential for explaining plant performance in alpine ecosystems. Based on field sampling along an elevational transect on the Tibetan Plateau, we quantified osmotic adjustment compounds, antioxidant indicators, and plant hormones in leaves of different species to examine interspecific differences in sensitivity to temperature and precipitation to characterize patterns of physiological plasticity among alpine plants. Along the elevational gradient, declining temperature results in increasing cold stress, whereas lower elevations are associated with reduced precipitation and intensified drought stress. Temperature primarily influenced plant physiological trait expression by promoting growth-related physiological processes, while precipitation variability mainly regulated traits associated with water stress. The three dominant alpine meadow species exhibited distinct patterns of physiological plasticity: Poa litwinowiana showed coordinated regulation of growth and defense pathways, whereas Carex moorcroftii and Carex parvula displayed more conservative response strategies, with physiological regulation tending to maintain homeostasis rather than strongly activating stress responses. These interspecific differences in physiological regulation were significantly associated with variations in plant height, cover, and dominance, providing trait-level physiological insights relevant to plant performance.

The fragile ecosystem of desert and desertification-prone regions (D & DPRs) in China is highly sensitive to climate change, landuse intensification, and human interventions such as deforestation and overgrazing. In response, large-scale ecological restoration programs have been implemented over the past decades, yet their effect and cost-effectiveness remain insufficiently understood. Here, by applying multi-source remote sensing data, employing the Geodetector model, and developing a Return on Investment (RI) index, we established a framework to quantify the ecological restoration effect and assess the cost-effectiveness of the ecological restoration programs launched in China’s D & DPRs. The results indicated that a marked shift in ecosystem dynamics occurred in 1999. A comparison of the pre-restoration (1982–1998) and post-restoration (1999–2020) periods revealed that the restoration and degradation occur simultaneously, with the proportions increasing by 15.5% and 21%, respectively. Spatially, the identified ecological restoration effect was concentrated in the northern Loess Plateau, the northeastern Inner Mongolia Plateau, and the Hexi Corridor, which were strongly linked to population, land management strategies and infrastructural accessibility. However, the cost-effectiveness analysis revealed that higher levels of ecological investment did not necessarily lead to greater ecological restoration effect. Instead, restoration efficiency varied substantially across different ecological and socio-economic contexts. These findings suggest that ecological restoration in China’s D & DPRs is not a uniform process but is contingent on social-ecological characteristics and investment strategies. Our results emphasize the need for adaptive, region-specific approaches to optimize restoration efforts and ensure the sustainable management of China’s D & DPRs.