Focusing on the surface sediments of the Yarlung Zangbo River in the Qinghai-Xizang Plateau,this study analyzes their provenance and evolutionary processes.River sediment samples were systematically collect-ed and analyzed using high-precision geochemical analytical techniques.Chondrite normalization,along with ele-mental ratios such as δEu,La/Yb,and Rb/Sr,and multivariate diagrams,were employed to characterize geochemi-cal features,reconstruct evolutionary processes,and determine sediment provenance.The results show that:(1)The total content of rare earth elements(∑REE)in this basin is generally high.The distribution of REEs is character-ized by significant enrichment of light rare earth elements,a typical negative Eu anomaly,and no obvious Ce anomaly.(2)There are clear spatial variations in weathering processes across the basin:Physical weathering dom-inates in the upper reaches,whereas chemical weathering becomes dominant in the lower reaches.(3)From the upper to the lower reaches,the mineral sorting of sediments gradually increases,and mineral maturity shows a significant increasing trend.(4)The geochemical mixing model shows that the provenance of sediments in the study area is mainly derived from metamorphic argillaceous rocks of the Himalayan orogenic belt(89.7%),with additional contributions from Himalayan leucogranites(8.3%)and Gangdese batholith granites(2.3%).These re-sults provide important geochemical evidence for understanding regional tectonic evolution processes and sedi-ment transport mechanisms.
To quantitatively assess the per capita carbon footprint and its driving factors in China,this study pro-vides a scientific basis for promoting coordinated regional carbon emission governance from both emission reduc-tion and carbon sequestration perspectives.Using the net primary productivity model,the per capita carbon foot-print in China and its provincial-level regions from 2009 to 2022 was estimated.The spatiotemporal patterns of the per capita carbon footprint were explored via exploratory spatial data analysis.Furthermore,from the multidi-mensional perspective of the economy-energy-ecology nexus,the spatial heterogeneity of factors influencing the per capita carbon footprint was analyzed using the multiscale geographically weighted regression model.The re-sults show that:(1)From 2009 to 2022,the per capita carbon footprint in China and its provincial-level regions exhibited a significant upward trend,with the annual growth rate peaking at 10.56%in 2011.The spatial distribu-tion of the per capita carbon footprint presented a pattern of being higher in the north and lower in the south.Hot-spots and sub-hotspots were highly concentrated in Inner Mongolia and its neighboring provinces,whereas sub-coldspots were scattered across southern China.(2)During the study period,the spatial center of gravity of the per capita carbon footprint shifted northwestward,while the main axis of spatial agglomeration showed a south-west-northeast trend.(3)In terms of influencing factors,economic development level serves as a core driving force,exerting a"bidirectional"positive-and-negative effect on per capita carbon footprint in conjunction with the proportion of cultivated land use.Population density,energy intensity,and energy flow act as positive driving factors,while urbanization rate and the proportion of newly increased forestland serve as negative inhibiting fac-tors.The results provide theoretical support for formulation of precision-oriented and differentiated regional poli-cies aimed at achieving carbon peaking and carbon neutrality.
The Longzhong region,a critical zone for ecological security within the upper reaches of the Yellow River,has historically been confronted with water scarcity and recurrent droughts,impeding its development.The elucidation of the mechanisms through which climatic factors and drought risk are associated is of practical signif-icance for the support of targeted drought mitigation,the optimization of water resource allocation,and the im-provement of the operation of water conservancy projects.This study utilized precipitation and potential evapo-transpiration(PET)data from 1980 to 2023 to systematically analyze the spatiotemporal evolution characteristics of drought and its coupled relationship with precipitation and PET.This analysis was conducted by applying methods such as the standardized precipitation evapotranspiration index(SPEI),climate tendency rate,and spatial interpolation.The results indicate that:(1)The drought evolution in the Longzhong region is characterized by three distinguishable stages.From 1980 to 1990,the frequency of droughts was 29.55%,from 1991 to 2010,it was 42.49%,and from 2011 to 2023,it was 23.72%.(2)From 1991 to 2023,the frequency of moderate-to-severe droughts during the spring and summer months reached 19.23%or higher,posing a significant threat to key agri-cultural periods.A notable finding was the highly significant increasing trend(P<0.01)exhibited by spring PET in Dingxi City,which served to exacerbate the ongoing drought conditions.(3)El Niño events increase the risk of drought,with the frequency of moderate-to-severe droughts rising 5.21 percentage points in El Niño years com-pared to non-El Niño years.The present study discloses the differential patterns between climatic factors and drought risk in the Longzhong region,thereby providing a scientific basis for regional drought mitigation strate-gies,optimization of agricultural planting structures,and informed scheduling of water conservancy projects.
The northern agropastoral ecotone serves as a critical ecological transition zone in China.The coordina-tion level between new-type urbanization development and agricultural ecosystem service influences regional re-source use efficiency and ecological stability,as well as its sustainable development potential.Focusing on 26 counties in the central northern agropastoral ecotone of China as the study area,this study constructs an evalua-tion system for new-type urbanization across four dimensions:population,economy,society,and agriculture.Based on land use data,an agricultural ecosystem service value assessment model is developed.Hotspot analysis,the coupling coordination degree model,and the geographical detector are employed to systematically analyze the spatiotemporal patterns and interaction mechanisms of new-type urbanization levels and agricultural ecosys-tem service values from 2010 to 2023.The results indicate that(1)The new-type urbanization level in the study area from 2010 to 2023 rose significantly,while agricultural ecosystem service values exhibited a fluctuating downward trend,with both variables maintaining a consistent"high in the east,low in the west"spatial distribu-tion.(2)The coupling coordination between new-type urbanization and agricultural ecosystem services is charac-terized by"low-level stagnation and intensifying polarization",with no counties yet achieving a state of coordi-nated development.(3)Geodetector analysis reveals that the driving mechanism is predominantly an"agricultur-al development-led"model,with per capita arable land and agricultural mechanization efficiency per unit area serving as the primary drivers.Interaction detection further shows an evolutionary shift in dominant factors from"economic-agricultural"to"intra-agricultural"synergies,ultimately resulting in a synergistic constraint driven by"resource-natural"factors.The results provide critical insights into the complex interactions between new-type urbanization and the agroecological environment,offering a scientific basis for formulating differentiated spatial governance policies that coordinately advance socio-economic development and agricultural ecological conservation.
Enhancing the livelihood resilience of poverty alleviation households is central to consolidating pover-ty reduction outcomes and preventing long-term poverty recurrence.Based on 2023 micro-survey data from 496 poverty alleviation households in Ulanqab,Inner Mongolia,China,this study measures farmers'livelihood resil-ience using the entropy method and the comprehensive index method.Multiple linear regression,mediation effect modeling,propensity score matching,and instrumental variable methods were employed to examine the effects and mechanisms of digital finance use and endogenous livelihood capital on household livelihood resilience.The findings are as follows:(1)Livelihood resilience reflects farmers'capacity to withstand risks and recover from livelihood shocks.Its key determinants include endogenous livelihood capital(personal health,household eco-nomic,human capital),as well as external support(digital finance).(2)Among the endogenous factors,better per-sonal health and stronger household economic conditions significantly improve livelihood resilience,whereas ad-vanced age significantly constrains it.(3)The use of digital finance significantly enhances livelihood resilience through two pathways:promoting agricultural technology adoption to improve production efficiency and facilitat-ing livelihood diversification to expand income sources.(4)The endogenous livelihood capital and digital finance operate synergistically,helping to overcome structural constraints associated with advanced age and low educa-tional attainment among poverty alleviation households.These results provide micro-level empirical evidence for optimizing livelihood support policies aimed at strengthening rural resilience and reducing the risk of poverty re-currence.
