Grassland degradation presents overwhelming challenges to biodiversity,ecosystem services,and the socioeconomic sustainability of dependent communities.However,a comprehensive synthesis of global knowledge on the fron...Grassland degradation presents overwhelming challenges to biodiversity,ecosystem services,and the socioeconomic sustainability of dependent communities.However,a comprehensive synthesis of global knowledge on the frontiers and key areas of grassland degradation research has not been achieved due to the limitations of traditional scientometrics methods.The present synthesis of information employed BERTopic,an advanced natural language processing tool,to analyze the extensive ecological literature on grassland degradation.We compiled a dataset of 4,504 publications from the Web of Science core collection database and used it to evaluate the geographic distribution and temporal evolution of different grassland types and available knowledge on the subject.Our analysis identified key topics in the global grassland degradation research domain,including the effects of grassland degradation on ecosystem functions,grassland ecological restoration and biodiversity conservation,erosion processes and hydrological models in grasslands,and others.The BERTopic analysis significantly outperforms traditional methods in identifying complex and evolving topics in large datasets of literature.Compared to traditional scientometrics analysis,BERTopic provides a more comprehensive perspective on the research areas,revealing not only popular topics but also emerging research areas that traditional methods may overlook,although scientometrics offers more specificity and detail.Therefore,we argue for the simultaneous use of both approaches to achieve more systematic and comprehensive assessments of specific research areas.This study represents an emerging application of BERTopic algorithms in ecological research,particularly in the critical research focused on global grassland degradation.It also highlights the need for integrating advanced computational methods in ecological research in this era of data explosion.Tools like the BERTopic algorithm are essential for enhancing our understanding of complex environmental problems,and it marks an important stride towards more sophisticated,data-driven analysis in ecology.展开更多
The escalating ecological consequences of state transitions have attracted significant attention in both theoretical and experimental studies,with a focus on determining the stable or equilibrium points of dynamic sys...The escalating ecological consequences of state transitions have attracted significant attention in both theoretical and experimental studies,with a focus on determining the stable or equilibrium points of dynamic systems[1-5].Identifying equilibrium states not only reveals a system's current status but also offers insights into its evolutionary trajectory under specific environmental conditions[6].展开更多
Structural information of grassland changes on the Tibetan Plateau is essential for understanding alterations in critical ecosystem functioning and their underlying drivers that may reflect environmental changes.Howev...Structural information of grassland changes on the Tibetan Plateau is essential for understanding alterations in critical ecosystem functioning and their underlying drivers that may reflect environmental changes.However,such information at the regional scale is still lacking due to methodological limitations.Beyond remote sensing indicators only recognizing vegetation productivity,we utilized multivariate data fusion and deep learning to characterize formation-based plant community structure in alpine grasslands at the regional scale of the Tibetan Plateau for the first time and compared it with the earlier version of Vegetation Map of China for historical changes.Over the past 40 years,we revealed that(1)the proportion of alpine meadows in alpine grasslands increased from 50%to 69%,well-reflecting the warming and wetting trend;(2)dominances of Kobresia pygmaea and Stipa purpurea formations in alpine meadows and steppes were strengthened to 76%and 92%,respectively;(3)the climate factor mainly drove the distribution of Stipa purpurea formation,but not the recent distribution of Kobresia pygmaea formation that was likely shaped by human activities.Therefore,the underlying mechanisms of grassland changes over the past 40 years were considered to be formation dependent.Overall,the first exploration for structural information of plant community changes in this study not only provides a new perspective to understand drivers of grassland changes and their spatial heterogeneity at the regional scale of the Tibetan Plateau,but also innovates large-scale vegetation study paradigm.展开更多
Ecologic vulnerable areas(EVAs)are the regions where ecosystems are fragile and vulnerable to sufferfrom degradation with external disturbances,e.g.environmental changes and human activities(Fengetal.2022;Wangetal.201...Ecologic vulnerable areas(EVAs)are the regions where ecosystems are fragile and vulnerable to sufferfrom degradation with external disturbances,e.g.environmental changes and human activities(Fengetal.2022;Wangetal.2019).EVAsinChina are widely distributed and account for more than 55%China's landarea(Ministryof Ecologyand Environment of the People's Republic of China 2008).Theecosystem in EVAs,chartered with low stability,weak resistance and high vulnerability,has been experiencing significant degradation owing to the impacts of global climate change and human activities(Bai et al.2018;Chen et al.202l;Yuetal.2022).展开更多
Differences in progress across sustainable development goals(SDGs)are widespread globally;meanwhile,the rising call for prioritizing specific SDGs may exacerbate such gaps.Nevertheless,how these progress differences w...Differences in progress across sustainable development goals(SDGs)are widespread globally;meanwhile,the rising call for prioritizing specific SDGs may exacerbate such gaps.Nevertheless,how these progress differences would influence global sustainable development has been long neglected.Here,we present the first quantitative assessment of SDGs’progress differences globally by adopting the SDGs progress evenness index.Our results highlight that the uneven progress across SDGs has been a hindrance to sustainable development because(1)it is strongly associated with many public health risks(e.g.,air pollution),social inequalities(e.g.,gender inequality,modern slavery,wealth gap),and a reduction in life expectancy;(2)it is also associated with deforestation and habitat loss in terrestrial and marine ecosystems,increasing the challenges related to biodiversity conservation;(3)most countries with low average SDGs performance show lower progress evenness,which further hinders their fulfillment of SDGs;and(4)many countries with high average SDGs performance also showcase stagnation or even retrogression in progress evenness,which is partly ascribed to the antagonism between climate actions and other goals.These findings highlight that while setting SDGs priorities may be more realistic under the constraints of multiple global stressors,caution must be exercised to avoid new problems from intensifying uneven progress across goals.Moreover,our study reveals that the urgent needs regarding SDGs of different regions seem complementary,emphasizing that regional collaborations(e.g.,demand-oriented carbon trading between SDGs poorly performed and well-performed countries)may promote sustainable development achievements at the global scale.展开更多
Emerging Internet services and applications attract increasing users to involve in diverse video-related activities,such as video searching,video downloading,video sharing and so on.As normal operations,they lead to a...Emerging Internet services and applications attract increasing users to involve in diverse video-related activities,such as video searching,video downloading,video sharing and so on.As normal operations,they lead to an explosive growth of online video volume,and inevitably give rise to the massive near-duplicate contents.Near-duplicate video retrieval(NDVR)has always been a hot topic.The primary purpose of this paper is to present a comprehensive survey and an updated review of the advance on large-scale NDVR to supply guidance for researchers.Specifically,we summarize and compare the definitions of near-duplicate videos(NDVs)in the literature,analyze the relationship between NDVR and its related research topics theoretically,describe its generic framework in detail,investigate the existing state-of-the-art NDVR systems.Finally,we present the development trends and research directions of this topic.展开更多
Water resource availability is the major limiting factor for sustainable development in drylands.Climate change intensifies the conflicting water demands between people and the environment and highlights the importanc...Water resource availability is the major limiting factor for sustainable development in drylands.Climate change intensifies the conflicting water demands between people and the environment and highlights the importance of effective water resource management for achieving a balance between economic development and environmental protection.In 2008,Inner Mongolia,typical dryland in northern China,proposed strict regulations on water exploitation and utilization aimed at achieving sustainable development.Our study is the first to investigate the effectiveness and performance of these long-standing water conservation regulations.Our analyses found that the regulations drove industrial transformation,evidenced by the decreasing proportion of environmentally harmful industries such as coal and steel,and the increasing proportion of tertiary industries(especially tourism).Following industrial transformation,economic development decoupled from industrial water consumption and subsequently led to reduced negative environmental impacts.Based on these results,adaptive strategies were developed for 12 cities by revealing and integrating their development pathways and relative status in achieving sustainable development.Integration and cooperation between cities were proposed,e.g.,a water trade agreement between eastern Inner Mongolia(an economically underdeveloped region with relatively abundant water resources)and central Inner Mongolia(an economically developed region with high water stress).Such an agreement may enable the holistic achievement of sustainable development across regions.By integrating the findings of our research,our study presents a reproducible framework for water-management-based sustainable development strategies in drylands.展开更多
Aims Prediction of changes in ecosystem gross primary productivity(GPP)in response to climatic variability is a core mission in the field of global change ecology.However,it remains a big challenge for the model commu...Aims Prediction of changes in ecosystem gross primary productivity(GPP)in response to climatic variability is a core mission in the field of global change ecology.However,it remains a big challenge for the model community to reproduce the interannual variation(IAV)of GPP in arid ecosystems.Accurate estimates of soil water content(SWC)and GPP sensitivity to SWC are the two most critical aspects for predicting the IAV of GPP in arid ecosystems.Methods We took a widely used model Biome-BGC as an example,to improve the model performances in a temperate grassland ecosystem.Firstly,we updated the estimation of SWC by modifying modules of evapotrainspiration,SWC vertical profile and field capacity.Secondly,we modified the function of controlling water-nitrogen relation,which regulates the GPP-SWC sensitivity.Important Findings The original Biome-BGC overestimated the SWC and underestimated the IAV of GPP sensitivity,resulting in lower IAV of GPP than the observations,e.g.it largely underestimated the reduction of GPP in drought years.In comparison,the modified model accurately reproduced the observed seasonal and IAVs in SWC,especially in the surface layer.Simulated GPP-SWC sensitivity was also enhanced and became closer to the observations by optimizing parameter controlling nitrogen mineralization.Consequently,the model's capability of reproducing IAV of GPP has been largely improved by the modifications.Our results demonstrate that SWC in the surface layer and the consequent effects on nitrogen availability should be among the first considerations for accurate modeling IAV of GPP in arid ecosystems.展开更多
基金financially supported by the First-Class Curriculum Program at the School of Economics and Management,University of the Chinese Academy of Sciencesthe National Natural Science Foundation of China(42041005)the National Social Science Foundation of China(23BTQ054)。
文摘Grassland degradation presents overwhelming challenges to biodiversity,ecosystem services,and the socioeconomic sustainability of dependent communities.However,a comprehensive synthesis of global knowledge on the frontiers and key areas of grassland degradation research has not been achieved due to the limitations of traditional scientometrics methods.The present synthesis of information employed BERTopic,an advanced natural language processing tool,to analyze the extensive ecological literature on grassland degradation.We compiled a dataset of 4,504 publications from the Web of Science core collection database and used it to evaluate the geographic distribution and temporal evolution of different grassland types and available knowledge on the subject.Our analysis identified key topics in the global grassland degradation research domain,including the effects of grassland degradation on ecosystem functions,grassland ecological restoration and biodiversity conservation,erosion processes and hydrological models in grasslands,and others.The BERTopic analysis significantly outperforms traditional methods in identifying complex and evolving topics in large datasets of literature.Compared to traditional scientometrics analysis,BERTopic provides a more comprehensive perspective on the research areas,revealing not only popular topics but also emerging research areas that traditional methods may overlook,although scientometrics offers more specificity and detail.Therefore,we argue for the simultaneous use of both approaches to achieve more systematic and comprehensive assessments of specific research areas.This study represents an emerging application of BERTopic algorithms in ecological research,particularly in the critical research focused on global grassland degradation.It also highlights the need for integrating advanced computational methods in ecological research in this era of data explosion.Tools like the BERTopic algorithm are essential for enhancing our understanding of complex environmental problems,and it marks an important stride towards more sophisticated,data-driven analysis in ecology.
基金supported by the funds from the National Natural Science Foundation of China(42041005 and 32101313)the CAS Strategic Priority Research Programme(A)(XDA20050103)Science&Technology Fundamental Resources Investigation Program(2022FY100100)。
文摘The escalating ecological consequences of state transitions have attracted significant attention in both theoretical and experimental studies,with a focus on determining the stable or equilibrium points of dynamic systems[1-5].Identifying equilibrium states not only reveals a system's current status but also offers insights into its evolutionary trajectory under specific environmental conditions[6].
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0304-02)Joint Chinese Academy of Sciences(CAS)-Max Planck Society(MPG)Research Project(HZXM20225001MI)+3 种基金the Strategic Priority Research Program A of Chinese Academy of Sciences(XDA20050104)the National Natural Science Foundation of China(42041005)CAS Light of West China Programthe Fundamental Research Funds for the Central Universities。
文摘Structural information of grassland changes on the Tibetan Plateau is essential for understanding alterations in critical ecosystem functioning and their underlying drivers that may reflect environmental changes.However,such information at the regional scale is still lacking due to methodological limitations.Beyond remote sensing indicators only recognizing vegetation productivity,we utilized multivariate data fusion and deep learning to characterize formation-based plant community structure in alpine grasslands at the regional scale of the Tibetan Plateau for the first time and compared it with the earlier version of Vegetation Map of China for historical changes.Over the past 40 years,we revealed that(1)the proportion of alpine meadows in alpine grasslands increased from 50%to 69%,well-reflecting the warming and wetting trend;(2)dominances of Kobresia pygmaea and Stipa purpurea formations in alpine meadows and steppes were strengthened to 76%and 92%,respectively;(3)the climate factor mainly drove the distribution of Stipa purpurea formation,but not the recent distribution of Kobresia pygmaea formation that was likely shaped by human activities.Therefore,the underlying mechanisms of grassland changes over the past 40 years were considered to be formation dependent.Overall,the first exploration for structural information of plant community changes in this study not only provides a new perspective to understand drivers of grassland changes and their spatial heterogeneity at the regional scale of the Tibetan Plateau,but also innovates large-scale vegetation study paradigm.
基金National Key RSDProgramofChina(GrantNo.2017YFA0604801)National Natural Science Foundation of China(Grant No.31922053)+1 种基金Key RGD Program of Hainan(Grant No.412 ZDYF2022SHFZ042)the start-up fund of Hainan University(Grant NO.KYQD(ZR)21096).
文摘Ecologic vulnerable areas(EVAs)are the regions where ecosystems are fragile and vulnerable to sufferfrom degradation with external disturbances,e.g.environmental changes and human activities(Fengetal.2022;Wangetal.2019).EVAsinChina are widely distributed and account for more than 55%China's landarea(Ministryof Ecologyand Environment of the People's Republic of China 2008).Theecosystem in EVAs,chartered with low stability,weak resistance and high vulnerability,has been experiencing significant degradation owing to the impacts of global climate change and human activities(Bai et al.2018;Chen et al.202l;Yuetal.2022).
基金This work was supported by the National Natural Science Foundation of China(42001267,42041005,and 42041007)the International Partnership Program of Chinese Academy of Sciences(121311KYSB20170004-04)the Chinese Academy of Sciences Strategic Priority Research Program(A)(grant no.XDA20050103)。
文摘Differences in progress across sustainable development goals(SDGs)are widespread globally;meanwhile,the rising call for prioritizing specific SDGs may exacerbate such gaps.Nevertheless,how these progress differences would influence global sustainable development has been long neglected.Here,we present the first quantitative assessment of SDGs’progress differences globally by adopting the SDGs progress evenness index.Our results highlight that the uneven progress across SDGs has been a hindrance to sustainable development because(1)it is strongly associated with many public health risks(e.g.,air pollution),social inequalities(e.g.,gender inequality,modern slavery,wealth gap),and a reduction in life expectancy;(2)it is also associated with deforestation and habitat loss in terrestrial and marine ecosystems,increasing the challenges related to biodiversity conservation;(3)most countries with low average SDGs performance show lower progress evenness,which further hinders their fulfillment of SDGs;and(4)many countries with high average SDGs performance also showcase stagnation or even retrogression in progress evenness,which is partly ascribed to the antagonism between climate actions and other goals.These findings highlight that while setting SDGs priorities may be more realistic under the constraints of multiple global stressors,caution must be exercised to avoid new problems from intensifying uneven progress across goals.Moreover,our study reveals that the urgent needs regarding SDGs of different regions seem complementary,emphasizing that regional collaborations(e.g.,demand-oriented carbon trading between SDGs poorly performed and well-performed countries)may promote sustainable development achievements at the global scale.
基金The work was supported by the National Natural Science Foundation of China(Grant Nos.61722204,61732007 and 61632007).
文摘Emerging Internet services and applications attract increasing users to involve in diverse video-related activities,such as video searching,video downloading,video sharing and so on.As normal operations,they lead to an explosive growth of online video volume,and inevitably give rise to the massive near-duplicate contents.Near-duplicate video retrieval(NDVR)has always been a hot topic.The primary purpose of this paper is to present a comprehensive survey and an updated review of the advance on large-scale NDVR to supply guidance for researchers.Specifically,we summarize and compare the definitions of near-duplicate videos(NDVs)in the literature,analyze the relationship between NDVR and its related research topics theoretically,describe its generic framework in detail,investigate the existing state-of-the-art NDVR systems.Finally,we present the development trends and research directions of this topic.
基金supported by the CAS Strategic Priority Research Programme(No.XDA20050103)the International Partnership Program of Chinese Academy of Sciences(No.121311KYSB20170004-04)and the National Natural Science Foundation of China(Grant No.42001267).
文摘Water resource availability is the major limiting factor for sustainable development in drylands.Climate change intensifies the conflicting water demands between people and the environment and highlights the importance of effective water resource management for achieving a balance between economic development and environmental protection.In 2008,Inner Mongolia,typical dryland in northern China,proposed strict regulations on water exploitation and utilization aimed at achieving sustainable development.Our study is the first to investigate the effectiveness and performance of these long-standing water conservation regulations.Our analyses found that the regulations drove industrial transformation,evidenced by the decreasing proportion of environmentally harmful industries such as coal and steel,and the increasing proportion of tertiary industries(especially tourism).Following industrial transformation,economic development decoupled from industrial water consumption and subsequently led to reduced negative environmental impacts.Based on these results,adaptive strategies were developed for 12 cities by revealing and integrating their development pathways and relative status in achieving sustainable development.Integration and cooperation between cities were proposed,e.g.,a water trade agreement between eastern Inner Mongolia(an economically underdeveloped region with relatively abundant water resources)and central Inner Mongolia(an economically developed region with high water stress).Such an agreement may enable the holistic achievement of sustainable development across regions.By integrating the findings of our research,our study presents a reproducible framework for water-management-based sustainable development strategies in drylands.
基金supported by the National Natural Science Foundation of China(31922053)the National Key Research and Development Program of China(2017YFA0604801).
文摘Aims Prediction of changes in ecosystem gross primary productivity(GPP)in response to climatic variability is a core mission in the field of global change ecology.However,it remains a big challenge for the model community to reproduce the interannual variation(IAV)of GPP in arid ecosystems.Accurate estimates of soil water content(SWC)and GPP sensitivity to SWC are the two most critical aspects for predicting the IAV of GPP in arid ecosystems.Methods We took a widely used model Biome-BGC as an example,to improve the model performances in a temperate grassland ecosystem.Firstly,we updated the estimation of SWC by modifying modules of evapotrainspiration,SWC vertical profile and field capacity.Secondly,we modified the function of controlling water-nitrogen relation,which regulates the GPP-SWC sensitivity.Important Findings The original Biome-BGC overestimated the SWC and underestimated the IAV of GPP sensitivity,resulting in lower IAV of GPP than the observations,e.g.it largely underestimated the reduction of GPP in drought years.In comparison,the modified model accurately reproduced the observed seasonal and IAVs in SWC,especially in the surface layer.Simulated GPP-SWC sensitivity was also enhanced and became closer to the observations by optimizing parameter controlling nitrogen mineralization.Consequently,the model's capability of reproducing IAV of GPP has been largely improved by the modifications.Our results demonstrate that SWC in the surface layer and the consequent effects on nitrogen availability should be among the first considerations for accurate modeling IAV of GPP in arid ecosystems.
