Accurate phenological information is essential for measuring ecosystem dynamics and carbon uptake.Southwest China is one of the country's largest terrestrial carbon sink regions and plays a crucial role in carbon ...Accurate phenological information is essential for measuring ecosystem dynamics and carbon uptake.Southwest China is one of the country's largest terrestrial carbon sink regions and plays a crucial role in carbon peaking and neutrality.However,its complex terrain,fragile ecosystem,and variable climate challenge carbon sink stability.Vegetation phenology significantly impacts carbon absorption and release,making accurate phenological data essential for understanding carbon sequestration dynamics.The widespread distribution of evergreen forests and their weak seasonal variation in canopy introduce significant uncertainties in extracting phenology using traditional remote sensing information in this region.These limitations can lead to inaccurate assessments of carbon sink dynamics.Therefore,precise phenology extraction and analysis are vital for improving ecosystem dynamics and the carbon cycle in Southwest China.Firstly,we employed different ways to evaluate the ability of solar-induced chlorophyll fluorescence(SIF)and traditional remote sensing information to extract phenology.Secondly,based on SIF,we analyzed the spatial and temporal changes in the start of the growing season(SOS),the end of the growing season(EOS),and the length of the growing season(LOS)from 2001 to 2020.Finally,we systematically analyzed the response of SOS and EOS to five preseason climatic factors.The results showed that(1)SIF outperformed traditional remote sensing information in extracting phenology.(2)Vegetation phenology exhibited significant spatial heterogeneity.Moreover,SOS,EOS,and LOS showed trends of advancement,delay,and extension both overall and across all vegetation types.(3)Precipitation was the main factor influencing SOS,while surface downward solar radiation and mean temperature were the main factors affecting EOS,and the phenology of different vegetation types showed a great difference in response to preseason climate factors.These findings improve our understanding of vegetation phenology and its dynamics over Southwest China.展开更多
[Objective]Vegetation restoration is an effective strategy for ecological improvement;however,inappropriate vegetation establishment can induce soil desiccation,thereby threatening ecosystem stability.Therefore,elucid...[Objective]Vegetation restoration is an effective strategy for ecological improvement;however,inappropriate vegetation establishment can induce soil desiccation,thereby threatening ecosystem stability.Therefore,elucidating the global response patterns of soil moisture to vegetation restoration and identifying research hotspots are critical for guiding ecological construction in arid regions.[Methods]We reviewed 6,152 articles concerning soil moisture and vegetation retrieved from the Web of Science platform.Using VOSviewer,we conducted analyses of keyword co-occurrence,publication trends,and research hotspots to systematically delineate the evolving trends in this field.[Results]The results indicate a significant increasing trend in the number of publications since 2000.Global research keywords are categorized into seven clusters,including vegetation,soil moisture,rainfall-erosion-infiltration,spatial heterogeneity,and climate change.In terms of highly cited papers in 2024,China and the United States maintain a significant lead.Global research demonstrates a strong dependency on typical regional geographical features(such as climate types and topography),exhibiting differentiated research focuses.Furthermore,studies extend beyond soil moisture itself to deeply couple with ecological processes such as vegetation restoration,soil respiration,carbon cycling,and hydrothermal conditions.[Conclusions]The long-term ecological effects of afforestation in arid regions remain unclear,and empirical data from key regions highlight the current urgency.Future research should integrate climate change dynamics,innovate monitoring methodologies,and deepen the understanding of regional differentiation to provide scientific support for the adaptive management of vegetation in arid regions.展开更多
The connection between climatic factors and grazing is essential for maintaining ecosystem function and vegetation productivity.This study examined the impact of grazing intensity on vegetation across a broad climatic...The connection between climatic factors and grazing is essential for maintaining ecosystem function and vegetation productivity.This study examined the impact of grazing intensity on vegetation across a broad climatic gradient spanning the Espinal,Argentine Low Monte,and Patagonian Steppe ecoregions of Argentina.The research was carried out at eight sampling sites with radial grazing gradients generated around artificial water sources(piospheres),exhibiting two contrasting response patterns of vegetation to grazing pressure.One of the response patterns shows a typical vegetation response to grazing that the vegetation productivity increases with the distance to the water sources(decreasing grazing intensity).The second pattern is found in drier regions,where vegetation presents an inverse productivity response that vegetation productivity is higher near water sources(high grazing intensity)due to increased shrub cover.Vegetation productivity was measured using the Normalized Difference Vegetation Index(NDVI).Vegetation patch structure and cover were determined for each site with high,medium,and low grazing intensities.Results indicated that shrub cover is the primary driver of vegetation productivity,showing contrasting responses to grazing intensity between the two identified patterns.While NDVI proved to be a reliable proxy for shrub cover and total vegetation cover(R2>0.70),it failed to reflect grass cover dynamics.Furthermore,mean annual temperature was more strongly correlated with vegetation cover changes,while grazing intensity significantly altered vegetation patch structure and soil cover distribution.Specifically,in drier regions,high grazing intensity led to larger patches while,in wetter regions,it led to smaller patches(fragmentation).Shrubs,with their deeper roots and drought tolerance,were less preferred and more resistant to grazing in arid environments and thrived under grazing pressure in these arid conditions.Our results underscored the need for adaptive management strategies in grazing systems.Traditional approaches may require significant adjustments,as the efficacy of management hinges on the interplay of specific climatic conditions and the varied responses of vegetation.Furthermore,effective conservation efforts should prioritize the recognition and protection of shrubs given their critical contribution to ecosystem function and biodiversity.Ultimately,this research provides a valuable framework to understand the complex dynamics between grazing and vegetation in arid and semi-arid environments,highlighting that sustainable grazing practices should be tailored to account for both climatic variables and the unique characteristics of different plant communities.展开更多
Vegetation plays an important role in the environmental transport behavior of organic pollutants,however,the different roles of crops and natural vegetation have been ignored in most previous studies.In this study,we ...Vegetation plays an important role in the environmental transport behavior of organic pollutants,however,the different roles of crops and natural vegetation have been ignored in most previous studies.In this study,we developed the BETR-Urban-Rural-Veg model to quantitatively evaluate the influences of both natural vegetation and crops on the multimedia transport processes of Phenanthrene(PHE)and Benzo(a)pyrene(BaP)in mainland of China.The geographic distribution of polycyclic aromatic hydrocarbon(PAH)emissions and concentrations were consistent,displaying higher levels in northern China while lower levels in southern China.Under seasonal simulations,for both natural vegetation and crops,PAH concentrations in winter and spring were 1.5 to 27-fold higher than in summer and autumn,especially for PHE.Owing to the higher leaf area index(LAI)of natural vegetation and harvesting of crops,the filter and sequestration effect of natural vegetation was stronger than crops,while the seasonal changes of PAH concentrations in crops were more significant than natural vegetation.Temperature,precipitation rates and LAI might have important influences on seasonal concentrations and overall persistence of PAHs.PHE was more sensitive to the impacts of seasonal environmental parameters.Under different landscape scenarios,average annual PAH concentrations in natural vegetation were always a little higher than those in crops,and the overall persistence of BaP was greatly affected increasing by 15.15%-16.47%.This improved model provides a useful tool for environmental management.The results of this study are expected to support land use plans and decision-making in China's mainland.展开更多
Urban forests are essential components of green infrastructure,however,rapid urbanization-induced changes in landscape patterns may affect their ecosystem services through complex ecological processes.A total of 184 s...Urban forests are essential components of green infrastructure,however,rapid urbanization-induced changes in landscape patterns may affect their ecosystem services through complex ecological processes.A total of 184 sample plots in the built-up areas of Nanchang,China,were used as research sites.Urbanization intensities were categorized by the rate of impervious surface area,and forest types were classified into landscape and relaxation forest,attached forest(AF),road forest(RF),and ecological public welfare forest.This study aimed to explore the spatial variations in vegetation characteristics and landscape pattern indices of different forest types under rapid urbanization.The results indicated that the largest patch index(LPI),aggregation index(AI),and percentage of landscape(PLAND)in RF and AF were lower than those in the other forest types(p<0.05).With increasing urbanization intensity,the mean perimeter-area ratio increased by 130.84%,whereas the PLAND,LPI,and AI decreased by 22−86%(p<0.05).Redundancy analysis and variation partitioning suggested that the interpretation rate of landscape pattern indices for variations in vegetation characteristics increased from low to heavy urbanization areas.Especially,the landscape shape index,patch connection index,PLAND,and mean patch size were significantly correlated with vegetation characteristics(e.g.,tree richness,herb coverage,and tree height).In the future,appropriate landscape layout superiority cases should be considered in different urbanization areas and forest types;for instance,increasing the patch connection index will beneficially improve the diversity of trees and herbs in heavy urbanization areas and the RF.This study serves as a reference for maximizing the ecosystem services of urban forests.展开更多
This study investigates the impact of vegetation-climate feedback on the global land monsoon system during the Last Interglacial(LIG,127000 years BP)and the mid-Holocene(MH,6000 years BP)using the earth system model E...This study investigates the impact of vegetation-climate feedback on the global land monsoon system during the Last Interglacial(LIG,127000 years BP)and the mid-Holocene(MH,6000 years BP)using the earth system model EC-Earth3.Our findings indicate that vegetation changes significantly influence the global monsoon area and precipitation patterns,especially in the North African and Indian monsoon regions.The North African monsoon region experienced the most substantial increase in vegetation during both the LIG and MH,resulting in significant increases in monsoonal precipitation by 9.8%and 6.0%,respectively.The vegetation feedback also intensified the Saharan Heat Low,strengthened monsoonal flows,and enhanced precipitation over the North African monsoon region.In contrast,the Indian monsoon region exhibited divergent responses to vegetation changes.During the LIG,precipitation in the Indian monsoon region decreased by 2.2%,while it increased by 1.6%during the MH.These differences highlight the complex and region-specific impacts of vegetation feedback on monsoon systems.Overall,this study demonstrates that vegetation feedback exerts distinct influences on the global monsoon during the MH and LIG.These findings highlight the importance of considering vegetation-climate feedback in understanding past monsoon variability and in predicting future climate change impacts on monsoon systems.展开更多
Understanding the dynamics of vegetation carbon sequestration(VCS)is essential for regional carbon neutrality strategies.This study revealed the spatiotemporal patterns of VCS and its relationship with anthropogenic c...Understanding the dynamics of vegetation carbon sequestration(VCS)is essential for regional carbon neutrality strategies.This study revealed the spatiotemporal patterns of VCS and its relationship with anthropogenic carbon emissions(ACEs)in Shandong Province,China during 2000-2020,and identified the sensitivity factors affecting VCS.The results show that:1)VCS increased consistently from 193.45 million t to 256.41 million t,with high values areas concentrated in the central,northeastern,and southeastern mountainous and hilly regions,while low values were found in water bodies and urban built-up areas.At the city level,Linyi,Yantai,Binzhou,and Jinan experienced the most significant rises-reaching up to 243000 t/yr.At the county level,Pingdu,Qixia,and Yiyuan also showed substantial growth,each exceeding 30400 t/yr.2)Digital Elevation Molde(DEM)was identified as the dominant natural factor influencing VCS distribution,while land use optimization measures,especially afforestation and farmland conversion in sloped terrain,were the primary human drivers of VCS increase.3)Urbanization and carbon neutrality were not mutually exclusive.While urban expansion locally reduced VCS,rural emigration enhanced carbon sinks in surrounding areas,partially offsetting urban losses.This compensatory mechanism supported VCS increases in nearly all cities and 90% of counties.Nevertheless,with ACEs continuing to rise and the offset ratio by VCS declining,achieving carbon neutrality requires regional strategies that integrate with accelerated energy conservation,emission reduction technologies,and energy transition.These findings provide a scientific basis for decomposing carbon neutrality targets across cities and counties in Shandong and a reference for developing localized land use policies in similar regions.展开更多
Sand dust belts span approximately one-fifth of the global land surface.In these regions,dust tends to settle on vegetation surfaces,altering the observed reflectance and affecting remote sensing detections.To enhance...Sand dust belts span approximately one-fifth of the global land surface.In these regions,dust tends to settle on vegetation surfaces,altering the observed reflectance and affecting remote sensing detections.To enhance the accuracy of maize growth monitoring in dust-affected regions,this study aims to quantify the effect of sand dust retention on maize during the tasseling stage in the Kashgar Prefecture,Xinjiang Uygur Autonomous Region,China,by analyzing changes in canopy reflectance and vegetation indices.First,field sampling was conducted to measure the key canopy structure parameters and dust retention levels of maize,and laboratory spectral measurements were performed on leaf spectral properties under gradient dust retention.The measured data were then used to drive the LargE-Scale remote sensing data and image Simulation framework(LESS)model for simulating realistic maize canopy spectra across different dust levels,with validation against Sentinel-2 imagery.Second,on the basis of the simulated and satellite-derived spectra,the dust resistance of 36 common vegetation indices was systematically evaluated,and new robust dust-resistant indices were developed.The results showed that compared with dust-free maize,the canopy reflectance of dust-retained maize followed an increase–decrease–increase pattern,with critical turning points at 735 and 1325 nm.The maximum reflectance difference of–0.11755(change rate:29.002%)occurred within the 735–1325 nm range at 24 g/m^(2)dust retention,and the minimum reflectance difference of 0.04285(change rate:148.950%)was observed in the 350–735 nm range under the same dust retention level.Among the 36 vegetation indices,only the global environment monitoring index(GEMI)and the ratio of transformed chlorophyll absorption in reflectance index to optimized soil-adjusted vegetation index(TCARI/OSAVI)exhibited dust resistance,with GEMI being effective below 6 g/m^(2)and TCARI/OSAVI remaining stable across all levels(average ratio:0.970).The newly developed indices in this study,(RE3–RE2)/(NIR–RE2),(RE3–RE2)/(RE4–RE2),and(NIR–RE2)/(RE4–RE2),retained values within the predefined dust-resistant range over the full dust retention levels of 0–24 g/m^(2),thus showing a more stable dust resistance compared with the commonly used 36 vegetation indices.Specially,(RE3–RE2)/(RE4–RE2)performed the most robustly in Sentinel-2 imagery,that is,58.020%of pixels were within the dust-resistant range,and an average ratio of 0.937 was obtained for the original-spectra index.This study provides a scientific basis for crop monitoring and management in dust-affected regions.展开更多
Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundat...Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes.展开更多
This research aims to analyse the spatio-temporal changes of vegetation cover in coastal regions of Char Fasson and Galachipa Upazila, Bangladesh for a period of 30 years (1994-2024) based on Landsat satellite imagery...This research aims to analyse the spatio-temporal changes of vegetation cover in coastal regions of Char Fasson and Galachipa Upazila, Bangladesh for a period of 30 years (1994-2024) based on Landsat satellite imagery and NDVI. Through the evaluation of NDVI this paper classifies vegetation as no water/bare vegetation, slightly densed vegetation, moderately densed vegetation, and highly densed vegetation. The findings reveal significant fluctuations in vegetation cover: from 1994 to 2004, there has been an increase in vegetation density implying that afforestation has created more moderate and highly densed vegetation out of density vegetation. However, between 2004 and 2014, vegetation cover decreased because some cyclones, like Sidr and Aila, affected the coastal forest of Bangladesh. Other attempts to afforestation supported improved coverage from vegetation between 2014 and 2024. These findings provide clear evidence of the sustainable benefits of coastal afforestation in the reduction of coastal erosion and storm surges that affect vegetation and coasts. Knowledge gained in this research is highly useful to the environmental planners on recommendations for sustainable land uses and preservation to build up ecological stability in Bangladesh weak coastal areas.展开更多
The hydrodynamic response of overland flow to vegetation coverage on convex slopes remains inadequately quantified despite it is critical for soil erosion control in terrains dominated by such topography.This study sy...The hydrodynamic response of overland flow to vegetation coverage on convex slopes remains inadequately quantified despite it is critical for soil erosion control in terrains dominated by such topography.This study systematically investigated the influence of varying vegetation coverage(0%,1.08%,3.24%,4.69%and 9.81%)on the hydrodynamic characteristics of convex slopes through indoor flume experiments under diverse flow discharges(5.5-13.5 m^(3)/h)and slopes(5°-25°).The results revealed three key hydrodynamic mechanisms:(1)Flow retardation and energy dissipation:Increasing vegetation coverage significantly reduced overland flow velocity and promoted higher flow depth,thereby enhancing water retention and energy dissipation.Both stream power(Ω)and unit stream power(ω)declined by 13.9%-30.1%compared to bare slopes.(2)Flow Regime Transition:Froude number(Fr)decreased with increasing vegetation coverage,promoting the transition from supercritical to subcritical flow.The Reynolds number(Re)consistently exceeded 500,indicating the absence of laminar flow.(3)Modification of flow resistance:Vegetation resistance increased nonlinearly with coverage.Maximum bed shear stress was observed at 4.69%coverage(23.5%higher than bare slopes).However,Manning’s(n)and Darcy-Weisbach(f)coefficients did not correlate clearly with Re,indicating that vegetation coverage and slope type feedback significantly change flow resistance mechanisms.展开更多
Understanding the complex relationship between vegetation change and both natural and anthropogenic factors is a subject of global importance.However,comprehensive explanations of vegetation cover trends across China...Understanding the complex relationship between vegetation change and both natural and anthropogenic factors is a subject of global importance.However,comprehensive explanations of vegetation cover trends across China’s different regions and the dynamic roles of their drivers remain limited.This study analyzed national and regional vegetation change trends from 2000 to 2020 and evaluated the evolving impacts of natural and anthropogenic factors.Results indicate that 44.14%of China’s land experienced significant increase(P<0.05)in vegetation coverage.The Northeast(A1),Southwest(A5),and South China(A8)regions showed extremely significant increases in vegetation cover,with over 65%of vegetation exhibiting extremely significant growth(P<0.01).In contrast,less than 25%of vegetation in Inner Mongolia(A2),Northwest(A3),and the Qinghai-Tibetan Plateau(A4)subregions demonstrated an extremely significant increasing trend(P<0.01).Precipitation(q=0.766)and land use type(q=0.636)were the most influential natural and anthropogenic factors,respectively,with their interaction(q=0.838)dominating national vegetation patterns.On the west side of the Hu Line,vegetation dynamics were mainly limited by arid and semi-arid climates,with precipitation as the dominant factor,though land use measures have contributed to some vegetation improvement.Between 2000 and 2020,the influence of precipitation on vegetation cover increased in regions A3 and A4,with q-values rising by 26.73%and 101.13%,respectively.Additionally,soil type exerted a significant effect(P<0.001)on vegetation cover across all regions,being most pronounced in A2(q=0.692).On the east side of the Hu Line,vegetation growth benefited generally from warm and humid conditions,while local decline in urbanized areas was largely attributable to land use change and economic expansion.Concurrently anthropogenic factors such as land use and population density increasingly influenced vegetation dynamics in eastern urban areas of the Hu Line.Population density and GDP were the most influential factors affecting vegetation cover in region A8,with q-values of 0.443 and 0.380,respectively(P<0.001).Future efforts should maintain the benefits of large-scale ecological projects and harmonize the relationship between urban vegetation and anthropogenic influences.展开更多
Climate change in High Mountain Asia(HMA)is characterized by elevation dependence,which results in vertical zoning of vegetation distribution.However,few studies have been conducted on the distribution patterns of veg...Climate change in High Mountain Asia(HMA)is characterized by elevation dependence,which results in vertical zoning of vegetation distribution.However,few studies have been conducted on the distribution patterns of vegetation,the response of vegetation to climate change,and the key climatic control factors of vegetation along the elevation gradient in this region.In this study,based on the Normalized Difference Vegetation index(NDVI),we investigated the evolution pattern of vegetation in HMA during 2001-2020 using linear trend and Bayesian Estimator of Abrupt change,Seasonality,and Trend(BEAST)methods.Pearson correlation analysis and partial correlation analysis were used to explore the response relationship between vegetation and climatic factors along the elevation gradient.Path analysis was employed to quantitatively reveal the dominant climatic factors affecting vegetation distribution along the elevation gradient.The results showed that NDVI in HMA increased at a rate of 0.011/10a from 2001 to 2020,and the rate of increase abruptly slowed down after 2017.NDVI showed a fluctuating increase at elevation zones 1-2(<2500 m)and then decreased at elevation zones 3-9(2500-6000 m)with the increase of elevation.NDVI was most sensitive to precipitation and temperature at a 1-month lag.With the increase of elevation,the positive response relationship of NDVI with precipitation gradually weakened,while that of NDVI with temperature was the opposite.The total effect coefficient of precipitation(0.95)on vegetation was larger than that of temperature(0.87),indicating that precipitation is the dominant control factor affecting vegetation growth.Spacially,vegetation growth is jointly influenced by precipitation and temperature,but the influence of precipitation on vegetation growth is dominant at each elevation zone.The results of this study contribute to understanding how the elevation gradient effect influences the response of vegetation to climate change in alpine ecosystems.展开更多
Understanding the characteristics and driving factors behind changes in vegetation ecosystem resilience is crucial for mitigating both current and future impacts of climate change. Despite recent advances in resilienc...Understanding the characteristics and driving factors behind changes in vegetation ecosystem resilience is crucial for mitigating both current and future impacts of climate change. Despite recent advances in resilience research, significant knowledge gaps remain regarding the drivers of resilience changes. In this study, we investigated the dynamics of ecosystem resilience across China and identified potential driving factors using the kernel normalized difference vegetation index(kNDVI) from 2000 to 2020. Our results indicate that vegetation resilience in China has exhibited an increasing trend over the past two decades, with a notable breakpoint occurring around 2012. We found that precipitation was the dominant driver of changes in ecosystem resilience, accounting for 35.82% of the variation across China, followed by monthly average maximum temperature(Tmax) and vapor pressure deficit(VPD), which explained 28.95% and 28.31% of the variation, respectively. Furthermore, we revealed that daytime and nighttime warming has asymmetric impacts on vegetation resilience, with temperature factors such as Tmin and Tmax becoming more influential, while the importance of precipitation slightly decreases after the resilience change point. Overall, our study highlights the key roles of water availability and temperature in shaping vegetation resilience and underscores the asymmetric effects of daytime and nighttime warming on ecosystem resilience.展开更多
Soil moisture has been considered as one of the main indicators that are widely used in the fields of hydrology, climate, ecology and others. The land surface temperature-vegetation index （LST-VI） space has comprehe...Soil moisture has been considered as one of the main indicators that are widely used in the fields of hydrology, climate, ecology and others. The land surface temperature-vegetation index （LST-VI） space has comprehensive information of the sensor from the visible to thermal infrared band and can well reflect the regional soil moisture conditions. In this study, 9 pairs of moderate-resolution imaging spectroradiometer （MODIS） products （MOD09A1 and MODllA2）, covering 5 provinces in Southwest China, were chosen to construct the LST-VI space, and then the spatial distribution of soil moisture in 5 provinces of Southwest China was monitored by the temperature vegetation dryness index （TVDI）. Three LST-VI spaces were constructed by normalized difference vegetation index （NDVI）, enhanced vegetation index （EVI）, and modified soil-adjusted vegetation index （MSAVI）, respectively. The correlations between the soil moisture data from 98 sites and the 3 TVDIs calculated by LST-NDVI, LST-EVI and LST-MSAVI, respectively, were analyzed. The results showed that TVDI was a useful parameter for soil surface moisture conditions. The TVDI calculated from the LST-EVI space （TVDIE） revealed a better correlation with soil moisture than those calculated from the LST-NDVI and LST-MSAVI spaces. From the different stages of the TVDIE space, it is concluded that TVDIE can effectively show the temporal and spatial differences of soil moisture, and is an effective approach to monitor soil moisture condition.展开更多
The effect of global climate change on vegetation growth is variable.Timely and effective monitoring of vegetation drought is crucial for understanding its dynamics and mitigation,and even regional protection of ecolo...The effect of global climate change on vegetation growth is variable.Timely and effective monitoring of vegetation drought is crucial for understanding its dynamics and mitigation,and even regional protection of ecological environments.In this study,we constructed a new drought index(i.e.,Vegetation Drought Condition Index(VDCI))based on precipitation,potential evapotranspiration,soil moisture and Normalized Difference Vegetation Index(NDVI)data,to monitor vegetation drought in the nine major river basins(including the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin,Yangtze River Basin,Southeast River Basin,Pearl River Basin,Southwest River Basin and Continental River Basin)in China at 1-month–12-month(T1–T12)time scales.We used the Pearson's correlation coefficients to assess the relationships between the drought indices(the developed VDCI and traditional drought indices including the Standardized Precipitation Evapotranspiration Index(SPEI),Standardized Soil Moisture Index(SSMI)and Self-calibrating Palmer Drought Severity Index(scPDSI))and the NDVI at T1–T12 time scales,and to estimate and compare the lag times of vegetation response to drought among different drought indices.The results showed that precipitation and potential evapotranspiration have positive and major influences on vegetation in the nine major river basins at T1–T6 time scales.Soil moisture shows a lower degree of negative influence on vegetation in different river basins at multiple time scales.Potential evapotranspiration shows a higher degree of positive influence on vegetation,and it acts as the primary influencing factor with higher area proportion at multiple time scales in different river basins.The VDCI has a stronger relationship with the NDVI in the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin and Yangtze River Basin at T1–T4 time scales.In general,the VDCI is more sensitive(with shorter lag time of vegetation response to drought)than the traditional drought indices(SPEI,scPDSI and SSMI)in monitoring vegetation drought,and thus it could be applied to monitor short-term vegetation drought.The VDCI developed in the study can reveal the law of unclear mechanisms between vegetation and climate,and can be applied in other fields of vegetation drought monitoring with complex mechanisms.展开更多
Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide(CO_(2))fertilization in hot and humid regions.The subtropical humid karst region is a hot and humid region;whether and to what exten...Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide(CO_(2))fertilization in hot and humid regions.The subtropical humid karst region is a hot and humid region;whether and to what extent CO_(2)fertilization affects vegetation changes in such regions remains unclear.In this study,we investigated the degree to which CO_(2)fertilization influences vegetation changes,along with their spatial and temporal differences,in the subtropical humid karst region using time-lag effect analysis,a random forest model,and multiple regression analysis.Results showed that CO_(2)fertilization plays an important role in vegetation changes,exhibiting clear spatial variations across different geomorphological zones,with its degree of influence ranging mainly between 11%and 25%.The highest contribution of CO_(2)fertilization was observed in the karst basin and non-karstic region,whereas the lowest contribution was found in the karst plateau region.Previous studies have primarily attributed vegetation changes in subtropical humid karst region to ecological engineering,leading to an overestimation of its contribution to these changes.The findings of this study enhance the understanding of the mechanism of vegetation changes in humid karst region and provide theoretical and practical insights for ecological and environmental protection in these regions.展开更多
Investigating the spatial distribution of vegetation in monsoonal-climate-dominated high mountain area and detecting its changes that occurred in paraglacial areas is crucial for understanding the cascading environmen...Investigating the spatial distribution of vegetation in monsoonal-climate-dominated high mountain area and detecting its changes that occurred in paraglacial areas is crucial for understanding the cascading environmental effects of shrinking glaciers.We used Landsat images from 1994 to 2022,obtained landscape distribution patterns of glaciers and vegetation in Mt.Gongga,and detected paraglacial vegetation changes under deglaciating environments.We observed there is a pronounced difference in glacier and vegetation coverage between the eastern and western slopes in Mt.Gongga,the eastern slope occupies 78.68% of vegetation area and 61.02% of glacier area,whilst the western slope occupies lower area.Exaggerate warming accelerated glacier retreat,and proglacial areas are generally characterized by very fast primary succession,resulting in an increase of 0.32 km^(2)in vegetation area within two typical glacier forefields on the eastern slope.The phenomenon of paraglacial slope failure following glacier thinning is widespread in Mt.Gongga,resulting in vegetation area decreased by 0.34 km^(2).Concurrently,the fast retreat of glaciers and changes in ice surface geomorphology have caused rapid dynamics in supraglacial vegetation developed on its lower debris-covered sections.We suggested that rapid changes of temperate glaciers can significantly influence paraglacial landform,leading to rapid dynamic changes of vegetation in a balance between colonization and destruction.展开更多
A macro-tidal tropical estuary with high fluvial discharge is characterized by both fragility and remarkable dynamism.This study utilizes the Salween River Delta(SRD)as a case example to examine the interplay between ...A macro-tidal tropical estuary with high fluvial discharge is characterized by both fragility and remarkable dynamism.This study utilizes the Salween River Delta(SRD)as a case example to examine the interplay between morphology and vegetation under similar tidal conditions.Our analysis of correlations and inferences revealed several significant trends in the SRD:(1)an overall expansion of land area and intertidal vegetation,with the most pronounced changes occurring in the eastern sector;(2)the predominance of river discharge influencing the southwestern and northern sectors,contrasted with the primary impact of storm surges in the eastern sector;and(3)three distinct causal relationships among estuarine morphology,vegetation,storm surges,and river discharge:a direct model where river discharge shapes estuarine morphology,a progressive model in which river discharge affects vegetation distribution,subsequently influencing estuarine morphology,and a hybrid model where storm surges directly impact vegetation and indirectly modify its distribution through changes in estuarine morphology.The stability of sediment supply and the role of intertidal vegetation are crucial for the continuous seaward advance,providing a vital foundation for the protection and development of estuarine deltas.展开更多
The productivity of vegetation is influenced by both climate change and human activities.Understanding the specific contributions of these influencing factors is crucial for ecological conservation and regional sustai...The productivity of vegetation is influenced by both climate change and human activities.Understanding the specific contributions of these influencing factors is crucial for ecological conservation and regional sustainability.This study utilized a combination of multi-source data to examine the spatiotemporal patterns of Net Primary Productivity(NPP)in the Yellow River Basin(YRB),China from 1982 to 2020.Additionally,a scenario-based approach was employed to compare Potential NPP(PNPP)with Actual NPP(ANPP)to determine the relative roles of climatic and human factors in NPP changes.The PNPP was estimated using the Lund-Potsdam-Jena General Ecosystem Simulator(LPJ-GUESS)model,while ANPP was evaluated by the Carnegie-Ames-Stanford Approach(CASA)model using different NDVI data sources.Both model simulations revealed that significant greening occurring in the YRB,with a gradual decrease observed from southeast to northwest.According to the LPJ_GUESS model simulations,areas experiencing an increasing trend in NPP accounted for 86.82% of the YRB.When using GIMMS and MODIS NDVI data with CASA model simulations,areas showing an increasing trend in NPP accounted for 71.42% and 97.02%,respectively.Furthermore,both climatic conditions and human factors had positive effects on vegetation restoration;approximated 41.15% of restored vegetation areas were influenced by both climate variation and human activities,while around 31.93% were solely affected by climate variation.However,it was found that human activities served as the principal driving force of vegetation degradation within the YRB,impacting 26.35% of degraded areas solely due to human activities.Therefore,effective management strategies encompassing both human activities and climate change adaptation are imperative for facilitating vegetation restoration within this region.These findings will valuable for enhancing our understanding in NPP changes and its underlying factors,thereby contributing to improved ecological management and the pursuit of regional carbon neutrality in China.展开更多
基金supported by the National Natural Science Foundation of China[Grant NO.42401465 and 42401464]Yunnan Fundamental Research Projects[Grant NO.202501AT070343,202401AU070169 and 202401CF070161]+1 种基金Natural Science Fund of Kunming University of Science and Technology(KKZ3202421125)Yunnan Provincial Talent Project“High-level Talent Training Support Plan”[YNWR-QNBJ-2020-031]。
文摘Accurate phenological information is essential for measuring ecosystem dynamics and carbon uptake.Southwest China is one of the country's largest terrestrial carbon sink regions and plays a crucial role in carbon peaking and neutrality.However,its complex terrain,fragile ecosystem,and variable climate challenge carbon sink stability.Vegetation phenology significantly impacts carbon absorption and release,making accurate phenological data essential for understanding carbon sequestration dynamics.The widespread distribution of evergreen forests and their weak seasonal variation in canopy introduce significant uncertainties in extracting phenology using traditional remote sensing information in this region.These limitations can lead to inaccurate assessments of carbon sink dynamics.Therefore,precise phenology extraction and analysis are vital for improving ecosystem dynamics and the carbon cycle in Southwest China.Firstly,we employed different ways to evaluate the ability of solar-induced chlorophyll fluorescence(SIF)and traditional remote sensing information to extract phenology.Secondly,based on SIF,we analyzed the spatial and temporal changes in the start of the growing season(SOS),the end of the growing season(EOS),and the length of the growing season(LOS)from 2001 to 2020.Finally,we systematically analyzed the response of SOS and EOS to five preseason climatic factors.The results showed that(1)SIF outperformed traditional remote sensing information in extracting phenology.(2)Vegetation phenology exhibited significant spatial heterogeneity.Moreover,SOS,EOS,and LOS showed trends of advancement,delay,and extension both overall and across all vegetation types.(3)Precipitation was the main factor influencing SOS,while surface downward solar radiation and mean temperature were the main factors affecting EOS,and the phenology of different vegetation types showed a great difference in response to preseason climate factors.These findings improve our understanding of vegetation phenology and its dynamics over Southwest China.
文摘[Objective]Vegetation restoration is an effective strategy for ecological improvement;however,inappropriate vegetation establishment can induce soil desiccation,thereby threatening ecosystem stability.Therefore,elucidating the global response patterns of soil moisture to vegetation restoration and identifying research hotspots are critical for guiding ecological construction in arid regions.[Methods]We reviewed 6,152 articles concerning soil moisture and vegetation retrieved from the Web of Science platform.Using VOSviewer,we conducted analyses of keyword co-occurrence,publication trends,and research hotspots to systematically delineate the evolving trends in this field.[Results]The results indicate a significant increasing trend in the number of publications since 2000.Global research keywords are categorized into seven clusters,including vegetation,soil moisture,rainfall-erosion-infiltration,spatial heterogeneity,and climate change.In terms of highly cited papers in 2024,China and the United States maintain a significant lead.Global research demonstrates a strong dependency on typical regional geographical features(such as climate types and topography),exhibiting differentiated research focuses.Furthermore,studies extend beyond soil moisture itself to deeply couple with ecological processes such as vegetation restoration,soil respiration,carbon cycling,and hydrothermal conditions.[Conclusions]The long-term ecological effects of afforestation in arid regions remain unclear,and empirical data from key regions highlight the current urgency.Future research should integrate climate change dynamics,innovate monitoring methodologies,and deepen the understanding of regional differentiation to provide scientific support for the adaptive management of vegetation in arid regions.
基金supported by the Universidad Nacional de Río Negro(PI-UNRN 40C-1088)the Consejo Nacional de Investigaciones Científicas y Técnicas(PIP-CONICET 2023-402).
文摘The connection between climatic factors and grazing is essential for maintaining ecosystem function and vegetation productivity.This study examined the impact of grazing intensity on vegetation across a broad climatic gradient spanning the Espinal,Argentine Low Monte,and Patagonian Steppe ecoregions of Argentina.The research was carried out at eight sampling sites with radial grazing gradients generated around artificial water sources(piospheres),exhibiting two contrasting response patterns of vegetation to grazing pressure.One of the response patterns shows a typical vegetation response to grazing that the vegetation productivity increases with the distance to the water sources(decreasing grazing intensity).The second pattern is found in drier regions,where vegetation presents an inverse productivity response that vegetation productivity is higher near water sources(high grazing intensity)due to increased shrub cover.Vegetation productivity was measured using the Normalized Difference Vegetation Index(NDVI).Vegetation patch structure and cover were determined for each site with high,medium,and low grazing intensities.Results indicated that shrub cover is the primary driver of vegetation productivity,showing contrasting responses to grazing intensity between the two identified patterns.While NDVI proved to be a reliable proxy for shrub cover and total vegetation cover(R2>0.70),it failed to reflect grass cover dynamics.Furthermore,mean annual temperature was more strongly correlated with vegetation cover changes,while grazing intensity significantly altered vegetation patch structure and soil cover distribution.Specifically,in drier regions,high grazing intensity led to larger patches while,in wetter regions,it led to smaller patches(fragmentation).Shrubs,with their deeper roots and drought tolerance,were less preferred and more resistant to grazing in arid environments and thrived under grazing pressure in these arid conditions.Our results underscored the need for adaptive management strategies in grazing systems.Traditional approaches may require significant adjustments,as the efficacy of management hinges on the interplay of specific climatic conditions and the varied responses of vegetation.Furthermore,effective conservation efforts should prioritize the recognition and protection of shrubs given their critical contribution to ecosystem function and biodiversity.Ultimately,this research provides a valuable framework to understand the complex dynamics between grazing and vegetation in arid and semi-arid environments,highlighting that sustainable grazing practices should be tailored to account for both climatic variables and the unique characteristics of different plant communities.
基金supported by the National Natural Science Foundation of China(Nos.42107420,U23A20157,and U1910207)Shanxi Province Science Foundation for Young Scholars(No.20210302124363).
文摘Vegetation plays an important role in the environmental transport behavior of organic pollutants,however,the different roles of crops and natural vegetation have been ignored in most previous studies.In this study,we developed the BETR-Urban-Rural-Veg model to quantitatively evaluate the influences of both natural vegetation and crops on the multimedia transport processes of Phenanthrene(PHE)and Benzo(a)pyrene(BaP)in mainland of China.The geographic distribution of polycyclic aromatic hydrocarbon(PAH)emissions and concentrations were consistent,displaying higher levels in northern China while lower levels in southern China.Under seasonal simulations,for both natural vegetation and crops,PAH concentrations in winter and spring were 1.5 to 27-fold higher than in summer and autumn,especially for PHE.Owing to the higher leaf area index(LAI)of natural vegetation and harvesting of crops,the filter and sequestration effect of natural vegetation was stronger than crops,while the seasonal changes of PAH concentrations in crops were more significant than natural vegetation.Temperature,precipitation rates and LAI might have important influences on seasonal concentrations and overall persistence of PAHs.PHE was more sensitive to the impacts of seasonal environmental parameters.Under different landscape scenarios,average annual PAH concentrations in natural vegetation were always a little higher than those in crops,and the overall persistence of BaP was greatly affected increasing by 15.15%-16.47%.This improved model provides a useful tool for environmental management.The results of this study are expected to support land use plans and decision-making in China's mainland.
基金supported by the National Natural Science Foundation of China(32460380,42007042)State Key Laboratory of Subtropical Silviculture(SKLSSKF2023-06)+2 种基金Natural Science Foundation of Jiangxi Province(20242BAB25389)National Undergraduate Innovation and Entrepreneurship Training Program(202410410029X)Jiangxi Province Graduate Student Innovation Special Fund Project(YC2024-S330).
文摘Urban forests are essential components of green infrastructure,however,rapid urbanization-induced changes in landscape patterns may affect their ecosystem services through complex ecological processes.A total of 184 sample plots in the built-up areas of Nanchang,China,were used as research sites.Urbanization intensities were categorized by the rate of impervious surface area,and forest types were classified into landscape and relaxation forest,attached forest(AF),road forest(RF),and ecological public welfare forest.This study aimed to explore the spatial variations in vegetation characteristics and landscape pattern indices of different forest types under rapid urbanization.The results indicated that the largest patch index(LPI),aggregation index(AI),and percentage of landscape(PLAND)in RF and AF were lower than those in the other forest types(p<0.05).With increasing urbanization intensity,the mean perimeter-area ratio increased by 130.84%,whereas the PLAND,LPI,and AI decreased by 22−86%(p<0.05).Redundancy analysis and variation partitioning suggested that the interpretation rate of landscape pattern indices for variations in vegetation characteristics increased from low to heavy urbanization areas.Especially,the landscape shape index,patch connection index,PLAND,and mean patch size were significantly correlated with vegetation characteristics(e.g.,tree richness,herb coverage,and tree height).In the future,appropriate landscape layout superiority cases should be considered in different urbanization areas and forest types;for instance,increasing the patch connection index will beneficially improve the diversity of trees and herbs in heavy urbanization areas and the RF.This study serves as a reference for maximizing the ecosystem services of urban forests.
基金supported by the Swedish Research Council(Vetenskapsradet,Grant No.202203129)the Project of Youth Science and Technology Fund of Gansu Province(Grant No.24JRRA439)partially funded by the Swedish Research Council(Vetenskapsradet,Grant No.2022-06725)。
文摘This study investigates the impact of vegetation-climate feedback on the global land monsoon system during the Last Interglacial(LIG,127000 years BP)and the mid-Holocene(MH,6000 years BP)using the earth system model EC-Earth3.Our findings indicate that vegetation changes significantly influence the global monsoon area and precipitation patterns,especially in the North African and Indian monsoon regions.The North African monsoon region experienced the most substantial increase in vegetation during both the LIG and MH,resulting in significant increases in monsoonal precipitation by 9.8%and 6.0%,respectively.The vegetation feedback also intensified the Saharan Heat Low,strengthened monsoonal flows,and enhanced precipitation over the North African monsoon region.In contrast,the Indian monsoon region exhibited divergent responses to vegetation changes.During the LIG,precipitation in the Indian monsoon region decreased by 2.2%,while it increased by 1.6%during the MH.These differences highlight the complex and region-specific impacts of vegetation feedback on monsoon systems.Overall,this study demonstrates that vegetation feedback exerts distinct influences on the global monsoon during the MH and LIG.These findings highlight the importance of considering vegetation-climate feedback in understanding past monsoon variability and in predicting future climate change impacts on monsoon systems.
基金Under the auspices of the National Natural Science Foundation of China(No.42476247,42461015)the Open Research Fund of Key Laboratory of Coastal Science and Integrated Management,Ministry of Natural Resources(No.2024COSIM01)Guangxi Science and Technology Base and Talent Special Project(No.GuikeAD23026194)。
文摘Understanding the dynamics of vegetation carbon sequestration(VCS)is essential for regional carbon neutrality strategies.This study revealed the spatiotemporal patterns of VCS and its relationship with anthropogenic carbon emissions(ACEs)in Shandong Province,China during 2000-2020,and identified the sensitivity factors affecting VCS.The results show that:1)VCS increased consistently from 193.45 million t to 256.41 million t,with high values areas concentrated in the central,northeastern,and southeastern mountainous and hilly regions,while low values were found in water bodies and urban built-up areas.At the city level,Linyi,Yantai,Binzhou,and Jinan experienced the most significant rises-reaching up to 243000 t/yr.At the county level,Pingdu,Qixia,and Yiyuan also showed substantial growth,each exceeding 30400 t/yr.2)Digital Elevation Molde(DEM)was identified as the dominant natural factor influencing VCS distribution,while land use optimization measures,especially afforestation and farmland conversion in sloped terrain,were the primary human drivers of VCS increase.3)Urbanization and carbon neutrality were not mutually exclusive.While urban expansion locally reduced VCS,rural emigration enhanced carbon sinks in surrounding areas,partially offsetting urban losses.This compensatory mechanism supported VCS increases in nearly all cities and 90% of counties.Nevertheless,with ACEs continuing to rise and the offset ratio by VCS declining,achieving carbon neutrality requires regional strategies that integrate with accelerated energy conservation,emission reduction technologies,and energy transition.These findings provide a scientific basis for decomposing carbon neutrality targets across cities and counties in Shandong and a reference for developing localized land use policies in similar regions.
基金supported by the Fundamental Research Funds for the Central Universities(N2001020)the National Natural Science Foundation of China(41201359).
文摘Sand dust belts span approximately one-fifth of the global land surface.In these regions,dust tends to settle on vegetation surfaces,altering the observed reflectance and affecting remote sensing detections.To enhance the accuracy of maize growth monitoring in dust-affected regions,this study aims to quantify the effect of sand dust retention on maize during the tasseling stage in the Kashgar Prefecture,Xinjiang Uygur Autonomous Region,China,by analyzing changes in canopy reflectance and vegetation indices.First,field sampling was conducted to measure the key canopy structure parameters and dust retention levels of maize,and laboratory spectral measurements were performed on leaf spectral properties under gradient dust retention.The measured data were then used to drive the LargE-Scale remote sensing data and image Simulation framework(LESS)model for simulating realistic maize canopy spectra across different dust levels,with validation against Sentinel-2 imagery.Second,on the basis of the simulated and satellite-derived spectra,the dust resistance of 36 common vegetation indices was systematically evaluated,and new robust dust-resistant indices were developed.The results showed that compared with dust-free maize,the canopy reflectance of dust-retained maize followed an increase–decrease–increase pattern,with critical turning points at 735 and 1325 nm.The maximum reflectance difference of–0.11755(change rate:29.002%)occurred within the 735–1325 nm range at 24 g/m^(2)dust retention,and the minimum reflectance difference of 0.04285(change rate:148.950%)was observed in the 350–735 nm range under the same dust retention level.Among the 36 vegetation indices,only the global environment monitoring index(GEMI)and the ratio of transformed chlorophyll absorption in reflectance index to optimized soil-adjusted vegetation index(TCARI/OSAVI)exhibited dust resistance,with GEMI being effective below 6 g/m^(2)and TCARI/OSAVI remaining stable across all levels(average ratio:0.970).The newly developed indices in this study,(RE3–RE2)/(NIR–RE2),(RE3–RE2)/(RE4–RE2),and(NIR–RE2)/(RE4–RE2),retained values within the predefined dust-resistant range over the full dust retention levels of 0–24 g/m^(2),thus showing a more stable dust resistance compared with the commonly used 36 vegetation indices.Specially,(RE3–RE2)/(RE4–RE2)performed the most robustly in Sentinel-2 imagery,that is,58.020%of pixels were within the dust-resistant range,and an average ratio of 0.937 was obtained for the original-spectra index.This study provides a scientific basis for crop monitoring and management in dust-affected regions.
文摘Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes.
文摘This research aims to analyse the spatio-temporal changes of vegetation cover in coastal regions of Char Fasson and Galachipa Upazila, Bangladesh for a period of 30 years (1994-2024) based on Landsat satellite imagery and NDVI. Through the evaluation of NDVI this paper classifies vegetation as no water/bare vegetation, slightly densed vegetation, moderately densed vegetation, and highly densed vegetation. The findings reveal significant fluctuations in vegetation cover: from 1994 to 2004, there has been an increase in vegetation density implying that afforestation has created more moderate and highly densed vegetation out of density vegetation. However, between 2004 and 2014, vegetation cover decreased because some cyclones, like Sidr and Aila, affected the coastal forest of Bangladesh. Other attempts to afforestation supported improved coverage from vegetation between 2014 and 2024. These findings provide clear evidence of the sustainable benefits of coastal afforestation in the reduction of coastal erosion and storm surges that affect vegetation and coasts. Knowledge gained in this research is highly useful to the environmental planners on recommendations for sustainable land uses and preservation to build up ecological stability in Bangladesh weak coastal areas.
基金financially supported by the National Natural Science Foundation of China(Grant NO.52279056)Inner Mongolia open list project(Grant NO.2024JBGS0023)。
文摘The hydrodynamic response of overland flow to vegetation coverage on convex slopes remains inadequately quantified despite it is critical for soil erosion control in terrains dominated by such topography.This study systematically investigated the influence of varying vegetation coverage(0%,1.08%,3.24%,4.69%and 9.81%)on the hydrodynamic characteristics of convex slopes through indoor flume experiments under diverse flow discharges(5.5-13.5 m^(3)/h)and slopes(5°-25°).The results revealed three key hydrodynamic mechanisms:(1)Flow retardation and energy dissipation:Increasing vegetation coverage significantly reduced overland flow velocity and promoted higher flow depth,thereby enhancing water retention and energy dissipation.Both stream power(Ω)and unit stream power(ω)declined by 13.9%-30.1%compared to bare slopes.(2)Flow Regime Transition:Froude number(Fr)decreased with increasing vegetation coverage,promoting the transition from supercritical to subcritical flow.The Reynolds number(Re)consistently exceeded 500,indicating the absence of laminar flow.(3)Modification of flow resistance:Vegetation resistance increased nonlinearly with coverage.Maximum bed shear stress was observed at 4.69%coverage(23.5%higher than bare slopes).However,Manning’s(n)and Darcy-Weisbach(f)coefficients did not correlate clearly with Re,indicating that vegetation coverage and slope type feedback significantly change flow resistance mechanisms.
基金Under the auspices of the National Natural Science Foundation of China(No.32371863)Fundamental Research Funds for the Central Universities(No.2572025AW39)。
文摘Understanding the complex relationship between vegetation change and both natural and anthropogenic factors is a subject of global importance.However,comprehensive explanations of vegetation cover trends across China’s different regions and the dynamic roles of their drivers remain limited.This study analyzed national and regional vegetation change trends from 2000 to 2020 and evaluated the evolving impacts of natural and anthropogenic factors.Results indicate that 44.14%of China’s land experienced significant increase(P<0.05)in vegetation coverage.The Northeast(A1),Southwest(A5),and South China(A8)regions showed extremely significant increases in vegetation cover,with over 65%of vegetation exhibiting extremely significant growth(P<0.01).In contrast,less than 25%of vegetation in Inner Mongolia(A2),Northwest(A3),and the Qinghai-Tibetan Plateau(A4)subregions demonstrated an extremely significant increasing trend(P<0.01).Precipitation(q=0.766)and land use type(q=0.636)were the most influential natural and anthropogenic factors,respectively,with their interaction(q=0.838)dominating national vegetation patterns.On the west side of the Hu Line,vegetation dynamics were mainly limited by arid and semi-arid climates,with precipitation as the dominant factor,though land use measures have contributed to some vegetation improvement.Between 2000 and 2020,the influence of precipitation on vegetation cover increased in regions A3 and A4,with q-values rising by 26.73%and 101.13%,respectively.Additionally,soil type exerted a significant effect(P<0.001)on vegetation cover across all regions,being most pronounced in A2(q=0.692).On the east side of the Hu Line,vegetation growth benefited generally from warm and humid conditions,while local decline in urbanized areas was largely attributable to land use change and economic expansion.Concurrently anthropogenic factors such as land use and population density increasingly influenced vegetation dynamics in eastern urban areas of the Hu Line.Population density and GDP were the most influential factors affecting vegetation cover in region A8,with q-values of 0.443 and 0.380,respectively(P<0.001).Future efforts should maintain the benefits of large-scale ecological projects and harmonize the relationship between urban vegetation and anthropogenic influences.
基金supported by the Xinjiang Uygur Autonomous Region Major Scientific and Technological Special Project Research and Demonstration on the Development Model of Ecological Agriculture and Efficient Utilization of Soil and Water Resources in Modern Irrigation Areas(2023A02002-1).
文摘Climate change in High Mountain Asia(HMA)is characterized by elevation dependence,which results in vertical zoning of vegetation distribution.However,few studies have been conducted on the distribution patterns of vegetation,the response of vegetation to climate change,and the key climatic control factors of vegetation along the elevation gradient in this region.In this study,based on the Normalized Difference Vegetation index(NDVI),we investigated the evolution pattern of vegetation in HMA during 2001-2020 using linear trend and Bayesian Estimator of Abrupt change,Seasonality,and Trend(BEAST)methods.Pearson correlation analysis and partial correlation analysis were used to explore the response relationship between vegetation and climatic factors along the elevation gradient.Path analysis was employed to quantitatively reveal the dominant climatic factors affecting vegetation distribution along the elevation gradient.The results showed that NDVI in HMA increased at a rate of 0.011/10a from 2001 to 2020,and the rate of increase abruptly slowed down after 2017.NDVI showed a fluctuating increase at elevation zones 1-2(<2500 m)and then decreased at elevation zones 3-9(2500-6000 m)with the increase of elevation.NDVI was most sensitive to precipitation and temperature at a 1-month lag.With the increase of elevation,the positive response relationship of NDVI with precipitation gradually weakened,while that of NDVI with temperature was the opposite.The total effect coefficient of precipitation(0.95)on vegetation was larger than that of temperature(0.87),indicating that precipitation is the dominant control factor affecting vegetation growth.Spacially,vegetation growth is jointly influenced by precipitation and temperature,but the influence of precipitation on vegetation growth is dominant at each elevation zone.The results of this study contribute to understanding how the elevation gradient effect influences the response of vegetation to climate change in alpine ecosystems.
基金National Key Research and Development Program,No.2021xjkk0303。
文摘Understanding the characteristics and driving factors behind changes in vegetation ecosystem resilience is crucial for mitigating both current and future impacts of climate change. Despite recent advances in resilience research, significant knowledge gaps remain regarding the drivers of resilience changes. In this study, we investigated the dynamics of ecosystem resilience across China and identified potential driving factors using the kernel normalized difference vegetation index(kNDVI) from 2000 to 2020. Our results indicate that vegetation resilience in China has exhibited an increasing trend over the past two decades, with a notable breakpoint occurring around 2012. We found that precipitation was the dominant driver of changes in ecosystem resilience, accounting for 35.82% of the variation across China, followed by monthly average maximum temperature(Tmax) and vapor pressure deficit(VPD), which explained 28.95% and 28.31% of the variation, respectively. Furthermore, we revealed that daytime and nighttime warming has asymmetric impacts on vegetation resilience, with temperature factors such as Tmin and Tmax becoming more influential, while the importance of precipitation slightly decreases after the resilience change point. Overall, our study highlights the key roles of water availability and temperature in shaping vegetation resilience and underscores the asymmetric effects of daytime and nighttime warming on ecosystem resilience.
基金Supported by the National Key Technologies Research and Development Program of the Ministry of Science and Technology of China during the 12th Five-Year Plan Period(Nos.2011BAD32B01 and 2012BAH29B02)
文摘Soil moisture has been considered as one of the main indicators that are widely used in the fields of hydrology, climate, ecology and others. The land surface temperature-vegetation index （LST-VI） space has comprehensive information of the sensor from the visible to thermal infrared band and can well reflect the regional soil moisture conditions. In this study, 9 pairs of moderate-resolution imaging spectroradiometer （MODIS） products （MOD09A1 and MODllA2）, covering 5 provinces in Southwest China, were chosen to construct the LST-VI space, and then the spatial distribution of soil moisture in 5 provinces of Southwest China was monitored by the temperature vegetation dryness index （TVDI）. Three LST-VI spaces were constructed by normalized difference vegetation index （NDVI）, enhanced vegetation index （EVI）, and modified soil-adjusted vegetation index （MSAVI）, respectively. The correlations between the soil moisture data from 98 sites and the 3 TVDIs calculated by LST-NDVI, LST-EVI and LST-MSAVI, respectively, were analyzed. The results showed that TVDI was a useful parameter for soil surface moisture conditions. The TVDI calculated from the LST-EVI space （TVDIE） revealed a better correlation with soil moisture than those calculated from the LST-NDVI and LST-MSAVI spaces. From the different stages of the TVDIE space, it is concluded that TVDIE can effectively show the temporal and spatial differences of soil moisture, and is an effective approach to monitor soil moisture condition.
基金funded by the National Natural Science Foundation of China(52179015,42301024)the Key Technologies Research&Development and Promotion Program of Henan(232102110025)the Cultivation Plan of Innovative Scientific and Technological Team of Water Conservancy Engineering Discipline of North China University of Water Resources and Electric Power(CXTDPY-9).
文摘The effect of global climate change on vegetation growth is variable.Timely and effective monitoring of vegetation drought is crucial for understanding its dynamics and mitigation,and even regional protection of ecological environments.In this study,we constructed a new drought index(i.e.,Vegetation Drought Condition Index(VDCI))based on precipitation,potential evapotranspiration,soil moisture and Normalized Difference Vegetation Index(NDVI)data,to monitor vegetation drought in the nine major river basins(including the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin,Yangtze River Basin,Southeast River Basin,Pearl River Basin,Southwest River Basin and Continental River Basin)in China at 1-month–12-month(T1–T12)time scales.We used the Pearson's correlation coefficients to assess the relationships between the drought indices(the developed VDCI and traditional drought indices including the Standardized Precipitation Evapotranspiration Index(SPEI),Standardized Soil Moisture Index(SSMI)and Self-calibrating Palmer Drought Severity Index(scPDSI))and the NDVI at T1–T12 time scales,and to estimate and compare the lag times of vegetation response to drought among different drought indices.The results showed that precipitation and potential evapotranspiration have positive and major influences on vegetation in the nine major river basins at T1–T6 time scales.Soil moisture shows a lower degree of negative influence on vegetation in different river basins at multiple time scales.Potential evapotranspiration shows a higher degree of positive influence on vegetation,and it acts as the primary influencing factor with higher area proportion at multiple time scales in different river basins.The VDCI has a stronger relationship with the NDVI in the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin and Yangtze River Basin at T1–T4 time scales.In general,the VDCI is more sensitive(with shorter lag time of vegetation response to drought)than the traditional drought indices(SPEI,scPDSI and SSMI)in monitoring vegetation drought,and thus it could be applied to monitor short-term vegetation drought.The VDCI developed in the study can reveal the law of unclear mechanisms between vegetation and climate,and can be applied in other fields of vegetation drought monitoring with complex mechanisms.
基金National Natural Science Foundation of China,No.41761003The Karst Science Research Center of Guizhou Province,No.U1812401。
文摘Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide(CO_(2))fertilization in hot and humid regions.The subtropical humid karst region is a hot and humid region;whether and to what extent CO_(2)fertilization affects vegetation changes in such regions remains unclear.In this study,we investigated the degree to which CO_(2)fertilization influences vegetation changes,along with their spatial and temporal differences,in the subtropical humid karst region using time-lag effect analysis,a random forest model,and multiple regression analysis.Results showed that CO_(2)fertilization plays an important role in vegetation changes,exhibiting clear spatial variations across different geomorphological zones,with its degree of influence ranging mainly between 11%and 25%.The highest contribution of CO_(2)fertilization was observed in the karst basin and non-karstic region,whereas the lowest contribution was found in the karst plateau region.Previous studies have primarily attributed vegetation changes in subtropical humid karst region to ecological engineering,leading to an overestimation of its contribution to these changes.The findings of this study enhance the understanding of the mechanism of vegetation changes in humid karst region and provide theoretical and practical insights for ecological and environmental protection in these regions.
基金Science and Technology Research Program of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,No.IMHE-CXTD-02,No.IMHE-ZDRW-06。
文摘Investigating the spatial distribution of vegetation in monsoonal-climate-dominated high mountain area and detecting its changes that occurred in paraglacial areas is crucial for understanding the cascading environmental effects of shrinking glaciers.We used Landsat images from 1994 to 2022,obtained landscape distribution patterns of glaciers and vegetation in Mt.Gongga,and detected paraglacial vegetation changes under deglaciating environments.We observed there is a pronounced difference in glacier and vegetation coverage between the eastern and western slopes in Mt.Gongga,the eastern slope occupies 78.68% of vegetation area and 61.02% of glacier area,whilst the western slope occupies lower area.Exaggerate warming accelerated glacier retreat,and proglacial areas are generally characterized by very fast primary succession,resulting in an increase of 0.32 km^(2)in vegetation area within two typical glacier forefields on the eastern slope.The phenomenon of paraglacial slope failure following glacier thinning is widespread in Mt.Gongga,resulting in vegetation area decreased by 0.34 km^(2).Concurrently,the fast retreat of glaciers and changes in ice surface geomorphology have caused rapid dynamics in supraglacial vegetation developed on its lower debris-covered sections.We suggested that rapid changes of temperate glaciers can significantly influence paraglacial landform,leading to rapid dynamic changes of vegetation in a balance between colonization and destruction.
基金National Natural Science Foundation of China,No.41906148,No.42271086Rejuvenating Yunnan Talents Support Plan Young Talent Program,No.XDYC-QNRC-2023-0322。
文摘A macro-tidal tropical estuary with high fluvial discharge is characterized by both fragility and remarkable dynamism.This study utilizes the Salween River Delta(SRD)as a case example to examine the interplay between morphology and vegetation under similar tidal conditions.Our analysis of correlations and inferences revealed several significant trends in the SRD:(1)an overall expansion of land area and intertidal vegetation,with the most pronounced changes occurring in the eastern sector;(2)the predominance of river discharge influencing the southwestern and northern sectors,contrasted with the primary impact of storm surges in the eastern sector;and(3)three distinct causal relationships among estuarine morphology,vegetation,storm surges,and river discharge:a direct model where river discharge shapes estuarine morphology,a progressive model in which river discharge affects vegetation distribution,subsequently influencing estuarine morphology,and a hybrid model where storm surges directly impact vegetation and indirectly modify its distribution through changes in estuarine morphology.The stability of sediment supply and the role of intertidal vegetation are crucial for the continuous seaward advance,providing a vital foundation for the protection and development of estuarine deltas.
基金Under the auspices of National Natural Science Foundation of China(No.41991231,U21A2011)。
文摘The productivity of vegetation is influenced by both climate change and human activities.Understanding the specific contributions of these influencing factors is crucial for ecological conservation and regional sustainability.This study utilized a combination of multi-source data to examine the spatiotemporal patterns of Net Primary Productivity(NPP)in the Yellow River Basin(YRB),China from 1982 to 2020.Additionally,a scenario-based approach was employed to compare Potential NPP(PNPP)with Actual NPP(ANPP)to determine the relative roles of climatic and human factors in NPP changes.The PNPP was estimated using the Lund-Potsdam-Jena General Ecosystem Simulator(LPJ-GUESS)model,while ANPP was evaluated by the Carnegie-Ames-Stanford Approach(CASA)model using different NDVI data sources.Both model simulations revealed that significant greening occurring in the YRB,with a gradual decrease observed from southeast to northwest.According to the LPJ_GUESS model simulations,areas experiencing an increasing trend in NPP accounted for 86.82% of the YRB.When using GIMMS and MODIS NDVI data with CASA model simulations,areas showing an increasing trend in NPP accounted for 71.42% and 97.02%,respectively.Furthermore,both climatic conditions and human factors had positive effects on vegetation restoration;approximated 41.15% of restored vegetation areas were influenced by both climate variation and human activities,while around 31.93% were solely affected by climate variation.However,it was found that human activities served as the principal driving force of vegetation degradation within the YRB,impacting 26.35% of degraded areas solely due to human activities.Therefore,effective management strategies encompassing both human activities and climate change adaptation are imperative for facilitating vegetation restoration within this region.These findings will valuable for enhancing our understanding in NPP changes and its underlying factors,thereby contributing to improved ecological management and the pursuit of regional carbon neutrality in China.
