Agroforestry is a ubiquitous landscape on the slopes in Loess Plateau, where soil moisture is a limiting factor for plant growth and development. The spatial and temporal characteristics of soil moisture were studied ...Agroforestry is a ubiquitous landscape on the slopes in Loess Plateau, where soil moisture is a limiting factor for plant growth and development. The spatial and temporal characteristics of soil moisture were studied in three types of agroforestry boundaries： forest-grassland, forest-cropland and shelterbelt-cropland. The result shows that soil moisture content decreased with soil depth increasing from the surface to 110 cm. Soil moisture content differed significantly among the three boundaries all in the rainy season （July-September）, dry season （May-June） and spring （March-April）. The horizontal distribution of soil moisture in different soil layers in the three types of boundaries showed different patterns with line form, wave form, scoop form or ＂W＂ form. The distance of edge influence （DEI） of soil moisture in different types of landscape boundaries was estimated by variance analysis and multiple comparisons. In dry season the DEI in 0-10 cm soil layer was 0.4 H （H, average height of trees）, which ranged from 0.2 H in grassland or in cropland to 0.2 H in forest field for both forest-grassland and forest-cropland boundaries, and 0.7 H （ranged from 0.2 H in cropland to 0.5 H in forest field） for shelterbelt-cropland boundary. In rainy season the DEI at soil depth of 0-110 cm was 0.7 H for the three boundaries. The results indicated that agroforestry type should be carefully selected to maintain soil moisture in land management, especially in restoring degraded land in Loess Plateau.展开更多
The high Zoige Basin （Ruoergai Plateau） on the eastern Tibetan Plateau is a fault depression formed during intensive uplifting of the Tibetan Plateau. The wetland is globally important in biodiversity and is compose...The high Zoige Basin （Ruoergai Plateau） on the eastern Tibetan Plateau is a fault depression formed during intensive uplifting of the Tibetan Plateau. The wetland is globally important in biodiversity and is composed of marshes, bogs, fens, wet meadows and shallow water interspersed with low hills and sub-alpine meadows. Most of the Zoige wetlands have long been one of the most important grazing lands in China. Recent rangeland policy has allowed grazing, and usable wetland areas have been being legally allocated to individuals or groups of households on a long-term lease basis. Privatizafion of the wetland has impacted the Zoige wetlands in aspects of hydrologic condition, landscape and biodiversity. The uneven spatial distribution of water resources onprivatelands has led to the practice of extracting ground water, which has decreased the perched water table in Zoige. Fencing off the rangelands and grazing on expanding sand dunes have affected landscapes. Variation in the water table has led to the changes in vegetation diversity, resulting in the changes in wildlife and aquatic diversities and ecosystem processes. Making use all year round of the pasture that was previously grazed only in summer has shrunk the daily activity space of wildlife, and the newly erected fences blocked the movement of wild animals looking for food in the snow to lower and open areas. To maintain the favorable conditions of the Zoige wetland ecosystem, the author suggests that, in addition to biophysical research and implementation of conservation practices, there is an immediate need to initiate an integrated management program, increase public awareness of wetland functions and provide better training for the local conservation staff.展开更多
Conventional farming-pastoral ecotones methods of delineating were not quantitative and could not fully show their spatial distribution. The present paper attempts to develop quantitative methods for mapping farming-...Conventional farming-pastoral ecotones methods of delineating were not quantitative and could not fully show their spatial distribution. The present paper attempts to develop quantitative methods for mapping farming-pastoral ecotones in China. Nine indicators, related to temperature, precipitation and altitude aspects, were selected to quantify ecological susceptibility of vegetation （crops and forage）. Methods of analytic hierarchy process （AHP） and expert score ranking combined with fuzzy set theory were applied to assign the weight for each indicator and to define the membership functions. The geographic information system （GIS） was used to manage the spatial database and conduct the spatial analysis. According to the spatial calculation of evaluation model integrated with GIS, the ecological susceptibility of vegetation （crops and forage） was mapped. Three different zones, pastoral area, farming-pastoral ecotones and farming area, were classified by spatial cluster analysis and the maximum likelihood classification for the numeric map of vegetation ecological susceptibility by GIS. This map was validated by the economic statistical result based on the ratio of the output value from animal husbandry in total output value of agriculture by the National Bureau of Statistics in China, indicating that the mapping of the farming-pastoral ecotones may be accepted.展开更多
Land change science （LCS） strives to understand and model land-use change, which will further advance the understanding of multiple issues in the socio-ecological systems. Based on GIS/RS techniques, autologistic mo...Land change science （LCS） strives to understand and model land-use change, which will further advance the understanding of multiple issues in the socio-ecological systems. Based on GIS/RS techniques, autologistic model, and household survey method, this study investigated major land use changes and their causes from 1978 to 2008 in Uxin Banner （county-level）, Inner Mongolia in China and then developed an understanding of the relationships between household livelihood and land-use pattern. Results showed that cultivated land increased from 1988 to 2000, and leveled offafter 2000. Built-up land increased stably for the period 1978 2008. The change of grassland and bare land differed among the three periods. From 1978 to 1988, grassland increased by 23.3%, and bare land decreased by 20.48%. From 1988 to 2000, bare land expanded by 1.7%, but grassland declined by 1.3%. From 2000 to 2008, an increase in grassland area by 1.8% was observed, but a decrease in bare land area by 9.0% was witnessed. The autologistic models performed better than logistic models as indicated by lower Akaike Information Criterion （AIC） values. Factors associated with human activities significantly correlated with the change of cultivated land, forest land, grassland, and built-up land. The produce prices and extensive cultivated land use are major issues in the farming area. This study suggests that completing land circulation systems and maintaining the stability of price are effective solutions. By contrast, reclamation and overgrazing are major concerns in the pastoral areas. Implementing environmental policies effectively, transferring population out of rural pastoral areas, and developing modem animal husbandry are effective ways to address these issues.展开更多
The aim of this research is to identify the most suitable land for forestry, afforestation and rangeland management in Hamadan province. This research has been accomplished using Makhdoum＇s model. In this research 30...The aim of this research is to identify the most suitable land for forestry, afforestation and rangeland management in Hamadan province. This research has been accomplished using Makhdoum＇s model. In this research 30 digital data layers are used. The Geographic Information System （GIS） has been used as main tool and overlay method has been used to implement the mentioned model. The results of this research revealed that the extent of favorite areas for fifth grade forestry, favorite areas for fourth grade afforestation, and favorite areas for third grade and fourth grade range management in the studied area. Based on the results of this research, the studied area has limited potentials for forestry and afforestation activities. The obtained results of evaluation also showed that the rangelands of Hamadan province are extremely poor. Since the rangelands have a substantial role in preservation of soil and water, therefore it is necessary to take appropriate measures for better exploitation of rangelands.展开更多
Michoacan brings 2.1% of national GDP, which is 12.5% to agriculture, Livestock is the fourth activity in economic importance in the State and develops in 43% of the territory （58,643 km：） using 27% of the populati...Michoacan brings 2.1% of national GDP, which is 12.5% to agriculture, Livestock is the fourth activity in economic importance in the State and develops in 43% of the territory （58,643 km：） using 27% of the population economically active. Michoacfin ranks third in national cattle inventory （1,608,523 heads） with fifth place in meat production （145,221 ton/year）. The production model is extended cow-breed, subject to season and availability of food （few rains shortage of forage during drought）, with 0.60 production of breed/cow/year, and a marked traditionalism in the form of production; also a high dependency to food based on the grazing. The inadequate national public policy expressed in the paternalism has limited the adoption of strategies to contribute to the solution of this problem. Therefore this study objective was to design and validate a strategy to increase the number of cow breeding/cow/year to season reproduction program, based on the use of synthetic progesterone ＂melengestrol acetate＂ （MGA） as a technology available, secure, easy to use, low cost and likely to be adoptable to the traditional model of production. Work was done in the dry tropics in the municipalities of Churumuco and Tzitzio, Michoacfin State, Mdxico. Used 133 bovine females with crossbreeding Bos indicus, diagnosed as not pregnant, 6.7 and 6.38 years old respectively for each municipality. Oral doses of 0.05 rag/day/cow of MGA during nine days then exposed to the presence of male. Data were analyzed using analysis of variance of a single way. The results indicate that the delivery rate was 58.33% in Churumuco and 61.86% in Tzitzio. This delivery rate represents an increase of 14%-16% of born per year considering that treated females become pregnant with traditional production system management. We concluded that the MGA is an appropriate strategy to the traditional production of tropical dry in MichoacO, n system that increases the rate of births and is likely to be accepted despite the paternalistic public policy prevailing in the country.展开更多
In the Eurasian forest-steppe,with increasing aridity,the balance between naturally co-existing forest and grassland patches is expected to shift towards grassland dominance in the long run,although feedback mechanism...In the Eurasian forest-steppe,with increasing aridity,the balance between naturally co-existing forest and grassland patches is expected to shift towards grassland dominance in the long run,although feedback mechanisms and changes in land-use may alter this process.In this study,we compared old and recent aerial photographs of Hungarian forest-steppes to find out whether and how the forest proportion and the number of forest patches change at the decadal time scale.The percentage area covered by forest significantly increased in all study sites.The observed forest encroachment may be a legacy from earlier land-use:due to ceased or reduced grazing pressure,forests are invading grasslands until the potential forest cover allowed by climate and soil is reached.The number of forest patches significantly increased at one site(Fülöpháza),while it decreased at two sites(Bugac and Orgovány)and showed no significant change at the fourth site(Tázlár).This indicates that forest encroachment can happen at least in two different ways:through the emergence of new forest patches in the grassland,and through the extension and coalescence of already existing forest patches.Though the present work revealed increasing tree cover at a decadal time scale,the dynamic process should be monitored in the future to see how the vegetation reacts to further aridification.This could help devise a conservation strategy,as the woody/non-woody balance has a profound influence on basic ecosystem properties.展开更多
Grazing exerts a profound influence on both the plant diversity and productivity of grasslands,while simultaneously exerting a significant impact on regulating grassland soil carbon sequestration.Moreover,besides alte...Grazing exerts a profound influence on both the plant diversity and productivity of grasslands,while simultaneously exerting a significant impact on regulating grassland soil carbon sequestration.Moreover,besides altering the taxonomic diversity of plant communities,grazing can also affect their diversity of functional traits.However,we still poorly understand how grazing modifies the relationship between plant functional diversity(FD)and soil carbon sequestration in grassland ecosystems.Here,we conducted a grazing manipulation experiment to investigate the effects of different grazing regimes(no grazing,sheep grazing(SG)and cattle grazing(CG))on the relationships between plant FD and soil carbon sequestration in meadow and desert steppe.Our findings showed that different livestock species changed the relationships between plant FD and soil organic carbon(SOC)in the meadow steppe.SG decoupled the originally positive relationship between FD and SOC,whereas CG changed the relationship from positive to negative.In the desert steppe,both SG and CG strengthened the positive relationship between FD and SOC.Our study illuminates the considerable impact of livestock species on the intricate mechanisms of soil carbon sequestration,primarily mediated through the modulation of various measures of functional trait diversity.In ungrazed meadows and grazed deserts,maintaining high plant FD is conducive to soil carbon sequestration,whereas in grazed meadows and ungrazed deserts,this relationship may disappear or even reverse.By measuring the traits and controlling the grazing activities,we can accurately predict the carbon sequestration potential in grassland ecosystems.展开更多
Under the conditions of climate warming,grassland degradation,frequent sandstorms,and fast increases in livestock numbers,coordinating animal husbandry and ecological protection is an important issue facing Mongolia.U...Under the conditions of climate warming,grassland degradation,frequent sandstorms,and fast increases in livestock numbers,coordinating animal husbandry and ecological protection is an important issue facing Mongolia.Using Khutag-Undur as an example,this study explores the dynamic process,future scenarios,and optimization strategies of the animal husbandry system in a typical Soum of Mongolia from 2015 to 2050 under three future climate socioeconomic scenarios of CMIP 6:SSP1-RCP2.6,SSP2-RCP4.5,and SSP5-RCP8.5.First,the animal husbandry system was deconstructed into three subsystems:grassland primary production,livestock secondary production,and herder consumption.Based on the negative feedback mechanism of forage-livestock balance,a system dynamics model for the Khutag-Undur Soum animal husbandry system was developed.This model integrates spatial data such as land cover and NPP,as well as statistical data on livestock,herder income and expenditures,sample plot surveys,and herder questionnaires.The model was used to simulate the historical changes(2015-2022)in forage production and carrying capacity,livestock stock,and livestock output of Khutag-Undur,and then to forecast the future scenarios of those variables for 2022-2050.Second,the most suitable future scenario for the Soum was identified by comparing the three future scenarios using a pastural system sustainability evaluation method.Finally,based on three indicators of livestock numbers,a two-step livestock reduction strategy was proposed.The main conclusions are that the rapid growth of livestock numbers in Khutag-Undur places considerable pressure on the grassland,and the SSP1-RCP2.6 scenario is the most suitable future scenario for the Soum.However,even in this suitable scenario,grassland overloading remains evident.The continuous implementation of a livestock reduction strategy is recommended to maintain the sustainable development of animal husbandry and grassland conservation.展开更多
Restoring degraded grassland ecosystems is of great significance for the sustainable development of grassland ecological service functions and the sustainable and healthy development of regional economies and societie...Restoring degraded grassland ecosystems is of great significance for the sustainable development of grassland ecological service functions and the sustainable and healthy development of regional economies and societies. Returning grazing land to grassland technology（RGLGT） is an important strategic technology for restoring degraded grassland ecosystems and achieving the sustainable development of the society and economy of pastoral areas in China. Researching the comprehensive evaluation system of the effects of RGLGT has an important significance for evaluating and adjusting national ecological policy. Based on collecting sample surveys from 221 farmers in 16 villages of 4 towns of Yanchi County, Ningxia Hui Autonomous Region in 2017, a model for evaluating the effects of implementing RGLGT was developed. The model included the characteristics of the technology, the ecological and social benefits of the technology, and the sustainability and economic benefits of the technology, it was used to complete a comprehensive effects evaluation of implementing RGLGT in Yanchi County that was based on use of the Analytic Hierarchy Process（AHP） method. The results showed that the comprehensive effect of implementing RGLGT is good overall and had a score of 0.5946. In terms of specific effects ranked from high to low, these were the ecological and social benefits of the technology, the economic benefits, the sustainability and the characteristics themselves. The implementation of RGLGT has resulted in good ecological and social benefits and economic benefits, but sustainability and characteristics of the technology are weak.展开更多
Global historical land use datasets are widely used in global environmental change studies; however, uncertainties in the included pasture data have not been evaluated. In this study, using trend, relative difference ...Global historical land use datasets are widely used in global environmental change studies; however, uncertainties in the included pasture data have not been evaluated. In this study, using trend, relative difference ratio(RDR), and spatial comparisons, we evaluated the accuracy of China pasture data in the HYDE(versions 3.1 and 3.2), SAGE, and PJ datasets using historical document-based reconstructions, including the land use datasets for China covering 1935–1997(hereafter Ge-dataset)and Northeast China covering the 1700 s–2000(hereafter Ye-dataset), and the satellite-based China's Land-Use/cover Datasets(CLUDs) for 1980–2015. Four important results were obtained.(1) China pasture area in the HYDE, SAGE, and PJ datasets and grassland area in the Ge-dataset, Ye-dataset, and CLUDs show both disparate trends and large differences in absolute values.(2)Spatially, 50.9%, 52.8%, and 63.0% pasture/grassland grids in 2000 had RDRs greater than 60% between HYDE3.1, HYDE3.2,and SAGE datasets, and CLUDs, respectively. The percentage of grids with RDRs less than 20% were 24.9%, 26.7%, and 16.0%,respectively.(3) Based on HYDE3.2, the spatial distribution of pasture in Northeast China over the last 300 year has expanded,which is in contrast to the results from the Ye-dataset, which shows the spatial distribution of grassland shrinking because of human reclamation activities.(4) The large contrasts between the global datasets and Chinese native datasets are due to differences in pasture/grassland definitions, land use practices, and spatial reconstruction methods.展开更多
基金supported by the National Key Tech-nologies R&D Program of China (No. 2006BAD03A0502)the Major State Basic Research Development Program of China (No. 2002CB111506)
文摘Agroforestry is a ubiquitous landscape on the slopes in Loess Plateau, where soil moisture is a limiting factor for plant growth and development. The spatial and temporal characteristics of soil moisture were studied in three types of agroforestry boundaries： forest-grassland, forest-cropland and shelterbelt-cropland. The result shows that soil moisture content decreased with soil depth increasing from the surface to 110 cm. Soil moisture content differed significantly among the three boundaries all in the rainy season （July-September）, dry season （May-June） and spring （March-April）. The horizontal distribution of soil moisture in different soil layers in the three types of boundaries showed different patterns with line form, wave form, scoop form or ＂W＂ form. The distance of edge influence （DEI） of soil moisture in different types of landscape boundaries was estimated by variance analysis and multiple comparisons. In dry season the DEI in 0-10 cm soil layer was 0.4 H （H, average height of trees）, which ranged from 0.2 H in grassland or in cropland to 0.2 H in forest field for both forest-grassland and forest-cropland boundaries, and 0.7 H （ranged from 0.2 H in cropland to 0.5 H in forest field） for shelterbelt-cropland boundary. In rainy season the DEI at soil depth of 0-110 cm was 0.7 H for the three boundaries. The results indicated that agroforestry type should be carefully selected to maintain soil moisture in land management, especially in restoring degraded land in Loess Plateau.
文摘The high Zoige Basin （Ruoergai Plateau） on the eastern Tibetan Plateau is a fault depression formed during intensive uplifting of the Tibetan Plateau. The wetland is globally important in biodiversity and is composed of marshes, bogs, fens, wet meadows and shallow water interspersed with low hills and sub-alpine meadows. Most of the Zoige wetlands have long been one of the most important grazing lands in China. Recent rangeland policy has allowed grazing, and usable wetland areas have been being legally allocated to individuals or groups of households on a long-term lease basis. Privatizafion of the wetland has impacted the Zoige wetlands in aspects of hydrologic condition, landscape and biodiversity. The uneven spatial distribution of water resources onprivatelands has led to the practice of extracting ground water, which has decreased the perched water table in Zoige. Fencing off the rangelands and grazing on expanding sand dunes have affected landscapes. Variation in the water table has led to the changes in vegetation diversity, resulting in the changes in wildlife and aquatic diversities and ecosystem processes. Making use all year round of the pasture that was previously grazed only in summer has shrunk the daily activity space of wildlife, and the newly erected fences blocked the movement of wild animals looking for food in the snow to lower and open areas. To maintain the favorable conditions of the Zoige wetland ecosystem, the author suggests that, in addition to biophysical research and implementation of conservation practices, there is an immediate need to initiate an integrated management program, increase public awareness of wetland functions and provide better training for the local conservation staff.
基金supported by the National Western Special Project (Project No. 2003BA901A20)
文摘Conventional farming-pastoral ecotones methods of delineating were not quantitative and could not fully show their spatial distribution. The present paper attempts to develop quantitative methods for mapping farming-pastoral ecotones in China. Nine indicators, related to temperature, precipitation and altitude aspects, were selected to quantify ecological susceptibility of vegetation （crops and forage）. Methods of analytic hierarchy process （AHP） and expert score ranking combined with fuzzy set theory were applied to assign the weight for each indicator and to define the membership functions. The geographic information system （GIS） was used to manage the spatial database and conduct the spatial analysis. According to the spatial calculation of evaluation model integrated with GIS, the ecological susceptibility of vegetation （crops and forage） was mapped. Three different zones, pastoral area, farming-pastoral ecotones and farming area, were classified by spatial cluster analysis and the maximum likelihood classification for the numeric map of vegetation ecological susceptibility by GIS. This map was validated by the economic statistical result based on the ratio of the output value from animal husbandry in total output value of agriculture by the National Bureau of Statistics in China, indicating that the mapping of the farming-pastoral ecotones may be accepted.
基金Under the auspices of National Natural Science Foundation of China(No.41371097,40871048)
文摘Land change science （LCS） strives to understand and model land-use change, which will further advance the understanding of multiple issues in the socio-ecological systems. Based on GIS/RS techniques, autologistic model, and household survey method, this study investigated major land use changes and their causes from 1978 to 2008 in Uxin Banner （county-level）, Inner Mongolia in China and then developed an understanding of the relationships between household livelihood and land-use pattern. Results showed that cultivated land increased from 1988 to 2000, and leveled offafter 2000. Built-up land increased stably for the period 1978 2008. The change of grassland and bare land differed among the three periods. From 1978 to 1988, grassland increased by 23.3%, and bare land decreased by 20.48%. From 1988 to 2000, bare land expanded by 1.7%, but grassland declined by 1.3%. From 2000 to 2008, an increase in grassland area by 1.8% was observed, but a decrease in bare land area by 9.0% was witnessed. The autologistic models performed better than logistic models as indicated by lower Akaike Information Criterion （AIC） values. Factors associated with human activities significantly correlated with the change of cultivated land, forest land, grassland, and built-up land. The produce prices and extensive cultivated land use are major issues in the farming area. This study suggests that completing land circulation systems and maintaining the stability of price are effective solutions. By contrast, reclamation and overgrazing are major concerns in the pastoral areas. Implementing environmental policies effectively, transferring population out of rural pastoral areas, and developing modem animal husbandry are effective ways to address these issues.
文摘The aim of this research is to identify the most suitable land for forestry, afforestation and rangeland management in Hamadan province. This research has been accomplished using Makhdoum＇s model. In this research 30 digital data layers are used. The Geographic Information System （GIS） has been used as main tool and overlay method has been used to implement the mentioned model. The results of this research revealed that the extent of favorite areas for fifth grade forestry, favorite areas for fourth grade afforestation, and favorite areas for third grade and fourth grade range management in the studied area. Based on the results of this research, the studied area has limited potentials for forestry and afforestation activities. The obtained results of evaluation also showed that the rangelands of Hamadan province are extremely poor. Since the rangelands have a substantial role in preservation of soil and water, therefore it is necessary to take appropriate measures for better exploitation of rangelands.
文摘Michoacan brings 2.1% of national GDP, which is 12.5% to agriculture, Livestock is the fourth activity in economic importance in the State and develops in 43% of the territory （58,643 km：） using 27% of the population economically active. Michoacfin ranks third in national cattle inventory （1,608,523 heads） with fifth place in meat production （145,221 ton/year）. The production model is extended cow-breed, subject to season and availability of food （few rains shortage of forage during drought）, with 0.60 production of breed/cow/year, and a marked traditionalism in the form of production; also a high dependency to food based on the grazing. The inadequate national public policy expressed in the paternalism has limited the adoption of strategies to contribute to the solution of this problem. Therefore this study objective was to design and validate a strategy to increase the number of cow breeding/cow/year to season reproduction program, based on the use of synthetic progesterone ＂melengestrol acetate＂ （MGA） as a technology available, secure, easy to use, low cost and likely to be adoptable to the traditional model of production. Work was done in the dry tropics in the municipalities of Churumuco and Tzitzio, Michoacfin State, Mdxico. Used 133 bovine females with crossbreeding Bos indicus, diagnosed as not pregnant, 6.7 and 6.38 years old respectively for each municipality. Oral doses of 0.05 rag/day/cow of MGA during nine days then exposed to the presence of male. Data were analyzed using analysis of variance of a single way. The results indicate that the delivery rate was 58.33% in Churumuco and 61.86% in Tzitzio. This delivery rate represents an increase of 14%-16% of born per year considering that treated females become pregnant with traditional production system management. We concluded that the MGA is an appropriate strategy to the traditional production of tropical dry in MichoacO, n system that increases the rate of births and is likely to be accepted despite the paternalistic public policy prevailing in the country.
基金supported by the National Research,Development and Innovation Office,Hungary[grant number FK 134384 to L.E.,KKP 144068 and K 137573 to P.T.,and FK 142428 to Z.B.]the János Bolyai Research Scholarship of the Hungarian Academy of Sciences(to L.E.and Z.B.)the Stipendium Hungaricum Scholarship(to K.V.H.and I.P.)。
文摘In the Eurasian forest-steppe,with increasing aridity,the balance between naturally co-existing forest and grassland patches is expected to shift towards grassland dominance in the long run,although feedback mechanisms and changes in land-use may alter this process.In this study,we compared old and recent aerial photographs of Hungarian forest-steppes to find out whether and how the forest proportion and the number of forest patches change at the decadal time scale.The percentage area covered by forest significantly increased in all study sites.The observed forest encroachment may be a legacy from earlier land-use:due to ceased or reduced grazing pressure,forests are invading grasslands until the potential forest cover allowed by climate and soil is reached.The number of forest patches significantly increased at one site(Fülöpháza),while it decreased at two sites(Bugac and Orgovány)and showed no significant change at the fourth site(Tázlár).This indicates that forest encroachment can happen at least in two different ways:through the emergence of new forest patches in the grassland,and through the extension and coalescence of already existing forest patches.Though the present work revealed increasing tree cover at a decadal time scale,the dynamic process should be monitored in the future to see how the vegetation reacts to further aridification.This could help devise a conservation strategy,as the woody/non-woody balance has a profound influence on basic ecosystem properties.
基金supported by the National Natural Science Foundation of China(31772652 and 31802113)China Scholarship Council(202006620065)。
文摘Grazing exerts a profound influence on both the plant diversity and productivity of grasslands,while simultaneously exerting a significant impact on regulating grassland soil carbon sequestration.Moreover,besides altering the taxonomic diversity of plant communities,grazing can also affect their diversity of functional traits.However,we still poorly understand how grazing modifies the relationship between plant functional diversity(FD)and soil carbon sequestration in grassland ecosystems.Here,we conducted a grazing manipulation experiment to investigate the effects of different grazing regimes(no grazing,sheep grazing(SG)and cattle grazing(CG))on the relationships between plant FD and soil carbon sequestration in meadow and desert steppe.Our findings showed that different livestock species changed the relationships between plant FD and soil organic carbon(SOC)in the meadow steppe.SG decoupled the originally positive relationship between FD and SOC,whereas CG changed the relationship from positive to negative.In the desert steppe,both SG and CG strengthened the positive relationship between FD and SOC.Our study illuminates the considerable impact of livestock species on the intricate mechanisms of soil carbon sequestration,primarily mediated through the modulation of various measures of functional trait diversity.In ungrazed meadows and grazed deserts,maintaining high plant FD is conducive to soil carbon sequestration,whereas in grazed meadows and ungrazed deserts,this relationship may disappear or even reverse.By measuring the traits and controlling the grazing activities,we can accurately predict the carbon sequestration potential in grassland ecosystems.
基金The National Key R&D Program of China(2022YFE0119200)The National Natural Science Foundation of China(32161143025,42371283)The Second Tibetan Plateau Scientific Expedition and Research Program(STEP),China(2019QZKK0603)。
文摘Under the conditions of climate warming,grassland degradation,frequent sandstorms,and fast increases in livestock numbers,coordinating animal husbandry and ecological protection is an important issue facing Mongolia.Using Khutag-Undur as an example,this study explores the dynamic process,future scenarios,and optimization strategies of the animal husbandry system in a typical Soum of Mongolia from 2015 to 2050 under three future climate socioeconomic scenarios of CMIP 6:SSP1-RCP2.6,SSP2-RCP4.5,and SSP5-RCP8.5.First,the animal husbandry system was deconstructed into three subsystems:grassland primary production,livestock secondary production,and herder consumption.Based on the negative feedback mechanism of forage-livestock balance,a system dynamics model for the Khutag-Undur Soum animal husbandry system was developed.This model integrates spatial data such as land cover and NPP,as well as statistical data on livestock,herder income and expenditures,sample plot surveys,and herder questionnaires.The model was used to simulate the historical changes(2015-2022)in forage production and carrying capacity,livestock stock,and livestock output of Khutag-Undur,and then to forecast the future scenarios of those variables for 2022-2050.Second,the most suitable future scenario for the Soum was identified by comparing the three future scenarios using a pastural system sustainability evaluation method.Finally,based on three indicators of livestock numbers,a two-step livestock reduction strategy was proposed.The main conclusions are that the rapid growth of livestock numbers in Khutag-Undur places considerable pressure on the grassland,and the SSP1-RCP2.6 scenario is the most suitable future scenario for the Soum.However,even in this suitable scenario,grassland overloading remains evident.The continuous implementation of a livestock reduction strategy is recommended to maintain the sustainable development of animal husbandry and grassland conservation.
基金National Key Research and Development Program of Chian(2016YFC0503703)West Projects of National Social Science Foundation(15XJY010)+1 种基金Humanities and Social Sciences Research and Planning Fund Projects of Education Ministry in 2013(13YJA630141)General Social Science Fund Project of Shaanxi Province in 2014(2014P21)
文摘Restoring degraded grassland ecosystems is of great significance for the sustainable development of grassland ecological service functions and the sustainable and healthy development of regional economies and societies. Returning grazing land to grassland technology（RGLGT） is an important strategic technology for restoring degraded grassland ecosystems and achieving the sustainable development of the society and economy of pastoral areas in China. Researching the comprehensive evaluation system of the effects of RGLGT has an important significance for evaluating and adjusting national ecological policy. Based on collecting sample surveys from 221 farmers in 16 villages of 4 towns of Yanchi County, Ningxia Hui Autonomous Region in 2017, a model for evaluating the effects of implementing RGLGT was developed. The model included the characteristics of the technology, the ecological and social benefits of the technology, and the sustainability and economic benefits of the technology, it was used to complete a comprehensive effects evaluation of implementing RGLGT in Yanchi County that was based on use of the Analytic Hierarchy Process（AHP） method. The results showed that the comprehensive effect of implementing RGLGT is good overall and had a score of 0.5946. In terms of specific effects ranked from high to low, these were the ecological and social benefits of the technology, the economic benefits, the sustainability and the characteristics themselves. The implementation of RGLGT has resulted in good ecological and social benefits and economic benefits, but sustainability and characteristics of the technology are weak.
基金supported by the National Key Research and Development Program of China on Global Change (Grant No. 2017YFA0603304)the National Natural Science Foundation of China (Grant Nos. 41671149, 41701228)
文摘Global historical land use datasets are widely used in global environmental change studies; however, uncertainties in the included pasture data have not been evaluated. In this study, using trend, relative difference ratio(RDR), and spatial comparisons, we evaluated the accuracy of China pasture data in the HYDE(versions 3.1 and 3.2), SAGE, and PJ datasets using historical document-based reconstructions, including the land use datasets for China covering 1935–1997(hereafter Ge-dataset)and Northeast China covering the 1700 s–2000(hereafter Ye-dataset), and the satellite-based China's Land-Use/cover Datasets(CLUDs) for 1980–2015. Four important results were obtained.(1) China pasture area in the HYDE, SAGE, and PJ datasets and grassland area in the Ge-dataset, Ye-dataset, and CLUDs show both disparate trends and large differences in absolute values.(2)Spatially, 50.9%, 52.8%, and 63.0% pasture/grassland grids in 2000 had RDRs greater than 60% between HYDE3.1, HYDE3.2,and SAGE datasets, and CLUDs, respectively. The percentage of grids with RDRs less than 20% were 24.9%, 26.7%, and 16.0%,respectively.(3) Based on HYDE3.2, the spatial distribution of pasture in Northeast China over the last 300 year has expanded,which is in contrast to the results from the Ye-dataset, which shows the spatial distribution of grassland shrinking because of human reclamation activities.(4) The large contrasts between the global datasets and Chinese native datasets are due to differences in pasture/grassland definitions, land use practices, and spatial reconstruction methods.
