Based on the definition of desertification adopted by United Nations Convention to Combat Desertification in Those Countries Experiencing Serious Drought and/or Desertification,particularly in Africa, first,the pat...Based on the definition of desertification adopted by United Nations Convention to Combat Desertification in Those Countries Experiencing Serious Drought and/or Desertification,particularly in Africa, first,the patterns of desertification in China are introduced.Second,desertification assessment indicator system that used in China is presented.It includes:(1)climate classification;(2)classification of land use;(3)classification of desertification patterns which include wind erosion,water erosion,salinization,and grassland degradation;(4)grading index of desertification that includes grading index of desertification caused by wind erosion,desertification caused by water erosion,desertification caused by salinization,indicators of grassland degradation classification.At last,some detailed factors that can be used as indicators in desertification assessment are discussed.展开更多
Windbreak system consisting of the forms of net, belt, sheet and point, has improved local eco environment greatly and promoted the level of social economy and local people's living. The result of environment imp...Windbreak system consisting of the forms of net, belt, sheet and point, has improved local eco environment greatly and promoted the level of social economy and local people's living. The result of environment impact assessment shows that the quality of eco environment has been improved obviously and the impact process is mainly positive after building of windbreak system in Daxing County of Beijing, a dry sub humid region. Effects of windbreak system and their environmental impacts are analyzed scientifically and reasonably in this paper. The study will enrich the theory of environment impact assessment and extend the scope of research, and will provide experience for the construction of windbreak system in the region.展开更多
Based on the desertification definition of United Nations Convention to Combat Desertification and features of desertification in China, three-level hierarchical classification system for desertification and quantitat...Based on the desertification definition of United Nations Convention to Combat Desertification and features of desertification in China, three-level hierarchical classification system for desertification and quantitative assessment methodology of desertification degree were developed and used to evaluate desertification danger degree across the country. The system is composed of three components: type of desertification, type of land utilization and degree of desertification. The type of desertification monitored in China was divided into 4 major categories, 15 sub-categories and 52 types. Vegetation coverage, soil characteristics, and topography are considered as three major indicators for quantitative assessment of desertified land. A simple, yet practically sound mathematical assessment model was built using these indicators. Furthurmore, a regional land desertification warning model was also constructed on the basis of the ratios of non-desertified land area to desertified land area in different degrees. The warning result of wind-erosion desertification at county scale for 12 provinces in northern China was also calculated by this model.展开更多
Keerqin sand land is located in the transitional terrain between the Northeast Plain and Inner Mongolia （42°41′-45°15′N, 118°35′-123°30′ E） in Northeast China and it is seriously affected by ...Keerqin sand land is located in the transitional terrain between the Northeast Plain and Inner Mongolia （42°41′-45°15′N, 118°35′-123°30′ E） in Northeast China and it is seriously affected by desertification. According to the configuration and ecotope of the earths surface, the coverage of vegetation, occupation ratio of bare sandy land and the soil texture were selected as evaluation indexes by using the field investigation data. The evaluation index system of Keerqin sandy desertification was established by using Remote Sensing data. and the occupation ratio of bare sandy land was obtained by mixed spectrum model. This index system is validated by the field investioation data and results indicate that it is suitable for the desertification evaluation of Keerqin.Foundation Item： This study is supported by a grant from the National Natural Science Foundation of China （No. 30371192）展开更多
In recent years, the ecological environment in the upper reaches of the Yellow River has been degraded due to natural and human factors. Environmental problems such as grassland degeneration, sandy desertification and...In recent years, the ecological environment in the upper reaches of the Yellow River has been degraded due to natural and human factors. Environmental problems such as grassland degeneration, sandy desertification and water erosion have seriously affected regional economic sustainable development. The objective of this paper was to detect sandy desertification in the upper reaches of the Yellow River by means of remote sensing and GIS. The Gonghe Basin was chosen as the study site, which is one of the most seriously degraded regions in the area. Based on an analysis of the multi-temporal and multi-spectral Landsat TM data with GIS, sandy desertification processes were detected. The results show that sandy desertified land has increased and intensified seriously in the upper reaches of the Yellow River for the period from 1987 to 1996. There are two desertification processes at work in the study area: sand dune reactivation and development of badlands through wind erosion. Excessive human activities play an important role in the occurrence and development of desertification in this area. At present, acceleration of the desertification process is attributed to irrational human economic activities. Grasslands as well as the ecological environment of this area have been seriously degraded, which has affected the regional economic sustainable development and endangered the security of the Longyangxia reservoir. It is necessary and urgent to combat desertification and protect the environment. The results show that full use of remote sensing data with GIS in monitoring and assessing desertification is an effective measure of quantitative research.展开更多
Rapid increase in desertification is an environ-mental concern,especially for the health and sustainabil-ity of ecosystems in changing climates.How ecosystems respond to such changes may be partially understood by stu...Rapid increase in desertification is an environ-mental concern,especially for the health and sustainabil-ity of ecosystems in changing climates.How ecosystems respond to such changes may be partially understood by studying interactions and performance of critically impor-tant groups such as soil fungi functional groups.This study investigated variations in diversities of three soil fungi functional guilds(saprotrophic,symbiotic,pathogenic)and influencing abiotic factors in a Pinus densata forest on the southeast Tibetan Plateau where desertification is intense.The results indicate desertification significantly decreased the proportion of dominant fungal guild-symbiotic fungi(mean relative abundance decreasing from 97.0%to 68.3%),in contrast to saprotrophic fungi(increasing from 2.7%to 25.7%)and pathogenic(from 0.3%to 5.9%).Soil pH had the most significant impact on fungal community structure and negatively correlated with symbiotic fungal richness,which was significantly lower in arid soils,and positively correlated with saprotrophic and pathogenic fungal alpha-diversity,which were abundant.Different community struc-tures and regulators of the three fungi communities were observed,with pH,total phosphorus and ammonium(NH_(4)^(+))as the main determinants.This study links the biotic and abi-otic components during desertification and the interactions between them,and may be used as indicators of ecosystem health and for amendments to mitigate the effects of a chang-ing climate.展开更多
Forest stands in the semi-arid environment of northern Mongolia have an essential role in controlling ongoing desertification in the surrounding landscape.Over the last decade,the total forest area has decreased drama...Forest stands in the semi-arid environment of northern Mongolia have an essential role in controlling ongoing desertification in the surrounding landscape.Over the last decade,the total forest area has decreased dramatically.The aim of this study was to evaluate the potential of natural regeneration as an essential element for ensuring sustainability of these forests.Based on field measurements from 120 plots in six sites,our assessment tool revealed five qualitative categories of forest regeneration,allowing us to assess impacts of both grazing and environmental conditions on the regeneration process.Grazing is a crucial factor and adversely affects regeneration.For sites with relatively low grazing intensity,low soil moisture levels represent the main reason for reduced regeneration.The approach to classification proposed in this study allows for the identification and interpretation of stand conditions where natural regeneration has failed.This study provides an important foundation to inform decisionmaking related to land protection and restoration actions.Our findings could be used in comparative studies and,importantly,may aid further mapping of Mongolian forests.展开更多
Background:Karst areas in southwestern China exhibit ecological degradation in the form of rocky desertification.Local governments launched large-scale afforestation and other ecological restoration programs to curb t...Background:Karst areas in southwestern China exhibit ecological degradation in the form of rocky desertification.Local governments launched large-scale afforestation and other ecological restoration programs to curb this trend.Soil thickness is a key limiting factor for vegetation restoration in Karst areas,but the relationship between ecological restoration and soil thickness remains unclear.Further,afforestation consumes large amounts of water,which impacts water supply in karst areas.In this study,we used GIS and statistical analyses to determine rocky desertification sensitivity and its driving factors in karst areas of Chongqing municipality over the past decade.Results:Soil thickness is one of the key factors that restrict ecological restoration of rocky desertification.From 2000 to 2010,rocky desertification sensitivity in karst areas was on the rise along with an increase in afforestation.Areas of high sensitivity were mainly distributed in Pengshui County,Wulong District,and Youyang County;Shizhu County had the lowest overall incidence of desertification.Spatial distribution of rocky desertification was significantly affected by rainfall and soil thickness.Regression analysis showed that the main factors controlling changes in rocky desertification in natural forest over time were precipitation which explained 23.73%of total variance,and soil thickness which explained 23.42%of total variance.Soil thickness and soil water content had a higher correlation coefficient(at 0.516)in natural forests than in planted forests.Conclusion:This study showed that increases in soil thickness in a karst area had a significant positive impact on the fragile ecological environment.This indicates that ecosystem restoration in karst areas will benefit from addressing soil thickness.展开更多
Forests in the aridlands of Sudan are distinctive in nature and require special attention due to the great role they play as a first and last line of defense against southward desertification.Thus,to determine their c...Forests in the aridlands of Sudan are distinctive in nature and require special attention due to the great role they play as a first and last line of defense against southward desertification.Thus,to determine their conservative and protective needs based on current conditions in the Wad Al-Bashir Forest(WF),toward ensuring sustainable forest resources in these areas,we used a systematic field survey,existing and available documents review and key informant interviews(KII),to collect data from 08 December 2017 to 15 May 2018.A severe depletion and changes in the forest tree cover and composition were found during the field survey,where species such as Balanitis aegyptiaca is threatened and invasive species(e.g.,Acacia nubica)have started to dominate.Reviewed documents have credited illegal cutting and agricultural activities for the changes in the forest status,whereas the KII indicated that past and current forest conservative and protective practices(CPPs),where forest clearance for agricultural,grazing,pests and disease control,were not given a deserved consideration as they relate to tree cutting and reforestation practices.Likewise,negligence of the needs of those who depend on the forest and inadequate funds have constrained implementation of some CPPs.Accordingly,on the basis of the results of this study,we recommend that CPPs associated with agriculture,grazing,forest fire,pest and disease control should be a top priority concern of forest authorities.Better financial support,which could be enriched by involving governmental and non-governmental organizations,is also needed to boost CPPs in the WF.Invasive species also need to be cleared and replaced by trees such as A.senegal and B.aegyptiaca that are of economic and environmental value.展开更多
文摘Based on the definition of desertification adopted by United Nations Convention to Combat Desertification in Those Countries Experiencing Serious Drought and/or Desertification,particularly in Africa, first,the patterns of desertification in China are introduced.Second,desertification assessment indicator system that used in China is presented.It includes:(1)climate classification;(2)classification of land use;(3)classification of desertification patterns which include wind erosion,water erosion,salinization,and grassland degradation;(4)grading index of desertification that includes grading index of desertification caused by wind erosion,desertification caused by water erosion,desertification caused by salinization,indicators of grassland degradation classification.At last,some detailed factors that can be used as indicators in desertification assessment are discussed.
文摘Windbreak system consisting of the forms of net, belt, sheet and point, has improved local eco environment greatly and promoted the level of social economy and local people's living. The result of environment impact assessment shows that the quality of eco environment has been improved obviously and the impact process is mainly positive after building of windbreak system in Daxing County of Beijing, a dry sub humid region. Effects of windbreak system and their environmental impacts are analyzed scientifically and reasonably in this paper. The study will enrich the theory of environment impact assessment and extend the scope of research, and will provide experience for the construction of windbreak system in the region.
基金the National Natural Science Foundation of China (Grant No.30070601 and 399904900)
文摘Based on the desertification definition of United Nations Convention to Combat Desertification and features of desertification in China, three-level hierarchical classification system for desertification and quantitative assessment methodology of desertification degree were developed and used to evaluate desertification danger degree across the country. The system is composed of three components: type of desertification, type of land utilization and degree of desertification. The type of desertification monitored in China was divided into 4 major categories, 15 sub-categories and 52 types. Vegetation coverage, soil characteristics, and topography are considered as three major indicators for quantitative assessment of desertified land. A simple, yet practically sound mathematical assessment model was built using these indicators. Furthurmore, a regional land desertification warning model was also constructed on the basis of the ratios of non-desertified land area to desertified land area in different degrees. The warning result of wind-erosion desertification at county scale for 12 provinces in northern China was also calculated by this model.
基金This study is supported by a grant from the National Natural Science Foundation of China （No. 30371192）
文摘Keerqin sand land is located in the transitional terrain between the Northeast Plain and Inner Mongolia （42°41′-45°15′N, 118°35′-123°30′ E） in Northeast China and it is seriously affected by desertification. According to the configuration and ecotope of the earths surface, the coverage of vegetation, occupation ratio of bare sandy land and the soil texture were selected as evaluation indexes by using the field investigation data. The evaluation index system of Keerqin sandy desertification was established by using Remote Sensing data. and the occupation ratio of bare sandy land was obtained by mixed spectrum model. This index system is validated by the field investioation data and results indicate that it is suitable for the desertification evaluation of Keerqin.Foundation Item： This study is supported by a grant from the National Natural Science Foundation of China （No. 30371192）
基金Project 40071066 supported by National Natural Science Foundation of China
文摘In recent years, the ecological environment in the upper reaches of the Yellow River has been degraded due to natural and human factors. Environmental problems such as grassland degeneration, sandy desertification and water erosion have seriously affected regional economic sustainable development. The objective of this paper was to detect sandy desertification in the upper reaches of the Yellow River by means of remote sensing and GIS. The Gonghe Basin was chosen as the study site, which is one of the most seriously degraded regions in the area. Based on an analysis of the multi-temporal and multi-spectral Landsat TM data with GIS, sandy desertification processes were detected. The results show that sandy desertified land has increased and intensified seriously in the upper reaches of the Yellow River for the period from 1987 to 1996. There are two desertification processes at work in the study area: sand dune reactivation and development of badlands through wind erosion. Excessive human activities play an important role in the occurrence and development of desertification in this area. At present, acceleration of the desertification process is attributed to irrational human economic activities. Grasslands as well as the ecological environment of this area have been seriously degraded, which has affected the regional economic sustainable development and endangered the security of the Longyangxia reservoir. It is necessary and urgent to combat desertification and protect the environment. The results show that full use of remote sensing data with GIS in monitoring and assessing desertification is an effective measure of quantitative research.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB31000000)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0307)+1 种基金the Key Project of the Open Competition in Jiangsu Forestry(No.LYKJ[2022]01)the Jiangsu Social Development Project(BE2022792).
文摘Rapid increase in desertification is an environ-mental concern,especially for the health and sustainabil-ity of ecosystems in changing climates.How ecosystems respond to such changes may be partially understood by studying interactions and performance of critically impor-tant groups such as soil fungi functional groups.This study investigated variations in diversities of three soil fungi functional guilds(saprotrophic,symbiotic,pathogenic)and influencing abiotic factors in a Pinus densata forest on the southeast Tibetan Plateau where desertification is intense.The results indicate desertification significantly decreased the proportion of dominant fungal guild-symbiotic fungi(mean relative abundance decreasing from 97.0%to 68.3%),in contrast to saprotrophic fungi(increasing from 2.7%to 25.7%)and pathogenic(from 0.3%to 5.9%).Soil pH had the most significant impact on fungal community structure and negatively correlated with symbiotic fungal richness,which was significantly lower in arid soils,and positively correlated with saprotrophic and pathogenic fungal alpha-diversity,which were abundant.Different community struc-tures and regulators of the three fungi communities were observed,with pH,total phosphorus and ammonium(NH_(4)^(+))as the main determinants.This study links the biotic and abi-otic components during desertification and the interactions between them,and may be used as indicators of ecosystem health and for amendments to mitigate the effects of a chang-ing climate.
基金This work was supported by funding provided by the project CEITEC 2020(LQ1601)project of the Czech Development Agency CzDA-RO-MN-2014-6-31210the Research Fund of the FFWT at Mendel University in Brno(Reg.Number:LDF_PSV_2017008).
文摘Forest stands in the semi-arid environment of northern Mongolia have an essential role in controlling ongoing desertification in the surrounding landscape.Over the last decade,the total forest area has decreased dramatically.The aim of this study was to evaluate the potential of natural regeneration as an essential element for ensuring sustainability of these forests.Based on field measurements from 120 plots in six sites,our assessment tool revealed five qualitative categories of forest regeneration,allowing us to assess impacts of both grazing and environmental conditions on the regeneration process.Grazing is a crucial factor and adversely affects regeneration.For sites with relatively low grazing intensity,low soil moisture levels represent the main reason for reduced regeneration.The approach to classification proposed in this study allows for the identification and interpretation of stand conditions where natural regeneration has failed.This study provides an important foundation to inform decisionmaking related to land protection and restoration actions.Our findings could be used in comparative studies and,importantly,may aid further mapping of Mongolian forests.
基金the National Key R&D Program of China(2016YFC0502304).
文摘Background:Karst areas in southwestern China exhibit ecological degradation in the form of rocky desertification.Local governments launched large-scale afforestation and other ecological restoration programs to curb this trend.Soil thickness is a key limiting factor for vegetation restoration in Karst areas,but the relationship between ecological restoration and soil thickness remains unclear.Further,afforestation consumes large amounts of water,which impacts water supply in karst areas.In this study,we used GIS and statistical analyses to determine rocky desertification sensitivity and its driving factors in karst areas of Chongqing municipality over the past decade.Results:Soil thickness is one of the key factors that restrict ecological restoration of rocky desertification.From 2000 to 2010,rocky desertification sensitivity in karst areas was on the rise along with an increase in afforestation.Areas of high sensitivity were mainly distributed in Pengshui County,Wulong District,and Youyang County;Shizhu County had the lowest overall incidence of desertification.Spatial distribution of rocky desertification was significantly affected by rainfall and soil thickness.Regression analysis showed that the main factors controlling changes in rocky desertification in natural forest over time were precipitation which explained 23.73%of total variance,and soil thickness which explained 23.42%of total variance.Soil thickness and soil water content had a higher correlation coefficient(at 0.516)in natural forests than in planted forests.Conclusion:This study showed that increases in soil thickness in a karst area had a significant positive impact on the fragile ecological environment.This indicates that ecosystem restoration in karst areas will benefit from addressing soil thickness.
基金This study was supported by Ministry of Higher Education and Scientifi c Research of Sudan.
文摘Forests in the aridlands of Sudan are distinctive in nature and require special attention due to the great role they play as a first and last line of defense against southward desertification.Thus,to determine their conservative and protective needs based on current conditions in the Wad Al-Bashir Forest(WF),toward ensuring sustainable forest resources in these areas,we used a systematic field survey,existing and available documents review and key informant interviews(KII),to collect data from 08 December 2017 to 15 May 2018.A severe depletion and changes in the forest tree cover and composition were found during the field survey,where species such as Balanitis aegyptiaca is threatened and invasive species(e.g.,Acacia nubica)have started to dominate.Reviewed documents have credited illegal cutting and agricultural activities for the changes in the forest status,whereas the KII indicated that past and current forest conservative and protective practices(CPPs),where forest clearance for agricultural,grazing,pests and disease control,were not given a deserved consideration as they relate to tree cutting and reforestation practices.Likewise,negligence of the needs of those who depend on the forest and inadequate funds have constrained implementation of some CPPs.Accordingly,on the basis of the results of this study,we recommend that CPPs associated with agriculture,grazing,forest fire,pest and disease control should be a top priority concern of forest authorities.Better financial support,which could be enriched by involving governmental and non-governmental organizations,is also needed to boost CPPs in the WF.Invasive species also need to be cleared and replaced by trees such as A.senegal and B.aegyptiaca that are of economic and environmental value.
