Land use is shaped by the interactions between nature and society, and these interactions can inhibit environmental sustainability and deplete the natural capital that provides the ecosystem services upon which humans...Land use is shaped by the interactions between nature and society, and these interactions can inhibit environmental sustainability and deplete the natural capital that provides the ecosystem services upon which humans depend. Urbanity Index and Landscape Vulnerability Indicator have been proposed to improve the impact interpretability of land use changes on sub-basin sustainability for local scenarios of biodiversity conservation. A time series of LandSat 5 Thematic Mapper remote sensing data from São Carlos municipality, Southeastern Brazil, for the years 1989, 2004 and 2014 revealed that land use changes in the sub-basins do not take place in a progressive and gradual way. Over the 25-year period, the main trends showed the loss and increase of forest cover so that it has remained quantitatively similar over time due to reduced agricultural land use. The aggregation of both indicators enabled the identification of greater naturalness and lower vulnerability, as well as lower naturalness and higher vulnerability under local sub-basin conditions, pointing the need for different strategies for sub-basin biodiversity conservation and sustainability. These preliminary scenarios provide a way to communicate problems of environmental sustainability at different landscape scales to the scientific community as well as to planners, policy makers and the broader public.展开更多
The Tarim River Basin, located in the typical arid region, is one of the key regions of LUCC research in China and plays an important role in maintaining the sustainable development of the western China. In recent yea...The Tarim River Basin, located in the typical arid region, is one of the key regions of LUCC research in China and plays an important role in maintaining the sustainable development of the western China. In recent years,the ecological environment of the Tarim River Basin has degraded greatly. In the lower reaches, in particular, the riverbed has been dried up for more than 20 years, which accelerated the desertification and has been a great threat to people′s lives. Taking the section of the Tarim River between Qiala Lake and Taitema Lake as a typical region, an investigation on land cover changes was carried out with the support of remote sensing information of 1988 and 2000 respectively. The changes of land cover in this region were obtained: 1) Cropland tended to increase. 2) Urban or Built-up Area in 2000 was 324.4ha more than that in 1988. 3) Waters expanded by 3476.51ha. 4) Woodland and Grassland decreased, while Barren Land increased by 3824.9ha. The total amount of land use/land cover change between 1988 and 2000 is small,which is only 0.355% of the total area. It shows that the developmental pace of the lower reaches of the Tarim River is relative slow. Based on these results, the authors assessed the landscape dynamics of this region and pointed out that the degree of desertification was strengthened and the landscape dominated by sand land was further characterized by salt desert.展开更多
The responses of spatiotemporal variation of ecosystem service values (ESVs) to landscape pattern from 1985 to 2005 in a typical Karst area of the northwest Guangxi Zhuang Autonomous Region,China,were examined us-ing ...The responses of spatiotemporal variation of ecosystem service values (ESVs) to landscape pattern from 1985 to 2005 in a typical Karst area of the northwest Guangxi Zhuang Autonomous Region,China,were examined us-ing remote sensing and geographic information system techniques in this paper.The total ecosystem service values de-clined significantly from 1985 to 1990,and then increased slowly from 1990 to 2005,almost equaled to the 1985 level.The ecosystem service values tended to decline from the west to the east and from mountainous regions to peak-cluster depression areas in 1985,1990,2000 and 2005 respectively.During the period from 1985 to 2005,the ecosystem ser-vice values have increased in the middle and eastern parts of the study area.Landscape pattern indices,such as total area,largest patch index,contagion,aggregative index,effective mesh and proportion of like adjacencies,are significantly correlated with ecosystem service values.This suggests that ecosystem service values tend to increase with the growth of patch area and patch connectivity.However,there are negative correlations between ecosystem service values and landscape pattern indices,such as division index and patch richness.It indicates that ecosystem service values decrease with patch fragmentation and patch size shrinkage.The ecosystem conditions in the typical Karst area have been improved because of the control measures of rocky desertification.It is important to protect key landscape types,such as woodland,shrub and grassland,and to increase patch size and connectivity to avoid further fragmentation.Furthermore,it is necessary to reduce disturbances to ensure the growth of ecosystem service values and to facilitate the sustainable development in this region.展开更多
The aggregation index (AI) is a classical ecology calculation method, which has been widely used for measuring the aggregation level of spatial patterns within a landscape scale in landscape ecological studies. Howeve...The aggregation index (AI) is a classical ecology calculation method, which has been widely used for measuring the aggregation level of spatial patterns within a landscape scale in landscape ecological studies. However, it has certain limitions. For instance, identical results can be obtained by AI even when the shape and number of landscape patches are totally different in two landscape units. Furthermore, the value of AI approaches to 1 if the landscape patch is large enough. To solve these problems, a logical limitation of the original AI equation was revised firstly. Secondly, an improved AI-J was developed based on the awareness of the effects of spatial distribution characteristics of patches and changing spatial scale on AI operation. Finally, the accuracy of AI and AI-J results were evaluated through a case study of city green patches in Chengdu, P. R. China. The results show that the calculated result of AI-J is more precise than that of AI and AI-J can be used to compare a certain landscape class under different spatial scales.展开更多
Urban landscape is directly perceived by residents and is a significant symbol of urbanization development.A comprehensive assessment of urban landscapes is crucial for guiding the development of inclusive,resilient,a...Urban landscape is directly perceived by residents and is a significant symbol of urbanization development.A comprehensive assessment of urban landscapes is crucial for guiding the development of inclusive,resilient,and sustainable cities and human settlements.Previous studies have primarily analyzed two-dimensional landscape indicators derived from satellite remote sensing,potentially overlooking the valuable insights provided by the three-dimensional configuration of landscapes.This limitation arises from the high cost of acquiring large-area three-dimensional data and the lack of effective assessment indicators.Here,we propose four urban landscapes indicators in three dimensions(UL3D):greenness,grayness,openness,and crowding.We construct the UL3D using 4.03 million street view images from 303 major cities in China,employing a deep learning approach.We combine urban background and two-dimensional urban landscape indicators with UL3D to predict the socioeconomic profiles of cities.The results show that UL3D indicators differs from two-dimensional landscape indicators,with a low average correlation coefficient of 0.31 between them.Urban landscapes had a changing point in2018–2019 due to new urbanization initiatives,with grayness and crowding rates slowing,while openness increased.The incorporation of UL3D indicators significantly enhances the explanatory power of the regression model for predicting socioeconomic profiles.Specifically,GDP per capita,urban population rate,built-up area per capita,and hospital count correspond to improvements of 25.0%,19.8%,35.5%,and 19.2%,respectively.These findings indicate that UL3D indicators have the potential to reflect the socioeconomic profiles of cities.展开更多
Recent evidence suggests that Brazilian Cerrado has been largely converted, mainly due to agribusiness activities and urbanization. Thus, the present work aimed to obtain the diagnosis of a watershed characterized by ...Recent evidence suggests that Brazilian Cerrado has been largely converted, mainly due to agribusiness activities and urbanization. Thus, the present work aimed to obtain the diagnosis of a watershed characterized by the expansion of sugar cane fields in the Brazilian Cerrado (Southeastern), employing integrity landscape indicators (Hemeroby, Urbanity Index, Landscape Vulnerability Index, and Water Quality Index) to verify the landscape naturalness, and the consequences of these actions to the ecosystem services provision. Remote sensing data for the years 1998, 2008, and 2018 were employed to verify the land-use changes in the Feijão River watershed (southeastern Brazil), as well as a matrix that considers the land use typologies and their capability to provide ecosystem services. The study area is classified as mixed land use, with the main categories related to agribusiness (sugar cane, pasture, bare soil). The Hemeroby and Urban Index denote naturalness declines over the years, and the observed patterns negatively impact ecosystem service provision. Landscape Vulnerability Index and Water Quality Index demonstrated that remaining vegetation cannot effectively retain pollutants, and severe impairments in the resilience of natural components of key ecosystem service providers (i.e. water and native vegetation) were observed. The results allowed the identification of priority areas for recovery and the maintenance of ecosystem services in agricultural lands.展开更多
Land use/cover change (LUCC) models are helpful tools for analyzing driving forces and processes of land use changes, assessing ecological impacts of land use change and decision-making for land use planning. Howeve...Land use/cover change (LUCC) models are helpful tools for analyzing driving forces and processes of land use changes, assessing ecological impacts of land use change and decision-making for land use planning. However, no single model is able to capture all the essential key processes to explore land use change at different spatial-temporal scales and make a full assessment of driving factors and macro-ecological impacts. Taken Ganzhou District as a case study, this paper describes an integrated analysis (IA) ap- proach by combining with system dynamics (SD) model, the Conversion of Land Use and its Effects at Small regional extent (CLUE-S) model and landscape indices method to analyze land use dynamics at different spatial-temporal scales. The SD model was used to calculate and predict demands for different land use types at the macro-scale as a whole during 2000-2035. The LUCC process was simulated at a high spatial resolution with the spatial consideration of land use spatial policies and restrictions to satisfy the balance between land use demand and supply by using the CLUE-S model, and Kappa values of the map simulation are 0.86 and 0.81 in 2000 and 2005, respectively. Finally, we evaluated the macro-ecological effect of LUCC and optimized sce- nario managements of land use by using landscape indices method. The IA approach could be used for better understanding the complexity of land use change and provide scientific support for land use planning and management, and the simulation results also could be used as a source data for scenario analysis of different hydrological and ecological processes based on different un- derlying surface of LUCC.展开更多
Optimal scale is one of the important issues in ecology and geography.Based on land-use data of the Tarim River Basin in Xinjiang of China in the 1950s,regarding the area of land use types as the parameter in scale se...Optimal scale is one of the important issues in ecology and geography.Based on land-use data of the Tarim River Basin in Xinjiang of China in the 1950s,regarding the area of land use types as the parameter in scale selecting,the histograms of the patches in area are charted.Then,by reinforcing the normalized scale variances(NSV) with 3 landscape indi-ces,the scale characteristics of land use in the Tarim River Basin can be summarized.(1) NSV in the Tarim River up to a maximum at scale of 1:50,000 which is considered appropriate for the Tarim River.(2) Diversity indices of saline land are consistent with NSV's.Diversity indices and NSV of sandy land showed that the appropriate scale is in the same scale domain.There is a significant difference between diversity indices and NSV of forestland and shrub-land.(3) Fractal dimension of sandy land and saline land showed a hierarchical structure at a scale of 1:10,000.Fractal dimension of forestland and shrubland are distributed under the same hierarchical structure in the region.展开更多
Land use change and landscape patterns have a large effect on land productivity and ecosystem biodiversity. Based on geographical information system technology and remote sensing data related to land use and land cove...Land use change and landscape patterns have a large effect on land productivity and ecosystem biodiversity. Based on geographical information system technology and remote sensing data related to land use and land cover of Jiangsu and Zhejiang provinces and Shanghai (Jiang-Zhe-Hu area), we analyzed patterns of landscape change and predicted land use dynamics using the CA-MARKOV model. We also analyzed the conversion rate and area among landscape classes using the CA-Markov model. We found that from 1980 to 2005, there was a significant decrease in the area of farmland, and much of this landscape was transformed into settlements. Most of the landscape classes have become fragmented and isolated. The areas of farmland, settlement land and water tend to be complex in their shape and spatial clustering. The shapes of other land class patches have become simpler, and overall landscape fragmentation has increased. Landscape diversity and heterogeneity have increased. The CAMARKOV model predicted that settlement land will continue to grow from 2005 to 2015, but the speed of conversion will be reduced. The speed of the reduction in farmland and forest has increased, and increased settlement areas are clustered along the Yangtze River. Land use dynamics and change in the landscape pattern have affected land productivity and made the ecosystem more sensitive and fragile in this study region.展开更多
Based on the interpretation and vector processing of remote sensing images in 1985 and 2000, the spatial changes of wetland landscape patterns in Dadu River catchment in the last two decades were studied using spatial...Based on the interpretation and vector processing of remote sensing images in 1985 and 2000, the spatial changes of wetland landscape patterns in Dadu River catchment in the last two decades were studied using spatial analysis method. Supported by Apack soft-ware, the indices of wetland landscape pattern were calculated, and the information entropy (IE) was also introduced to show the changes of wetland landscape information. Results showed that wetland landscape in this region was characteristic of patch-corridor-matrix configuration and dominantly consisted of natural wetlands. Landscape patterns changed a little with low fragment and showed concentrated distribution with partial scattered distribution during the period from 1985 to 2000. The values of patch density and convergence index kept stable, and the values of diversity, evenness indices decrease, while dominance and and IE showed a slight fractal dimension indices were increased. All types of wetland landscapes had higher adjacency probabilities with grassland landscape in 1985 and 2000, and there was extremely weak hydrological link and large spatial gap among river, glacier, reservoir and pond wetlands due to low adjacency matrix values. Since their cumulative contribution exceeded 81% through the PCA analysis, the agriculture activities would be the main driving force to the landscape changes during the past 15 years.展开更多
Two model polygons in the Central Mongolia are considered for investigation of vegetation dynamics. They are located in rainless climatic zones -- arid and semiarid. For the emphasized polygons plots of the NDVI tempo...Two model polygons in the Central Mongolia are considered for investigation of vegetation dynamics. They are located in rainless climatic zones -- arid and semiarid. For the emphasized polygons plots of the NDVI temporal variation and NDVI maps of its multi-temporal values on the base of Landsat TM imagery are constructed. The full-scale landscape indication of the selected NDVI areas with different values with the step through 0.1 is conducted. This indication is supported by the analysis of vegetation to environmental groups for drought resistance. Almost the entire territory of the emphasized polygons vegetation digression during this period was traced. The analysis of the time variation of NDVI shows a decrease of its values. This indicates a trend xerophytization already sparse vegetation of Gobi. In the semiarid climatic zone a digression vegetation trend is directly related to heavy load on the pastures.展开更多
文摘Land use is shaped by the interactions between nature and society, and these interactions can inhibit environmental sustainability and deplete the natural capital that provides the ecosystem services upon which humans depend. Urbanity Index and Landscape Vulnerability Indicator have been proposed to improve the impact interpretability of land use changes on sub-basin sustainability for local scenarios of biodiversity conservation. A time series of LandSat 5 Thematic Mapper remote sensing data from São Carlos municipality, Southeastern Brazil, for the years 1989, 2004 and 2014 revealed that land use changes in the sub-basins do not take place in a progressive and gradual way. Over the 25-year period, the main trends showed the loss and increase of forest cover so that it has remained quantitatively similar over time due to reduced agricultural land use. The aggregation of both indicators enabled the identification of greater naturalness and lower vulnerability, as well as lower naturalness and higher vulnerability under local sub-basin conditions, pointing the need for different strategies for sub-basin biodiversity conservation and sustainability. These preliminary scenarios provide a way to communicate problems of environmental sustainability at different landscape scales to the scientific community as well as to planners, policy makers and the broader public.
基金Under the auspices of Special Science Foundation for Doctoral Subject of Universities,Ministry of Education(No.20020001019)
文摘The Tarim River Basin, located in the typical arid region, is one of the key regions of LUCC research in China and plays an important role in maintaining the sustainable development of the western China. In recent years,the ecological environment of the Tarim River Basin has degraded greatly. In the lower reaches, in particular, the riverbed has been dried up for more than 20 years, which accelerated the desertification and has been a great threat to people′s lives. Taking the section of the Tarim River between Qiala Lake and Taitema Lake as a typical region, an investigation on land cover changes was carried out with the support of remote sensing information of 1988 and 2000 respectively. The changes of land cover in this region were obtained: 1) Cropland tended to increase. 2) Urban or Built-up Area in 2000 was 324.4ha more than that in 1988. 3) Waters expanded by 3476.51ha. 4) Woodland and Grassland decreased, while Barren Land increased by 3824.9ha. The total amount of land use/land cover change between 1988 and 2000 is small,which is only 0.355% of the total area. It shows that the developmental pace of the lower reaches of the Tarim River is relative slow. Based on these results, the authors assessed the landscape dynamics of this region and pointed out that the degree of desertification was strengthened and the landscape dominated by sand land was further characterized by salt desert.
基金Under the auspices of National Natural Science Foundation of China (No.31000223,41071340)National Key Technology Research and Development Program of China (No.2009BADC6B008)Western Light Program of Talent Cultivation of Chinese Academy of Sciences
文摘The responses of spatiotemporal variation of ecosystem service values (ESVs) to landscape pattern from 1985 to 2005 in a typical Karst area of the northwest Guangxi Zhuang Autonomous Region,China,were examined us-ing remote sensing and geographic information system techniques in this paper.The total ecosystem service values de-clined significantly from 1985 to 1990,and then increased slowly from 1990 to 2005,almost equaled to the 1985 level.The ecosystem service values tended to decline from the west to the east and from mountainous regions to peak-cluster depression areas in 1985,1990,2000 and 2005 respectively.During the period from 1985 to 2005,the ecosystem ser-vice values have increased in the middle and eastern parts of the study area.Landscape pattern indices,such as total area,largest patch index,contagion,aggregative index,effective mesh and proportion of like adjacencies,are significantly correlated with ecosystem service values.This suggests that ecosystem service values tend to increase with the growth of patch area and patch connectivity.However,there are negative correlations between ecosystem service values and landscape pattern indices,such as division index and patch richness.It indicates that ecosystem service values decrease with patch fragmentation and patch size shrinkage.The ecosystem conditions in the typical Karst area have been improved because of the control measures of rocky desertification.It is important to protect key landscape types,such as woodland,shrub and grassland,and to increase patch size and connectivity to avoid further fragmentation.Furthermore,it is necessary to reduce disturbances to ensure the growth of ecosystem service values and to facilitate the sustainable development in this region.
基金Funded by the National 11th Five-Year Technology Based PlanTopic of China (No. 2006BAJ05A13)
文摘The aggregation index (AI) is a classical ecology calculation method, which has been widely used for measuring the aggregation level of spatial patterns within a landscape scale in landscape ecological studies. However, it has certain limitions. For instance, identical results can be obtained by AI even when the shape and number of landscape patches are totally different in two landscape units. Furthermore, the value of AI approaches to 1 if the landscape patch is large enough. To solve these problems, a logical limitation of the original AI equation was revised firstly. Secondly, an improved AI-J was developed based on the awareness of the effects of spatial distribution characteristics of patches and changing spatial scale on AI operation. Finally, the accuracy of AI and AI-J results were evaluated through a case study of city green patches in Chengdu, P. R. China. The results show that the calculated result of AI-J is more precise than that of AI and AI-J can be used to compare a certain landscape class under different spatial scales.
基金supported by the National Key R&D Program of China(2022YFF1303101)。
文摘Urban landscape is directly perceived by residents and is a significant symbol of urbanization development.A comprehensive assessment of urban landscapes is crucial for guiding the development of inclusive,resilient,and sustainable cities and human settlements.Previous studies have primarily analyzed two-dimensional landscape indicators derived from satellite remote sensing,potentially overlooking the valuable insights provided by the three-dimensional configuration of landscapes.This limitation arises from the high cost of acquiring large-area three-dimensional data and the lack of effective assessment indicators.Here,we propose four urban landscapes indicators in three dimensions(UL3D):greenness,grayness,openness,and crowding.We construct the UL3D using 4.03 million street view images from 303 major cities in China,employing a deep learning approach.We combine urban background and two-dimensional urban landscape indicators with UL3D to predict the socioeconomic profiles of cities.The results show that UL3D indicators differs from two-dimensional landscape indicators,with a low average correlation coefficient of 0.31 between them.Urban landscapes had a changing point in2018–2019 due to new urbanization initiatives,with grayness and crowding rates slowing,while openness increased.The incorporation of UL3D indicators significantly enhances the explanatory power of the regression model for predicting socioeconomic profiles.Specifically,GDP per capita,urban population rate,built-up area per capita,and hospital count correspond to improvements of 25.0%,19.8%,35.5%,and 19.2%,respectively.These findings indicate that UL3D indicators have the potential to reflect the socioeconomic profiles of cities.
文摘Recent evidence suggests that Brazilian Cerrado has been largely converted, mainly due to agribusiness activities and urbanization. Thus, the present work aimed to obtain the diagnosis of a watershed characterized by the expansion of sugar cane fields in the Brazilian Cerrado (Southeastern), employing integrity landscape indicators (Hemeroby, Urbanity Index, Landscape Vulnerability Index, and Water Quality Index) to verify the landscape naturalness, and the consequences of these actions to the ecosystem services provision. Remote sensing data for the years 1998, 2008, and 2018 were employed to verify the land-use changes in the Feijão River watershed (southeastern Brazil), as well as a matrix that considers the land use typologies and their capability to provide ecosystem services. The study area is classified as mixed land use, with the main categories related to agribusiness (sugar cane, pasture, bare soil). The Hemeroby and Urban Index denote naturalness declines over the years, and the observed patterns negatively impact ecosystem service provision. Landscape Vulnerability Index and Water Quality Index demonstrated that remaining vegetation cannot effectively retain pollutants, and severe impairments in the resilience of natural components of key ecosystem service providers (i.e. water and native vegetation) were observed. The results allowed the identification of priority areas for recovery and the maintenance of ecosystem services in agricultural lands.
基金supported by the National Basic Research Program of China (Contract No. 91125019)National Natural Science Foundation of China (Contract Nos.40971291,40901291)
文摘Land use/cover change (LUCC) models are helpful tools for analyzing driving forces and processes of land use changes, assessing ecological impacts of land use change and decision-making for land use planning. However, no single model is able to capture all the essential key processes to explore land use change at different spatial-temporal scales and make a full assessment of driving factors and macro-ecological impacts. Taken Ganzhou District as a case study, this paper describes an integrated analysis (IA) ap- proach by combining with system dynamics (SD) model, the Conversion of Land Use and its Effects at Small regional extent (CLUE-S) model and landscape indices method to analyze land use dynamics at different spatial-temporal scales. The SD model was used to calculate and predict demands for different land use types at the macro-scale as a whole during 2000-2035. The LUCC process was simulated at a high spatial resolution with the spatial consideration of land use spatial policies and restrictions to satisfy the balance between land use demand and supply by using the CLUE-S model, and Kappa values of the map simulation are 0.86 and 0.81 in 2000 and 2005, respectively. Finally, we evaluated the macro-ecological effect of LUCC and optimized sce- nario managements of land use by using landscape indices method. The IA approach could be used for better understanding the complexity of land use change and provide scientific support for land use planning and management, and the simulation results also could be used as a source data for scenario analysis of different hydrological and ecological processes based on different un- derlying surface of LUCC.
基金National Natural Science Foundation of China,No.40571030No.40730633
文摘Optimal scale is one of the important issues in ecology and geography.Based on land-use data of the Tarim River Basin in Xinjiang of China in the 1950s,regarding the area of land use types as the parameter in scale selecting,the histograms of the patches in area are charted.Then,by reinforcing the normalized scale variances(NSV) with 3 landscape indi-ces,the scale characteristics of land use in the Tarim River Basin can be summarized.(1) NSV in the Tarim River up to a maximum at scale of 1:50,000 which is considered appropriate for the Tarim River.(2) Diversity indices of saline land are consistent with NSV's.Diversity indices and NSV of sandy land showed that the appropriate scale is in the same scale domain.There is a significant difference between diversity indices and NSV of forestland and shrub-land.(3) Fractal dimension of sandy land and saline land showed a hierarchical structure at a scale of 1:10,000.Fractal dimension of forestland and shrubland are distributed under the same hierarchical structure in the region.
基金National Natural Science Foundation of China (41271556)the National Basic Research Priorities Program of China (2007FY110300)
文摘Land use change and landscape patterns have a large effect on land productivity and ecosystem biodiversity. Based on geographical information system technology and remote sensing data related to land use and land cover of Jiangsu and Zhejiang provinces and Shanghai (Jiang-Zhe-Hu area), we analyzed patterns of landscape change and predicted land use dynamics using the CA-MARKOV model. We also analyzed the conversion rate and area among landscape classes using the CA-Markov model. We found that from 1980 to 2005, there was a significant decrease in the area of farmland, and much of this landscape was transformed into settlements. Most of the landscape classes have become fragmented and isolated. The areas of farmland, settlement land and water tend to be complex in their shape and spatial clustering. The shapes of other land class patches have become simpler, and overall landscape fragmentation has increased. Landscape diversity and heterogeneity have increased. The CAMARKOV model predicted that settlement land will continue to grow from 2005 to 2015, but the speed of conversion will be reduced. The speed of the reduction in farmland and forest has increased, and increased settlement areas are clustered along the Yangtze River. Land use dynamics and change in the landscape pattern have affected land productivity and made the ecosystem more sensitive and fragile in this study region.
文摘Based on the interpretation and vector processing of remote sensing images in 1985 and 2000, the spatial changes of wetland landscape patterns in Dadu River catchment in the last two decades were studied using spatial analysis method. Supported by Apack soft-ware, the indices of wetland landscape pattern were calculated, and the information entropy (IE) was also introduced to show the changes of wetland landscape information. Results showed that wetland landscape in this region was characteristic of patch-corridor-matrix configuration and dominantly consisted of natural wetlands. Landscape patterns changed a little with low fragment and showed concentrated distribution with partial scattered distribution during the period from 1985 to 2000. The values of patch density and convergence index kept stable, and the values of diversity, evenness indices decrease, while dominance and and IE showed a slight fractal dimension indices were increased. All types of wetland landscapes had higher adjacency probabilities with grassland landscape in 1985 and 2000, and there was extremely weak hydrological link and large spatial gap among river, glacier, reservoir and pond wetlands due to low adjacency matrix values. Since their cumulative contribution exceeded 81% through the PCA analysis, the agriculture activities would be the main driving force to the landscape changes during the past 15 years.
基金Russian Foundation for Basic Research(120598066r_sibir_a)
文摘Two model polygons in the Central Mongolia are considered for investigation of vegetation dynamics. They are located in rainless climatic zones -- arid and semiarid. For the emphasized polygons plots of the NDVI temporal variation and NDVI maps of its multi-temporal values on the base of Landsat TM imagery are constructed. The full-scale landscape indication of the selected NDVI areas with different values with the step through 0.1 is conducted. This indication is supported by the analysis of vegetation to environmental groups for drought resistance. Almost the entire territory of the emphasized polygons vegetation digression during this period was traced. The analysis of the time variation of NDVI shows a decrease of its values. This indicates a trend xerophytization already sparse vegetation of Gobi. In the semiarid climatic zone a digression vegetation trend is directly related to heavy load on the pastures.