Changes of cultivated land patterns caused by major water conservation projects are rarely reported. We selected the Three Gorges Reservoir area in China to study the change in area and landscape pattern of the cultiv...Changes of cultivated land patterns caused by major water conservation projects are rarely reported. We selected the Three Gorges Reservoir area in China to study the change in area and landscape pattern of the cultivated land in the head,central, and tail areas of the reservoir that took place between 1992 and 2015;we then studied the spatial distribution of the cultivated land in the three parts of the reservoir;finally, we studied the driving forces behind the changes in the cultivated land. The results derived are as follows.(1) During the construction of the Three Gorges Project(TGP, 1992–2015), the area of cultivated land around the reservoir decreased by30.23 million ha. This reduction occurred in phases:the most severe change in cultivated land occurred during the later stage of the project(2002–2010);only 0.62 million ha of cultivated land did not change between 1992 and 2015.(2) Spatial pattern analysis showed that the cultivated land in the three parts of the reservoir changed from a northern distribution to a southern distribution;thus, the area of cultivated land in the north decreased over the time period. The area of cultivated land in the head and tail areas decreased by varying degrees, while it increased in the central area over the 23 years, indicating that the change in cultivated land showed regional differences.(3) The TGP, the policy of reverting farmland to forest,and urbanization were the main driving factors for the change of cultivated land, but there were differences in their impacts at different stages.(4) According to the patch dynamics of the land cover change, the degree of change gradually intensified during the early and later stages of the project and then stabilized during the operational period. Our research provides scientific support for the protection of cultivated land resources and food security in the reservoir area and for the coordination of social and economic development, which is of great significance to sustainable development in the reservoir area.展开更多
An increase in extreme precipitation events due to future climate change will have a decisive influence on the formation of debris flows in earthquake-stricken areas. This paper aimed to describe the possible impacts ...An increase in extreme precipitation events due to future climate change will have a decisive influence on the formation of debris flows in earthquake-stricken areas. This paper aimed to describe the possible impacts of future climate change on debris flow hazards in the Upper Minjiang River basin in Northwest Sichuan of China, which was severely affected by the 2008 Wenchuan earthquake. The study area was divided into 1285 catchments, which were used as the basic assessment units for debris flow hazards. Based on the current understanding of the causes of debris flows, a binary logistic regression model was used to screen key factors based on local geologic, geomorphologic, soil,vegetation, and meteorological and climatic conditions. We used the weighted summation method to obtain a composite index for debris flow hazards, based on two weight allocation methods: Relative Degree Analysis and rough set theory. Our results showed that the assessment model using the rough set theory resulted in better accuracy. According to the bias corrected and downscaled daily climate model data, future annual precipitation(2030-2059) in the study area are expected to decrease, with an increasing number of heavy rainfall events. Under future climate change, areas with a high-level of debris flow hazard will be even more dangerous, and 5.9% more of the study area was categorized as having a high-level hazard. Future climate change will cause an increase in debris flow hazard levels for 128 catchments, accounting for 10.5% of the total area. In the coming few decades, attention should be paid not only to traditional areas with high-level of debris flow hazards, but also to those areas with an increased hazard level to improve their resilience to debris flow disasters.展开更多
Economic losses caused by wild boars(Sus scrofa)continue to increase in the Three Gorges Reservoir Area.We selected 206 farmers in Wuqiaohe Basin as survey respondents using random stratified sampling.The distribution...Economic losses caused by wild boars(Sus scrofa)continue to increase in the Three Gorges Reservoir Area.We selected 206 farmers in Wuqiaohe Basin as survey respondents using random stratified sampling.The distribution and impacts of wild boars were examined using a questionnaire survey and spatial analysis.The results showed that:(1)The density of farmer settlements is low and most peasants’households are located on the forest edge.Due to large-scale labor migration,a high proportion of farmland(25.85%)has been abandoned and an even higher proportion of farmland(40.48%)has been returned to forest.(2)The probability of wild boar damage to peasant households was 67.96%.Yields of corn and sweet potato decreased by 24.87%and 28.24%,respectively,with a total economic loss of approximately 2,590,100 RMB/yr in the Wuqiaohe basin.Sixty-five percent of the affected cultivatedlands were located within approximately 150 m of the forest edges.(3)The wild boar damage coefficient was significantly and negatively correlated with the distance between the peasants’household and the forest edge,the density of the settlements,and the area of cultivated land.The wild boar damage coefficient shows a significant positive correlation with the area of farmland returned to forest.(4)The damage activity caused by wild boars began to occur7-8 years ago,and the destruction has been more frequently and seriously observed in the last 4-5 years.(5)We make suggestions for wild boar control and management measures including developing a compensation policy.The compensation standard is related to the land area returning from farmland to forests and the actual cultivated land area.展开更多
Payment for ecosystem services(PES) has become an increasingly popular means of ecosystem conservation. Opportunity cost is an important factor to increase the investment efficiency of PES projects.However, the distri...Payment for ecosystem services(PES) has become an increasingly popular means of ecosystem conservation. Opportunity cost is an important factor to increase the investment efficiency of PES projects.However, the distribution of opportunity cost is usually unclear in mountainous regions due to the obvious environment changes. In this study, we developed a framework to assess the distribution of agricultural opportunity costs in mountainous regions and applied this method to Baoxing County, a typical mountainous county in Sichuan Province of southwest China. Planting suitability of 17 crops was assessed based on agricultural statistics and natural conditions data within a GIS environment.Agricultural opportunity cost was quantified with a weighted summation of farmers' willingness to cultivate and each crop's opportunity cost. Finally,specific agricultural opportunity cost was obtained according to the spatial areas of the protection programs and land use status. The results showed that agricultural opportunity costs of PES in Baoxing County were estimated to be more than $30 million,with a mean of 400.85 $/ha. Agricultural opportunity costs in mountainous regions displayed some obvious spatial variation and areas with lower agricultural opportunity costs could be selected as priority areas for PES. Our findings revealed that the planting suitability evaluation can make agricultural opportunity costs mapping more reasonable. It will be helpful for the PES programs implementation in mountainous regions.展开更多
Assessing the impact of climate change is important for ecosystem conservation and plant recovery, especially in climate sensitive regions.Various studies suggested that the K?ppen classification is an effective metho...Assessing the impact of climate change is important for ecosystem conservation and plant recovery, especially in climate sensitive regions.Various studies suggested that the K?ppen classification is an effective method to depict climate change. However, these studies were restricted to large scales or of limited accuracy due to uncertainties in climate model projections. In addition, the impact of elevation on the shift of climate zones, as compared with other factors, is less emphasized. To address these issues we compiled the K?ppen Climate Classification(period 1961-2010) for the study area,Sichuan Province, China. The spatial resolution was selected as 1 km × 1 km. Sichuan Province may be characterized by 3 main climate classes and 10 subtypes. The east-west gradient of the climatic regimes in Sichuan is represented by the main climate classes, warm temperate climates(C), snow climates(D) and polar climates(E), at which the most abundant class is C. The most abundant subtype is snow climate with dry winter and cool summer(Dwc).Shifts in K?ppen climate classes reflect the observed trend of increasing temperature. Finally, the elevation showed an obvious impact on the distribution and the change of climate classes in Sichuan Province. Theshift of areas covered by K?ppen climate classes increases with elevation.展开更多
With the accelerated urbanization,human activities pose serious threats to species because of fragmentation.Planning conservation corridors between habitats could improve species mobility in order to address the human...With the accelerated urbanization,human activities pose serious threats to species because of fragmentation.Planning conservation corridors between habitats could improve species mobility in order to address the human disturbance.However,there are a limited number of studies that focus on assessing the effect of human activities on species movement in mountain areas as well as how to integrate different conservation models relating to conservation corridors identification.In our study,we modified the resistance model and took land use data as input parameters to quantify the impacts of human activities in mountain areas.Meanwhile,different conservation planning models,including Circuit model and Least Cost Path(LCP)algorithm,were integrated.Moreover,our approach was applied to identify giant panda corridors in Miarro nature reserve,Caopo nature reserve,and Wolong nature reserve.The results suggested that the impacts of human activities were limited in valley regions due to topography by resistance model.Secondly,Circuit model demonstrated that the conservation corridors for giant panda could not be identified between the Miarro and the Caopo nature reserves.Additionally,more detailed corridors between habitats were planned by the LCP algorithm.Furthermore,we also identified bottlenecks for migration in each corridor,indicating that human activities’interference was the primary cause.Our approach not only could connect habitats for conservation in mountain areas but also found out that the corridor could not be identified between habitats.展开更多
基金funded by the 135 Strategic Program of the Institute of Mountain Hazards and Environment, CAS (Grant No. SDS135-1703)Coupled relationship and regulation mechanism between rural livelihoods and ecosystem services in the Three Gorges Reservoir Area (No.41371539)
文摘Changes of cultivated land patterns caused by major water conservation projects are rarely reported. We selected the Three Gorges Reservoir area in China to study the change in area and landscape pattern of the cultivated land in the head,central, and tail areas of the reservoir that took place between 1992 and 2015;we then studied the spatial distribution of the cultivated land in the three parts of the reservoir;finally, we studied the driving forces behind the changes in the cultivated land. The results derived are as follows.(1) During the construction of the Three Gorges Project(TGP, 1992–2015), the area of cultivated land around the reservoir decreased by30.23 million ha. This reduction occurred in phases:the most severe change in cultivated land occurred during the later stage of the project(2002–2010);only 0.62 million ha of cultivated land did not change between 1992 and 2015.(2) Spatial pattern analysis showed that the cultivated land in the three parts of the reservoir changed from a northern distribution to a southern distribution;thus, the area of cultivated land in the north decreased over the time period. The area of cultivated land in the head and tail areas decreased by varying degrees, while it increased in the central area over the 23 years, indicating that the change in cultivated land showed regional differences.(3) The TGP, the policy of reverting farmland to forest,and urbanization were the main driving factors for the change of cultivated land, but there were differences in their impacts at different stages.(4) According to the patch dynamics of the land cover change, the degree of change gradually intensified during the early and later stages of the project and then stabilized during the operational period. Our research provides scientific support for the protection of cultivated land resources and food security in the reservoir area and for the coordination of social and economic development, which is of great significance to sustainable development in the reservoir area.
基金jointly funded by the 135 Strategic Program of the Institute of Mountain Hazards and Environment,CAS(Grant No.SDS135-1703)the National Key Basic Research Program of China(973 program)(Grant No.2015CB452702)
文摘An increase in extreme precipitation events due to future climate change will have a decisive influence on the formation of debris flows in earthquake-stricken areas. This paper aimed to describe the possible impacts of future climate change on debris flow hazards in the Upper Minjiang River basin in Northwest Sichuan of China, which was severely affected by the 2008 Wenchuan earthquake. The study area was divided into 1285 catchments, which were used as the basic assessment units for debris flow hazards. Based on the current understanding of the causes of debris flows, a binary logistic regression model was used to screen key factors based on local geologic, geomorphologic, soil,vegetation, and meteorological and climatic conditions. We used the weighted summation method to obtain a composite index for debris flow hazards, based on two weight allocation methods: Relative Degree Analysis and rough set theory. Our results showed that the assessment model using the rough set theory resulted in better accuracy. According to the bias corrected and downscaled daily climate model data, future annual precipitation(2030-2059) in the study area are expected to decrease, with an increasing number of heavy rainfall events. Under future climate change, areas with a high-level of debris flow hazard will be even more dangerous, and 5.9% more of the study area was categorized as having a high-level hazard. Future climate change will cause an increase in debris flow hazard levels for 128 catchments, accounting for 10.5% of the total area. In the coming few decades, attention should be paid not only to traditional areas with high-level of debris flow hazards, but also to those areas with an increased hazard level to improve their resilience to debris flow disasters.
基金supported by the 135 strategic program of the institute of mountain hazards and environment, CAS (NO. SDS-135-1703)national natural science foundation of China (No. 41401664)
文摘Economic losses caused by wild boars(Sus scrofa)continue to increase in the Three Gorges Reservoir Area.We selected 206 farmers in Wuqiaohe Basin as survey respondents using random stratified sampling.The distribution and impacts of wild boars were examined using a questionnaire survey and spatial analysis.The results showed that:(1)The density of farmer settlements is low and most peasants’households are located on the forest edge.Due to large-scale labor migration,a high proportion of farmland(25.85%)has been abandoned and an even higher proportion of farmland(40.48%)has been returned to forest.(2)The probability of wild boar damage to peasant households was 67.96%.Yields of corn and sweet potato decreased by 24.87%and 28.24%,respectively,with a total economic loss of approximately 2,590,100 RMB/yr in the Wuqiaohe basin.Sixty-five percent of the affected cultivatedlands were located within approximately 150 m of the forest edges.(3)The wild boar damage coefficient was significantly and negatively correlated with the distance between the peasants’household and the forest edge,the density of the settlements,and the area of cultivated land.The wild boar damage coefficient shows a significant positive correlation with the area of farmland returned to forest.(4)The damage activity caused by wild boars began to occur7-8 years ago,and the destruction has been more frequently and seriously observed in the last 4-5 years.(5)We make suggestions for wild boar control and management measures including developing a compensation policy.The compensation standard is related to the land area returning from farmland to forests and the actual cultivated land area.
基金funded by National Natural Science Foundation of China(Grant Nos.41371539)Western Light Talent Culture Project:Standard of Payment for Ecosystem Service based on GISGEF(Global Environment Fund)Project:Payment for Watershed Services in the Chishui River Basin for the Conservation of Globally Significant Biodiversity(Grant Nos.00089388)
文摘Payment for ecosystem services(PES) has become an increasingly popular means of ecosystem conservation. Opportunity cost is an important factor to increase the investment efficiency of PES projects.However, the distribution of opportunity cost is usually unclear in mountainous regions due to the obvious environment changes. In this study, we developed a framework to assess the distribution of agricultural opportunity costs in mountainous regions and applied this method to Baoxing County, a typical mountainous county in Sichuan Province of southwest China. Planting suitability of 17 crops was assessed based on agricultural statistics and natural conditions data within a GIS environment.Agricultural opportunity cost was quantified with a weighted summation of farmers' willingness to cultivate and each crop's opportunity cost. Finally,specific agricultural opportunity cost was obtained according to the spatial areas of the protection programs and land use status. The results showed that agricultural opportunity costs of PES in Baoxing County were estimated to be more than $30 million,with a mean of 400.85 $/ha. Agricultural opportunity costs in mountainous regions displayed some obvious spatial variation and areas with lower agricultural opportunity costs could be selected as priority areas for PES. Our findings revealed that the planting suitability evaluation can make agricultural opportunity costs mapping more reasonable. It will be helpful for the PES programs implementation in mountainous regions.
基金partly funded by The national ecological environment ten years (2000-2010) change remote sensing survey and evaluation project--Chengdu-Chongqing urban agglomeration ecological environment situation and ten years change investigation and assessment (Project No. STSN-12-05)Sino-Norwegian Biodiversity and Climate Change Project (Grant No. C/IV/S//11/242-02)
文摘Assessing the impact of climate change is important for ecosystem conservation and plant recovery, especially in climate sensitive regions.Various studies suggested that the K?ppen classification is an effective method to depict climate change. However, these studies were restricted to large scales or of limited accuracy due to uncertainties in climate model projections. In addition, the impact of elevation on the shift of climate zones, as compared with other factors, is less emphasized. To address these issues we compiled the K?ppen Climate Classification(period 1961-2010) for the study area,Sichuan Province, China. The spatial resolution was selected as 1 km × 1 km. Sichuan Province may be characterized by 3 main climate classes and 10 subtypes. The east-west gradient of the climatic regimes in Sichuan is represented by the main climate classes, warm temperate climates(C), snow climates(D) and polar climates(E), at which the most abundant class is C. The most abundant subtype is snow climate with dry winter and cool summer(Dwc).Shifts in K?ppen climate classes reflect the observed trend of increasing temperature. Finally, the elevation showed an obvious impact on the distribution and the change of climate classes in Sichuan Province. Theshift of areas covered by K?ppen climate classes increases with elevation.
基金funded by National Nature Science Foundation of China(Grant No.41701114)the West Light Foundation of The Chinese Academy of Sciences(Grant No.Y7R280080)the Research on Conservation and Breeding of Plant Diversity in Giant Panda National Park(Grant No.2018SZDZX0035)
文摘With the accelerated urbanization,human activities pose serious threats to species because of fragmentation.Planning conservation corridors between habitats could improve species mobility in order to address the human disturbance.However,there are a limited number of studies that focus on assessing the effect of human activities on species movement in mountain areas as well as how to integrate different conservation models relating to conservation corridors identification.In our study,we modified the resistance model and took land use data as input parameters to quantify the impacts of human activities in mountain areas.Meanwhile,different conservation planning models,including Circuit model and Least Cost Path(LCP)algorithm,were integrated.Moreover,our approach was applied to identify giant panda corridors in Miarro nature reserve,Caopo nature reserve,and Wolong nature reserve.The results suggested that the impacts of human activities were limited in valley regions due to topography by resistance model.Secondly,Circuit model demonstrated that the conservation corridors for giant panda could not be identified between the Miarro and the Caopo nature reserves.Additionally,more detailed corridors between habitats were planned by the LCP algorithm.Furthermore,we also identified bottlenecks for migration in each corridor,indicating that human activities’interference was the primary cause.Our approach not only could connect habitats for conservation in mountain areas but also found out that the corridor could not be identified between habitats.
