The paper discusses methods to compensate for the costs incurred in the supply of forest ecological services (FES), i.e. government dominated and market-based instruments as well as progress made so far in China. Fa...The paper discusses methods to compensate for the costs incurred in the supply of forest ecological services (FES), i.e. government dominated and market-based instruments as well as progress made so far in China. Factors which constrain the supply of these services and potential policy improvements are presented.展开更多
The report of the 19th National Congress of the Communist Party of China stated that it was necessary to establish and practice the concept that lucid waters and lush mountains are invaluable assets,treat the ecologic...The report of the 19th National Congress of the Communist Party of China stated that it was necessary to establish and practice the concept that lucid waters and lush mountains are invaluable assets,treat the ecological environment as life,and coordinate the management of mountains,rivers,forests,farmlands,lakes and grasslands.In recent years,China has organized a series of pilot projects for the ecological protection and restoration of mountains,rivers,forests,farmlands,lakes and grasslands,breaking the boundary between administrative divisions,departmental management and ecological elements,and implementing conservation and restoration oriented towards the improvement of ecosystem services,so as to solve the problem of the lack of overall planning for ecological protection and restoration projects and the separated management of ecological elements.This study systematically elaborated the theoretical basis and connotation characteristics of ecological protection and restoration of mountains,rivers,forests,farmlands,lakes and grasslands.It proposed the implementation path of ecological protection and restoration project of mountains,rivers,forests,farmlands,lakes and grasslands by taking the water source conservation area of Beijing-Tianjin-Hebei as a case,so as to provide reference for the implementation and decision-making management of ecological protection and restoration projects in various regions.展开更多
Background:Forests contribute to human wellbeing through the provision of important ecosystem services.Methods:In this study,we investigated how the perceived importance of ecosystem services may impact the overall ...Background:Forests contribute to human wellbeing through the provision of important ecosystem services.Methods:In this study,we investigated how the perceived importance of ecosystem services may impact the overall benefit provided by managed watersheds at the Hubbard Brook Experimental Forest over a 45-year period,using standardized measures of service capacity weighted by service importance weights derived from a survey of beneficiaries.Results:The capacity of watersheds to regulate water flow and quality was high in all watersheds throughout the study period,whereas cultural services such as scenic beauty declined after harvest.Impacts on greenhouse gas regulation depended on the efficiency with which harvested biomass was used.Surveys revealed that stakeholders placed high value on all ecosystem services,with regulating and cultural services seen as more important than provisioning services.When service metrics were weighted by survey responses and aggregated into a single measure,total service provision followed the same overall trend as greenhouse gas regulation.Where biomass use was less efficient in terms of greenhouse gas emissions,harvesting resulted in an overall "ecosystem service debt";where use was more efficient,this "ecosystem service debt" was reduced.Beneficiaries' educational backgrounds significantly affected overall assessment of service provision.Beneficiaries with college or university degrees incurred smaller "ecosystem service debts" and were less negatively affected by harvesting overall.Conclusions:This study highlights the importance of including empirical measures of beneficiary preference when attempting to quantify overall provision of ecosystem services to human beneficiaries over time.展开更多
This paper presents a study on species diversity and its ecological service function in the plateau area in western Sichuan. The results show that species diversity in the plantations on the cutover land has a tendenc...This paper presents a study on species diversity and its ecological service function in the plateau area in western Sichuan. The results show that species diversity in the plantations on the cutover land has a tendency to increase and that its ecological service function is to be improved with stand age growing. The species diversity in forest communities is also gradually increased on different succession stage till reaching a climax level. But the species diversity in the climax community is slightly decreased before it reaches a relatively constant status. Ecological service function of diversity is gradually strengthened with the progress of succession. In addition, species diversity in a stand in a similar site and at a same age differs among forest types. Species diversity index within a coniferous and broad-leaved mixed forest is larger than that within a coniferous forest. Meanwhile, species diversity enriches as the tree density increases.展开更多
This methodological investigation deals with measurement and valuation of ecological service functions for urban green space. Social, economic and ecological dimensions for such types of function were analyzed and a ...This methodological investigation deals with measurement and valuation of ecological service functions for urban green space. Social, economic and ecological dimensions for such types of function were analyzed and a concept “integrated ecological service functions” (IESF) was put forward for evaluation. Based upon this conceptual approach, an index system for measuring IESF for urban green space was established. With a methodological integration of fuzzy mathematics, decision making analysis and Delphi method, an AHP fuzzy evaluation techniques for IESF for urban green space, called AFIFUG method, was developed. Such a method has been directly applied to the land use strategic planning of Tianjin out ring green belt(TOGB), and its analysis results have been successfully put into operation.展开更多
Net Primary Productivity (NPP) is the basis of the material and energy transport calculation in ecosystem studies. NPP directly reflects the production capacity of plant communities under natural conditions. Ecosystem...Net Primary Productivity (NPP) is the basis of the material and energy transport calculation in ecosystem studies. NPP directly reflects the production capacity of plant communities under natural conditions. Ecosystem services are hot topics in the field of ecology. Many studies calculate ecosystem service value based on NPP. Taking Guanshanhu District of Guiyang City, Guizhou Province as the research object, using TM, ETM<sup>+</sup>, Gaofen2 and MOD17A3HGF.006 as data sources, this paper analyzed the change of ecosystem service value based on NPP in 2000, 2010 and 2020. The results showed that the area of forest ecosystem increased during 2000-2010 and decreased during 2010-2020. The artificial surface grew rapidly from 1146.82 hm<sup>2</sup> to 7544.29 hm<sup>2</sup> during 2000-2020. The farmland ecosystem decreased from 13308.29 hm<sup>2</sup> to 6342.33 hm<sup>2</sup> during 2000-2020. With the dynamic changes in ecosystem spatial distribution and component structure, the total NPP in 2000, 2010 and 2020 was 12.58 × 10<sup>4</sup> t, 11.90 × 10<sup>4</sup> t and 11.78 × 10<sup>4</sup> t, respectively, showing a decreasing trend. The total value of natural and semi-natural ecosystems services based on NPP showed an increasing trend, which was ¥ 6.938 × 10<sup>8</sup> in 2000, ¥ 8.052 × 10<sup>8</sup> in 2010 and ¥ 10.306 × 10<sup>8</sup> in 2020 respectively. The ecosystem contributed the most to the ecological service value in 2000 was farmland, but in 2010 and 2020, it was the forest ecosystem. The ecological service value of grassland and wetland was relatively small, while the ratio of the wetland ecological service value displayed a decreasing trend. In the future, it is necessary to establish a strict pretrial system for land use, so as to effectively protect the natural and semi-natural ecosystems and fulfill the growing ecological demands of residents.展开更多
Osmia solitary bees are important pollinators of various crops worldwide.Refrigeration has been widely used to synchronize the emergence time of Osmia species from cocoons with the blooming time of different crops,but...Osmia solitary bees are important pollinators of various crops worldwide.Refrigeration has been widely used to synchronize the emergence time of Osmia species from cocoons with the blooming time of different crops,but the fitness of Osmia after refrigeration remains unknown.Here,the effects of long-term refrigeration at 0℃on the vitality,flight ability,and metabolism of Osmia excavata,which is known as the"king of pollination"in China,were studied.The survival rate(>90%before 120 d),weight loss rate(<15%after 170 d),and mean flight speed of 0.excavata were not greatly affected after long-term refrigeration.The content of fats,which have antifreeze and energy storage properties,was not significantly altered in O.excavata before 130 d of refrigeration,which might explain why the survival rates and flight speed of O.excavata remained high after long-term refrigeration.However,the flight duration and distance decreased significantly(P<0.05),and both were positively correlated with the reduced trehalose levels in 0.excavata(r=[+0.69]-[+0.71];P<0.05).Overall,these findings indicate that the pollination potential of O.excavata for various crops with different flowering periods is high after long-term refrigeration;however,long-term refrigeration may decrease pollination efficiency.Our findings highlight new research directions that could improve the ecological service function of refrigerated O.excavata.展开更多
Climate change and rapid urbanization pose significant challenges to the conservation and management of agricultural heritage systems,including decline in agricultural land,loss of labor,and ecosystem degradation.Alth...Climate change and rapid urbanization pose significant challenges to the conservation and management of agricultural heritage systems,including decline in agricultural land,loss of labor,and ecosystem degradation.Although existing studies have proposed general strategies with theoretical guidance and specific strategies for particular systems to promote the conservation of agricultural heritage systems,there remains a large knowledge gap in effective and differentiated management strategies at the regional level.This is especially so in China because of the clear regional differences in the natural and socioeconomic conditions of the widely distributed China Nationally Important Agricultural Heritage Systems(China-NIAHS).In this study,we integrated multi-source data and spatial analysis to reveal the distribution characteristics of existing China-NIAHS and proposed differentiated management strategies.Results show that there are four clustering distribution zones of China-NIAHS,i.e.,the northwest clustering zone west of the Heihe-Tengchong Line(ZoneⅠ),the clustering belt with‘Northeast-Hebei-Shandong'as core(ZoneⅡ),the Yangtze River Delta clustering zone(ZoneⅢ),and the Hunan-Chongqing-Yunnan-Guizhou clustering zone(ZoneⅣ).Different management strategies are proposed for the China-NIAHS in each clustering zone.Specifically,ZoneⅠshould focus on maintaining their ecological functions and services,while ZoneⅡshould aim for livelihood supply,sustainable resource use,and ecological protection.For ZoneⅢ,rapid urbanization could become a positive driving force for China-NIAHS conservation through sustainable tourism and reasonable urban zoning.ZoneⅣshould emphasize the mutual support between characteristic product development and the brand effect of the China-NIAHS.These findings will help establish regional and targeted management strategies for China-NIAHS and provide a reference for the conservation of agricultural heritage systems in other countries.展开更多
Grassland is the largest ecosystem on the Qinghai–Tibetan Plateau(QTP)and provides multiple ecosystem functions and services.Understanding the endowment of the QTP grassland and how to revitalize it have profound imp...Grassland is the largest ecosystem on the Qinghai–Tibetan Plateau(QTP)and provides multiple ecosystem functions and services.Understanding the endowment of the QTP grassland and how to revitalize it have profound implications for the sustainable use and efficient conservation of these unique and globally valuable ecosystems.In this paper,we highlight the importance of the QTP grassland in regional and global settings,stress the values of the QTP grassland in ecological and socioeconomic dimensions,and emphasize the actions needed to restore degraded grassland in the QTP region.The QTP is the largest single area of alpine grassland in the world and an important gene pool of alpine biological resources.The QTP grassland covers two critical ecoregions for conserving the best and most representative habitats for alpine biodiversity on the planet.The QTP grassland is also regarded as one of the best carriers and objects of socio-ecological systems in the world.To promote the resilience and sustainability of the QTP grassland through adaptation,different parties need to work together tofind feasible options to resist shock,stresses,and disturbance and to maintain the fundamental functions and basic structures of the QTP grassland.展开更多
Introduction:Public urban parks are accessible to everyone in a city.The time people need to reach a public park influences the accessibility of the park.Parks far away from home are less accessible because of time to...Introduction:Public urban parks are accessible to everyone in a city.The time people need to reach a public park influences the accessibility of the park.Parks far away from home are less accessible because of time to spend to reach them than those in the neighborhood.Good green urban infrastructure aims to provide different types of parks(by size and structure)to all urban dwellers.The network of parks should allow all inhabitants to have access to parks within close proximity to their residences.Methods:This paper aims to investigate the accessibility of parks as related to the social status of the inhabitants.This was investigated using the example of a clearly socially stratified city(Tabriz,Iran),in which a part of the urban society(by total number and social status)has better or worse access to urban parks.The example of urban parks shows which services are supplied on site and who the potential users are within an accessible distance.The services are qualified by structural park indicators and quantified by the quantity of these indicators.The distances are calculated on the basis of the size of the parks.Different distance circles around the parks indicate from where most of the users are coming,depending on park category.A quantification of population as related to potential users by social status in different distances to the parks shows the accessibility of parks for different quantities of inhabitants and different social strata.The classification of social status(high,middle,and low)was carried out by General Census of statistical center in 2005,informal settlement project data,statistical blocks data,land price in Tabriz municipality,and master and detailed plan reports.Results:Many households do not enjoy government recommended levels of access to public green spaces in Tabriz,and the results highlight the social segregation in park distribution and their accessibility.Conclusions:The best parks are located in the high social status areas,and the accessibility is the best among all societal levels.展开更多
Crop straw is an important natural resource in China because it is rich in nutrients.When returned to fields after harvests,the straw can improve soil quality and the next crop’s yield.Evaluating the economic values ...Crop straw is an important natural resource in China because it is rich in nutrients.When returned to fields after harvests,the straw can improve soil quality and the next crop’s yield.Evaluating the economic values of the main ecological services of a farmland ecosystem while implementing the straw return technique can be a more systematic and comprehensive approach to better understand the contribution of straw return to the development of ecological agriculture.Based on the data of a field experiment established in 2010 with varying numbers of years of straw return,four ecological services,i.e.,agricultural product and industrial raw materials,atmospheric regulation and purification,soil nutrient accumulation,and water conservation,were selected to estimate a net ecosystem service value(ESV)of a wheat field’s ecosystem services.Agro-ecosystem service appraisal theories were applied to estimate the economic value of each service.Results showed that straw returning improved the total ESV in the wheat system.Compared to the no straw return treatment,1 year,3 years,5 years or 7 years of straw returning altered the economic value of the agricultural product and industrial raw materials(EVAIM)by-5.93%to 7.84%and improved atmospheric regulation(EVAR)by 13.66%-30.80%,soil nutrient accumulation(EVSNA)by 59.87%-233.31%and water conservation(EVWC)by 2.60%-13.26%.The total ESV of wheat plots with 1-7 years of straw returning was 3.67%-27.41%higher than that with no straw return,and the total ESV increased with the increase in years of straw return.The proportion of EVAIM out of the total ESV in this wheat field system was highest(accounted for 47.09%-55.64%),followed by EVAR and EVWC.The value of EVSNA was the lowest.However,the proportion of EVSNA was higher than that of water conservation after the fifth year of straw return.In general,the adoption of continuous straw returning in a wheat field ecosystem is ecologically valuable.The results can inform the development and implementation of ecological compensation policies involving straw return.展开更多
文摘The paper discusses methods to compensate for the costs incurred in the supply of forest ecological services (FES), i.e. government dominated and market-based instruments as well as progress made so far in China. Factors which constrain the supply of these services and potential policy improvements are presented.
文摘The report of the 19th National Congress of the Communist Party of China stated that it was necessary to establish and practice the concept that lucid waters and lush mountains are invaluable assets,treat the ecological environment as life,and coordinate the management of mountains,rivers,forests,farmlands,lakes and grasslands.In recent years,China has organized a series of pilot projects for the ecological protection and restoration of mountains,rivers,forests,farmlands,lakes and grasslands,breaking the boundary between administrative divisions,departmental management and ecological elements,and implementing conservation and restoration oriented towards the improvement of ecosystem services,so as to solve the problem of the lack of overall planning for ecological protection and restoration projects and the separated management of ecological elements.This study systematically elaborated the theoretical basis and connotation characteristics of ecological protection and restoration of mountains,rivers,forests,farmlands,lakes and grasslands.It proposed the implementation path of ecological protection and restoration project of mountains,rivers,forests,farmlands,lakes and grasslands by taking the water source conservation area of Beijing-Tianjin-Hebei as a case,so as to provide reference for the implementation and decision-making management of ecological protection and restoration projects in various regions.
基金support from the USDA Forest Service's Northeastern States Research Cooperative(NSRC)in collaboration with the Hubbard Brook Research Foundationthe Cary Institute of Ecosystem Studies
文摘Background:Forests contribute to human wellbeing through the provision of important ecosystem services.Methods:In this study,we investigated how the perceived importance of ecosystem services may impact the overall benefit provided by managed watersheds at the Hubbard Brook Experimental Forest over a 45-year period,using standardized measures of service capacity weighted by service importance weights derived from a survey of beneficiaries.Results:The capacity of watersheds to regulate water flow and quality was high in all watersheds throughout the study period,whereas cultural services such as scenic beauty declined after harvest.Impacts on greenhouse gas regulation depended on the efficiency with which harvested biomass was used.Surveys revealed that stakeholders placed high value on all ecosystem services,with regulating and cultural services seen as more important than provisioning services.When service metrics were weighted by survey responses and aggregated into a single measure,total service provision followed the same overall trend as greenhouse gas regulation.Where biomass use was less efficient in terms of greenhouse gas emissions,harvesting resulted in an overall "ecosystem service debt";where use was more efficient,this "ecosystem service debt" was reduced.Beneficiaries' educational backgrounds significantly affected overall assessment of service provision.Beneficiaries with college or university degrees incurred smaller "ecosystem service debts" and were less negatively affected by harvesting overall.Conclusions:This study highlights the importance of including empirical measures of beneficiary preference when attempting to quantify overall provision of ecosystem services to human beneficiaries over time.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Scicnces(KZCX2-SW-319-4)
文摘This paper presents a study on species diversity and its ecological service function in the plateau area in western Sichuan. The results show that species diversity in the plantations on the cutover land has a tendency to increase and that its ecological service function is to be improved with stand age growing. The species diversity in forest communities is also gradually increased on different succession stage till reaching a climax level. But the species diversity in the climax community is slightly decreased before it reaches a relatively constant status. Ecological service function of diversity is gradually strengthened with the progress of succession. In addition, species diversity in a stand in a similar site and at a same age differs among forest types. Species diversity index within a coniferous and broad-leaved mixed forest is larger than that within a coniferous forest. Meanwhile, species diversity enriches as the tree density increases.
文摘This methodological investigation deals with measurement and valuation of ecological service functions for urban green space. Social, economic and ecological dimensions for such types of function were analyzed and a concept “integrated ecological service functions” (IESF) was put forward for evaluation. Based upon this conceptual approach, an index system for measuring IESF for urban green space was established. With a methodological integration of fuzzy mathematics, decision making analysis and Delphi method, an AHP fuzzy evaluation techniques for IESF for urban green space, called AFIFUG method, was developed. Such a method has been directly applied to the land use strategic planning of Tianjin out ring green belt(TOGB), and its analysis results have been successfully put into operation.
文摘Net Primary Productivity (NPP) is the basis of the material and energy transport calculation in ecosystem studies. NPP directly reflects the production capacity of plant communities under natural conditions. Ecosystem services are hot topics in the field of ecology. Many studies calculate ecosystem service value based on NPP. Taking Guanshanhu District of Guiyang City, Guizhou Province as the research object, using TM, ETM<sup>+</sup>, Gaofen2 and MOD17A3HGF.006 as data sources, this paper analyzed the change of ecosystem service value based on NPP in 2000, 2010 and 2020. The results showed that the area of forest ecosystem increased during 2000-2010 and decreased during 2010-2020. The artificial surface grew rapidly from 1146.82 hm<sup>2</sup> to 7544.29 hm<sup>2</sup> during 2000-2020. The farmland ecosystem decreased from 13308.29 hm<sup>2</sup> to 6342.33 hm<sup>2</sup> during 2000-2020. With the dynamic changes in ecosystem spatial distribution and component structure, the total NPP in 2000, 2010 and 2020 was 12.58 × 10<sup>4</sup> t, 11.90 × 10<sup>4</sup> t and 11.78 × 10<sup>4</sup> t, respectively, showing a decreasing trend. The total value of natural and semi-natural ecosystems services based on NPP showed an increasing trend, which was ¥ 6.938 × 10<sup>8</sup> in 2000, ¥ 8.052 × 10<sup>8</sup> in 2010 and ¥ 10.306 × 10<sup>8</sup> in 2020 respectively. The ecosystem contributed the most to the ecological service value in 2000 was farmland, but in 2010 and 2020, it was the forest ecosystem. The ecological service value of grassland and wetland was relatively small, while the ratio of the wetland ecological service value displayed a decreasing trend. In the future, it is necessary to establish a strict pretrial system for land use, so as to effectively protect the natural and semi-natural ecosystems and fulfill the growing ecological demands of residents.
基金supported by the Bee Industry Innovation Team of Shandong Province,National Natural Science Foundation of China(32202316)Agricultural Science and Technology Innovation Project of Shandong Academy of Agricultural Sciences(CXGC2023D01,CXGC2023F04).
文摘Osmia solitary bees are important pollinators of various crops worldwide.Refrigeration has been widely used to synchronize the emergence time of Osmia species from cocoons with the blooming time of different crops,but the fitness of Osmia after refrigeration remains unknown.Here,the effects of long-term refrigeration at 0℃on the vitality,flight ability,and metabolism of Osmia excavata,which is known as the"king of pollination"in China,were studied.The survival rate(>90%before 120 d),weight loss rate(<15%after 170 d),and mean flight speed of 0.excavata were not greatly affected after long-term refrigeration.The content of fats,which have antifreeze and energy storage properties,was not significantly altered in O.excavata before 130 d of refrigeration,which might explain why the survival rates and flight speed of O.excavata remained high after long-term refrigeration.However,the flight duration and distance decreased significantly(P<0.05),and both were positively correlated with the reduced trehalose levels in 0.excavata(r=[+0.69]-[+0.71];P<0.05).Overall,these findings indicate that the pollination potential of O.excavata for various crops with different flowering periods is high after long-term refrigeration;however,long-term refrigeration may decrease pollination efficiency.Our findings highlight new research directions that could improve the ecological service function of refrigerated O.excavata.
基金Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA23100203。
文摘Climate change and rapid urbanization pose significant challenges to the conservation and management of agricultural heritage systems,including decline in agricultural land,loss of labor,and ecosystem degradation.Although existing studies have proposed general strategies with theoretical guidance and specific strategies for particular systems to promote the conservation of agricultural heritage systems,there remains a large knowledge gap in effective and differentiated management strategies at the regional level.This is especially so in China because of the clear regional differences in the natural and socioeconomic conditions of the widely distributed China Nationally Important Agricultural Heritage Systems(China-NIAHS).In this study,we integrated multi-source data and spatial analysis to reveal the distribution characteristics of existing China-NIAHS and proposed differentiated management strategies.Results show that there are four clustering distribution zones of China-NIAHS,i.e.,the northwest clustering zone west of the Heihe-Tengchong Line(ZoneⅠ),the clustering belt with‘Northeast-Hebei-Shandong'as core(ZoneⅡ),the Yangtze River Delta clustering zone(ZoneⅢ),and the Hunan-Chongqing-Yunnan-Guizhou clustering zone(ZoneⅣ).Different management strategies are proposed for the China-NIAHS in each clustering zone.Specifically,ZoneⅠshould focus on maintaining their ecological functions and services,while ZoneⅡshould aim for livelihood supply,sustainable resource use,and ecological protection.For ZoneⅢ,rapid urbanization could become a positive driving force for China-NIAHS conservation through sustainable tourism and reasonable urban zoning.ZoneⅣshould emphasize the mutual support between characteristic product development and the brand effect of the China-NIAHS.These findings will help establish regional and targeted management strategies for China-NIAHS and provide a reference for the conservation of agricultural heritage systems in other countries.
基金National Key R&D Program of China,Grant/Award Number:2021YFE0112400National Science Foundation of China,Grant/Award Number:U20A2007-01Second Tibetan Plateau Scientific Expedition and Research Program,Grant/Award Number:2019QZKK0307。
文摘Grassland is the largest ecosystem on the Qinghai–Tibetan Plateau(QTP)and provides multiple ecosystem functions and services.Understanding the endowment of the QTP grassland and how to revitalize it have profound implications for the sustainable use and efficient conservation of these unique and globally valuable ecosystems.In this paper,we highlight the importance of the QTP grassland in regional and global settings,stress the values of the QTP grassland in ecological and socioeconomic dimensions,and emphasize the actions needed to restore degraded grassland in the QTP region.The QTP is the largest single area of alpine grassland in the world and an important gene pool of alpine biological resources.The QTP grassland covers two critical ecoregions for conserving the best and most representative habitats for alpine biodiversity on the planet.The QTP grassland is also regarded as one of the best carriers and objects of socio-ecological systems in the world.To promote the resilience and sustainability of the QTP grassland through adaptation,different parties need to work together tofind feasible options to resist shock,stresses,and disturbance and to maintain the fundamental functions and basic structures of the QTP grassland.
文摘Introduction:Public urban parks are accessible to everyone in a city.The time people need to reach a public park influences the accessibility of the park.Parks far away from home are less accessible because of time to spend to reach them than those in the neighborhood.Good green urban infrastructure aims to provide different types of parks(by size and structure)to all urban dwellers.The network of parks should allow all inhabitants to have access to parks within close proximity to their residences.Methods:This paper aims to investigate the accessibility of parks as related to the social status of the inhabitants.This was investigated using the example of a clearly socially stratified city(Tabriz,Iran),in which a part of the urban society(by total number and social status)has better or worse access to urban parks.The example of urban parks shows which services are supplied on site and who the potential users are within an accessible distance.The services are qualified by structural park indicators and quantified by the quantity of these indicators.The distances are calculated on the basis of the size of the parks.Different distance circles around the parks indicate from where most of the users are coming,depending on park category.A quantification of population as related to potential users by social status in different distances to the parks shows the accessibility of parks for different quantities of inhabitants and different social strata.The classification of social status(high,middle,and low)was carried out by General Census of statistical center in 2005,informal settlement project data,statistical blocks data,land price in Tabriz municipality,and master and detailed plan reports.Results:Many households do not enjoy government recommended levels of access to public green spaces in Tabriz,and the results highlight the social segregation in park distribution and their accessibility.Conclusions:The best parks are located in the high social status areas,and the accessibility is the best among all societal levels.
基金This work was partially supported by A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),the National Key R&D Program of China(Grant No.2018YFD0200500)the Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences(Agricultural Academy Office(2014)No.216)+1 种基金and the Fundamental Research Funds for the Central Public Research Institutes(Grant No.S202010-02)The authors acknowledge the anonymous reviewers for their insightful comments on the manuscript.
文摘Crop straw is an important natural resource in China because it is rich in nutrients.When returned to fields after harvests,the straw can improve soil quality and the next crop’s yield.Evaluating the economic values of the main ecological services of a farmland ecosystem while implementing the straw return technique can be a more systematic and comprehensive approach to better understand the contribution of straw return to the development of ecological agriculture.Based on the data of a field experiment established in 2010 with varying numbers of years of straw return,four ecological services,i.e.,agricultural product and industrial raw materials,atmospheric regulation and purification,soil nutrient accumulation,and water conservation,were selected to estimate a net ecosystem service value(ESV)of a wheat field’s ecosystem services.Agro-ecosystem service appraisal theories were applied to estimate the economic value of each service.Results showed that straw returning improved the total ESV in the wheat system.Compared to the no straw return treatment,1 year,3 years,5 years or 7 years of straw returning altered the economic value of the agricultural product and industrial raw materials(EVAIM)by-5.93%to 7.84%and improved atmospheric regulation(EVAR)by 13.66%-30.80%,soil nutrient accumulation(EVSNA)by 59.87%-233.31%and water conservation(EVWC)by 2.60%-13.26%.The total ESV of wheat plots with 1-7 years of straw returning was 3.67%-27.41%higher than that with no straw return,and the total ESV increased with the increase in years of straw return.The proportion of EVAIM out of the total ESV in this wheat field system was highest(accounted for 47.09%-55.64%),followed by EVAR and EVWC.The value of EVSNA was the lowest.However,the proportion of EVSNA was higher than that of water conservation after the fifth year of straw return.In general,the adoption of continuous straw returning in a wheat field ecosystem is ecologically valuable.The results can inform the development and implementation of ecological compensation policies involving straw return.