The Lake Chad located in the west-central Africa in the Sahel region at the edge of the Sahara experienced severe drought during 1970s and 1980s and overexploitation (unintegrated and unsustainable use), which is a re...The Lake Chad located in the west-central Africa in the Sahel region at the edge of the Sahara experienced severe drought during 1970s and 1980s and overexploitation (unintegrated and unsustainable use), which is a result of variant land uses and water management practices during the last 50 years. This resulted in a decline of the water level in the Lake and surrounding rivers. The present study analyzed satellite images of Lake Chad from Landsat-MSS, Landsat-OLI to investigate the change of the open water surface area during the years of 1973, 1987, 2001, 2013, and 2017. Supervised classifications were performed for the land cover analysis. The open water area in 1973 was covering 16,157.34 km<sup>2</sup> approximately, and that was 64.6% of the total lake area in the 1960s. As an ultimate result of the extreme drought that the study area witnessed through 1970s-1980s, the open water area has decreased to 1831.44 km<sup>2</sup>, <i>i.e.</i> around 11.33%, compared to that in 1973. The dilemma that the study area is suffering from is believed to be a catastrophic complication of the aforementioned drought crisis, which arose as an ultimate result the climate change, global warming, and the unintegrated and unsustainable use of water challenges the study area is still encountering.展开更多
Jordan has,</span><span style="font-family:""> </span><span style="font-family:"">to a satisfactory degree,</span><span style="font-family:"&quo...Jordan has,</span><span style="font-family:""> </span><span style="font-family:"">to a satisfactory degree,</span><span style="font-family:""> </span><span style="font-family:"">managed its scarce water resources, especially during the last few decades due to the regional conflicts and refugee waves hosted in the country since 1948.</span><span style="font-family:""> </span><span style="font-family:"">The waves of refugees in 1967, and after), returnees from the Gulf States 1991/92, during the first Gulf war), Lebanon (1970s and 1980s), Iraq (2003 and after, and lastly Syria (2011-2017 have</span><span style="font-family:""> </span><span style="font-family:"">as well</span><span style="font-family:""> </span><span style="font-family:"">severely impacted the management of water resources which has negatively impacted the water sector especially in terms of allocating new water resources to satisfy the needs of the country. In addition, shortsightedness of some water policy-makers has led to the deteriorations in the water resources quantitatively and qualitatively, which has resulted in social and economic discomfort of the population. In this article, the shortcomings in the water sector are addressed, such as setting an end to groundwater overexploitation, providing water to the population in a continuous way, improving water use efficiency in agricultural uses and the way forward is</span><span style="font-family:""> </span><span style="font-family:"">delineated</span><span style="font-family:""> </span><span style="font-family:"">based on a critical judgment of the actual situation of the water sector in order to reach at a more robust water sector with all its</span><span style="font-family:""> </span><span style="font-family:"">positive impacts on the social, economic and political life in the country.展开更多
Land subsidence phenomena caused by the overexploitation of the aquifers require the holistic knowledge of the geological, tectonic, hydrogeological and especially the geotechnical conditions of the affected sites in ...Land subsidence phenomena caused by the overexploitation of the aquifers require the holistic knowledge of the geological, tectonic, hydrogeological and especially the geotechnical conditions of the affected sites in order to be mitigated. The current paper focuses on the study of the phenomena taking place at the Amyntaio sub-basin, northern Greece, hosting the homonymous open pit coal mine,operating there the last two decades. The mining as well as the rising agriculture activities have led to a significant drawdown of the ground water level triggering extensive ground subsidence phenomena,causing damages at the nearby villages, infrastructure and farmlands. The production and evaluation of engineering geological–geotechnical maps as well as of thematic tectonic and hydrogeological maps proved that the knowledge of this data is crucial for the interpretation of the land subsidence mechanism and the spatial distribution of its effects.展开更多
Biodiversity conservation and sustainably utilizing natural resources improve the benefits of ecotourism development. Ecotourism development makes values for sustainably using biodiversity creating economic developmen...Biodiversity conservation and sustainably utilizing natural resources improve the benefits of ecotourism development. Ecotourism development makes values for sustainably using biodiversity creating economic development opportunities. This study reviews literature and reveals objectives, conflicts and resolutions for achieving biodiversity conservation through ecotourism development in Sri Lanka. This paper describes conservation objectives in terms of preserving and fostering biodiversity, habitat restoration and managing biodiversity, and making values for natural assets through ecotourism activities. Degradation and destruction of habitat, overexploitation and illegal extraction of species, emissions of greenhouse gasses for climate change, contamination and pollution of the environment, and spread of exotic species are identified as the main conflicts. Conservation resolutions are discussed on education and awareness-raising activities for biodiversity conservation, in-situ conservation and ex-situ preservation of species, integrating biodiversity into ecotourism development, integrating management of biodiversity and ecotourism, linking ecotourism industry and conservation organizations, ecotourism policy and legislations for biodiversity conservation, and imposition of rules and regulations. Policy solutions and building capacity among institutions and other stakeholders for governance and sustainable conservation of biodiversity are key for sustainable ecotourism development.展开更多
A field survey was carried out to determine the vegetation structure of the Lukanga Swamp Ramsar site in central Zambia. The aim of the study was to identify the different vegetation communities, species composition a...A field survey was carried out to determine the vegetation structure of the Lukanga Swamp Ramsar site in central Zambia. The aim of the study was to identify the different vegetation communities, species composition and distribution patterns for improved habitat management. Sampling was conducted in all recognizable vegetation communities. The results of the survey showed that the swamp was a littoral palustrine wetland predominantly characterized by the dominance of Leersia hexandria Swartz (42.02%), Typha capensis Rohrb (62.43%), Phragmites australis (Cav.) Trin. ex Steud (33.61%), Aeschynomeme fluitans Peter (31.58%) and Polygonum senegalense Meisn (48.8%). The occurrence of Vossia cuspidata Griff and Cyperus papyrusL was restricted to small and isolated locations. Short Termitaria was generally covered by Acrocerus macrum Stapf (35.25%) while tall Termitaria was dominated by Panicum maximum Jacq. (26.00%). The most important woody plant species included Combretum ghasalense Engl. et Diels (I. V = 62.88), Pseudolachnostylis maprouneifolia Pax ((I. V = 90.48), Albizia adianthifolia (Schmacher) W.F. Wight (I. V = 135.63) Isoberlinia angolensis Hyle and Brenan (I. V = 87.25). The current structure of the hydrophytes composition observed in this study was an indication of a generally silting wetland, while the dominant occurrence of understorey woody plants in the surrounding vegetation signified degraded miombo vegetation. It was concluded that the ecological status of wetland habitat was potentially threatened by mainly anthropogenic activities such as;wildfires, and unsustainable exploitation of surrounding vegetation. Further research is required to examine water flows, eutrophication and the long-term effects of deforestation on the ecological functioning of the wetland.展开更多
After Kyrgyzstan gained independence in 1991, the importance of the primary sector for food- and energy-supply increased significantly. This has led to a discussion about the sustainability of current firewood use. We...After Kyrgyzstan gained independence in 1991, the importance of the primary sector for food- and energy-supply increased significantly. This has led to a discussion about the sustainability of current firewood use. We investigated firewood collection and use practices in three selected villages and analysed differences between the annual increment of woody biomass and firewood consumption for heating during winter months. The calculated individual firewood consumption is on average 3.90 kg/capita/heating day and the calculation of differences between increment and consumption shows that in minimum one village the surrounding forests are overused for firewood collection. Pressure on the forest and the overuse of preferred tree species for firewood can lead to an overuse of the resource and to a decrease in the genetic diversity of these species in the walnut-fruit forests which are considered as a biodiversity hotspot of international significance due to the diversity of woody.展开更多
Groundwater overexploitation is a serious problem in the Turpan Basin,Xinjiang Uygur Autonomous Region of China,causing groundwater level declines and ecological and environmental problems such as the desiccation of k...Groundwater overexploitation is a serious problem in the Turpan Basin,Xinjiang Uygur Autonomous Region of China,causing groundwater level declines and ecological and environmental problems such as the desiccation of karez wells and the shrinkage of lakes.Based on historical groundwater data and field survey data from 1959 to 2021,we comprehensively studied the evolution of groundwater recharge and discharge terms in the Turpan Basin using the groundwater equilibrium method,mathematical statistics,and GIS spatial analysis.The reasons for groundwater overexploitation were also discussed.The results indicated that groundwater recharge increased from 14.58×10^(8)m^(3)in 1959 to 15.69×10^(8)m^(3)in 1980,then continued to decrease to 6.77×10^(8)m^(3)in 2021.Groundwater discharge increased from 14.49×10^(8)m^(3)in 1959 to 16.02×10^(8)m^(3)in 1989,while continued to decrease to 9.97×10^(8)m^(3)in 2021.Since 1980,groundwater recharge-discharge balance has been broken,the decrease rate of groundwater recharge exceeded that of groundwater discharge and groundwater recharge was always lower than groundwater discharge,showing in a negative equilibrium,which caused the continuous decrease in groundwater level in the Turpan Basin.From 1980 to 2002,groundwater overexploitation increased rapidly,peaking from 2003 to 2011 with an average overexploitation rate of 4.79×10^(8)m^(3)/a;then,it slowed slightly from 2012 to 2021,and the cumulative groundwater overexploitation was 99.21×10^(8)m^(3)during 1980-2021.This research can provide a scientific foundation for the restoration and sustainable use of groundwater in the overexploited areas of the Turpan Basin.展开更多
文摘The Lake Chad located in the west-central Africa in the Sahel region at the edge of the Sahara experienced severe drought during 1970s and 1980s and overexploitation (unintegrated and unsustainable use), which is a result of variant land uses and water management practices during the last 50 years. This resulted in a decline of the water level in the Lake and surrounding rivers. The present study analyzed satellite images of Lake Chad from Landsat-MSS, Landsat-OLI to investigate the change of the open water surface area during the years of 1973, 1987, 2001, 2013, and 2017. Supervised classifications were performed for the land cover analysis. The open water area in 1973 was covering 16,157.34 km<sup>2</sup> approximately, and that was 64.6% of the total lake area in the 1960s. As an ultimate result of the extreme drought that the study area witnessed through 1970s-1980s, the open water area has decreased to 1831.44 km<sup>2</sup>, <i>i.e.</i> around 11.33%, compared to that in 1973. The dilemma that the study area is suffering from is believed to be a catastrophic complication of the aforementioned drought crisis, which arose as an ultimate result the climate change, global warming, and the unintegrated and unsustainable use of water challenges the study area is still encountering.
文摘Jordan has,</span><span style="font-family:""> </span><span style="font-family:"">to a satisfactory degree,</span><span style="font-family:""> </span><span style="font-family:"">managed its scarce water resources, especially during the last few decades due to the regional conflicts and refugee waves hosted in the country since 1948.</span><span style="font-family:""> </span><span style="font-family:"">The waves of refugees in 1967, and after), returnees from the Gulf States 1991/92, during the first Gulf war), Lebanon (1970s and 1980s), Iraq (2003 and after, and lastly Syria (2011-2017 have</span><span style="font-family:""> </span><span style="font-family:"">as well</span><span style="font-family:""> </span><span style="font-family:"">severely impacted the management of water resources which has negatively impacted the water sector especially in terms of allocating new water resources to satisfy the needs of the country. In addition, shortsightedness of some water policy-makers has led to the deteriorations in the water resources quantitatively and qualitatively, which has resulted in social and economic discomfort of the population. In this article, the shortcomings in the water sector are addressed, such as setting an end to groundwater overexploitation, providing water to the population in a continuous way, improving water use efficiency in agricultural uses and the way forward is</span><span style="font-family:""> </span><span style="font-family:"">delineated</span><span style="font-family:""> </span><span style="font-family:"">based on a critical judgment of the actual situation of the water sector in order to reach at a more robust water sector with all its</span><span style="font-family:""> </span><span style="font-family:"">positive impacts on the social, economic and political life in the country.
文摘Land subsidence phenomena caused by the overexploitation of the aquifers require the holistic knowledge of the geological, tectonic, hydrogeological and especially the geotechnical conditions of the affected sites in order to be mitigated. The current paper focuses on the study of the phenomena taking place at the Amyntaio sub-basin, northern Greece, hosting the homonymous open pit coal mine,operating there the last two decades. The mining as well as the rising agriculture activities have led to a significant drawdown of the ground water level triggering extensive ground subsidence phenomena,causing damages at the nearby villages, infrastructure and farmlands. The production and evaluation of engineering geological–geotechnical maps as well as of thematic tectonic and hydrogeological maps proved that the knowledge of this data is crucial for the interpretation of the land subsidence mechanism and the spatial distribution of its effects.
文摘产卵场保护区建立是养护渔业资源和渔业可持续发展的重要方式,为验证大陈洋产卵场保护区建立的效果,以大陈洋产卵场保护区为研究区域,基于层次分析法(analytic hierarchy process),以2018年春(4月)、秋(11月)两季渔业资源和环境调查数据为依据,从产卵场保护区的环境和生态(一级指标)角度考虑,建立以污染物、水质、群落结构、资源密度等7个二级指标和26个三级指标的评价体系,通过综合健康评价指数(comprehensive health indicator,I_(c,h)),表征大陈洋产卵场保护区健康状况,并利用2021年春(4月)、秋(11月)两季渔业资源调查数据与保护区建立初期渔业资源情况进行对比。结果显示:2018年大陈洋产卵场保护区春季和秋季I_(c,h)分别为0.514和0.511,均处于亚健康状态。虽然保护区内环境状况优良,但保护区内生物多样性低,资源密度和资源补充群体数量不足,这表明大陈洋产卵场保护区渔业资源情况不容乐观。经过一段时间的恢复,保护区内渔业资源情况略有所好转,说明保护区的设立有一定的效果。综合健康评价体系在一定程度上客观地反映了大陈洋产卵场保护区健康状况,研究结果可为保护区建立效果评价提供基础数据,也对大陈洋地区的渔业可持续发展具有重要意义。
文摘Biodiversity conservation and sustainably utilizing natural resources improve the benefits of ecotourism development. Ecotourism development makes values for sustainably using biodiversity creating economic development opportunities. This study reviews literature and reveals objectives, conflicts and resolutions for achieving biodiversity conservation through ecotourism development in Sri Lanka. This paper describes conservation objectives in terms of preserving and fostering biodiversity, habitat restoration and managing biodiversity, and making values for natural assets through ecotourism activities. Degradation and destruction of habitat, overexploitation and illegal extraction of species, emissions of greenhouse gasses for climate change, contamination and pollution of the environment, and spread of exotic species are identified as the main conflicts. Conservation resolutions are discussed on education and awareness-raising activities for biodiversity conservation, in-situ conservation and ex-situ preservation of species, integrating biodiversity into ecotourism development, integrating management of biodiversity and ecotourism, linking ecotourism industry and conservation organizations, ecotourism policy and legislations for biodiversity conservation, and imposition of rules and regulations. Policy solutions and building capacity among institutions and other stakeholders for governance and sustainable conservation of biodiversity are key for sustainable ecotourism development.
文摘A field survey was carried out to determine the vegetation structure of the Lukanga Swamp Ramsar site in central Zambia. The aim of the study was to identify the different vegetation communities, species composition and distribution patterns for improved habitat management. Sampling was conducted in all recognizable vegetation communities. The results of the survey showed that the swamp was a littoral palustrine wetland predominantly characterized by the dominance of Leersia hexandria Swartz (42.02%), Typha capensis Rohrb (62.43%), Phragmites australis (Cav.) Trin. ex Steud (33.61%), Aeschynomeme fluitans Peter (31.58%) and Polygonum senegalense Meisn (48.8%). The occurrence of Vossia cuspidata Griff and Cyperus papyrusL was restricted to small and isolated locations. Short Termitaria was generally covered by Acrocerus macrum Stapf (35.25%) while tall Termitaria was dominated by Panicum maximum Jacq. (26.00%). The most important woody plant species included Combretum ghasalense Engl. et Diels (I. V = 62.88), Pseudolachnostylis maprouneifolia Pax ((I. V = 90.48), Albizia adianthifolia (Schmacher) W.F. Wight (I. V = 135.63) Isoberlinia angolensis Hyle and Brenan (I. V = 87.25). The current structure of the hydrophytes composition observed in this study was an indication of a generally silting wetland, while the dominant occurrence of understorey woody plants in the surrounding vegetation signified degraded miombo vegetation. It was concluded that the ecological status of wetland habitat was potentially threatened by mainly anthropogenic activities such as;wildfires, and unsustainable exploitation of surrounding vegetation. Further research is required to examine water flows, eutrophication and the long-term effects of deforestation on the ecological functioning of the wetland.
基金supported by Swiss National Science Foundation,the Karl Popper Foundation and the Vontobel Foundation in the framework of the project"ORECH-LES"
文摘After Kyrgyzstan gained independence in 1991, the importance of the primary sector for food- and energy-supply increased significantly. This has led to a discussion about the sustainability of current firewood use. We investigated firewood collection and use practices in three selected villages and analysed differences between the annual increment of woody biomass and firewood consumption for heating during winter months. The calculated individual firewood consumption is on average 3.90 kg/capita/heating day and the calculation of differences between increment and consumption shows that in minimum one village the surrounding forests are overused for firewood collection. Pressure on the forest and the overuse of preferred tree species for firewood can lead to an overuse of the resource and to a decrease in the genetic diversity of these species in the walnut-fruit forests which are considered as a biodiversity hotspot of international significance due to the diversity of woody.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region,China(2021D01A99)the National Natural Science Foundation of China(51969029).
文摘Groundwater overexploitation is a serious problem in the Turpan Basin,Xinjiang Uygur Autonomous Region of China,causing groundwater level declines and ecological and environmental problems such as the desiccation of karez wells and the shrinkage of lakes.Based on historical groundwater data and field survey data from 1959 to 2021,we comprehensively studied the evolution of groundwater recharge and discharge terms in the Turpan Basin using the groundwater equilibrium method,mathematical statistics,and GIS spatial analysis.The reasons for groundwater overexploitation were also discussed.The results indicated that groundwater recharge increased from 14.58×10^(8)m^(3)in 1959 to 15.69×10^(8)m^(3)in 1980,then continued to decrease to 6.77×10^(8)m^(3)in 2021.Groundwater discharge increased from 14.49×10^(8)m^(3)in 1959 to 16.02×10^(8)m^(3)in 1989,while continued to decrease to 9.97×10^(8)m^(3)in 2021.Since 1980,groundwater recharge-discharge balance has been broken,the decrease rate of groundwater recharge exceeded that of groundwater discharge and groundwater recharge was always lower than groundwater discharge,showing in a negative equilibrium,which caused the continuous decrease in groundwater level in the Turpan Basin.From 1980 to 2002,groundwater overexploitation increased rapidly,peaking from 2003 to 2011 with an average overexploitation rate of 4.79×10^(8)m^(3)/a;then,it slowed slightly from 2012 to 2021,and the cumulative groundwater overexploitation was 99.21×10^(8)m^(3)during 1980-2021.This research can provide a scientific foundation for the restoration and sustainable use of groundwater in the overexploited areas of the Turpan Basin.
