The marshes of southern Iraq are of great value due to their roles in the economy,environment,heritage,tourism,and agriculture.However,the region has witnessed remarkable transformations in land cover,influenced by hu...The marshes of southern Iraq are of great value due to their roles in the economy,environment,heritage,tourism,and agriculture.However,the region has witnessed remarkable transformations in land cover,influenced by human interventions and natural environmental factors.In this research,the Central Marshlands were selected for study and monitoring.These Marshes form the Mesopotamian Marshes,a vital part of the Tigris-Euphrates river system.This area 2 formerly covered an area of approximately 3,000 km and was once home to the lives of Marsh Arabs and their animals.The primary objective of this study was to compile a set of satellite images covering the same marshland region over several decades.The data used includes images captured by various Landsat missions:MSS(1975),TM(1983&1993),ETM+(2003),and the Operational Land Imager(OLI)from Landsat 8(2015).Satellite images were combined and pre-processed through steps such as layer stacking to create composite images from multiple bands.Several image classification methods were applied,and the classification results showed a significant and unprecedented increase in the percentage of water in the marsh,reaching 16%in 2003.This was combined with vegetation identification techniques,including the identification of vegetation boundaries to detect areas of dense vegetation.In addition,the relative depth of the water was measured to estimate marsh water levels,with the best result obtained in 2003.The normalized mean vegetation index(NDVI)calculated in this study had its best value in 1984 due to the spread of reeds and papyrus during this period.Papyrus is the raw material in the sugar industry,providing a significant economic boost.展开更多
The regularity of CH 4 emission from marshland in the Sanjiang Plain was studied by sampling in the open field and analyzing under laboratory condition, the annual emission amount is also estimated. By Grey Relativel...The regularity of CH 4 emission from marshland in the Sanjiang Plain was studied by sampling in the open field and analyzing under laboratory condition, the annual emission amount is also estimated. By Grey Relatively Analysis we know that the soil temperature in the 10 cm depth of grass root layer is close related with CH 4 emission. CH 4 emission has different kinds of diurnal emission modes:before dawn maximum mode, night maximum mode and irregular fluctuation mode. The seasonal variation trend of CH 4 emission rates is going up steadily from May to August and dropping down from September,the maximum lies behind the maximum of temperature. CH 4 emission rates of different marshland types are different, the CH 4 emission rate of Glyceriaspiculosa-Carex marshland is always higher than that of Carex lasiocarpa marshland. The paper also studies the difference of CH 4 emission rates in different managing modes and analyzes the emission rates between China and U.S.A. The result shows: the average value of CH 4 emission rate is 17.26mg/(m 2·h),the annual amount of CH 4 emission is about 0.75Tg.展开更多
Marshlands are important ecosystem for living organisms. The Southern Iraqi Marshland is the central habitat for freshwater fish, provides habitat for important populations of wildlife and serves as a source of income...Marshlands are important ecosystem for living organisms. The Southern Iraqi Marshland is the central habitat for freshwater fish, provides habitat for important populations of wildlife and serves as a source of income for native economies through reed harvesting. Studies have shown that variability in climate and human-induced factors affects the spatial dynamics of marsh ecosystems. This study assessed wetland changes in the Southern Iraqi Marshlands using Remotely Sensed Data from 1986 to 2019 using Landsat satellite imagery for four epochs: 1986, 2000, 2010 and 2019. To achieve this, thirty (30) pixels were obtained in selected land cover theme and their signatures were merged into one class. Furthermore, the selected pixels were recoded and merged into ten (10) land cover classes. The multi-layer classes created were shallow water, deep water, dense marsh, medium marsh, sparse marsh, dense vegetation, medium vegetation, sparse vegetation, dry soil and wet soil. The areal extents of the land cover types were calculated for 1986, 2000, 2010 and 2019. Normalized Difference Vegetation Index (NDVI) differencing was also carried in order to highlight trends in vegetation from 1986 to 2019. The study correlated historical trends of human activities as a central factor in the degradation of marshland (by 16.25%) from 1986 to 2000. However, by the year 2000 to 2010, there was an 11.36% increase in the total marshland area, which remained almost unchanged between 2010 and 2019. In 1986, NDVI was relatively stable at 0.73 in the Al-Hammar and Al-Hwaizeh Marsh. However, by 2000, the areas of dense vegetation cover reduced drastically by over 90%. In 2010, the NDVI index indicated trends of increasing water body and an outward cluster of healthier vegetation continuing to 2019.展开更多
Salinization becomes a very serious problem affecting the restoration assessment of the newly re-flooded marshes of the Mesopotamian southern Iraq. From mid-1970 to early-1990, the whole marsh area was influenced by w...Salinization becomes a very serious problem affecting the restoration assessment of the newly re-flooded marshes of the Mesopotamian southern Iraq. From mid-1970 to early-1990, the whole marsh area was influenced by water shortage and desiccation processes. Increasing the average salinity level in the re-flooded marshes is acting versus their recovery progress and significantly affecting their aquatic biota. This study will examine the contributions of dams’ construction and desiccation on increasing the salinity level with in the Mesopotamian marshlands overtime. Water discharge and salinity concentration were monitored in the direct water inputs and outlets of the three marshlands from May 2006 to February 2007 on a monthly basis, while salinity and major ions concentrations including “Ca1+, Mg2+, Cl1-, and SO42-” were monitored in 28 re-flooded marshes from March 2005 to August 2008 on a seasonal basis. The study indicate that increasing the salinity level in the Mesopotamian marshlands is due to three reasons: 1) The overtime increasing in the salinity level of their direct water inputs, due to dams’ constructions;2) the increase of the Arab Gulf tide via Shatt Al-Arab river due to the reduction of the water level in the outlets of the Central and Al-Hammar marshlands;and 3) the huge accumulation of salts due to desiccation.展开更多
The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology was applied to detect changes in perennial vegetation cover at marshland sites in Northern California reported to have undergone restor...The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology was applied to detect changes in perennial vegetation cover at marshland sites in Northern California reported to have undergone restoration between 1999 and 2009. Results showed extensive contiguous areas of restored marshland plant cover at 10 of the 14 sites selected. Gains in either woody shrub cover and/or from a recovery of herbaceous cover that remains productive and evergreen on a year round basis could be mapped out from the image results. However, LEDAPS may not be highly sensitive changes in wetlands that have been restored mainly with seasonal herbaceous cover (e.g., vernal pools), due to the ephemeral nature of the plant greenness signal. Based on this evaluation, the LEDAPS methodology would be capable of fulfilling a pressing need for consistent, continual, low-cost monitoring of changes in marshland ecosystems of the Pacific Flyway.展开更多
Environmental protection is one of the most important measures to achieve the long run and sustainability of living organisms in the world.The study was conducted in Burera and Gicumbi districts with the main aim of a...Environmental protection is one of the most important measures to achieve the long run and sustainability of living organisms in the world.The study was conducted in Burera and Gicumbi districts with the main aim of assessing the impact of environment protection in Rwanda.A case study of Rugezi Marchland.Data were collected using a structured questionnaire and analyzed using SPSS statistical software version 20 and STATA statistical software vision 13.Off-farm income,occupation,educational level,age,and farm size,showed a positive relationship with Rugezi marchland protection.Variables such as value of product distance to Rugezi marchland,gender,and family size had a negative influence on Rugezi marchland protection.The study also indicated that factors such as water management,increase of grass species,increase of wild animals and birds,modern house construction,zero grazing keeping revealing a positive relationship with Rugezi marchland protection.Two most serious problems encountered are the lack of occupation and low level of education.展开更多
A positive biodiversity-ecosystem functioning(BEF)relationship is frequently reported for biotic communities with low diversity levels.However,whether this is also true for highly diverse soil microbial communities re...A positive biodiversity-ecosystem functioning(BEF)relationship is frequently reported for biotic communities with low diversity levels.However,whether this is also true for highly diverse soil microbial communities remains unclear.The study explored the BEF relationships between species richness and nitrogen(N)-transforming capability of nirK-and nirS-nitrite reducers,nitrous oxide reducers,and nitrite oxidizer communities in soils from five different vegetation types.The results consistently indicated negative BEF patterns in these N-transforming microbes.The relative abundance of keystone taxa from co-occurrence networks increased substantially with species richness but was negatively correlated with functional performance.Network complexity decreased in communities with high species richness.These findings suggest that negative selection and biotic competition may simultaneously generate negative BEF patterns.A conceptual model was also proposed in which the BEF relationship followed a quadratic curve that varied with the level of diversity.Microbial diversity is crucial for maintaining the balance of ecological systems because microorganisms play key roles in nutrient cycling and other essential biogeochemical processes.Recent studies have shown that increased diversity may not always lead to improved ecosystem function.The current study indicated that function decreased with species richness in soil Ntransforming bacterial communities.Keystone taxa were positively correlated with species richness but negatively correlated with function.Community complexity decreased with increasing species richness.These findings suggest that both negative selection effects and biotic competition may simultaneously generate negative biodiversity-ecosystem functional relationships.展开更多
Background:Schistosomiasis is a global snail-transmitted infectious disease of poverty.Transmission control had been achieved in China in 2015 after the control efforts for over 60 years.Currently,the remaining core r...Background:Schistosomiasis is a global snail-transmitted infectious disease of poverty.Transmission control had been achieved in China in 2015 after the control efforts for over 60 years.Currently,the remaining core regions endemic for Schistosoma japonicum are mainly located in the marshland and lake regions along the Yangtze River basin.Methods:During the period from 2001 through 2015,an integrated environmental improvement of the marshlands was carried out through the implementation of industrial,agricultural and resources development projects in Yizheng County along the Yangtze River.S.japonicum infection in humans,livestock and snails was estimated by serology,stool examination,hatching technique and microscopy during the 15-year study period to evaluate the effect of the integrated environmental improvement on control and elimination of schistosomiasis.Results:A 0.05%overall rate of S.japonicum infection was observed in snails during the 15-year study period,and no infected snails were detected since 2012.The overall prevalence of S.japonicum infection was 0.09%in humans during the study period,and no human infection was found since 2012.In addition,only 13 bovines were identified with S.japonicum infection in 2003 during the 15-year study period,and since 2004,no infection was found in livestock.Conclusion:The results of the present study demonstrate that the implementation of industrial,agricultural and water resources development projects,not only alters snail habitats in marshland regions,and promotes local economic development,which appears a win-to-win strategy to block the transmission of S.japonicum and accelerate socio-economic development along the Yangtze River.展开更多
Background:Wetland loss is a global concern due to its enormous ecosystem services.Marshland,a typical natural wetland,which is concentrated in the Sanjiang Plain,has undergone dramatic loss in the last several decade...Background:Wetland loss is a global concern due to its enormous ecosystem services.Marshland,a typical natural wetland,which is concentrated in the Sanjiang Plain,has undergone dramatic loss in the last several decades.The spatiotemporal changes in marshland were studied based on Landsat images of the Sanjiang Plain from 1980 to 2016 with the land use maps in 1980,1995,2000,2005,2010,and 2016 using land use dynamic degree and landscape indices.The driving forces of marshland loss,including biophysical factors,socio-economic factors,and land management,were analyzed with boosted regression trees(BRTs)methods.Results:The area of marshland loss was 7372 km^(2),which accounted for 65.7%of the area of marshland in 1980;however,the paddy field area was expanded by 22,313 km^(2).The lost marshland was mainly converted to dry farmland(47.5%)and paddy field(47.2%)during 1980-2016.Both the landscape pattern of the study area and marshland became increasingly fragmented.The relatively important factors responsible for marshland loss were biophysical factors,socio-economic factors,and land management,which accounted for 65.2%,25.5%,and 8.4%,respectively.The most important driving forces with high“relative influence”were“distance to river,”which accounted for 20.6%of the total variance explained.The“relative influence”of potential crop yield and ditch density reached 20.2%and 8.4%,respectively.Conclusion:Significant land use changes have occurred in the Sanjiang Plain over the past 37 years,with characteristics of rapid paddy field expansion and drastic marshland loss.Meanwhile,marshland fragmentation continued to increase.Reclamation was the main reason for the large-scale marshland loss.Biophysical factors influenced the decisions regarding the locations of marshland loss.Moreover,climate factors(i.e.,average annual precipitation and average annual temperature)also played an important role in marshland loss.These results can provide helpful knowledge for understanding the patterns and reasons for marshland loss and protecting and managing strategies for wetlands restoration.展开更多
文摘The marshes of southern Iraq are of great value due to their roles in the economy,environment,heritage,tourism,and agriculture.However,the region has witnessed remarkable transformations in land cover,influenced by human interventions and natural environmental factors.In this research,the Central Marshlands were selected for study and monitoring.These Marshes form the Mesopotamian Marshes,a vital part of the Tigris-Euphrates river system.This area 2 formerly covered an area of approximately 3,000 km and was once home to the lives of Marsh Arabs and their animals.The primary objective of this study was to compile a set of satellite images covering the same marshland region over several decades.The data used includes images captured by various Landsat missions:MSS(1975),TM(1983&1993),ETM+(2003),and the Operational Land Imager(OLI)from Landsat 8(2015).Satellite images were combined and pre-processed through steps such as layer stacking to create composite images from multiple bands.Several image classification methods were applied,and the classification results showed a significant and unprecedented increase in the percentage of water in the marsh,reaching 16%in 2003.This was combined with vegetation identification techniques,including the identification of vegetation boundaries to detect areas of dense vegetation.In addition,the relative depth of the water was measured to estimate marsh water levels,with the best result obtained in 2003.The normalized mean vegetation index(NDVI)calculated in this study had its best value in 1984 due to the spread of reeds and papyrus during this period.Papyrus is the raw material in the sugar industry,providing a significant economic boost.
文摘The regularity of CH 4 emission from marshland in the Sanjiang Plain was studied by sampling in the open field and analyzing under laboratory condition, the annual emission amount is also estimated. By Grey Relatively Analysis we know that the soil temperature in the 10 cm depth of grass root layer is close related with CH 4 emission. CH 4 emission has different kinds of diurnal emission modes:before dawn maximum mode, night maximum mode and irregular fluctuation mode. The seasonal variation trend of CH 4 emission rates is going up steadily from May to August and dropping down from September,the maximum lies behind the maximum of temperature. CH 4 emission rates of different marshland types are different, the CH 4 emission rate of Glyceriaspiculosa-Carex marshland is always higher than that of Carex lasiocarpa marshland. The paper also studies the difference of CH 4 emission rates in different managing modes and analyzes the emission rates between China and U.S.A. The result shows: the average value of CH 4 emission rate is 17.26mg/(m 2·h),the annual amount of CH 4 emission is about 0.75Tg.
文摘Marshlands are important ecosystem for living organisms. The Southern Iraqi Marshland is the central habitat for freshwater fish, provides habitat for important populations of wildlife and serves as a source of income for native economies through reed harvesting. Studies have shown that variability in climate and human-induced factors affects the spatial dynamics of marsh ecosystems. This study assessed wetland changes in the Southern Iraqi Marshlands using Remotely Sensed Data from 1986 to 2019 using Landsat satellite imagery for four epochs: 1986, 2000, 2010 and 2019. To achieve this, thirty (30) pixels were obtained in selected land cover theme and their signatures were merged into one class. Furthermore, the selected pixels were recoded and merged into ten (10) land cover classes. The multi-layer classes created were shallow water, deep water, dense marsh, medium marsh, sparse marsh, dense vegetation, medium vegetation, sparse vegetation, dry soil and wet soil. The areal extents of the land cover types were calculated for 1986, 2000, 2010 and 2019. Normalized Difference Vegetation Index (NDVI) differencing was also carried in order to highlight trends in vegetation from 1986 to 2019. The study correlated historical trends of human activities as a central factor in the degradation of marshland (by 16.25%) from 1986 to 2000. However, by the year 2000 to 2010, there was an 11.36% increase in the total marshland area, which remained almost unchanged between 2010 and 2019. In 1986, NDVI was relatively stable at 0.73 in the Al-Hammar and Al-Hwaizeh Marsh. However, by 2000, the areas of dense vegetation cover reduced drastically by over 90%. In 2010, the NDVI index indicated trends of increasing water body and an outward cluster of healthier vegetation continuing to 2019.
文摘Salinization becomes a very serious problem affecting the restoration assessment of the newly re-flooded marshes of the Mesopotamian southern Iraq. From mid-1970 to early-1990, the whole marsh area was influenced by water shortage and desiccation processes. Increasing the average salinity level in the re-flooded marshes is acting versus their recovery progress and significantly affecting their aquatic biota. This study will examine the contributions of dams’ construction and desiccation on increasing the salinity level with in the Mesopotamian marshlands overtime. Water discharge and salinity concentration were monitored in the direct water inputs and outlets of the three marshlands from May 2006 to February 2007 on a monthly basis, while salinity and major ions concentrations including “Ca1+, Mg2+, Cl1-, and SO42-” were monitored in 28 re-flooded marshes from March 2005 to August 2008 on a seasonal basis. The study indicate that increasing the salinity level in the Mesopotamian marshlands is due to three reasons: 1) The overtime increasing in the salinity level of their direct water inputs, due to dams’ constructions;2) the increase of the Arab Gulf tide via Shatt Al-Arab river due to the reduction of the water level in the outlets of the Central and Al-Hammar marshlands;and 3) the huge accumulation of salts due to desiccation.
文摘The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology was applied to detect changes in perennial vegetation cover at marshland sites in Northern California reported to have undergone restoration between 1999 and 2009. Results showed extensive contiguous areas of restored marshland plant cover at 10 of the 14 sites selected. Gains in either woody shrub cover and/or from a recovery of herbaceous cover that remains productive and evergreen on a year round basis could be mapped out from the image results. However, LEDAPS may not be highly sensitive changes in wetlands that have been restored mainly with seasonal herbaceous cover (e.g., vernal pools), due to the ephemeral nature of the plant greenness signal. Based on this evaluation, the LEDAPS methodology would be capable of fulfilling a pressing need for consistent, continual, low-cost monitoring of changes in marshland ecosystems of the Pacific Flyway.
文摘Environmental protection is one of the most important measures to achieve the long run and sustainability of living organisms in the world.The study was conducted in Burera and Gicumbi districts with the main aim of assessing the impact of environment protection in Rwanda.A case study of Rugezi Marchland.Data were collected using a structured questionnaire and analyzed using SPSS statistical software version 20 and STATA statistical software vision 13.Off-farm income,occupation,educational level,age,and farm size,showed a positive relationship with Rugezi marchland protection.Variables such as value of product distance to Rugezi marchland,gender,and family size had a negative influence on Rugezi marchland protection.The study also indicated that factors such as water management,increase of grass species,increase of wild animals and birds,modern house construction,zero grazing keeping revealing a positive relationship with Rugezi marchland protection.Two most serious problems encountered are the lack of occupation and low level of education.
基金supported by the Central Public-Interest Scientific Institution Basal Research Fund(Grant No.CAFYBB2019QB001)the National Key R&D Fund(Grant No.2023YFF130440302)the Natural Science Foundation of China(Grant No.31870099).
文摘A positive biodiversity-ecosystem functioning(BEF)relationship is frequently reported for biotic communities with low diversity levels.However,whether this is also true for highly diverse soil microbial communities remains unclear.The study explored the BEF relationships between species richness and nitrogen(N)-transforming capability of nirK-and nirS-nitrite reducers,nitrous oxide reducers,and nitrite oxidizer communities in soils from five different vegetation types.The results consistently indicated negative BEF patterns in these N-transforming microbes.The relative abundance of keystone taxa from co-occurrence networks increased substantially with species richness but was negatively correlated with functional performance.Network complexity decreased in communities with high species richness.These findings suggest that negative selection and biotic competition may simultaneously generate negative BEF patterns.A conceptual model was also proposed in which the BEF relationship followed a quadratic curve that varied with the level of diversity.Microbial diversity is crucial for maintaining the balance of ecological systems because microorganisms play key roles in nutrient cycling and other essential biogeochemical processes.Recent studies have shown that increased diversity may not always lead to improved ecosystem function.The current study indicated that function decreased with species richness in soil Ntransforming bacterial communities.Keystone taxa were positively correlated with species richness but negatively correlated with function.Community complexity decreased with increasing species richness.These findings suggest that both negative selection effects and biotic competition may simultaneously generate negative biodiversity-ecosystem functional relationships.
基金This study was supported by the grants from the National Science&Technology Pillar Program of China(grant no.2009BAI78B07)Jiangsu Provincial Department of Science and Technology(grant no.BL2014021)+1 种基金Jiangsu Provincial Young Talents in Medical Sciences(grant no.QNRC2016621)Jiangsu Department of Health(grant nos.X201408 and X201410).
文摘Background:Schistosomiasis is a global snail-transmitted infectious disease of poverty.Transmission control had been achieved in China in 2015 after the control efforts for over 60 years.Currently,the remaining core regions endemic for Schistosoma japonicum are mainly located in the marshland and lake regions along the Yangtze River basin.Methods:During the period from 2001 through 2015,an integrated environmental improvement of the marshlands was carried out through the implementation of industrial,agricultural and resources development projects in Yizheng County along the Yangtze River.S.japonicum infection in humans,livestock and snails was estimated by serology,stool examination,hatching technique and microscopy during the 15-year study period to evaluate the effect of the integrated environmental improvement on control and elimination of schistosomiasis.Results:A 0.05%overall rate of S.japonicum infection was observed in snails during the 15-year study period,and no infected snails were detected since 2012.The overall prevalence of S.japonicum infection was 0.09%in humans during the study period,and no human infection was found since 2012.In addition,only 13 bovines were identified with S.japonicum infection in 2003 during the 15-year study period,and since 2004,no infection was found in livestock.Conclusion:The results of the present study demonstrate that the implementation of industrial,agricultural and water resources development projects,not only alters snail habitats in marshland regions,and promotes local economic development,which appears a win-to-win strategy to block the transmission of S.japonicum and accelerate socio-economic development along the Yangtze River.
基金This research was supported by the National Key R&D Program of China(No.2016YFC0500401)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23070103).
文摘Background:Wetland loss is a global concern due to its enormous ecosystem services.Marshland,a typical natural wetland,which is concentrated in the Sanjiang Plain,has undergone dramatic loss in the last several decades.The spatiotemporal changes in marshland were studied based on Landsat images of the Sanjiang Plain from 1980 to 2016 with the land use maps in 1980,1995,2000,2005,2010,and 2016 using land use dynamic degree and landscape indices.The driving forces of marshland loss,including biophysical factors,socio-economic factors,and land management,were analyzed with boosted regression trees(BRTs)methods.Results:The area of marshland loss was 7372 km^(2),which accounted for 65.7%of the area of marshland in 1980;however,the paddy field area was expanded by 22,313 km^(2).The lost marshland was mainly converted to dry farmland(47.5%)and paddy field(47.2%)during 1980-2016.Both the landscape pattern of the study area and marshland became increasingly fragmented.The relatively important factors responsible for marshland loss were biophysical factors,socio-economic factors,and land management,which accounted for 65.2%,25.5%,and 8.4%,respectively.The most important driving forces with high“relative influence”were“distance to river,”which accounted for 20.6%of the total variance explained.The“relative influence”of potential crop yield and ditch density reached 20.2%and 8.4%,respectively.Conclusion:Significant land use changes have occurred in the Sanjiang Plain over the past 37 years,with characteristics of rapid paddy field expansion and drastic marshland loss.Meanwhile,marshland fragmentation continued to increase.Reclamation was the main reason for the large-scale marshland loss.Biophysical factors influenced the decisions regarding the locations of marshland loss.Moreover,climate factors(i.e.,average annual precipitation and average annual temperature)also played an important role in marshland loss.These results can provide helpful knowledge for understanding the patterns and reasons for marshland loss and protecting and managing strategies for wetlands restoration.
