Variable and unpredictable food resources at stopover sites bring severe challenges to migrating shorebirds. Opportunistic foraging strategies, referring to shorebirds consuming prey in proportion to their availabilit...Variable and unpredictable food resources at stopover sites bring severe challenges to migrating shorebirds. Opportunistic foraging strategies, referring to shorebirds consuming prey in proportion to their availability, allow shorebirds to replenish fuel and nutrient reserves efficiently for continuing their migration. Chongming Dongtan, located in the Yangtze River estuary of eastern China, is the first major stopover site of shorebirds on the Chinese mainland during their northward migration. We investigated the diet of Great Knots (Calidris tenuirostris) at Chongming Dongtan during the spring stopovers of 2009 and 2010 through benthos sampling and dropping analysis. The benthos samples were categorized into gastropods, bivalves, polychaetes, crustaceans and insect larvae. Dropping analysis indicated that gastropods and bivalves constituted more than 70% of the diet of the Great Knot, with Assiminea violacea and Corbicula fluminea being the most frequently consumed. Chi-square tests indicated that for each prey category, there was no significant difference between the frequency of its occurrence in the benthos samples and dropping samples during the early stopover periods of 2009 and 2010 and during the late stopover periods of 2010. Although there was a statistically significant difference between the frequency of occurrence of prey in the total macrobenthos and in the droppings of the Great Knots during the late stopover period in 2009, the more abundant prey were more frequently consumed by the Great Knots. This suggests that Great Knots adopted an opportunistic foraging strategy during their stopover at Chongming Dongtan.展开更多
The environmental quality of heavy metals （Pb, Cd, Cr, As, Hg） in agricultural surface soil of Chongming Island was assessed by national, local and professional standards based on a large scale investigation, in whi...The environmental quality of heavy metals （Pb, Cd, Cr, As, Hg） in agricultural surface soil of Chongming Island was assessed by national, local and professional standards based on a large scale investigation, in which 28 samples from vegetable plots, 65 samples from paddy fields and 9 samples from watermelon fields were collected from whole island area. Results showed that the average concentration of Pb, Cd, Cr, As and Hg was 21.6 mg.kg^-l,0.176 mg.kg^-1, 69.4 mg.kg^-1, 9.209 mg.kg^-1 and 0.128 mg.kg^-1, respectively. Compared with the background value of Shanghai City soil, except for Pb and Cr, all the other heavy metals average concentrations in Chongming Island agricultural surface soil exceeded their corresponding natural-background values. The concentrations of Cd, As and Hg were 33.0%, 1.2% and 26.3% higher than the background value of Shanghai City, respectively. In addition, inverse distance interpolation （IDW） tool of GIS was also applied to study the spatial variation of heavy metals. The results indicated that most of agricultural soil quality was good, and the ratio of ecological, good soil, certified soil and disqualified soil were 1.26%, 97.1%, 1.47% and 0.12%, respectively. About 10.1%, 85.7%, 27.0%, 55.4% and 55.2% soil samples exceeded the Pb, Cd, Cr, As and Hg background value of Shanghai City, respectively. Among these three land use type soils, vegetable soil was most seriously polluted by heavy metals, which is probably related to the over-application of pesticides. The annual deposition fluxes of Pb, Cd, As and Hg were 7736μg·m^-2·a^-1, 208μg·m^-2·a^-1, 2238μg·m^-2·a^-1 and 52.8 μg·m^-2·a^-1 respectively. Crop straw burning was the important source of heavy metals of atmospheric deposition, and atmospheric deposition contributed a lot to heavy metals in agricultural soil in Chongming Island.展开更多
The investigations on the organic carbon （OC） of core sediments were carried out in Chongming east tidal fiat （CM） during Scirpus mariqueter growing stage （from April to December 2004） in Yangtze Estuary. The Ya...The investigations on the organic carbon （OC） of core sediments were carried out in Chongming east tidal fiat （CM） during Scirpus mariqueter growing stage （from April to December 2004） in Yangtze Estuary. The Yangtze River annually transports a runoff discharge of 30,000 m^3/s, carrying about 480 million tons of sediments to the estuarine and coastal area, which formed a great OC pool. In the sampling spots, seven quadrats of 50 cm × 50 cm and five sediments cores of 20 cm deep （40 cm deep in December） were randomly established in order to collect vegetations and core sediments samples during the low tide each month except November. After pretreatment, the core sediments were sieved and their OC contents were measured according to the potassium dichromate method. The results show that the higher surface sediment OC content in summer comes from allochthonous terrigenous particle settlements on the Chongming east middle tidal fiat S. mariqueter zone. In autumn and winter, the decomposing of the defoliated S. mariqueter increases the surface sediments OC content. Settling velocity, sediment temperature and S. mariqueter growth are the main factors that can control the sediment carbon content. Summer is the “carbon losing” period of the tidal fiat sediments, while from September, it changes into the “carbon accumulating” period of sediment OC pool because of the decomposing of dead S. mariqueter community in the sediments. From this alternation of “carbon losing” period and “carbon accumulating” period, we conclude that carbon in the OC pool of the middle tidal fiat S. mariqueter zone sediments mainly comes from the atmospheric carbon rooted by S. mariqueter photosynthesis.展开更多
Chongming Island, the third largest island in China and the largest alluvialisland in the world, is situated in the north of Shanghai Municipality at the mouth of theChangjiang (Yangtze) River. Along the fertile and p...Chongming Island, the third largest island in China and the largest alluvialisland in the world, is situated in the north of Shanghai Municipality at the mouth of theChangjiang (Yangtze) River. Along the fertile and prosperous sea coast there are a total area ofover 120 x 10~3ha, with a population of 735 000, accruing some 500ha of new tidal land resourcescome from silt, sand and mud carried by the Changjiang River every year, extending about 140m peryear. This dynamic process of alluvial growth has run for some 1500 years. Mudflat on ChongmingIsland at the mouth of the Changjiang River is a resting ground for migratory birds and host morethan a hundred species, including rare cranes and geese. But the local people keep reclaiming thetidal land for economic development. Obviously, it is crucial to have a well-concerted plan forfuture exploitation. In this study, we attempted to investigate the status changes of land use andwild life habitats on Chongming Island in recent 10 years, and then analyzed different humanactivities and their effects on wild life habitats using satellite image data (1990, 1997 and 2000)as well as field survey. Based on the analysis, this study explored the relationships between islandgrowth and land use/cover change (LUCC), predicted what the habitat would be like in the future andtried to find more effective use of this new growing resource. At last, this study provided somepreliminary management plans for Chongming Island that will coordinate the development of localeconomies and the conservation of wild life and their habitats.展开更多
The analysis of vegetation-environment relationships has always been a study hotspot in ecology. A number of biotic, hydrologic and edaphic factors have great influence on the distribution of macrophytes within salt m...The analysis of vegetation-environment relationships has always been a study hotspot in ecology. A number of biotic, hydrologic and edaphic factors have great influence on the distribution of macrophytes within salt marsh.Since the exotic species Spartina alterniflora（S. alterniflora） was introduced in 1995, a rapid expansion has occurred at Chongming Dongtan Nature Reserve（CDNR） in the Changjiang（Yangtze） River Estuary, China.Several important vegetation-environment factors including soil elevation, tidal channels density（TCD）,vegetation classification and fractional vegetation cover（FVC） were extracted by remote sensing method combined with field measurement. To ignore the details in interaction between biological and physical process,the relationship between them was discussed at a large scale of the whole saltmarsh. The results showed that Scirpus mariqueter（S. mariqueter） can endure the greatest elevation variance with 0.33 m throughout the marsh in CDNR. But it is dominant in the area less than 2.5 m with the occurrence frequency reaching 98%. S. alterniflora has usually been found on the most elevated soils higher than 3.5 m but has a narrow spatial distribution. The rapid decrease of S. mariqueter can be explained by stronger competitive capacity of S. alterniflora on the high tidal flat. FVC increases with elevation which shows significant correlation with elevation（r=0.30, p〈0.001）. But the frequency distribution of FVC indicates that vegetation is not well developed on both elevated banks near tidal channels from the whole scale mainly due to tidal channel lateral swing and human activities. The significant negative correlation（r=–0.20, p〈0.001） was found between FVC and TCD, which shows vegetation is restricted to grow in higher TCD area corresponding to lower elevation mainly occupied by S. mariqueter communities. The maximum occurrence frequency of this species reaches to 97% at the salt marsh with TCD more than 8 m/m2.展开更多
Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic car...Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic carbon(DOC)in submarine groundwater(well water and pore water)in salt marshes plays an important role in advective exchange between the salt marshes and coastal waters.However,the molecular characteristics of DOC in salt marsh groundwater are poorly understood because of the complex DOC structures and hydrodynamic process.In this study,fl uorescent components and refractory DOC(RDOC)in submarine groundwater from a salt marsh(Chongming Island,China)and adjacent coastal water were characterized by fl uorescence spectroscopy and nuclear magnetic resonance spectroscopy.The fl uorescent components identifi ed by parallel factor analysis indicated that humic-like substances dominated the chromophoric dissolved organic matter in the submarine groundwater.The chromophoric dissolved organic matter and dissolved organic matter in the submarine groundwater had non-conservative behaviors because of additions from terrestrial humic substances.The nuclear magnetic resonance spectra indicated that bioactive substances(carbohydrates)contributed only 13.2%-14.8%of the dissolved organic matter in the submarine groundwater but carboxyl-rich alicyclic molecules(CRAMs),the main components of RDOC,contributed 64.5%of the dissolved organic matter.Carbohydrates and CRAMs contributed 16.4%and 61.7%of the dissolved organic matter in the coastal water,similar to the contributions for submarine groundwater.The DOC concentration in submarine groundwater was 386±294μmol/L,which was signifi cantly higher than that in coastal water(91±19μmol/L).The high DOC concentrations and>60%relative RDOC content suggested that submarine groundwater may be an important source of RDOC to coastal seawater.This information will be helpful for estimating the climate eff ects of salt marsh blue carbon.展开更多
With climate change and rising sea levels,the coastal zone’s flood risk is deteriorating.Previous researches have shown a gradually degrading capacity of traditional hard engineering structures(e.g.,seawall,dikes)on ...With climate change and rising sea levels,the coastal zone’s flood risk is deteriorating.Previous researches have shown a gradually degrading capacity of traditional hard engineering structures(e.g.,seawall,dikes)on flood mitigation due to problems such as land subsidence and insufficient maintenance.To remedy the defects,the"building with nature concept"for coastal protection with saltmarshes was examined by combining field measurements and numerical simulations.The advantages of saltmarsh over traditional seawall on flood protection was demonstrated from the perspective of both flood area mitigation and economic gain,based on scenario simulations.Results show that tidal wetlands are essential in mitigating significant wave heights(Hs)and current velocities even during storm conditions.The storm wave and current velocity reduction ratio(RRw and RRc)by saltmarshes on Chongming Dongtan Shoal(CMDS)during Typhoon 9711 is approximately 11%and 51%,respectively.The wave and current mitigation by Scirpus mariqueter are more efficient than Spartina alterniflora and Phragmites australis during measurements in 2010,which were approximately 0.3 m and 0.2 m/s,0.125 m and 0.155 m/s,0.086 m and 0.128 m/s per kilometer width,respectively.The summer saltmarsh area 54.2 km2 on CMDS protects approximately 32 km^(2)land area behind the seawall from being flooded,equivalent to the seawall heightening of approximately 0.42 m on equivalent flood mitigation.The performance of cost-and-benefit analysis shows a relatively higher(by 3%–7%)net present value(NPV)and a higher(by 1.5 times)benefit-cost ratio(BC)of nature-based solution(i.e.,saltmarsh restoration)compared with traditional hard engineering solution(i.e.,seawall construction).Thus,building seawall with nature,such as a hybrid flood protection measure,should be implemented in the future coastal redesign and maintenance.展开更多
Haemaphysalis ticks are pathogenic vectors that threaten human and animal health and were identified in Chongming,the third largest island in China.To understand the distribution of these ticks and determine their pot...Haemaphysalis ticks are pathogenic vectors that threaten human and animal health and were identified in Chongming,the third largest island in China.To understand the distribution of these ticks and determine their potential invasion risk,this study aimed to identify the habitat suitability of the dominant tick H.flava based on natural environmental factors.Geographic information system(GIS)images were combined with sample points from tick investigations to map the spatial distribution of H.flava.Data on 19 bioclimatic variables,environmental variables,and satellite-based landscapes of Chongming Island were retrieved to create a landcover map related to natural environmental determinants of H.flava.These data included 38 sites associated with the vectors to construct species distribution models with MaxEnt,a model based on the maximum entropy principle,and to predict habitat suitability for H.flava on Chongming Island in 2050 and 2070 under different climate scenarios.The model performed well in predicting the H.flava distribution,with a training area under the curve of 0.84 and a test area under the curve of 0.73.A habitat suitability map of the whole study area was created for H.flava.The resulting map and natural environment analysis highlighted the importance of the normalized difference vegetation index and precipitation in the driest month for the bioecology of H.flava,with 141.61 km^(2)(11.77%),282.94 km^(2)(23.35%),and 405.30 km^(2)(33.69%)of highly,moderately,and poorly suitable habitats,respectively.The distribution decreased by 135.55 km^(2) and 138.82 km^(2) in 2050 and 2070,respectively,under the shared socioeconomic pathway(SSP)1.2.6 climate change scenario.However,under SSP 5.8.5,the total area will decrease by 128.5 km^(2) in 2050 and increase by 151.64 km^(2) in 2070.From a One Health perspective,this study provides good knowledge that will guide tick control efforts to prevent the spread of Haemaphysalis ticks or transmission risk of Haemaphysalis-borne infections at the human-animal-environment interface on the island.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.30670269,31071939)
文摘Variable and unpredictable food resources at stopover sites bring severe challenges to migrating shorebirds. Opportunistic foraging strategies, referring to shorebirds consuming prey in proportion to their availability, allow shorebirds to replenish fuel and nutrient reserves efficiently for continuing their migration. Chongming Dongtan, located in the Yangtze River estuary of eastern China, is the first major stopover site of shorebirds on the Chinese mainland during their northward migration. We investigated the diet of Great Knots (Calidris tenuirostris) at Chongming Dongtan during the spring stopovers of 2009 and 2010 through benthos sampling and dropping analysis. The benthos samples were categorized into gastropods, bivalves, polychaetes, crustaceans and insect larvae. Dropping analysis indicated that gastropods and bivalves constituted more than 70% of the diet of the Great Knot, with Assiminea violacea and Corbicula fluminea being the most frequently consumed. Chi-square tests indicated that for each prey category, there was no significant difference between the frequency of its occurrence in the benthos samples and dropping samples during the early stopover periods of 2009 and 2010 and during the late stopover periods of 2010. Although there was a statistically significant difference between the frequency of occurrence of prey in the total macrobenthos and in the droppings of the Great Knots during the late stopover period in 2009, the more abundant prey were more frequently consumed by the Great Knots. This suggests that Great Knots adopted an opportunistic foraging strategy during their stopover at Chongming Dongtan.
基金National Natural Science Foundation of China, No.40701164, No.40730526 Public Project of Ministry of Environmental Protection of China, No.WFLY-2009-1-SK-06-03 National Key Water Program during the 1 lth Five-Year Plan Period, No.2009ZX07317-006
文摘The environmental quality of heavy metals （Pb, Cd, Cr, As, Hg） in agricultural surface soil of Chongming Island was assessed by national, local and professional standards based on a large scale investigation, in which 28 samples from vegetable plots, 65 samples from paddy fields and 9 samples from watermelon fields were collected from whole island area. Results showed that the average concentration of Pb, Cd, Cr, As and Hg was 21.6 mg.kg^-l,0.176 mg.kg^-1, 69.4 mg.kg^-1, 9.209 mg.kg^-1 and 0.128 mg.kg^-1, respectively. Compared with the background value of Shanghai City soil, except for Pb and Cr, all the other heavy metals average concentrations in Chongming Island agricultural surface soil exceeded their corresponding natural-background values. The concentrations of Cd, As and Hg were 33.0%, 1.2% and 26.3% higher than the background value of Shanghai City, respectively. In addition, inverse distance interpolation （IDW） tool of GIS was also applied to study the spatial variation of heavy metals. The results indicated that most of agricultural soil quality was good, and the ratio of ecological, good soil, certified soil and disqualified soil were 1.26%, 97.1%, 1.47% and 0.12%, respectively. About 10.1%, 85.7%, 27.0%, 55.4% and 55.2% soil samples exceeded the Pb, Cd, Cr, As and Hg background value of Shanghai City, respectively. Among these three land use type soils, vegetable soil was most seriously polluted by heavy metals, which is probably related to the over-application of pesticides. The annual deposition fluxes of Pb, Cd, As and Hg were 7736μg·m^-2·a^-1, 208μg·m^-2·a^-1, 2238μg·m^-2·a^-1 and 52.8 μg·m^-2·a^-1 respectively. Crop straw burning was the important source of heavy metals of atmospheric deposition, and atmospheric deposition contributed a lot to heavy metals in agricultural soil in Chongming Island.
基金NationalNaturalScience Foundation ofChina,No.40173030No.40131020+3 种基金ExcellentYoung TeacherProgram ofthe M inistry ofEducationKey Program ofShanghaiScience Foundation,No.02DJ14029Science & TechnologyDepartment of Shanghai, No.04DZ19301 Project
文摘The investigations on the organic carbon （OC） of core sediments were carried out in Chongming east tidal fiat （CM） during Scirpus mariqueter growing stage （from April to December 2004） in Yangtze Estuary. The Yangtze River annually transports a runoff discharge of 30,000 m^3/s, carrying about 480 million tons of sediments to the estuarine and coastal area, which formed a great OC pool. In the sampling spots, seven quadrats of 50 cm × 50 cm and five sediments cores of 20 cm deep （40 cm deep in December） were randomly established in order to collect vegetations and core sediments samples during the low tide each month except November. After pretreatment, the core sediments were sieved and their OC contents were measured according to the potassium dichromate method. The results show that the higher surface sediment OC content in summer comes from allochthonous terrigenous particle settlements on the Chongming east middle tidal fiat S. mariqueter zone. In autumn and winter, the decomposing of the defoliated S. mariqueter increases the surface sediments OC content. Settling velocity, sediment temperature and S. mariqueter growth are the main factors that can control the sediment carbon content. Summer is the “carbon losing” period of the tidal fiat sediments, while from September, it changes into the “carbon accumulating” period of sediment OC pool because of the decomposing of dead S. mariqueter community in the sediments. From this alternation of “carbon losing” period and “carbon accumulating” period, we conclude that carbon in the OC pool of the middle tidal fiat S. mariqueter zone sediments mainly comes from the atmospheric carbon rooted by S. mariqueter photosynthesis.
文摘Chongming Island, the third largest island in China and the largest alluvialisland in the world, is situated in the north of Shanghai Municipality at the mouth of theChangjiang (Yangtze) River. Along the fertile and prosperous sea coast there are a total area ofover 120 x 10~3ha, with a population of 735 000, accruing some 500ha of new tidal land resourcescome from silt, sand and mud carried by the Changjiang River every year, extending about 140m peryear. This dynamic process of alluvial growth has run for some 1500 years. Mudflat on ChongmingIsland at the mouth of the Changjiang River is a resting ground for migratory birds and host morethan a hundred species, including rare cranes and geese. But the local people keep reclaiming thetidal land for economic development. Obviously, it is crucial to have a well-concerted plan forfuture exploitation. In this study, we attempted to investigate the status changes of land use andwild life habitats on Chongming Island in recent 10 years, and then analyzed different humanactivities and their effects on wild life habitats using satellite image data (1990, 1997 and 2000)as well as field survey. Based on the analysis, this study explored the relationships between islandgrowth and land use/cover change (LUCC), predicted what the habitat would be like in the future andtried to find more effective use of this new growing resource. At last, this study provided somepreliminary management plans for Chongming Island that will coordinate the development of localeconomies and the conservation of wild life and their habitats.
基金Program Strategic Scientific Alliances between China and the Netherlands under contract No.2008DFB90240Open Research Fund Program for State Key Laboratory of Estuarine and Coastal Research under contract No.SKLEC201207Open Research Fund Program for Shandong Province Key Laboratory of Marine Ecology Environment and Disaster Prevention under contract No.2012011
文摘The analysis of vegetation-environment relationships has always been a study hotspot in ecology. A number of biotic, hydrologic and edaphic factors have great influence on the distribution of macrophytes within salt marsh.Since the exotic species Spartina alterniflora（S. alterniflora） was introduced in 1995, a rapid expansion has occurred at Chongming Dongtan Nature Reserve（CDNR） in the Changjiang（Yangtze） River Estuary, China.Several important vegetation-environment factors including soil elevation, tidal channels density（TCD）,vegetation classification and fractional vegetation cover（FVC） were extracted by remote sensing method combined with field measurement. To ignore the details in interaction between biological and physical process,the relationship between them was discussed at a large scale of the whole saltmarsh. The results showed that Scirpus mariqueter（S. mariqueter） can endure the greatest elevation variance with 0.33 m throughout the marsh in CDNR. But it is dominant in the area less than 2.5 m with the occurrence frequency reaching 98%. S. alterniflora has usually been found on the most elevated soils higher than 3.5 m but has a narrow spatial distribution. The rapid decrease of S. mariqueter can be explained by stronger competitive capacity of S. alterniflora on the high tidal flat. FVC increases with elevation which shows significant correlation with elevation（r=0.30, p〈0.001）. But the frequency distribution of FVC indicates that vegetation is not well developed on both elevated banks near tidal channels from the whole scale mainly due to tidal channel lateral swing and human activities. The significant negative correlation（r=–0.20, p〈0.001） was found between FVC and TCD, which shows vegetation is restricted to grow in higher TCD area corresponding to lower elevation mainly occupied by S. mariqueter communities. The maximum occurrence frequency of this species reaches to 97% at the salt marsh with TCD more than 8 m/m2.
基金Supported by the Natural Science Foundation of Shanghai(No.19ZR1415300)the Zhejiang Provincial Natural Science Foundation of China(No.LQ21D060005)the China Postdoctoral Science Foundation(No.2020M681931)。
文摘Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic carbon(DOC)in submarine groundwater(well water and pore water)in salt marshes plays an important role in advective exchange between the salt marshes and coastal waters.However,the molecular characteristics of DOC in salt marsh groundwater are poorly understood because of the complex DOC structures and hydrodynamic process.In this study,fl uorescent components and refractory DOC(RDOC)in submarine groundwater from a salt marsh(Chongming Island,China)and adjacent coastal water were characterized by fl uorescence spectroscopy and nuclear magnetic resonance spectroscopy.The fl uorescent components identifi ed by parallel factor analysis indicated that humic-like substances dominated the chromophoric dissolved organic matter in the submarine groundwater.The chromophoric dissolved organic matter and dissolved organic matter in the submarine groundwater had non-conservative behaviors because of additions from terrestrial humic substances.The nuclear magnetic resonance spectra indicated that bioactive substances(carbohydrates)contributed only 13.2%-14.8%of the dissolved organic matter in the submarine groundwater but carboxyl-rich alicyclic molecules(CRAMs),the main components of RDOC,contributed 64.5%of the dissolved organic matter.Carbohydrates and CRAMs contributed 16.4%and 61.7%of the dissolved organic matter in the coastal water,similar to the contributions for submarine groundwater.The DOC concentration in submarine groundwater was 386±294μmol/L,which was signifi cantly higher than that in coastal water(91±19μmol/L).The high DOC concentrations and>60%relative RDOC content suggested that submarine groundwater may be an important source of RDOC to coastal seawater.This information will be helpful for estimating the climate eff ects of salt marsh blue carbon.
基金The National Natural Science Foundation of China under contract Nos 51761135024,42171282 and 41701001the Key Projects of Intergovernmental Science and Technology Innovation Cooperation of the Ministry of Science and Technology in China under contract No.2018YFE0109900+1 种基金the International Science&Technology Cooperation s of Shanghai Science and Technology Commission under contract No.19230712400the China Postdoctoral Science Foundation under contract No.2018M630414。
文摘With climate change and rising sea levels,the coastal zone’s flood risk is deteriorating.Previous researches have shown a gradually degrading capacity of traditional hard engineering structures(e.g.,seawall,dikes)on flood mitigation due to problems such as land subsidence and insufficient maintenance.To remedy the defects,the"building with nature concept"for coastal protection with saltmarshes was examined by combining field measurements and numerical simulations.The advantages of saltmarsh over traditional seawall on flood protection was demonstrated from the perspective of both flood area mitigation and economic gain,based on scenario simulations.Results show that tidal wetlands are essential in mitigating significant wave heights(Hs)and current velocities even during storm conditions.The storm wave and current velocity reduction ratio(RRw and RRc)by saltmarshes on Chongming Dongtan Shoal(CMDS)during Typhoon 9711 is approximately 11%and 51%,respectively.The wave and current mitigation by Scirpus mariqueter are more efficient than Spartina alterniflora and Phragmites australis during measurements in 2010,which were approximately 0.3 m and 0.2 m/s,0.125 m and 0.155 m/s,0.086 m and 0.128 m/s per kilometer width,respectively.The summer saltmarsh area 54.2 km2 on CMDS protects approximately 32 km^(2)land area behind the seawall from being flooded,equivalent to the seawall heightening of approximately 0.42 m on equivalent flood mitigation.The performance of cost-and-benefit analysis shows a relatively higher(by 3%–7%)net present value(NPV)and a higher(by 1.5 times)benefit-cost ratio(BC)of nature-based solution(i.e.,saltmarsh restoration)compared with traditional hard engineering solution(i.e.,seawall construction).Thus,building seawall with nature,such as a hybrid flood protection measure,should be implemented in the future coastal redesign and maintenance.
基金supported in part by The International Joint Laboratory on Tropical Diseases Control in the Greater Mekong Subregion fund(21410750200)the Science and Technology Commission of Shanghai,China and The Science and Technology Innovation Project fund of the School of Global Health,Shanghai Jiao Tong University School of Medicine(SGHKJCX2021-05,SGHKJCX2021-04),China.
文摘Haemaphysalis ticks are pathogenic vectors that threaten human and animal health and were identified in Chongming,the third largest island in China.To understand the distribution of these ticks and determine their potential invasion risk,this study aimed to identify the habitat suitability of the dominant tick H.flava based on natural environmental factors.Geographic information system(GIS)images were combined with sample points from tick investigations to map the spatial distribution of H.flava.Data on 19 bioclimatic variables,environmental variables,and satellite-based landscapes of Chongming Island were retrieved to create a landcover map related to natural environmental determinants of H.flava.These data included 38 sites associated with the vectors to construct species distribution models with MaxEnt,a model based on the maximum entropy principle,and to predict habitat suitability for H.flava on Chongming Island in 2050 and 2070 under different climate scenarios.The model performed well in predicting the H.flava distribution,with a training area under the curve of 0.84 and a test area under the curve of 0.73.A habitat suitability map of the whole study area was created for H.flava.The resulting map and natural environment analysis highlighted the importance of the normalized difference vegetation index and precipitation in the driest month for the bioecology of H.flava,with 141.61 km^(2)(11.77%),282.94 km^(2)(23.35%),and 405.30 km^(2)(33.69%)of highly,moderately,and poorly suitable habitats,respectively.The distribution decreased by 135.55 km^(2) and 138.82 km^(2) in 2050 and 2070,respectively,under the shared socioeconomic pathway(SSP)1.2.6 climate change scenario.However,under SSP 5.8.5,the total area will decrease by 128.5 km^(2) in 2050 and increase by 151.64 km^(2) in 2070.From a One Health perspective,this study provides good knowledge that will guide tick control efforts to prevent the spread of Haemaphysalis ticks or transmission risk of Haemaphysalis-borne infections at the human-animal-environment interface on the island.
