New urbanization targets at coordinated urban-rural development, and construction of ecological and livable environment, it is the foundation for breaking urban-rural dual structure of China and promoting the agricult...New urbanization targets at coordinated urban-rural development, and construction of ecological and livable environment, it is the foundation for breaking urban-rural dual structure of China and promoting the agricultural modernization. Small cities and towns as carriers of new urbanization have already become important paths of realizing new urbanization and solving problems concerning 300 million peasants in China. Considering the requirements of new urbanization, this paper took Luzhou City in Sichuan Province for example to explore development path suitable for small cities and towns in west China and gave pertinent suggestions.展开更多
Total mercury in soil,water,plant,insects,fishes and bird feathers were determined to study mercury distribution and accumulation in typical wetland ecosystems in the Sanjiang Plain,Northeast China.Results show that t...Total mercury in soil,water,plant,insects,fishes and bird feathers were determined to study mercury distribution and accumulation in typical wetland ecosystems in the Sanjiang Plain,Northeast China.Results show that total mercury concentrations in soils of Deyeuxia angustifolia wetland and Carex lascarpa wetland are 0.046 mg/kg and 0.063 mg/kg,respectively.Total mercury concentration in water bodies is 0.053 μg/L on average.Of four plants studied,total mercury in moss is the highest with the mean of 0.132 mg/kg.Of 10 terrestrial insect species studied,total mercury in centipede(Scolopendra spp.) is the highest with the mean of 0.515 mg/kg while total mercury in grasshopper(Oxya spp.) bodies is the lowest.Total mercury concentrations in the herbivorous,omnivorous and predatory insects are 10.18 ng/g,16.47 ng/g and 213.35 ng/g on average,respectively.Total mercury concentrations of the adult feather(549.88 ± 63.04 ng/g),nestling feather(55.15 ± 23.53 ng/g),and eggshell(22.05 ± 5.96 ng/g) of the Grey heron(Ardea cinerea) are higher than those of the Great egret(Egretta alba)(adult feather:446.57 ± 90.89 ng/g;nestling feather:32.99 ± 17.15 ng/g;eggshell:21.02 ± 3.17 ng/g) in the wetlands of the Sanjiang Plain.The bioconcentration factors decrease in the order of piscivorous fish muscle > omnivorous fish muscle > herbivorous fish > insect.展开更多
文摘New urbanization targets at coordinated urban-rural development, and construction of ecological and livable environment, it is the foundation for breaking urban-rural dual structure of China and promoting the agricultural modernization. Small cities and towns as carriers of new urbanization have already become important paths of realizing new urbanization and solving problems concerning 300 million peasants in China. Considering the requirements of new urbanization, this paper took Luzhou City in Sichuan Province for example to explore development path suitable for small cities and towns in west China and gave pertinent suggestions.
文摘了解迁徙路线和迁徙前后活动规律对候鸟的保护具有重要意义.2019年23月,在鄱阳湖对20只豆雁(Anser fabalis)佩戴了卫星跟踪器,研究了鄱阳湖豆雁越冬种群的迁徙路线和活动特征.结果表明,最早的个体在3月12日开始北迁,较晚的个体4月25日北迁,截至6月20日仍有部分个体没有迁徙.豆雁卫星追踪时间为60.5±15.6天(n=19),迁徙距离为1349.5±1004.9 km(n=18),迁徙时间为34.7±16.1天(n=18),停歇地的数量为6±3(n=18).豆雁的春季迁徙路线可以分为东线和中线两部分,东线经过我国安徽、江苏、山东、辽宁、吉林、黑龙江,进入俄罗斯;中线经过我国湖北、安徽、河南、河北、内蒙古,进入蒙古.豆雁在30°~40°N之间较少做长时间的停留,而在40°~50°N之间会做2.7±1.1次(n=9)较长时间的停歇,每次停歇长达12.7±7.2天(n=24),东北平原和内蒙古高原东部是豆雁重要的中途停歇地.豆雁日间的活动量显著高于夜间,迁徙前期的活动量显著高于迁徙期,迁徙前期在8:009:00和18:0019:00两个时段为活动高峰,迁徙期每天7:008:00和18:0019:00两个时段为活动高峰.在不同环境温度区内豆雁的活动距离存在显著差异(n=8827,df=9,P=0.000),在0~5℃时的平均活动距离最大,为4.9±14.4 km/h.
基金Under the auspices of National Natural Science Foundation of China (No. 41001026)Major State Basic Research Development Program of China (No. 2010CB951304)Frontier Program of Northeast Institute of Geography and Agroecology (No. KZCX3-SW-NA09-03)
文摘Total mercury in soil,water,plant,insects,fishes and bird feathers were determined to study mercury distribution and accumulation in typical wetland ecosystems in the Sanjiang Plain,Northeast China.Results show that total mercury concentrations in soils of Deyeuxia angustifolia wetland and Carex lascarpa wetland are 0.046 mg/kg and 0.063 mg/kg,respectively.Total mercury concentration in water bodies is 0.053 μg/L on average.Of four plants studied,total mercury in moss is the highest with the mean of 0.132 mg/kg.Of 10 terrestrial insect species studied,total mercury in centipede(Scolopendra spp.) is the highest with the mean of 0.515 mg/kg while total mercury in grasshopper(Oxya spp.) bodies is the lowest.Total mercury concentrations in the herbivorous,omnivorous and predatory insects are 10.18 ng/g,16.47 ng/g and 213.35 ng/g on average,respectively.Total mercury concentrations of the adult feather(549.88 ± 63.04 ng/g),nestling feather(55.15 ± 23.53 ng/g),and eggshell(22.05 ± 5.96 ng/g) of the Grey heron(Ardea cinerea) are higher than those of the Great egret(Egretta alba)(adult feather:446.57 ± 90.89 ng/g;nestling feather:32.99 ± 17.15 ng/g;eggshell:21.02 ± 3.17 ng/g) in the wetlands of the Sanjiang Plain.The bioconcentration factors decrease in the order of piscivorous fish muscle > omnivorous fish muscle > herbivorous fish > insect.
