Impact of human activities on soil respiration: A review          下载免费PDF全文

Fang Zhang  Tao Wang  Xian Xue  Jian Guo 《寒旱区科学》2009,1(4):0287-0299

Soil respiration is one of the primary fluxes of carbon between soils and the atmosphere.It is produced by rhizosphere respiration and soil microbial respiration.Soil respiration is not only affected by environmental factors,but also changes with the hu-man-induced disturbances of ecosystems.Land-use,the measures of land management,the pollution of soil,and so on can affect soil respiration and change the soil efflux.According to some research,the authors summed up their impacts on soil respiration by human activities through land-use changes and land-management measures among agroecosystem,grassland ecosystem,and for-est ecosystem.The results showed that (1) when adding fertilization to farmland,the soil respiration will increase;(2) fenced land can decrease soil respiration,while soil respiration in the grazed land at a grassland ecosystem will decline with the increasing of grazing intensity;(3) with grassland fertilization;farmland cultivation;fire,fertilization,and cutting of forest,conflicting results were found in the changes of soil respiration.Perhaps plant species,site condition,and measurement season can lead to different results on soil respiration.  相似文献   

黑河流域水资源系统演变和人类活动影响   总被引：4，自引：0，他引：4  

刘少玉  张光辉  张翠云  周晓妮 《吉林大学学报(地球科学版)》2008,38(5)

黑河流域降水集中于山区,平原稀少。50多年来,除了20世纪70—80年代上游的中东部地区降水偏多外,其它区域为正常变化;蒸发量从山区向平原逐渐增大,除了中游蒸发量显示稳定变化外,山区和下游区表现为减少趋势;黑河多年出山径流量呈现稳定变化,但在中下游盆地间的正义峡水文站,径流量自20世纪80年代中期以来,出现了非常明显的减少过程:这是受到中游地区地下水开采量增加、补给量减少和水位下降的影响,主要是中游地区人口数量增多、大规模扩耕灌溉和水工建设作用的结果。计算表明,人类活动影响强度:20世纪50年代占18%,60—70年代占28%,80—90年代占54%;上游占1%,中游占87%,下游占12%。这说明黑河中游80—90年代是人类活动影响强度达到最大的地区。因此,提出了充分认识流域水资源系统演变规律性,约束人类活动的影响,均衡保护利用流域水资源的有关建议。  相似文献   

Impact of Human Activities on Depositional Process of Tidal Flat in Quanzhou Bay of China   总被引：2，自引：0，他引：2  

WANG Aijun 《中国地理科学(英文版)》2007,17(3):265-269

As a very important component of a coastal system,tidal flats come to be a focus of the studies on land-ocean interaction in the coastal zone because those areas are subjected to intense human activities and are highly sensitive to the global change.The Quanzhou Bay,located along the middle part of Fujian coast of China,covers about 136.4km2,and the area of coastal wetland in the entire bay from intertidal to subtidal with 6m of water depth accounts for 96% of the total area.Seven short cores were collected and divided in situ with the interval of 5cm on the coastal wetlands of Quanzhou Bay on April 19,2006.The sediment samples were scattered and the grain sizes were measured by using Mastersizer 2000.Human beings' activities on tidal flat have disturbed the vertical distribution of sediments in stratigraphic sequence and accelerated the sedimentation rates.Grain size analysis results show that the grain size diameters increase and sediment becomes worse sorted towards the sea under the strong human disturbance;Spartina alterniflora can play a role of trapping the fine sediment;but near the bank,the sediment becomes coarse and there are two peak values on frequency curve influenced by the sandpile.The trough formed by human activities along the coastline changes the transport path of water and suspended sediment.The sediments are transported through the trough and deposit in it during the flood;the ebb flow is retarded by the flow output through the adjacent trough,and the deposited sediment can not be re-suspended;then,the sedimentation rate increases.In situ observation show that the sedimentation rate is about 8-10cm/yr.  相似文献   

Quantitative Assessment of Impacts of Regional Climate and Human Activities on Saline-alkali Land Changes： A Case Study of Qian＇an County, Jilin Province     

LIAN Yi  WANG Jie  TU Gang  REN Hongling  SHEN Baizhu  ZHI Keguang  LI Shangfeng  GAO Zongting 《中国地理科学(英文版)》2010,20(1):91-97

Interdecadal and interannual variations of saline-alkali land area in Qian’an County, Jilin Province, China were comprehensively analyzed in this paper by means of satellite remote sensing interpretation, field flux observations and regional climate diagnosis. The results show that on the interannual scale, the impact of climate factors accounts for 71.6% of the total variation of the saline-alkali land area, and that of human activities accounts for 28.4%. Therefore the impact of climate factors is obviously greater than that of human activities. On the interdecadal scale, the impact of climate factors on the increase of the saline-alkali land area accounts for 43.2%, and that of human activities accounts for 56.8%. The impact of human activities on the variation of saline-alkali land area is very clear on the interdecadal scale, and the negative impact of human activities on the environment should not be negligible. Besides, changes in the area of heavy saline-alkali land have some indication for development of saline-alkali land in Qian’an County.  相似文献   

近45 a黑龙江省春季风速变化的区域特征分析     

刘春生  孙彦坤  秦铁 《黑龙江气象》2009,26(1)

用方差极大正交旋转REOF方法,将经过均一性检验、分布较均匀的黑龙江省1961～2005年25个测站春季风速变化分为5个区,并对各区风速变化特征进行了分析,最后探讨了人类活动对风速变化的可能影响.结果表明:近45 a来,黑龙江省各个区域风速均呈减小趋势,人类活动可能是导致春季风速减小的一个原因.  相似文献   

Impact of global change on transmission of human infectious diseases     

WU XiaoXu  TIAN HuaiYu  ZHOU Sen  CHEN LiFan  XU Bing 《中国科学:地球科学(英文版)》2014,57(2):189-203

Global change,which refers to large-scale changes in the earth system and human society,has been changing the outbreak and transmission mode of many infectious diseases.Climate change affects infectious diseases directly and indirectly.Meteorological factors including temperature,precipitation,humidity and radiation influence infectious disease by modulating pathogen,host and transmission pathways.Meteorological disasters such as droughts and floods directly impact the outbreak and transmission of infectious diseases.Climate change indirectly impacts infectious diseases by altering the ecological system,including its underlying surface and vegetation distribution.In addition,anthropogenic activities are a driving force for climate change and an indirect forcing of infectious disease transmission.International travel and rural-urban migration are a root cause of infectious disease transmission.Rapid urbanization along with poor infrastructure and high disease risk in the rural-urban fringe has been changing the pattern of disease outbreaks and mortality.Land use changes,such as agricultural expansion and deforestation,have already changed the transmission of infectious disease.Accelerated air,road and rail transportation development may not only increase the transmission speed of outbreaks,but also enlarge the scope of transmission area.In addition,more frequent trade and other economic activities will also increase the potential risks of disease outbreaks and facilitate the spread of infectious diseases.  相似文献   

基于气候变化和人类活动影响的土地利用分析——以新疆阿克苏河流域绿洲为例   总被引：4，自引：3，他引：1  

王生霞  丁永建  叶柏生  廖杰  谢遵义 《冰川冻土》2012,34(4):828-835

以1990、2000、2010年3期Landsat TM影像为土地利用基础数据,结合1990年以来的社会经济资料和反映气候变化的气温、降水数据,对1990年以来阿克苏河流域绿洲土地利用变化进行了分析.结果表明:1990-2010年期间,耕地、建设用地以单向转入为主,耕地对绿洲"扩张"贡献最大,前期(1990-2000年)的贡献率为129.1%,后期(2001-2010年)的贡献率提高到142.5%;草地、水域以单向转出为主,草地对绿洲"萎缩"贡献最大,前期的贡献率是-39.8%,后期是-34.8%;其次是水域,前期对绿洲的贡献率是-1%,后期是-9.3%;河漫滩、林地、湿地在前期对绿洲的"扩张"贡献率分别是7.5%、0.3%和5.1%,后期对绿洲的"萎缩"贡献率分别是-2.4%、-0.02%和-0.4%.近20a来流域绿洲规模整体上持续扩张.通过分析绿洲土地利用驱动力系统可以看出,绿洲土地利用类型变化主要受人类活动影响,气候变化起基础性作用.  相似文献   

Runoff change of Naoli River in Northeast China in 1955–2009 and its influencing factors     

Xiaolin Song  Xianguo Lu  Zhengmao Liu  Yonghe Sun 《中国地理科学(英文版)》2012,22(2):144-153

Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 for Bao′an station, from 1955 to 2009 for Baoqing station, from 1956 to 2009 for Caizuizi station and from 1978 to 2009 for Hongqiling station. The influences of climate change and human activities on runoff change were investigated, and the causes of hydrological regime change were revealed. The seasonal runoff distribution of the Naoli River was extremely uneven, and the annual change was great. Overall, the annual runoff showed a significant decreasing trend. The annual runoff of Bao′an, Baoqing, and Caizuizi stations in 2009 decreased by 64.1%, 76.3%, and 84.3%, respectively, compared with their beginning data recorded. The wet and dry years of the Naoli River have changed in the study period. The frequency of wet year occurrence decreased and lasted longer, whereas that of dry year occurrence increased. The frequency of dry year occurrence increased from 25.0%-27.8% to 83.9%-87.5%. The years before the 1970s were mostly wet, whereas those after the 1970s were mostly dry. Precipitation reduction and land use changes contributed to the decrease in annual runoff. Rising temperature and water project construction have also contributed important effects on the runoff change of the Naoli River.  相似文献   

2000-2013年浑善达克沙地植被净初级生产力变化研究     

元志辉  池勇峰  雷军  包刚  包玉海  萨楚拉  咏梅 《冰川冻土》2017,39(1)

利用卫星遥感资料和地面气象观测资料,基于CASA模型及其他数理方法估算了浑善达克沙地2000-2013年生长季(4-10月)植被净初级生产力(NPP),并对其时空变化特征进行了分析,讨论了气候因子和人类活动对植被净初级生产力的影响.结果表明:14年间,研究区生长季的植被净初级生产力呈波动中增加趋势,多年平均NPP为239.8 gC·m-2·a-1.整个研究区表现为高NPP值(大于150 gC·m-2·a-1)的植被面积在增加,低NPP值(小于150 gC·m-2·a-1)的植被面积在减少.在空间分布上,研究区的北部、中部和南部边缘区域的植被NPP增加趋势较明显,而东部和西部部分区域未发生明显的趋势性变化.总体而言,研究区植被净初级生产力变化趋势与降水量的关系更密切,其相关系数达到0.86,是驱动植被NPP年际波动的最直接因素.而与温度呈负相关,相关系数为-0.42.综合考虑气候因素和人类活动对沙地NPP的影响发现,温度降低、种饲料面积、年末牲畜存栏头数和羊的数量的减少是NPP值提高的关键因素.  相似文献   

人类活动对中国滨海湿地的影响及其保护对策   总被引：8，自引：0，他引：8  

徐东霞  章光新 《湿地科学》2007,5(3):282-288

人类为了获取大量生产和生活资料对滨海湿地资源进行了大规模的开发利用活动,给滨海湿地生态系统带来了严重的负面影响,如石油开发造成了石油污染、植被退化和动物栖息地减少等,大大降低了滨海湿地的生态功能和社会与经济效益。以辽河三角洲湿地、黄河三角洲湿地、红树林湿地等滨海湿地为例,从石油开发、湿地污染、土地利用变化、湿地开发、城市和港口建设、水利工程建设、湿地水文过程和热带海岸开发等方面探讨了人类活动对中国滨海湿地的影响,并提出了保护滨海湿地的对策和建议。  相似文献