摘要
为了解草地管理利用方式对生态系统与大气间水汽交换量的影响程度和影响机制,本研究在内蒙古典型温性草原区域选取相互毗邻的三块不同管理利用方式(放牧,围封禁牧和开垦)草地,利用连有同化箱的便携式红外气体分析仪(LI-6 400),对生态系统蒸散过程进行了全天测定。结果显示,草地围封禁牧和开垦均显著改变了植被群落特征,相比放牧样地,围封禁牧样地蒸散增加了28.01%(P<0.01),而生长C4作物的开垦样地的蒸散量则下降18.62%(P<0.05)。各利用管理方式草地的气温,空气湿度和饱和水汽压差在日间的动态变化均能较好解释蒸散速率的动态变化,其中气温对生态系统蒸散速率的影响具有昼夜差异性,夜间蒸散速率对气温变化的响应敏感性显著低于白天。研究表明,草原区域人类管理利用方式差异造成的生态系统结构、功能变化可能会显著影响区域地表与大气间的水汽交换。
Evapotranspiration(ET)plays an important role in ecosystem water budgets. Land-use changes in the ecotone between Mongolia steppe and north China agricultural region are frequent and involve large areas,probably due to the increasing conflict between environmental stress and economy food demands. These land- use changes include reclaiming(R) and gazing exclusion(GE)induced impacts on water budgets for original grazing(G)grassland. Through atmospheric transport,the changes may affect local environmental conditions and impact precipitation in downwind regions. In our research,it was hypothesized that different land use/ management directly influenced the environmental factors that affect land- atmosphere water vapor fluxes,and influenced environmental sensitivities that jointly changed evapotranspiration. To examine the effects of different human use/management patterns including grazing,grazing exclusion and cultivation on grassland evapotranspiration,simultaneous measurements were conducted in three adjoining grassland ecosystems with different land use/management patterns,typical of northern China steppe. Evaporation was determined by chambers connected to a por Tablele infrared gas analyzer(Li- 6400). Observations and experiments was conducted in August,when grassland biomass peaked. Our results indicate that in adjoined areas,compared to grazing community,ET in grazing exclusion areas increased significantly,28.01% increase in grazing excluded,and decreased in reclaimed community by 18.62% in reclaimed community. In addition,the air temperature sensitivity of ET was higher at daytime,and decreased during the night in all three communities. Despite environmental conditions,vapor exchange varied with different human management in these communities,since the community characteristics(e.g. soil organic carbon,biomass,LAI)change;the grassland management pattern also affected the relationship between vapor exchange and environmental factors,and may simultaneously contribute to changes in water budgets.
出处
《资源科学》
CSSCI
CSCD
北大核心
2015年第2期342-350,共9页
Resources Science
基金
国家重点基础研究发展规划项目(编号:2010CB950902)
国家自然科学基金(编号:31070427)
中国科学院地理科学与资源研究所青年人才项目(编号:2013RC203)
关键词
草地
管理利用方式
蒸散
放牧
围封禁牧
草地开垦
内蒙古
grassland use/management change
evapotranspiration
grazing
grazing exclusion
steppe cultivation
Inner Mongolia
