【作者】 刘芳；

【导师】 王炜； 朴顺姬；

【作者基本信息】 内蒙古大学 ， 生态学， 2004， 硕士

【摘要】 本文在2003年7、8月份，从群落尺度上采用LI-6262CO₂／H₂O红外气体分析仪连接气室的方法，测定了典型草原带不同类型植物群落的蒸散量、CO₂吸收量的日进程、昼夜进程和季节动态。经数据统计处理和比较分析不同群落蒸散量、CO₂吸收量与特定生境间的相互关系，得出如下结论： 1、在退化的群落中，蒸散以土壤蒸发的物理学过程为主，群落的水分利用效率低；在植被状况相对较好的群落中，蒸散以植物蒸腾的生物学过程为主，群落水分利用效率高；在基本一致的降水量下，退化群落因日蒸散总量较少而存在未被充分利用的水资源。 2、环境因子中，光照强度和气温是影响蒸散量的两个重要环境因子。以群落蒸散量为因变量，光照强度和气温为自变量进行定量分析，得出群落蒸散量与光照强度和气温的高斯关系模型。该模型除可以较为客观地描述变量间的定量关系外，还可用于时间（生长季）、空间（研究区）蒸散量的整合。 3、生长季高峰期土壤贮水量（0～50cm）、群落蒸散量以及耗水量随着群落的退化，不断降低，在重度退化的群落中，三者的值均达到最低；随着群落退化恢复演替的进行，又不断增加，且当演替接近顶级群落时，三者的值同时趋近于最大。在衡量退化群落是否恢复、以及恢复至何种程度，也可将此作为一个衡量的标准。 4、群落CO₂吸收量与群落植被状况有密切关系。没有发生退化的接近原生植被、地表没有枯落物或有少量枯落物存在的群落在整个生长季都表现为大气CO₂的汇；接近原生植被，但地表有大量枯落物存在的群落只有在植物光合作用高峰期，才表现为大气CO₂的汇；严重退化群落在生长季表现为大气CO₂的源。更多还原

【Abstract】 Applying means of connecting LI-6262CO2/H2O analyzer to the chamber,this paper studied on the changes of evapotranspiration and CO2 absorption of different communities across a day and growing season in typical steppe July and August 2003 .Analysing the relationships among evapotranspiration, CO2 absorption and their environment by statistic means ,we came to such conclusions:1 Degraded communities were characterized by physical process evaporation and lower water efficiency,while communities with good vegetations were distinguished by their biological process evapotranspiration and higher water efficiency. There was water resources not used in degraded communities because of their less evapotranspiration under the similar precipitation conditions.2 Light intensity and temperature were the two important environmental factors affecting evapotranspiration.Let light intensity and temperature as independent variables and evapotranspiration as dependant one,establish model among them in order to calculate evapotranspiration of the whole growth season across the region.3 Capacity of water use, evapotranspiration and ecological use of water decreased along with the deterioration of communities so that the minimum values existed in the communities degraded seriously and increased along with the recovery successionof degraded communities and came to the maximum values in the climax ones.For those reasons,we could regard them as standard that weigh the degree how the communities degraded and how they recovered.4 Quantity of CO2 absorption was mainly affected by vegetation conditions.Initial communities that had little dead litter were the sink of CO2 across the whole growth season,while the ones that degraded seriously were the source of itlnitial communities had dead soil covering were the sink of CO2 only when their photosynthesis got to the peak.更多还原