水分胁迫对三江平原典型湿地植物种群高度与密度的影响

Influences of Long-term Water Stress on Typical Plant Populations in the Sanjiang Plain Wetlands

基于为期3年的水文模拟实验,分析了长期干旱与淹水胁迫对三江平原典型湿草甸、沼泽化草甸及沼泽群落的优势种群——小叶章和毛苔草种群高度和密度的影响。结果显示,在不同群落中,小叶章和毛苔草种群高度总体均随水位升高而增加,毛苔草种群密度总体均随水位升高而下降,而小叶章种群密度随水位升高变化无明显规律性;随水分胁迫时间延长,各水位梯度下两种植物种群高度和密度具有波动性。研究表明,两优势种群在单优群落与混合群落中对水分胁迫均表现出不同的响应特征,种群竞争对两个种群的水分需求具有重要影响;两优势种群对水分胁迫的响应特征与水分胁迫的幅度及持续时间有关,毛苔草种群对水分胁迫的响应更为敏感,而两个种群指标中以种群高度对水分胁迫的响应更为敏感。

Based on a 3-year hydrologic simulation experiment,we analyzed the effects of the long-term drought and inundation on the typical dominant species of wet meadow,marsh and swamp meadow communities Calamagrostis angustifolia and Carex lasiocarpa population in the Sanjiang Plain.The results showed that in different communities,population height of the C.angustifolia and C.lasiocarpa generally increased as the water increased,and population density of C.lasiocarpa declined while that of C.angustifolia with no significant changes;and population height and density of the two plants fluctuated with prolonged stress.The two dominant species both responded differently to water stress when in a single dominant and mixed communities,and species competition had an important influence on water requirements of the two populations;In addition,responses of the two dominant species to water stress were related to the magnitude and duration of stress.C.lasiocarpa was more sensitive to water stress than C.angustifolia,and the population height was more sensitive than the population density.