玛曲县沙漠化草地褐鳞苔草固沙特性初探

Sand-Fixing Characteristics of Carex Brunnescens of Desert Grassland in Maqu County of the Yellow River

褐鳞苔草(Carex brunnescens)是玛曲县沙漠化草地固沙的先锋植物,对维护玛曲高寒草地生物多样性和生态系统稳定性有重要作用。为了揭示褐鳞苔草种群的繁殖及固沙特征,对其地下部分的形态结构与种群繁殖特征,种群密度和地下部分数量指标与积沙特征的相互关系进行了研究,结果表明:褐鳞苔草地下茎(水平茎)高度发达,当地面被风沙覆盖后,地下水平茎会迅速延长并在茎节点上长出垂直茎,垂直茎快速向上生长并穿透沙面形成新的植株(沙埋深度小于50 cm),周而复始使地下茎形成多层网状结构,起到固沙作用。当种群密度小于146株/m2、地下茎直径小于1.40mm、一级根系直径大于0.627 mm时存在明显的风蚀现象;种群密度为146~158株/m2、地下茎直径为1.40 mm、一级根系直径为0.612~0.627 mm时固沙效果较好;种群密度大于158株/m2、地下茎直径大于1.40 mm、一级根系直径小于0.612 mm时出现明显的堆积现象。以上结果表明,通过人工辅助和工程措施,褐鳞苔草可作为玛曲高寒沙漠化草地生态治理的优良草种,具有良好的推广应用前景。

Carex brunnescens is pioneer plant to fix sand of desert grassland in Maqu,the first bend of the Yellow River. It is of great significance on keeping the biodiversity and ecosystem stability of alpine grassland in Maqu. In order to reveal the propagation characteristics and sandfixing of Carex brunnescens population,the paper studied the characteristics of morphological structure of its underground part and population propagation and the interrelationship between the population density and accumulated sand feature,quantity index of the underground part and accumulated sand feature. The outcomes show that the underground stems( horizontal stem) of Carex brunnescens are highly developed.When the land surface is covered by sandstorm,the horizontal stems will quickly extend and grow vertical stems at stem nodes and the vertical stems rapidly grow upward and penetrate the sand forming new plants( the cover depth is less than 50 cm). It develops in circles to form multi-layer network structure,playing the function of sand-fixing. When the population density is smaller than 146 plant / m^2,the diameter of underground stem is less than 1. 40 mm and the diameter of primary root system is greater than 0. 627 mm,it has obvious wind erosion; when the population density is 146-158 plant / m^2,the diameter of underground stem is 1. 40 mm and the diameter of primary root system is 0. 612-0.627 mm,it has sand-fixing effect; when the population density is great than 158 plant / m^2,the diameter of underground stem is great than 1.40 mm and the diameter of primary root system is smaller than 0. 612 mm,it has obvious sand accumulation. The above shows that Carex brunnescens can be used as excellent grass for ecological control of alpine desert grassland in Maqu through artificial assistant and engineering measures and it has good prospects of popularization and application.