毛乌素沙地油蒿植冠下生物结皮分布特征及其影响因素研究

Pattern of Biological Soil Crust and Its Driving Factors under Artemisia ordosica in Mu Us Sandy Land

在毛乌素沙地采用样线法调查了油蒿植冠下生物结皮分布状况并对其影响因素进行了分析。结果表明:油蒿植冠下生物结皮厚度分布不均匀,生物结皮厚度的最大值出现在距油蒿根部20 cm处,厚度值为0.84 cm,20 cm处向外生物结皮厚度呈环带状降低,距离每增加10 cm生物结皮厚度平均下降约0.07 cm。东南方向上生物结皮分布半径长于其他3个方向,西北方向生物结皮分布半径短于其他方向;距油蒿根部相同距离处东南方向生物结皮最厚,西北方向生物结皮最薄。油蒿植株下生物结皮的分布与枯落物的分布关系密切,枯落物是影响油蒿植株下生物结皮形成的重要因素,同时枯落物的分布又受到油蒿植冠形态和当地风况的影响。

The distribution of biological soil crust under Artemisia ordosica in the Mu Us Sandy land is studied by means of line transect sampling,and the pattern of biological soil crust and its driving factors are analyzed.The results show that the thickness of biological soil crust under Artemisia ordosica is uneven.The maximum thickness,0.84 cm,occurs at the position of 20 cm from the basal root.Outward from the position,the thickness of biological soil crust reduces in ring by a rate of 0.07cm every 10 cm.The radius of biological soil crust is longer southeastward than that in the other three directions,while that northwestward is shorter.The biological soil crust is the thickest southeastward and thinnest northwestward.The analysis shows a significant correlation between the distribution of litterfall and biological soil crusts under Artemisia ordosica,suggesting litterfall is an important factor to accelerate the development of biological soil crust.The pattern of litterfall is controlled by the local wind regime and the canopy shape of Artemisia ordosica.