台特玛湖干涸湖盆区植物风影沙丘的形态特征

对台特玛湖干涸湖盆区盐穗木、柽柳和碱蓬3种植物风影沙丘的形态参数进行野外了测定，应用统计学方法，分析对比了不同植物风影沙丘的形态特征及阻沙能力。结果表明：（1）风影沙丘处于由沙嘴向沙堆演化阶段，沙丘形态参数间相关性显著（P<0.01），其中沙丘高度与水平尺度相关性较好，沙丘垂向发育速度快于水平扩展。（2）风影沙丘与植物形态参数间亦存在相关性，受植物生物特性的影响，不同植物的相关性差异较大，其中碱蓬呈高度正相关（R>0.85，沙丘背风坡坡度除外），盐穗木次之，柽柳灌丛相关性微弱。（3）在相同的区域环境下，3种植物的单株阻沙能力呈柽柳 > 盐穗木 > 碱蓬，盐穗木、碱蓬积沙量受株高影响较大，两者呈二次函数关系；柽柳积沙量主要取决于灌丛迎风剖面的面积。

Morphological characteristics of shadow dunes of plant at dry lakebed of Taitema Lake

Nebkhas was widely distributed in the arid region of northwest China. More researches on the sand-pile and sandbags stage of nebkhas have been done in recent years, but few have been conducted on the shadow dune originated from the plants. Therefore, in this study, the morphological parameters of shadow dunes of three plant species,Halostachys caspica,Tamarix ramosissima and Suaeda glauca,were studied at dry lakebed of Taitema Lake. The morphological characteristics of shadow dunes and sand trapping capability of three plant species were compared and analyzed by the approaches of least significant difference, correlation analysis and regression analysis. The results indicate that the length, width and height of three kinds of shadow dunes presented a significant correlation(P<0.01)with the correlation coefficients ranging from 0.392 to 0.995. There was a better correlation between the height and horizontal scale of shadow dunes(R>0.6). The vertical development of the dunes was faster than the horizontal expansion. The morphological parameters of shadow dunes were correlated with the morphological parameters of their plants. But the correlation between different plants and their shadow dunes were different. This difference was mainly influenced by the biological nature of the plant. In the same area, the sand trapping capability of individuals of three plants was shown as Tamarix ramosissima > Halostachys caspica > Suaeda glauca, the amount of sand trapped by on average unit crown volume of the plant was Suaeda glauca > Halostachys caspica > Tamarix ramosissima. The amount of deposited sand trapped by Halostachys caspica and Suaeda glauca kept a quadratic relationship with plant height. The sand trapped by Tamarix ramosissima dune was mainly influenced by the windward area of the shrub. The result of this paper was of great significance for understanding the interaction between plants and sand-blown activities, and evaluating the sand trapping capability of plants.