塔里木河下游植物调查最小取样面积分析

采用巢式样方法,对塔里木河下游两个断面6条样带38块64 m×64 m样地进行调查,选用线性和非线性种-面积模型,对调查区不同比例因子植物调查最小取样面积、最小取样面积与不同地下水条件的关系进行了分析。根据种-面积曲线的最优模型,当比例因子取值包括群落50%、60%、70%、80%和90%的植物种类时,最小调查样地面积分别为418 m2、707 m2、1 138 m2、1 702 m2和2 656 m2;随着离河距离增加,物种数减少,植物的生长势降低。当比例因子取值包括群落50%植物种类、地下水埋深由离河50 m的1.57 m到离河1 500 m的7.53 m变化时,离河不同距离各级最小取样面积变化较大,地下水条件是植物种类调查最小取样面积变化的关键因素。

Analysis on the Minimum Sampling Area of Vegetation Survey in the Lower Reaches of the Tarim River

The minimum sampling area with different vegetation species proportion and the relationships between the minimum sampling area and groundwater conditions are analyzed based on the linear, non-linear species-area models and nested sampling investigation of 38 basic quadrats of 64 m×64 m in the lower reaches of the Tarim River. The results show that optimal model can be established by species-area curve, and the minimum sampling areas are 418 m2, 707 m2, 1 138 m2, 1 702 m2 and 2 656 m2 respectively when the proportions of quadrat species to community species are 50%, 60%, 70%, 80% and 90% respectively. The number of vegetation species decreases and the grow vigor of plants drops with the increase of the distance off the Tarim River. When the proportion of quadrat species to community species is 50%, the minimum sampling areas change with the change of the groundwater levels at different distances off the Tarim River, and the groundwater condition is the key factor resulting in the variation of minimum sampling area.