样带法在测定草地植物群落最小面积中的应用

Application of transect sampling method in the research minimum area of grassland plant community

利用样带法对内蒙古草甸草原不同放牧强度的植物群落最小面积进行了研究,采用2种模型对种-面积曲线进行了拟合,应用3个标准确定了群落的最小面积和样带的最短长度及临界样方数量。研究结果表明,通过剩余标准差(RSE)、相关指数(CRI)、偏差绝对值的平均值(AAD)和相对偏差绝对值的平均值(AARD)4个指标的检验,对数模型的拟合效果最佳。样带上样方的取样间隔为1m时,轻度放牧区的群落最小面积为3.36m2,中度放牧区的群落最小面积为3.69m2,重度放牧区的群落最小面积为3.15m2,重度放牧区的群落最小面积显著低于其他放牧梯度(P<0.05)。因此,对于整个放牧系列应采用最大的群落最小面积(3.69m2),则取样样带的最短长度为36.9m,每条样带的临界样方数量为37个。

The minimum area of a meadow steppe under different grazing intensity in Inner Mongolian grasslands was studied by transect sampling method. Species-area curve was fitted by two kinds of models, and the minimum area and the shortest length of the transect and the critical number of quadrats were determined by three standards. The results showed that tested by the residual standard error（RSE）, the correlation index（CRI）, average of absolute deviation（AAD） and average of absolute relative deviation（AARD） four indexes test, the fitting result of logarithm model was best. When sampling by quadrat with 1m interval on the transect, the community minimum area of light grazing was 3.36 m^2, and that with moderate grazing was 3.69 m^2, while that with heavy grazing was 3.15 m^2. The community minimum area with heavy grazing were significantly lower than those nuder others grazing intensities （P0.05）. Therefore, for the entire grazing sequence, the maximum area of 3.69 m^2, the shortest transect length of 36.9 m and the critical number of quadrats of 37, are recommended for accurate surveys of the meadow steppe in the area.