青藏高原高寒草地植物多样性调查方法的比较

Comparison of different sampling techniques for alpine grassland plant diversity on Qinghai-Tibet Plateau

为比较高寒草地植物多样性各类调查方法的实际效果,提高高寒草地植物多样性研究结果的效率及准确性,本文以青藏高原地区的3种主要草地类型——高寒草甸、高寒草原和高寒荒漠草地为研究对象,分别采用同心圆样线-样方法、Daubenmire样线法、大样方-样线法和改进的巢式样方法进行植物多样性调查,分析比较不同调查方法对3类高寒草地植物多样性的监测效果和成本效率,以期筛选出准确性较高、成本较低的调查方法。结果表明:(1)物种数-调查时间关系的拟合曲线显示,随着研究样地物种数的增多,4种方法间完成样地植物多样性调查所耗时间的差异变大;(2)在物种丰富度相对较高的高寒草甸和高寒草原上,改进的巢式样方法监测到的物种丰富度最高,但该方法所耗工时最长,相对而言同心圆样线-样方法最经济有效;(3)在物种丰富度相对较低的高寒荒漠上,4种方法监测的物种多样性准确度和调查所需的工时相差不大。但是,考虑方法简便性,大样方-样线法为最佳。

To compare the effects of different sampling techniques for alpine grassland and im- prove the efficiency and accuracy of alpine grassland plant diversity study, we applied four differ- ent methods to investigate the diversity in three main types of grassland in Qinghai-Tibet Plateau （alpine meadow, alpine steppe and alpine desert）. The methods included center-staked transect- quadrat method, Daubenmire transect method as modified by the USDA Forest Service, large quadrat-transect method proposed by the USDA Agricultural Research Service, and modified Whittaker multi-scale vegetation plot method. Through analysis of monitoring effectiveness and cost efficiency of the three kinds of alpine grassland plant diversity, we screened out the investi- gation method which had the highest accuracy and lowest cost. Species number-time cost curves indicated that the difference of consumption time of four methods became larger as the species number in sampling plots increased. In alpine meadow and alpine steppe, which had relatively higher species richness, the modified Whittaker multi-scale vegetation plot method can detect the highest species richness; however, this method costs the longest time. Relatively, the center- staked transect-quadrat method was the most economical. In alpine desert with low species rich- ness, the time cost of investigation and the accuracy of species diversity did not vary much among the four investigation methods. As a whole, considering the simplicity, large quadrat-transect method was the best one for investigation.