浅谈稀疏标准化方法(Rarefaction)及其在群落多样性研究中的应用

RAREFACTION AND ITS APPLICATION TO THE STUDY OF DIVERSITY OF PALAEOCOMMUNITIES

古生物学常涉及多样性对比的研究。因为待比较的样本通常大小不一,所以直接对原始数据进行比较一般并不准确。稀疏标准化方法使两样本在大小不同的情况下也可进行多样性对比,因此在古生物领域应用广泛,但该方法在群落多样性研究中使用不多。在一些相关应用研究案例中,使用者通常未能考虑稀疏化方法的使用条件和局限性,其中相交的稀疏化曲线很难或不能比较的问题更是经常为人所忽视。本文针对群落研究中多样性的对比问题介绍两类稀疏化方法,并强调其使用条件及局限性。以新发现的华夏正形贝腕足动物群为例讨论该方法的使用,同时对该动物群4个采样点的稀疏化数据进行曲线拟合分析,求解曲线交点,对稀疏化数据进行外插值运算,并借此首次为稀疏化曲线交叉不可解的问题提出一个解决方案。

In the process of diversity comparison, results directly der nerally not unequal. T to compare ived from raw accurate since he rarefact diversities data comparison sample sizes are ion method makes it are ge usually possible of samples with different sizes. The method is widely used in palaeontology, but is rarely adopted in palaeocommunity research. In previous studies, the prerequisites and limitations of the rarefaction method, especially the comparison problem between intersecting curves, were often ignored. This paper is focused on the diversity comparison of palaeocommunity. It introduces two kinds of rarefaction techniques and em-phasizes the prerequisites and limitations of the method. The recently found Cathaysiorthis bra- chiopod fauna is used as an example, and using the data of 4 collections from different localities. Exponential curve fitting and extrapolation of the rarefied data is used for the first time to fix the comparison problem amongst intersected rarefaction curves.