Grassle J Frederick, Smith Woollcott
Woods Hole Oceanographic Institution, 02543, Woods Hole, Massachusetts, USA.
Oecologia. 1976 Mar;25(1):13-22. doi: 10.1007/BF00345030.
We propose a new measure of similarity, the normalized expected species shared or NESS. The measure is based on the expected number of species shared between random samples of size, m, drawn from a population. The NESS measure is shown to be a generalization of Morisita's similarity and is demonstrated to be less biased than other commonly used measures. The contribution of dominant and rare species is explicit according to the sample size, m, chosen. For large m, NESS is sensitive to the less common species in the populations to be compared.The NESS measure has been used to cluster a 2-year sequence of subtidal benthic samples taken after a severe disturbance. The NESS measure is responsive to the less common species so that both a temporal progression in community recovery and seasonal variation are revealed.
我们提出了一种新的相似性度量方法，即归一化期望共享物种数（NESS）。该度量基于从总体中抽取的大小为m的随机样本之间共享的期望物种数。结果表明，NESS度量是森下相似性的推广，并且证明其偏差小于其他常用度量。根据所选样本大小m，优势种和稀有种的贡献是明确的。对于较大的m，NESS对要比较的总体中较不常见的物种敏感。NESS度量已用于对严重干扰后采集的2年潮下带底栖样本序列进行聚类。NESS度量对较不常见的物种有响应，从而揭示了群落恢复的时间进程和季节变化。
