Taxonomic and numerical sufficiency in depth- and salinity-controlled marine paleocommunities

Numerical and taxonomic resolution of compositional datasets affects investigator’s ability to detect and measure relationships between communities and environmental factors. We test whether varying numerical (untransformed, square-root- and fourth-root transformed relative abundance, and presence-absence data) and taxonomic resolutions (species, genera, families) reveal different insights into Lower to Middle Miocene molluscan communities along bathymetric and salinity gradients. The marine subtidal has a more even species-abundance distribution, a higher number of rare species, and a higher species-family and species-genus ratio than the three habitats with higher fluctuations in salinity and other physical parameters (marine and estuarine intertidal, estuarine subtidal). Taxonomic aggregation and numerical transformation of data result in very different ordinations, although all habitats differ significantly from each other at all taxonomic and numerical levels. Rank correlations bet...

组成数据集的数值分辨率与分类分辨率，会影响研究者检测并量化群落与环境因子之间关系的能力。我们测试了不同的数值处理方式（未转换、平方根转换及四次方根转换的相对丰度，以及有无数据）与分类分辨率（物种、属、科），能否为揭示早中新世至中中新世软体动物群落在水深梯度和盐度梯度上的特征提供不同视角。与盐度及其他物理参数波动更大的三个生境（海洋与河口潮间带、河口潮下带）相比，海洋潮下带具有更均匀的物种丰度分布、更多的稀有物种，以及更高的物种-科和物种-属比值。尽管所有生境在所有分类和数值水平上均存在显著差异，但数据的分类聚合与数值转换会产生截然不同的排序结果。秩相关（rank correlations）的...