Results of multivariate PERMANOVA to test for differences in holdfast sessile (a) and mobile (b) assemblage between regions (fixed) and sites (random, nested within region).

Habitable holdfast space (HHS) was included as a covariable in the analysis. Permutations were based on a Bray-Curtis similarity matrix generated from fourth-root transformed biomass/abundance data. Results of univariate PERMANOVA to test for differences in assemblage-level univariate metrics (taxon richness and total biomass) in holdfast assemblages are also shown (c–f). Permutations for univariate analysis were based on a Euclidean distance similarity matrix generated from untransformed diversity data. All tests used a maximum of 4999 permutations under a reduced model; significant effects (P

本分析将可栖息固着空间（Habitable holdfast space, HHS）作为协变量纳入。置换检验基于经四次方根转换的生物量/丰度数据生成的布雷-柯蒂斯相似性矩阵（Bray-Curtis similarity matrix）。本研究同时展示了用于检验固着群落的群落水平单变量指标（类群丰富度与总生物量）差异的单变量置换多元方差分析（Permutational Multivariate Analysis of Variance, PERMANOVA）结果（图c至f）。单变量分析的置换检验基于未经转换的多样性数据生成的欧氏距离相似性矩阵。所有检验均在简化模型下最多进行4999次置换；显著效应（P