Figure 3.

Venn-diagrams showing the results of variation partitioning performed on (a) Environmental model (Env) and Geographical model (PCNM_G), (b) Environmental model (Env) and Topographic model (PCNM_T), and (c) Environmental model (Env) and Directional spatial model (AEM) for benthic diatom metacommuntiy in the study area. Variation explained uniquely and jointly, and the unexplained fractions were shown as the number in each part of the figures (total variation = 1). The significance of each testable fraction was expressed as ^■P < 0.1, ^*P < 0.05, ^**P < 0.01, ^***P < 0.001.