Results
Taxonomic
richness
Environment (represented by the first two PCA axes) was predominant in
explaining variation in taxonomic richness in all organism groups (Fig.
2). It varied between 10.6 and 52.2%, and was statistically significant
in almost all organism groups except for phototrophic and heterotrophic
microeukaryotes. The effect of relative spatial position (closeness
centrality) was also relevant for some taxa varying between 1.9 and
9.3% explained variation. It was the highest and statistically
significant in rotifers (9.3%, F(1,50)=9.08, p=0.004)
and crustaceans (1.9%, F(1,50)=3.94, p=0.047), while
only marginally significant in prokaryotes (2.8%,
F(1,50)=3.05, p=0.091) and dipterans (3.4%,
F(1,50)=3.30, p=0.068; Table S3 and S4, Supporting
Information). The relationship between taxonomic richness and centrality
(with the environment partialled out) was positive in all these groups
(Fig. S3, Supporting information).