Assessing large-scale macrobenthic community shifts in the Aegean Sea using novel beta diversity modelling methods....

The effects of large-scale environmental gradients on the spatial patterns of macrobenthic communities used in marine health assessment were evaluated using beta diversity methods. In this work, beta diversity partitioning and relevant ecological modelling methods revealed clear patterns between the northern and the southern parts of the Aegean Sea (Greece). A community turnover point was observed in the Evoikos Gulf marking the transition between the northern and the southern communities. The increased beta diversity in this work was due to species replacement driven mainly by the latitudinal gradients of bottom temperature and salinity whereas species richness did not present substantial differences between the Aegean macrobenthic communities. These findings are attributed to the ability of beta diversity methods to detect the environmental filtering that occurs in these marine provinces through the assessment of biotic interactions in respect to geographic distance. We propose a new standpoint of using beta diversity measures for benthic environmental assessment on a large spatial scale and in marine areas characterised by environmental gradients.