Scale-specific effects of environmental variables on benthic macrophyte and invertebrate communities in the Vaindloo area, the central Gulf of Finland

We quantified the relative importance of scale-specific variability of macroalgal and benthic invertebrate communities in the Vaindloo area, the central Gulf of Finland. Macrophyte communities had a clear variability minimum at 8 km spatial scale. In contrast to macrophytes, the scale-specific variability of benthic invertebrate communities was small with no clear variability peak or minimum. The spatial distribution patterns of macrophytes and benthic invertebrates did not vary with regard to the species composition and dominance structure of communities. Among environmental variables the coverage of boulders and depth contributed most to the variability of the species composition and biomass dominance structure of macrophytes as well as of the species composition of benthic invertebrates. In addition to these environmental factors, the variability in the abundance and biomass dominance structure of benthic invertebrates was described by coastal slope, exposure, and cover of sediment size fractions other than boulders. The study suggests that the scale-specific variability of marine communities is complex and differs notably among different ecosystem elements. The variability of macrophytes and benthic invertebrate communities was also described by the abiotic environment operating at multiple spatial scales.