Describing lake fish communities : Do presence–absence and biomass data show similar spatial and environmental relationships?

We examined if community―environment and community―geographical-location relationships differ between presence―absence and biomass data of lake fishes. Our study lakes ranged across very long gradients of the features of boreal lakes in the ecoregions of Finland, providing an excellent opportunity to examine patterns in lake fish communities. Fish community structure responded to multiple environmental gradients, yet there was a clear pattern of succession from salmonids in oligotrophic lakes through European perch in mesotrophic lakes to cyprinids in eutrophic lakes. Such patterns prevailed especially in the biomass data. Partitioning of variation in the species matrix between environmental and spatial variables did not reveal clear differences between presence-absence and biomass data. Although slightly different combinations of environmental factors were included in the constrained ordination models, the relatively similar variation in presence―absence and biomass data along environmental and spatial gradients suggests that they may be used interchangeably to describe community―environment relationships at large geographical extents.