Abiotic predictors of faunal communities in an ombrotrophic peatland lagg and an open peat bog

Abstract

Most ecological research has hitherto focused more on sea and lake ecosystems than on peatland habitats. The primary objectives of this paper were to analyse the ciliate, rotifer, cladoceran, copepod and insect assemblages in a horizontal lagg and an open peat bog, and to assess the influence of physical and chemical parameters on their communities. Sampling was done in a transitional bog from May to October 2012 in a transect comprising the lagg and the open peatbog. The first two axes of a principal component analysis accounted for 49.8% of the total variance in the composition of the faunal communities studied. The distribution of samples in ordination space suggested that the habitats are distributed along the gradient of water level and the gradients of total organic carbon and nutrients. Assemblages of all groups investigated showed a strong compositional gradient correlated with surface water and phosphates. However, species composition of ciliates and rotifers was explained by conductivity and/or chlorophyll-a concentration. The results suggest that the lagg zone of a bog can function as an ecotone, with significantly greater species richness and abundance of faunal communities.