Human-sensitive bryophytes retreat into the depth of forest fragments in central European landscape

Abstract

An importance of the edge effect and other environmental factors on bryophyte communities has been repeatedly evaluated in boreal forests whereas only rarely in forest remnants in traditionally inhabited landscape of central Europe. Adopting the design of a previous study dealing with vascular plants, we examined whether species richness and composition of bryophyte communities in 23 forest fragments (0.1-255 ha) in a representative upland agricultural landscape in central Bohemia coincides with the same environmental factors as vascular plants and if so, whether congruently or not. According to generalized additive models, bryophyte species richness and composition were significantly related to forest vegetation type, stand basal area and soil pH, analogous to vascular plants. Distribution of human-sensitive bryophyte species was further associated with slope aspect and an unlimited longrange edge effect, shown by increased occurrence of human-sensitive bryophytes along the entire distance gradient from the forest edge (0-477 m). Communities of bryophytes and vascular plants were highly congruent in species richness, species turnover and even in number of species with similar colonization ability. We conclude that requirements of human-sensitive bryophytes are fulfilled only in the core areas of large forest fragments. The small size of most current forest fragments and the range of the edge effect suggest that spatial patterns of bryophyte species composition within forest fragments have been substantially altered in the entire region of central Europe.