Effect of meander restoration on macroinvertebratebiodiversity: the case of the Borová stream(Blanskí½ Les, Czech Republic)

This study brings a view on the effects of restoration of a formerly channelized small submontane stream situated in the Blanský Les Protected Landscape Area (South Bohemia, Czech Republic) on macroinvertebrate assemblages as an indicator group. The restoration project was carried out during two stages (1998 and 2000). It consisted of excavating a new channel to restore the historic meandering pattern. The evaluation of this project is primarily based on the comparison of composition between pre-restoration (1995) and post-restoration (2000–2003) macroinvertebrate samples focusing on species richness, species composition, and representation of rare Ephemeroptera and Plecoptera species. The analyses showed a substantial increase in species richness that was especially prominent shortly after the restoration intervention. This increase was not only due to the creation of lentic habitats, but was even observed at every single sampling site of the stream. The DCA ordination of species composition of the pre- and post-restoration sites indicated a considerable increase in the between-site diversity. This was apparently caused mainly by the establishing of lentic habitats, whereas diversity of lotic sites showed only a slight increase, which was most prominent during the last year of the sampling period. The shift in the species composition was profound for lotic sites as well. Although the restoration intervention considerably increased species richness and markedly changed species composition, there was no detectable increase of rare or vulnerable Ephemeroptera and Plecoptera species.