Caddisflies (Trichoptera) of Protected Calcareous Fen Habitats: Assemblages, Environmental Drivers, Indicator Species, and Conservation Issues

Abstract

The caddisflies (Trichoptera) of calcareous fen habitats, in contrast to those of other peatland types, have been poorly researched. We thus conducted a two-year study in south-eastern Poland encompassing four types of such habitats—drained and undrained fens and water bodies (pools and ditches) located within the fens—in order to define trichopteran reference assemblages (PCoA), indicator species (IndVal analysis), and the drivers (both natural and those associated with landscape management, including area protection) responsible for caddisfly species distribution (CCA). The most important environmental driver was habitat persistence. Distance-based RDA analysis revealed a distinct pattern in the distribution of species with or without diapause along the persistence gradient. Environmental drivers associated with plants were also crucial for both fens and water bodies. The key factor influencing the caddisfly assemblages of pools and ditches was the use and management of the surrounding land, whereas in the fens, it was the level of area protection. Physical and chemical water parameters had no statistically significant impact on the assemblages. Some factors can be modified by humans (e.g., water level regulation, vegetation, and landscape management) to maintain healthy ecosystems for aquatic insects.

Drivers for the Diversity of Mollusc Communities in Unique Calcareous Fen Habitats

“…Ongoing climate change is altering the carbon balance in fens and threatening their flora and fauna [4]. Calcareous fens support an incredibly rich and diverse range of plants and animals, including rare and endangered species and have a high conservation value on a world scale [5][6][7]. Therefore the calcareous fens with Cladium mariscus and species of the Caricion davallianae are protected under the EU Habitats Directive [8] (code of the Habitats Directive Annex I: 7210).…”