Species richness and diversity of caddisflies (Trichoptera) in a selected area in mid-western Poland (Lubuskie Province)

Abstract

The information about the distribution of caddisflies (Trichoptera) in mid-western Poland being a part of the Wielkopolsko-Kujawska Lowland (WKL) faunistic region is still scarce compared to other regions. To close the knowledge gap, we investigated caddisflies larvae and occasionally imagines in a selected area in mid-western Poland in 2011. The aim was the preliminary estimation of species richness and abundance of protected, rare and endangered species in this part of WKL. For the study 63 sampling sites representing broad spectrum of habitat types were chosen and analysed with various ecological indices. In total, 75 species: 46 as larvae and 51 as imagines were found in the area. Among them, one protected species (Crunoecia irrorata), 5 listed in the Polish Red List (Erotesis baltica, Hydropsyche bulgaromanorum, Ylodes simulans, Limnephulus borealis and L. fuscinervis), and 11 species not reported for WKL yet were found in the area. In the whole material, the most frequent and dominant species was Limnephilus flavicornis. In contrast, 50 species were recorded in less than 5% of sites. The highest species richness was found in rivers and fish ponds with total number of 33 and 32 species, respectively, whereas the lowest one in springs (5 species) and bogs (6 species). The highest species diversity obtained with probability of intraspecific
encounter (PIE) Index was found in fish ponds (0.90) and rivers (0.85) as well. In contrast, streams had the lowest PIE value (0.60) in the area. The most valuable habitat types with regard to protected, endangered and rare species were rivers and fish ponds, as well as lakes and streams of lower importance. To conclude, our investigation indicated a high species richness and diversity in the area, which was related to high habitat heterogeneity, thus having significant importance for biodiversity preservation in mid-western Poland. Moreover, fish ponds and rivers were the most valuable habitat types significantly contributing to species richness, diversity and preservation of rare and endangered species in this area.