Diversity of caddisflies (Trichoptera) in springbrooks of the Western Carpathian spring fens: Are their assemblages distinct from neighbouring streams?
|Year of publication||2016|
|Type||Appeared in Conference without Proceedings|
|Description||Spring fens are habitats characterised by specific abiotic conditions, such as relatively constant temperature and flow regime, low water depth and predominantly organic substrate. Owing to their island distribution in the landscape, springs and their communities are considered to be isolated from the surrounding habitats. One of the most diversified and abundant groups of spring aquatic macroinvertebrates are caddisflies (Trichoptera) which include many specialists adapted to specific conditions of these habitats. The main aim of this study is a comparison of caddisfly assemblages inhabiting springbrooks that drain spring fens in the Western Carpathians, with assemblages of the neighbouring streams. The Western Carpathian spring fens are relict biotopes with valuable fauna and flora, scattered sparsely in the eastern part of the Czech Republic and the northern part of Slovakia. Larvae of caddisflies were sampled at 25 pairs of springbrooks and neighbouring streams, three mesohabitats (riffle, pool, moss) were investigated separately in the streams. More heterogeneous mesohabitat structure of streams resulted in significantly higher (altogether 63 species) species richness in comparison with the springbrooks (40 species). When comparing stream mesohabitats, riffles are preferred by more species than pools. Moss patches were inhabited mostly by juveniles of many different species. Springbrooks and streams shared 37% of caddisfly species which included lotic taxa dominating in the studied streams and less abundant in the springbrooks (e.g. Sericostoma sp., Rhyacophila tristis, Chaetopteryx fusca/polonica), and spring specialists (crenobiontic and crenophilous species) frequent in springbrooks, but rare in the streams (e.g. Beraea maurus, B. pullata, Ernodes sp., Crunoecia irrorata, Agapetus fuscipes). About 16% of species found exclusively in the springbrooks comprised some rare crenobiontic species (e.g. Synagapetus dubitans, Micropterna lateralis) and all lentic species (e.g. Limnephilus ignavus, Oligostomis reticulata). The remaining 47% of caddisflies restricted in the streams can be characterized as lotic species typical for rhithral or potamal streams (e.g. Allogamus auricollis, Halesus sp., Hydropsyche saxonica, Philopotamus montanus, Rhyacophila nubila). The comparison of springbrooks and stream mesohabitats using non-metric multidimensional scaling (NMDS) showed that caddisfly assemblages of springbrooks are similar to those of the pools, likely due to shared lotic species preferring slow-flowing water and organic substrate.|