Remnants of spring fens in the Bohemian-Moravian Highlands: the occurrence and coexistence of (not only) molluscan glacial relicts
| Autoři | |
|---|---|
| Rok publikování | 2018 |
| Druh | Další prezentace na konferencích |
| Fakulta / Pracoviště MU | |
| Citace | |
| Popis | Fens are groundwater-fed wetlands distinctive by a constant moisture and low productivity of vegetation. These rare and ecologically specific habitats are still frequently distributed across the boreal zone, chiefly in Scandinavia, however southwards they have become highly fragmented and isolated. Some of these are of refugial nature and host isolated populations of cold adapted species, considered as glacial relicts. So far, most of the mollusc research on fens of the Czechia and Slovakia has been focused on the Western Carpathian fens, especially calcareous tufa forming sites, being rich in molluscs and frequently hosting snail glacial relicts, e.g. Pupilla alpicola and Geyer’s whorl snail (Vertigo geyeri). Until recently, malacologists have been overlooking fens in Bohemian-Moravian Highlands, which are slightly acidic to neutral in terms of water pH. Likely because of lack of calcareous sites, mollusc communities at these fens were expected to be poor in species without any rare or protected species. However, in 2011, Geyer’s whorl snail was discovered in the area followed by Vertigo lilljeborgi in the following year. Such findings have started systematic research, as many of these fens are known to harbour several glacial relicts of vascular plants (e.g. Carex chordorrhiza and C. diandra) and brown mosses (e.g. Paludella squarrosa and Scorpidium scorpioides). Potentially suitable sites for glacial relict snails were identified based on relict plant and moss occurrence. 55 fens have been examined, with 31 snail species recorded in total (22 terrestrial and nine aquatic). Geyer’s whorl snail was found at 23 localities and V. lilljeborgi at four. Nesovitrea petronella, a denizen of fen and meadow wetlands and also considered a relict species, was found at five sites. These findings indicate a historical continuity of fens in the Bohemian-Moravian Highlands, though recently surviving in only several small fragments out of the original notably higher extent if compared with the situation 70 years ago. Therefore they deserve the highest level of protection and further research is needed, both ecological and palaeoecological. |