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The investigations were carried out in post-exploitation water bodies (subsidence pools, sand- and gravel pits) situated in urbanised and over-industrialised region of Upper Silesia. The least diversified leech (Hirudinea) communities occured in subsidence pools, because of the very high concentration of chlorides, sulphates and phosphates in their water, which is moreover very hard and of high BOD5 value. In other kinds of studied water bodies greater leech species diversity was observed. Most of the species found in studied water bodies occur commonly in various freshwater habitats, what may point out the lack of peculiarity of leech communities in these unnatural conditions.
In two fishponds (area of 1.6 ha and 0.2 ha, depth to 1.5 m) in Silesian Upland (Southern Poland) rare in Europe species Aulodrilus japonicus Yamaguchi, 1953 was found to the first time in Polish fauna. The water bodies are slightly acid, soft (total hardness up to 96 mg CaCO₃ l⁻¹) and nutrient rich. A. japonicus occurred during the whole study period (from March to November) in both ponds. The greatest abundance (up to 120 ind.m⁻²) was observed in the summer, however the mature specimens were never found.
A new locality of the Asian thermophilic aquatic oligochaete Branchiura sowerbyi Beddard, 1892(Oligochaeta, Naididae) was recorded in the Upper Oder River. Until now, this species has been only noted in a few localities in Poland: in the Szczecin Lagoon at the mouth of Oder River to Baltic Sea, in the heated Konin lake system (West Poland) and in the middle course of the Oder River. In our study, B. sowerbyi was found on one site (108 km of the river course) that is located more than 400 km from its previous recordings in the Oder River. This finding may show that B. sowerbyi has spread upstream. It should be noted that, as a rule, low abundance of this species may be the reason for the small number of its recordings, so further studies related to distribution and impact of B. sowerbyi on native oligochaetes are needed.
The water bodies formed in forest complexes are characterised by a significant degree of isolation from other aquatic environments as well as from urban agglomerations. In industrial areas, they are refuges of biological diversity. The long-term ecological research carried out in woodland ponds has allowed us to identify a new site of the occurrence of Placobdella costata (F. Müller) (Hirudinida: Glossiphoniidae) in Poland, the fourth in the southern part of the country. Furthermore, ecological information about the habitat and accompanying freshwater leeches are given.
The research conducted in settling ponds located in the coal basin in Upper Silesia (southern Poland), detected in one of them presence of the widgeon grass Ruppia maritima. Currently, it is the only inland site of this species in Poland. The widgeon grass creates underwater meadows in the shore zone of the settling pond and it grows in dense communities together with the common reed Phragmites australis in the coastal zone. Apart from these two plants, no other species were found. The morphological features of the vegetative and generative organs of the studied population of R. maritima is similar to those that have been reported from Europe. The bottom of the pond is atypical for R. maritima – it is covered by mine waste. The water of the settling pond has a high salinity and the water chemistry corresponds to the more natural environments that are inhabited by widgeon grass. This substitute habitat, which imitates the natural environment of R. maritima contributes to the good development of these species. However the studied settling pond offers unstable conditions due to the ongoing mining activity and requires permanent monitoring.
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