Macroinvertebrates of the post-mining calcareous brooks: comparison with the natural calcareous spring brooks
|Surface brown-coal mining influences negatively well-developed ecosystems and results in creation of new anthropogenic habitats. The formation of extensive spoil heaps with specific bedrock chemistry, which determines an occurrence of brooks with a calcium carbonate (tufa) precipitation, is an unavoidable consequence of open-coast mining in the Sokolov Coal Basin (western part of the Czech Republic). These brooks characterised by basic pH and low levels of nutrients may provide suitable habitats for many rare and highly specialised invertebrates that are scarce in intensively exploited agricultural landscape. On the other hand, the colonization of these unique biotopes by aquatic biota can be strongly limited by harsh water chemistry. In our study we focused on the description of the macroinvertebrate composition of post-mining calcareous brooks (Velká podkrušnohorská spoil heap, Sokolov Coal Basin) and on the comparison of macroinvertebrate diversity between post-mining brooks and natural calcareous spring brooks, which are located on the western margin of Carpathians. For data analyses we used these groups of aquatic macroinvertebrates: Clitellata, Ephemeroptera, Plecoptera, Odonata, Trichoptera, Coleoptera and Diptera. In comparison with natural sites, taxa richness of post-mining sites was lower, however, the species composition was similar. Moreover, several nationally threatened species and spring specialists were shared between post-mining and natural sites. As a result, we may consider post-mining calcareous brooks as surrogate habitats for aquatic macroinvertebrate biota of natural calcareous spring brooks.