From Extremely Acidic to Alkaline – Diversity of Aquatic Invertebrates in Forest Mining Lakes under the Pressure of Acidification

Human activities, including mining industry, have considerably degraded the water habitats worldwide. Acidification has severely affected aquatic environments with acidifying pollutants and constitute threat to freshwater biodiversity. The study area is unique for addressing the effects of mining-related acidification on biodiversity in freshwater ecosystems along a pH gradient (2.4-9.6). Using multivariate ordination techniques, we analysed taxa distribution to determine how variations in invertebrate composition correlated with environmental factors. The results revealed differences in pH of water, salinity indicators, hardness, and content of calcium, nitrites, and iron. The highest iron content, relatively high values of conductivity and chlorides was found in the extremely acidic mining lakes. A clear decreasing tendency was observed for the number of taxa with increasing acidity (Oligochaeta, Chironomidae, Glossiphonidae). The density of Hirudinidae, Lestidae, Libellulidae, Caenidae, Sialidae, Dytiscidae, Helodidae, Hydrophilidae and Polycentropodidae increased along with decreasing pH. Specific communities were found with increasing acidity, therefore a progressive increase in acidity will probably have further influence on biological life and water chemistry. The data yielded offer an opportunity to fill knowledge gaps concerning less-studied aquatic environments and links environmental pollution with communities, which is especially important because forest habitats are especially exposed to different climatic factors and threats.