Ecohydrological Conditions in Urban Wells and Patterns of Invertebrate Fauna Distribution (Kraków, Poland)

Groundwaters are threatened by various kinds of contaminants, especially in cities. The results of an ecohydrological analysis (hydrobiological, chemical and geological) conducted in 91 urban wells in Kraków showed their effect on fauna composition and abundance. In 74 wells, the presence of invertebrates, chiefly characteristic for surface water, as well as Collembola was stated. Copepoda were found in 40 wells, whereas Nematoda, Annelida and Diptera larvae were found at over a dozen sites. Microturbellaria, Rotifera, Ostracoda and Amphipoda were present in only a few wells. The aim of this article was to find the patterns of invertebrates' distribution in the wells to further understanding of their relationships with groundwater chemistry and the geological background. This is especially important in light of the anthropogenic pollution occurring in wells and the desired attainment of the good ecological status of groundwater. According to Student's t-test, the presence of fauna did not depend on the studied environmental factors, whereas Pearson correlations showed that total fauna abundance and Copepoda occurrence positively correlated with water temperature which was higher in the city in comparison to that in rural wells. The value of the Shannon–Wiener index and the number of taxa negatively correlated with the well's depth. High variations of water chemical parameters caused by mixed lithology and hydrogeology as well as spotty contamination may affect the occurrence of fauna.