Impact of Water Retention Practices in Forests on the Biodiversity of Ground Beetles (Coleoptera: Carabidae)

This study was carried out in an area covered by the “Increasing retention capacity and prevention of floods and droughts in forest ecosystems in lowland areas” land drainage development project. The aim was to evaluate the impact of transformations in a habitat following the project’s implementation on the structure of assemblages of epigeic ground beetles, in the context of the overall trend of decreasing biodiversity. The entomological observations were commenced before launching the planned hydro-technical development at the study area and were repeated 11 years later. During the two years of observations (2008 and 2019), 3311 specimens of ground beetles, representing 89 species, were captured. Water regulation affected the composition of ground beetle assemblages. After the small water retention program had been completed, a quantitative and qualitative decrease in ground beetles was observed. The groundwork for the development caused some disturbances in the habitat, leading to, amongst other things, higher soil moisture, which was conducive to the establishment of ground beetle assemblages other than those observed before the water retention project. After the hydro-technical objects had been constructed, the share of large and small zoophages with higher moisture preferences (hygrophilous species) increased, while the contribution of xerophilous hemizoophages decreased