EN
The study presents the results of research on the impact of anthropogenic factors on the biodiversity of the Noctuidae occurring in marsh ecosystems of the Biebrza valley. During the study 299 noctuid moths species were recorded, out of which 31 are stenotopic, characteristic of marsh and peat bog ecosystems. A comparative analysis which included exclusive characteristic species and similarity indices of the communities of the studied sites in the three basins of the Biebrza valley proved the highest biodiversity of Bagno Ławki in the southern basin. Consequently, it indicates the lowest transformation level of the marsh ecosystems of the basin. On the other hand, the most regressive changes were found on the sites located in the middle basin.