Aquatic vegetation in Lake Kuźnickie has changed over the last 40 years due to improved water quality. Rush vegetation has decreased, while charophytes have become more important. The endangered charophyte Lychnothamnus barbatus has recovered. However, overall biodiversity and species richness have decreased, with only four dominant species remaining. The lake has shifted from being eutrophic with vascular plants to mesotrophic with charophytes, indicating good water quality.