Past anthropogenic changes in the lake ecosystems of late glacial landscapes in north-eastern Poland

Damage to water resources and lake ecosystems can be attributed to rapid economic development and urban expansion in recent decades, but the current state of our environment is also influenced by processes in the more distant past. The aim of this study was to evaluate the effects of lake drainage programmes in north-eastern Poland from the second half of the nineteenth century. Few studies of landscape transformation in the region deal with the loss of lakes resulting from land reclamation in the nineteenth century, despite its significant impact on water resources. During that period a total of 143 lakes were drained in the Olsztyn Lakeland. By 1914 only 3% of the original lakes remained. Today, the majority of drained lakes are sites of marginal importance to the natural environment or the economy. Drained lakes can be reclaimed and transformed into water retention reservoirs to enhance the local landscape.