Four Centuries of Human Impact on Aquatic Environments in the sediments of the Bug River oxbow lakes (Mazovia, Poland)

The area of the White Forest (Puszcza Biała), located in the north-eastern part of Mazovia, stretches between the Narew and Bug rivers and occupies a region in east-central Poland. Over the last four hundred years, its landscape has changed markedly from dense forest, through a period of growing human pressure, to present-day efforts at restoration and renaturation. In the Middle Ages and early modern period, the forest was protected by the bishops of Płock against excessive exploitation. This situation changed during the partitions of Poland: both the Prussian and later the Russian administrations intensified logging and gradually expanded settlement. In the 20th century, centrally planned economic policies further stressed local ecosystems, for example through extensive land drainage and melioration.

In this project, we present results from four short organic sediment cores collected in different parts of the White Forest, at Morzyczyn, Nowa Wieś, Wszebory and Zarzetka. We analysed the cores using X-ray fluorescence (XRF), pollen analysis (palynology), macroscopic charcoal, subfossil Chironomidae (non-biting midges) and basic sedimentological methods. By combining Chironomidae data with the other proxies, we investigate how different levels of human activity have affected nearby aquatic ecosystems. Although humans have always been closely connected with nature, this region offers an unusually good opportunity to separate human and natural influences. We can draw on rich historical records documenting population, land ownership and agriculture, and we know a great deal about the climate history of the last few centuries. Together, this allows us to disentangle the specific impact of human activity on local water bodies.

Our approach represents a unique integration of archival data (written historical sources) with environmental archives (paleoecological reconstructions derived from biogenic sediments from oxbow lakes and/or peatlands, as well as comprehensive soil analyses). In this way, gaps or uncertainties in one line of evidence can be cross-checked and complemented by the other. The studied sites also differ in parish affiliation and in how the surrounding land was managed, which helps us compare contrasting land-use histories. Riparian zones began to be intensively cultivated only after 1764, when river regulation and large-scale forest clearing were introduced, significantly altering the region’s hydrology. This system enabled part of the local population to survive the crisis of the 19th century, and it remained in use until 1947.

Notably, the studied timeframe encompasses two major crises: the first related to crop failures between 1840 and 1890, when natural conditions led to famine and disease; and the second—an ecological crisis around 1980, when an increase in deformities of the Chironomidae mentum (mouthpart) on head capsules appears in the record, which we attribute to intensified human impact and pollution.

This project is funded by the National Science Center (No. 2021/43/B/HS3/02636).