Peat bog and alluvial deposits reveal land degradation during 16th- and 17th-century colonisation of the Western Carpathians (Czech Republic)

Abstract

Wallachian (shepherd) colonisation of the upper parts of the Carpathians, the second largest mountain range in Europe, provides a unique opportunity to study human-induced ecological changes and subsequent sediment mobilisation within slope and fluvial systems. The Wallachians came to the nearly pristine landscape in the Czech part of the Western Carpathians during the 16th to 17th century bringing large-scale deforestation and grazing to the upper parts of its ridges. Despite the importance of this event, there is a lack of high-resolution multiproxy reconstructions to help decipher the relative influence of anthropogenic and climate factors on this landscape. Here, we provide an approximately 2.1-kyr record obtained from a peat bog where, using chronological, sedimentological, and pollen analyses, we were able to differentiate between environmental conditions before, during, and after colonisation. Prior to colonisation, climate deterioration following the onset of Little Ice Age caused changes in forest composition and erosion events (causing a ~ad 0–1500 gap in the record). Abrupt human-induced deforestation detected in the pollen record, together with the abundant fine-grained minerogenic content of peat deposits between ad ~1640 and ad 1870, corresponds to increased run-off and sheet erosion on slopes, enhanced by Little Ice Age climate deterioration. The sedimentary record in alluvial deposits downstream indicates that the colonisation of the mountain slopes in this region not only had a local effect on soil degradation, but it also increased the net aggradation of overbank deposits within valley floors. After reforestation, net aggradation was replaced by river incision into alluvia.