Environmental implications of past socioeconomic events in Greater Poland during the last 1200 years. Synthesis of paleoecological and historical data

Abstract

We explored the past environmental history inferred from a fen located in northwestern Poland, in a historically important location. Pollen, plant macrofossils, micro- and macrocharcoal particles, and non-pollen palynomorphs were analyzed continuously in a 1-cm resolution, supplemented with archeological data and historical written sources. The last 1200-year environmental history of the fen was supported with accelerator mass spectrometry (AMS) radiocarbon (14C) dating (19 dates per 172 cm of the profile) and validated by 59 210 Pb dates. Our research showed that primeval oak–hornbeam forests near the Kazanie mire disappeared gradually, starting from 1035 ± 20 cal. yr CE, due to the economic development of the newly formed Polish (Piast) statehood. The pollen data revealed no shortage of oak timber during the 11th century, as recorded by previous studies in the area between Poznań and Gniezno. The Czech invasion in 1039 CE, which was associated with mass depopulation and domestic crisis, seemed to be manifested by the increase of pioneer Betula taking advantage of weaker human impact. Substantial land-use changes started with the further development of Polish statehood between the 15th and the 16th century CE, as reflected by cultivated land, ruderal, and meadow and pasture pollen indicators, as well as the rise of microcharcoal influx. The economy of Poland was disrupted by a noticeable socioeconomic collapse in the 17th century CE, which caused depopulation (by approximately 67.5%) and a decline in arable land (by 35%). Paleoecological data reflect this socio-environmental crisis with a decrease in all anthropogenic indicators, rapid forest regeneration, and secondary succession of pine on the abandoned land. According to palynological data, rapid landscape transformation due to agricultural reforms and industrialization commenced in the 19th century CE and was associated with the expansion of pastures, meadows, and arable lands. The following rapid decrease of cultivated land pollen indicators in 1940 ± 10 cal. yr CE is linked with the economic collapse after World War II and/or the implementation of new crops which produce less pollen.