The Sirok Nyírjes-tó peat bog provides an almost full Holocene climatic record reconstructed by bog surface wetness investigations based on plant macrofossil analysis. The method of bog surface wetness reconstruction has not so far been adapted to the characterization of continental peat bogs. The emergence of a deep oligotrophic lake was dated to cc. 9500 cal. yr BP. The driest phase of the peatland was recorded at 6400 cal. yr BP, at the time of the Holocene climatic optimum. The deterioration of the climate, which began at 3500 cal BP, culminates here in the Carpathian Basin, as was shown by numerous records. An increase in the amount of Sphagna from 2800 cal. yr BP in the Nyires-tó peat bog marks the cooling of the climate and the accompanying rise in rainfall. The first oligotrophic Sphagnum peatland developed at Sirok between 2300 and 1500 cal. yr BP. Since 2300 cal. yr BP a record of alternating phases of Sphagnum peatlands and sedge/reed peatlands was demonstrated. A sudden expansion of Sphagna was recorded at least 10 times. Sphagnum-peaks at 2150, 1750, 1300, 1000, 850, 500 and 200 cal. yr BP perfectly match the humid periods identified in western Europe.
A new quantitative paleobotanical method for the description of Quaternary organic sediments is presented. The Peat Component System, with the paleobotanical description of macroscopic organic material, allowed us to reconstruct the hydroseral succession. The modified "semi-quantitative quadrate and leaf-count macrofossil analysis technique" (QLCMA) was used to quantify the peat components. This quantitative plant macrofossil technique, together with pollen, mollusk, and radiocarbon analyses, was used to reconstruct the postglacial mire development of an eutrophic peat bog in S Hungary. The analysis of the Holocene peat sequence was used to reconstruct the development of a filling-up spillstream of the river Danube. Multiple cores made it possible to reconstruct vegetation development in space and time.
The study aims to contribute to the medieval environmental history of the eastern periphery of the Transylvanian Plain (Câmpia Transilvaniei/Mezőség). With the help of archaeological and historical data and the multi-aspect analysis of undisturbed core sequences, the economic life of the Pauline Monastery founded in the 14th century near Sâncraiu de Mureş (Marosszentkirály) and the surrounding villages was investigated. The multidisciplinary research focuses on the paleochannels of the Mureş and the artificial watercourses (ditches) that branch off the river, and the mills built on them. The work also provides new data on the general environmental changes in the middle course of the Mureş river during the Middle Ages and the early modern period, which are largely due to the very intense human activity here.
The investigation of a 8.1 m long peat sequence from Tăul fărăfund (“Bottomless Lake,” Transylvanian Basin, Northern Romania) offers a series representing wetland development since the Middle Holocene. The most striking feature of the sequence is a cca. 900 year-long hiatus caused by peatcutting in the 14th century AD. An artificial reservoir was constructed there in the Late Middle Ages by the excavation of the uppermost peat layer, afflicting a significant environmental impact on this remote location. One of the oldest documented Hungarian settlements from the time of the Hungarian Kingdom (11th century AD, presumably with previous history) in Transylvania was discovered in the vicinity of the former reservoir by an archaeological field survey. By harmonising historical data and the exact chronological sequence of the borehole, the creation of the reservoir was inserted into the local history of the developing mediaeval settlement network at the time when some of the early settlements had been abandoned and a permanent village was established, with a church and upscale landowners, in the area of present-day Băgău in the 13th to 14th century AD. Significant environmental impacts have emerged during this transitional period around the reservoir.
The medieval market-town of Sic (Szék in Hungarian) was an important Transylvanian settlement due to its remarkable salt mining. The impact of the mining activities on the environment and the history of water management were investigated based on a palaeoecological study, performed on the large Reedbed of Sic (Stufărişurile/Nádas-tó). We found that in the last 3000 years the anthropogenic impact has been continuous in the territory, but the types and intensity of the disturbances changed with time. The most notable environmental transitions took place after 1000 AD, suggesting a significant intensification of salt mining. Forest cover significantly drop, but salt concentration and the frequency of halophytic species in the investigated marshland increased during the Late Middle Ages. The dominance of halophytic marshland species reached their peak in the 17th century. This coincides with the apogee of mining activities and human lake management. The most remarkable deforestation occurred in the 18th century, when the present-day landscape with negligible forest cover was developed.