Middle to Late Holocene vegetation shifts in the NW Transylvanian lowlands (Romania)

Abstract

Abstract. The Iaz peat bog, located in northwestern Transylvania at 300 m a.s.l., was cored to study the Middle to Late Holocene vegetation shifts in the area. The pollen record is supported by seven 14 C datings. The base of the sequence starts in the Middle Holocene, when the outer woodlands were dominated by Corylus avellana together with other components of the Quercetum mixtum. The local establishment of Carpinus betulus occurred at 5700 cal. yr BP with maximum values at around 4900 cal. yr BP. At 4800 cal. yr BP, Fagus sylvatica became locally established and expanded, possibly as a result of moist climatic conditions and dominated the mesothermophilous woodlands from 4300 cal. yr BP onwards. During the periods of greater moisture, the deciduous forest was overgrown by the hygrophilous Alnus glutinosa belt. Indications of human activities in the area were recorded since 6300 cal. yr BP, when Cerealia and Secale pollen and other ruderal taxa start to appear regularly throughout the sequence. Although intense at times, the anthropogenic factor only played a major role in the vegetation changes during the last 635 years.

Late Holocene palaeohydrological changes in a Sphagnum peat bog from NW Romania based on testate amoebae

“…The peat core recovered from Iaz reached 540 cm (Grindean et al, 2014) but due to poor preservation of the fossils, the testate amoebae tests could be studied only to the depth of 365 cm. The present study will take into consideration only this part.…”

“…3-4). The complete description of the sequence and the accumulation rate are discussed in Grindean et al (2014).…”

“…Because of the poor preservation of the pollen in the bottom part of the sequence and a possible hiatus at around 520 cm the first radiocarbon date (8380 ± 50 BP) was ruled out. Therefore, pollen stratigraphic markers from nearby sites were used for assigning the beginning of the peat sedimentation from our sequence to a given age (Grindean et al, 2014). Thus our record starts at about 7000 cal yr BP and the TA analysis at about 3050 cal yr BP.…”

An integrated airborne laser scanning approach to forest management and cultural heritage issues: a case study at Porolissum, Romania

“…Moreover, besides being mandatory for defensive purposes, the deforestation event is also supported by paleoenvironmental studies that indicate a large scale deforestation within this region (Rosch & Fischer 2000, Tanţău et al 2003, Tanțău et al 2006, Feurdean 2010, Tanţǎu et al 2014. Oak, beech, and hornbeam show a decrease in the pollen spectra during a time span overlapping the Roman period (Grindean et al 2014). It is thus considered that, in the 2 nd century AD, the Roman frontiers area from Porolissum was an open landscape with intense military activities and huge defensive structures, in contrast to the present forest habitat dominance.…”

“…The project also scheduled large scale geophysical surveys and archaeological exca-vations (Opreanu & Lăzărescu 2012, Opreanu et al 2013a and paleoenvironmental studies (Grindean et al 2014). It also included mapping of vegetation and topographical patterns in forested areas , Roman et al 2016) and mapping small watersheds and wetland features from beneath the forest canopy.…”