A 9000 year record of cyclic vegetation changes identified in a montane peatland deposit located in the Eastern Carpathians (Central-Eastern Europe): Autogenic succession or regional climatic influences?

The scientific merit of this paper resides from:
• It is the very first study concerning the development of a bog in Central-Eastern Europe.
• The use of high-quality data set i.e., high-temporal resolution, continuous plant macrofossil record.
• Hypothesis testing of a hotly debated subject regarding the driving factors for peatland development and functioning, that is regional climate changes versus autogenic succession from an area where nothing is known about the subject.
• Implication of the use of ombrothrophic mountains bog as a palaeoclimatic archive.
• Consolidates the geographical coverage of proxy reconstruction of past climate variability in a poorly studied region.

We present a high-resolution, continuous plant macrofossil remains record complemented by a pollen sequence from Tăul Muced bog, in the Eastern Carpathian Mountains (Romania). The record spans the last 9000 years and we test whether peatland development in the Eastern Carpathians is linked to climate change or to autogenic succession. We find that Sphagnum magellanicum was the dominant peat-forming species for ca. 8000 years but we also identify ten phases of increased representation of Eriophorum vaginatum at approximately 8100, 7550, 6850, 6650, 5900, 4650, 3150, 1950, 1450, and 750 cal yr BP. Visual inspection and wavelet analysis show that the episodic increases in the relative abundances of Eriophorum vaginatum were simultaneous with decreased abundances of Sphagnum magellanicum and Sphagnum angustifolium. Comparison with published palaeoclimatic records in this region suggests that these cyclical successions of S. magellanicum and E. vaginatum appear to be primarily a result of climate changes, with E. vaginatum developing mainly during dry phases and S. magellanicum during wetter periods. We therefore suggest that the development of this peatland was largely influenced by changing climatic conditions, although the role of autogenic plant succession cannot be excluded. Our results show the value of ombrotrophic peat deposits as archives of past climate change.