The Pleistocene flora of Bezhan, southeast Albania: early appearance of extant tree species

ABSTRACT

The piggyback basin of Bezhan, southeastern Albania, was formed during the late Neogene and contains Pliocene/Pleistocene deposits. These continental deposits consist of marls, siltstones and clays separated by a thin series of lignite-seams alternating with clays (Bezhan formation). We investigated leaf fossils and dispersed pollen from marls of the upper portion of this formation. Fifty-two plant taxa comprising algae, gymnosperms, and angiosperms were recovered. Of these, at least 19% belong to extant species and less than 16% belong to taxa today extinct in western Eurasia. Tsuga is represented by three pollen taxa with affinities to modern Chinese, Japanese, and North American species. Herbaceous taxa indicative of steppe (Artemisia, Amaranthaceae) occur in low quantities (≤1%) suggesting an interglacial setting. Four vegetation units are recognised: Wet riparian and aquatic vegetation, mesic oak forest, dry sub-Mediterranean woodland, and montane conifer forest. A comparison of the Bezhan flora with well-dated Pliocene and Pleistocene floras of Italy suggests a Calabrian (late early Pleistocene) age for the upper unit. This estimate is based on the abundance of extant taxa, the absence of subtropical taxa, and threshold values of particular taxa (Tsuga, Carya). The findings are in agreement with age estimates for extant tree species from molecular studies.

KEYWORDS:

• Plant macrofossils
• pollen
• Quercus cerris
• sub-Mediterranean vegetation belt
• extant tree species
• Calabrian

Acknowledgements

Thanks are due to Hans Kerp and Benjamin Bomfleur, Münster, for making the Kleinhölter collection accessible. We also would like to thank Oleg Mandic and Andreas Kroh, Vienna, for help with establishing contacts with Albanian colleagues and for help with literature. Thomas Neubauer, Göttingen, is thanked for clarifying the stratigraphic range of some molluscs. Valuable suggestions by the reviewers Adele Bertini and Jean-Pierre Suc are highly appreciated. This study was financed by a VR grant to TD. HTG was supported by The Scientific and Technological Research Council of Turkey (TÜBİTAK), 2219 Post-Doctoral Research Fellowship Program (2017/2), project no. 1059B191700382.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

This study was financed by a grant of the Swedish Research Council (VR; project no. 2015-03986) to TD. HTG was supported by The Scientific and Technological Research Council of Turkey (TÜBİTAK), 2219 Post-Doctoral Research Fellowship Program (2017/2), project no. 1059B191700382.