S. Bottema

The Younger Dryas in the Eastern Mediterranean

Abstract The Younger Dryas period is traced in pollen diagrams of the Eastern Mediterranean by means of radiocarbon dates. The biostratigraphy in terms of pollen assemblages is compared with the absolute time scale. The Younger Dryas as a pollen assemblage zone is at best vaguely visible in those parts that at present carry steppe or other open vegetation. The part that nowadays carries forest produces pollen zones, including the Younger Dryas, which resemble those of parts of Europe. Palynological developments in parts of the Eastern Mediterranean differ appreciably, which implies that the vegetation developed differently also. This suggests that the climatic development in the various parts of the region was not the same.

A LATE QUATERNARY POLLEN DIAGRAM FROM LAKE URMIA (NORTHWESTERN IRAN)

Abstract In this study, the Late Glacial and Holocene vegetation and climate development of the Urmia region in northwestern Iran are discussed. The pollen evidence indicates that Artemisia steppe dominated the area up to about 9000 yr B.P. Precipitation, possibly in the form of torrential showers, ran off directly to the lake basin. Some increase in precipitation enabled a grass steppe to develop during the middle part of the Late Glacial. During this period detrital minerals were hardly transported to the lake. It is assumed that the increase in precipitation caused an increase in vegetation cover which in turn prevented direct run-off. Between 9000 and 8000 yr B.P. forest-steppe developed and c. 7000 yr B.P. vegetation became established that is similar to the present vegetation. The pollen diagrams of Urmia, Zeribar (Iran), Van (eastern Turkey) and Akgol (central Turkey) were correlated with each other. The age of the Van diagram, based upon varve dating, falls out of line, which throws doubt upon the validity of the dating method for this site.

PALYNOLOGICAL INVESTIGATIONS ON CRETE

Abstract The holocene vegetation history of Crete has been studied palynologically on the basis of a core from the mouth of the Platys River near Aghia Galini. The pollen spectra suggest a forest cover in the island in which pine played an important role during the earlier part whereas oak, especially the deciduous type, is the dominant tree during most of the time afterwards. The almost complete absence of Mediterranean elements (though generally severely under-represented) is in striking contrast to the vegetation today. The presence or absence of some tree species is discussed, as well as the correlation of the diagram with spectra from deep-sea cores.

PREHISTORIC CEREAL GATHERING AND FARMING IN THE NEAR-EAST - THE POLLEN EVIDENCE

In this contribution the use of Cerealia-type pollen as an indicator of the presence of wild cereal species or their domesticated derivatives is discussed, especially for the Near East. Various aspects of pollen analysis in connection with modern as well as subfossil pollen are studied. The identifiability, production and dispersal of pollen of wild and domesticated cereals are treated. Modern reference material is used and field tests are performed. Attention is drawn to threshing or storing as an important source of cereal pollen. The evidence on Cerealia-type pollen found in the subfossil record or in modern surface samples is dealt with.

HOLOCENE VEGETATION OF THE VAN AREA - PALYNOLOGICAL AND CHRONOLOGICAL EVIDENCE FROM SOGUTLU, TURKEY

Evidence of the terrestrial pollen precipitation in the Van area, obtained from the marsh of Söğütlü, is compared with the lacustrine record from Lake Van, eastern Turkey. The radiocarbon chronology of the vegetation history of the Van area is compared with that from varve counting. The first method produced the most probable results, supported by palynological investigations in other parts of Turkey and Iran. The combination of radiocarbon dating and palynological correlation dates the sediments of Lake Van 1100 to 2200 years older than the varve dating.The indicator value of Cerealia-type pollen as evidence of prehistoric agriculture is discussed and compared with results from observations on modern crops. In the present study, Cerealia-type pollen may have been produced by wild grasses growing in the marsh.

Relationship between recent pollen deposition and airborne pollen concentration

Abstract In the reconstruction of past or recent vegetation the study of deposited pollen plays an important role. As reference value, very often the pollen content of moss polsters (“moss cushions”) is assessed to estimate the pollen depositions (“influx”) from the air. Recently, the data from moss-polster sampling and from sedimentation-trap sampling have been compared, showing both similarities and inconsistencies in the two sets of data. Whether the relative pollen presence in moss polsters is in accordance with airborne pollen concentrations as assessed by continuous volumetric air sampling has been studied rather scarcely. This relationship between recent pollen deposition and airborne pollen concentration has been studied also in Leiden by comparing the percentages with which 28 frequent pollen types were represented in a continuous volumetric air sampler over a period of 9 years, with the percentages with which they were extracted from moss polsters collected at three sites in the vicinity of the air sampler. It appears that some types are relatively strongly under-represented in moss polsters, especially Urtica . Consequently, a number of other types are relatively over-represented in moss polsters. This finding should have consequences for the interpretation of the results of observations on sub-fossil and more recent pollen deposition in relation to vegetation reconstruction.

A note on the pollen representation of ivy (Hedera helix L.)

Pollen productivity and dispersal of ivy (Hedera helix) is discussed on the basis of a simple surface sample study in a situation that has been followed for about 30 yr. The pollen production of a special ivy plant was estimated for the flowering season of 1998. Hedera pollen dispersal was followed along a transect for up to 70 m from the source. The results confirm that Hedera is greatly under-represented in modem pollen assemblages. Some implications of this for interpreting fossil pollen assemblages are discussed

Late Glacial and Holocene vegetation history at Lake Yeniçağa, northern Turkey

Pollen diagrams from Lake Yeniçağa in northern Turkey published by Beug (Quaternary Paleoecology, Yale University Press, New Haven, 1967) and Bottema et al. (Palaeohistoria 35/36(1993/1994):13–72, 1995) are connected, reflecting the development of the vegetation over the time from the Older Dryas period to about ad 800. The sequence can be divided into four pollen zones with several subzones. Six periods of continuous human impact are described.