Hans-Jürgen Beug

Pollen distribution in hemipelagic surface sediments of the South China Sea and its relation to modern vegetation distribution

Abstract This paper analyses the distribution of pollen in the surface sediments of the South China Sea as recorded in 28 samples from the area 6°09′–20°07′N and 112°05′–119°45′E, at water depths of 329–4307 m. Pollen concentrations range from 444 kgrains/g (dry wt) on the lower part of the continental slope in the northeast to zero in the central basin below 4000 m water depth. Pollen distribution patterns in the concentration and percentage isopolls (incorporating data from the literature) reflect the routes and mechanisms of pollen transport, pollen source areas and considerable systematic differences between north and south. The northern SCS is distinguished by very high concentrations due to the high production and effective long-distance transport of pine pollen and fern spores. The maximum of their concentration occurs in the north, adjacent to the convergence of the Bashi and Taiwan Straits, rather than near the estuaries of big rivers, and stretches as a saddle from NE to SW, consistent with the direction of the NE winter monsoon and sea current. This pattern implies that pine pollen and fern spores, adapted to wind transport and water flotation, come from the northeast through the straits borne on the winter monsoon and sea current forced by it. Their source areas should cover large regions, probably including south and southeast China. Most pollen of tropical and subtropical broad-leaved trees found in the northern part of the SCS occur in low concentrations, however, these concentrations decrease uniformly offshore, implying a fluvial discharge from nearby lowlands in South China. In the southern part of the SCS, pollen of tropical and subtropical broad-leaved trees predominate. Total pollen concentrations, however, are much lower, only 1/10 of those of the northern part. The greatest concentrations occur offshore north Borneo and decrease toward deep water, suggesting fluvial input from relatively local sources on the adjacent islands (e.g. Borneo).

Vegetation and climate changes during the last 21 000 years in S.W. Africa based on a marine pollen record

A high resolution marine pollen record from site GeoB1023, west of the northern Namib desert provides data on vegetation and climate change for the last 21 ka at an average resolution of 185 y. Pollen and spores are mainly delivered to the site by the Cunene river and by surface and mid-tropospheric wind systems. The main pollen source areas are located between 13°S and 21°S, which includes the northern Namib desert and semi-desert, the Angola-northern Namibian highland, and the north-western Kalahari. The pollen spectra reflect environmental changes in the region. The last glacial maximum (LGM) was characterised by colder and more arid conditions than at present, when a vegetation with temperate elements such as Asteroideae, Ericaceae, and Restionaceae grew north of 21°S. At 17.5 ka cal. B.P., an amelioration both in temperature and humidity terminated the LGM but, in the northern Kalahari, mean annual rainfall in the interval 17.5-14.4 ka cal. B.P. was probably 100–150 mm lower than at present (400–500 mm/y). The Late-glacial to early Holocene transition includes two arid periods, i.e. 14.4–12.5 and 10.9–9.3 ka cal. B.P. The last part of the former period may be correlated with the Younger Dryas. The warmest and most humid period in the Holocene occurred between 6.3 and 4.8 ka cal. B.P. During the last 2000 years, human impact, as reflected by indications of deforestation, enhanced burning and overgrazing, progressively intensified.

On the forest history of the Dalmatian coast

Abstract The Postglacial history of the vegetation of southern Dalmatia is studied by means of pollen analysis of the lake deposits of the Malo Jezero on the island Mljet. The pollen diagrams reflect four forest periods: 1. (1) Period A: period of deciduous oak forest. About 7,000 (beginning of sedimentation)-5,600 B.C. 2. (2) Period B: Juniperus-Phillyrea period. Beginning of eu-mediterranean climate conditions. 5,600-4,300 B.C. 3. (3) Period C: Quercus ilex period. 4,300-about 200 B.C. 4. (4) Period D: Pinus-Quercus ilex period. Sediments of the last 1,900−2,000 years are lacking.

Studies on the vegetation history of Lake Varna region, northern Black Sea coastal area of Bulgaria

On the basis of pollen analytical investigations of two cores from Lake Varna and Lake Beloslav, the vegetation history of the Lake Varna region is traced back to the beginning of the 6th millennium B.C. A two-fold zoning system is used whereby the pollen diagrams are divided into pollen zones, based on tree migration patterns, and settlement periods. Pollen zone 1 is characterised by the absence of Carpinus betulus and Fagus sylvatica. The spread of hornbeam started at ca. 6500 B.C. (pollen zone 2) and beech at ca. 6200 B.C. (pollen zone 3), the latter being the last tree to spread into the region and considerably enrich the forests of the study area. Of the many pollen taxa representing plants that are favoured by open habitats and hence potentially indicative of human impact, only a few taxa are regarded as reliable indicators of human activity. These include above all Triticum-type, and also Secale and to a certain extent Plantago lanceolata, Rumex and Polygonum aviculare. The spatial pattern of settlements is somewhat different in the areas represented by the two profiles. At both sites the first period of settlement occurred during the 6th millennium B.C. (early Neolithic). After the Neolithic period, the main settlement periods of the Eneolithic and the Early and Middle Bronze Age are recorded. On the other hand, land-use history during the Greek and Roman periods is poorly recorded. Studies on the stratigraphy, diatoms and molluscs indicate that the sixth Black Sea transgression (6500–5800 B.C.), which reached −10 m, had considerable influence on the limnological environment.

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.