Pim de Klerk

What’s in a name?: Some thoughts on pollen classification, identification, and nomenclature in Quaternary palynology

Abstract Recent developments in Quaternary palaeopalynology necessitate an increased attention to the classification and nomenclature of pollen types. This paper discusses the differences between palaeopalynological and actuo pollen morphological pollen classification and their consequences for pollen identification and for the interpretation of pollen data. The obscure character of pollen types, that leads to confusion in pollen typology and nomenclature, is analysed and various nomenclatural approaches are reviewed. It is concluded that fossil pollen can not – beyond reasonable doubt – be ascribed to recent and native taxa that produce the same kind of pollen. A pollen type should therefore be defined as a limitative collection of morphological properties (e.g. by reference to a concrete key), not as pollen of a taxon. All types distinguished have to be defined separately (e.g. by referring to a concrete key in the name of every pollen type), when various keys are used in combination or when types deviate from types in those keys. Observed pollen types and interpreted taxa should be kept clearly separated in the discussion. Finally, some suggestions are offered for putting these conclusions into practice.

Changing vegetation patterns in the Endinger Bruch area (Vorpommern, NE Germany) during the Weichselian Lateglacial and Early Holocene

Abstract Comparison of the pollen record of several cores at different distances to palaeo-vegetation units enabled reconstruction of changing vegetation patterns during the Weichselian Lateglacial and Early Holocene in and around the Endinger Bruch (Vorpommern, NE Germany). Various vegetation phases of the complete Lateglacial are discussed, which are introduced to avoid a widespread scientific confusion about stratigraphic terminology. During Open vegetation phase I, the upland was inhabited mainly by herbs, in which during the Hippophae phase, Hippophae shrubs expanded. Open vegetation phase II was mainly dominated by herbs and (dwarf)shrubs. During the Lateglacial Betula/Pinus forest phase, the upland vegetation closed, and subsequently opened-up again in Open vegetation phase III. A new expansion of forests took place during the Early Holocene Betula/Pinus forest phase. A comparison with pollen diagrams from southern regions shows that Vorpommern, Germany, can be considered as a separate vegetation region during the Lateglacial with respect to the openness of the vegetation during Open vegetation phases II and III, and with respect to Pinus expansion during the Lateglacial Betula/Pinus forest phase.

In search of finiteness: the limits of fine-resolution palynology of Sphagnum peat:

High-resolution analysis of ombrogenous peats often reveals pollen frequencies that change markedly from one sample to the next, indicating limited postdepositional mixing. This raises the question whether — with sufficiently thin samples — seasonal differences in pollen deposition can be observed. Seasonal resolution in peat would provide a dating technique with an accuracy similar to that of other, annually banded archives. To study the limits of temporal resolution, contiguous 0.5 mm thick slices of slightly humified Sphagnum section Cuspidata peat were palynologically analysed. No seasonal patterns in the pollen stratigraphy could be observed. This is ascribed to the mixing of pollen grains as a result of small-scaled vertical water movements and to the horizontal mode of shoot layering in the Sphagnum species. The latter process may also be the cause of a smoothed annual signal. Because of the absence of seasonal differentiation, the palynological distinction of annual peat layers is not feasible.

Region-Specific Sensitivity of Anemophilous Pollen Deposition to Temperature and Precipitation

Understanding relations between climate and pollen production is important for several societal and ecological challenges, importantly pollen forecasting for pollinosis treatment, forensic studies, global change biology, and high-resolution palaeoecological studies of past vegetation and climate fluctuations. For these purposes, we investigate the role of climate variables on annual-scale variations in pollen influx, test the regional consistency of observed patterns, and evaluate the potential to reconstruct high-frequency signals from sediment archives. A 43-year pollen-trap record from the Netherlands is used to investigate relations between annual pollen influx, climate variables (monthly and seasonal temperature and precipitation values), and the North Atlantic Oscillation climate index. Spearman rank correlation analysis shows that specifically in Alnus, Betula, Corylus, Fraxinus, Quercus and Plantago both temperature in the year prior to (T-1), as well as in the growing season (T), are highly significant factors (TApril rs between 0.30 [P<0.05[ and 0.58 [P<0.0001]; TJuli-1 rs between 0.32 [P<0.05[ and 0.56 [P<0.0001]) in the annual pollen influx of wind-pollinated plants. Total annual pollen prediction models based on multiple climate variables yield R2 between 0.38 and 0.62 (P<0.0001). The effect of precipitation is minimal. A second trapping station in the SE Netherlands, shows consistent trends and annual variability, suggesting the climate factors are regionally relevant. Summer temperature is thought to influence the formation of reproductive structures, while temperature during the flowering season influences pollen release. This study provides a first predictive model for seasonal pollen forecasting, and also aides forensic studies. Furthermore, variations in pollen accumulation rates from a sub-fossil peat deposit are comparable with the pollen trap data. This suggests that high frequency variability pollen records from natural archives reflect annual past climate variability, and can be used in palaeoecological and -climatological studies to bridge between population- and species-scale responses to climate forcing.

Presence of Camptotheca in the Red River Delta (North Vietnam) during the Holocene Revealed by Palynological Studies

Aims: Evaluation of the presence of the important medicinal tree genus Camptotheca in the Red River Delta (northern Vietnam) during the Holocene. Place and Duration of Study: Institute of Botany and Landscape Ecology (Greifswald University), between March 2003 and May 2006.