Basis Of Pollen Data Research Articles

Late Miocene vegetation and climate reconstruction based on pollen data from the Sofia Basin (West Bulgaria)

The analysis of fossil palynomorh assemblages in the Late Miocene freshwater sediments of the Sofia Basin (West Bulgaria) was done to collect data on the vegetation and climate dynamics during the Late Miocene. On the basis of pollen data, we described the main palaeocomunities developed in the region. The mixed mesophytic forests dominated the vegetation in which species of Quercus, Ulmus, Zelkova, Fagus, Carpinus, Betula, Castanea, Corylus, Pterocarya, Carya, Juglans, and Eucommia played important roles. Swamp forests were also recorded, including Taxodiaceae, Alnus, Glyptostrobus, Nyssa, and Myrica. Herbaceous vegetation was distributed in the middle part of the section, with a maximum of 35.5%. The vegetation dynamic passes through several phases, which were associated with changes in paleoclimate and palaeoecological conditions. Coexistence Approach (CA) was applied to palynological data to calculate four climatic parameters. The values of coexistence intervals for mean annual temperatures are 13.6–16.6°C, with winter temperatures being 3.7–6.6°C and summer temperatures being 23.6–27.8°C. Mean annual precipitation ranged most frequently between 828 and 1308mm. The palaeoclimatic reconstruction illustrates existence of a warm-temperate and relatively humid climate with higher mean annual temperature than the present day climate.

Development of a symptom load index: enabling temporal and regional pollen season comparisons and pointing out the need for personalized pollen information

This study describes the development of an index, the symptom load index, to compare the severity of pollen seasons for pollen allergy sufferers during different seasons in different geographical regions. This is done by comparing symptom data with pollen data. This study is based on symptom data of the Patients’ Hayfever Diary (PHD) and on pollen data from the European Aeroallergen Network (EAN). The PHD allows objective assessment of the season severity. Season length calculated on the basis of pollen data from the EAN and all records of users in a specific region are included in calculation of the symptom load index. It is thus not influenced by pollen counts during the season. Its application to pollen seasons of the three important pollen types birch, grass and ragweed in Austria and Germany from 2009 to 2013 proved that the impact of a pollen season on allergy sufferers is not correlated with total pollen loads. The possibility to calculate the pollen season in the allergy sufferers’ point of view is a novelty that inaugurates new pathways for the future of pollen information. Furthermore, such an index will be of value for the establishment of personalized pollen information and for calculations of pollen thresholds.

Vegetation changes and human activity around Lake Łańskie (Olsztyn Lake District, NE Poland) from the mid Holocene, based on palynological study

ABSTRACT Bottom sediments of Lake Łańskie in NE Poland (Olsztyn Lake District) were studied by pollen analysis, and vegetation changes from ca 4800 BC to modern times were reconstructed based on the results. Due to rapid sedimentation the changes in plant cover are recorded with high resolution. The variation of pollen spectra composition reflects changing shares of deciduous trees and the continuous dominance of pine forest. Nowadays the surroundings of Lake Łańskie are also heavily forested but as early as 1100 AD the deciduous trees began to be eliminated. On the basis of pollen data, five phases of increased human activity were distinguished. Based on the available archaeological chronology of local settlements, the first stage is connected with para-Neolithic groups of Ząbie-Szestno type and the Lusatian culture. They are followed by the West Baltic Barrow culture, Wielbark culture and Early Medieval Prussian tribes. The pollen record shows low intensity of exploitation of the terrain around Lake Łańskie, probably attributable to the brevity of episodes of human occupation in the near vicinity of the lake. The last phase, covering part of the Middle Ages (since ca 1000 AD) and modern times, is reflected in the most distinct vegetation changes on the pollen diagram, caused by increased intensity of settlement. In spite of the distinct diminution of forest cover around the lake the scale of deforestation was much lower than at other sites in NE Poland. The main aims of this paper were to describe the changes in the palaeoenvironment which took place around Lake Łańskie (Olsztyn Lake District) and to find those changes in the plant cover which were the effect of human activity, and to confirm whether the changes of palaeoenvironment around Lake Łańskie were noted at the same time in adjacent areas.

Dynamics of the range of Artemisia genus over the territory of Western Siberia and adjacent regions in holocene in connection with climate change on the basis of pollen data

Reconstruction of the dynamics of the range of Artemisia genus was carried out with the help of palynoareological method on the basis of the data of 97 pollen diagrams from the territory of Western Siberia and the Altai-Sayan mountainous region over the millennial time sections since the Late Glacial time till the present time. It was revealed that the maximal spread of the Artemisia steppe communities (probably of the cryoarid pattern) occurred at the territory under examination at 13–10 ka yr BP. After the time point of 9 ka yr BP a fundamental change in landscapes of Western Siberia occurred which resulted in the disintegration of previously continuous Artemisia steppe cover into separate blocks. Since 8 ka yr BP the Artemisia steppe communities of modern appearance occupied the zones of modern steppe and forest-steppe of Western Siberia and Northern Kazakhstan while over the taiga zone the Artemisia plant communities were spread occasionally under the extra zonal conditions and as the pioneering plant groupings on naturally disturbed soils. Since the time point of 4 ka yr BP till the present time the northern boundary of the steppe zone under-went pulsing shifts to the north and back and also broadening and narrowing of isolated insular steppes in Altai-Sayan mountain region took place. At present time we observe an increase in the role of plants of Artemisia genus in the tundra zone of Western Siberia and in the Altai mountains.

A multiproxy record of late Holocene natural and anthropogenic environmental change from the Sphagnum peat bog Dürres Maar, Germany: implications for quantitative climate reconstructions based on pollen

AbstractPollen data are well established for quantitative climate reconstructions over long timescales, including the Holocene and older interglacials. However, anthropogenically induced environmental change in central Europe was strong during the last 4 ka, challenging quantitative reconstructions of this time period. Here we present quantitative climate reconstructions based on pollen analyses and evaluate them with the peat humification record and the stable carbon isotopes of Sphagnum plant material (δ13Ccellulose). All analyses were carried out on the same 7.5 m long, largely ombrotrophic peat bog section from Dürres Maar. Three different methods were used for the quantitative climate reconstructions on the basis of the pollen data: (1) a probabilistic indicator taxa approach (the ‘pdf method’); (2) a modern analogue technique based on pollen taxa from modern surface samples (cMAT); and (3) a modern analogue technique expanded by plant functional types (pMAT). At Dürres Maar the peat humification is only affected by peat cutting during the Roman period and the Middle Ages. The stable carbon isotopes are seemingly unaffected by human impact. Thus both proxies provide independent data to evaluate the reconstructions on the basis of pollen data. The quantitative climate reconstructions on the basis of the individual methods are in general relatively similar. Nevertheless, distinct differences between the individual approaches are also apparent, which could be attributed to taxa that reflect human impact on a local to regional scale. While the pdf method appears to be relatively robust to all observed anthropogenically induced vegetation changes, it potentially underestimates climate variability. This method is therefore expected to be independent of local site characteristics and to provide robust quantitative estimates of climatic trends rather than of climatic variability of small amplitude. This is of value for palaeoclimate reconstructions of older interglacials, for which neither multiple sites nor independent climate proxies are available for comparison. Copyright © 2009 John Wiley & Sons, Ltd.

Pollen morphology of Gaultheria L. and related genera of subfamily Vaccinioideae: Taxonomic and evolutionary significance

The pollen morphology of 86 samples from 84 species of Gaultheria and the closely related genera Chamaedaphne, Craibiodendron, Diplycosia, Eubotrys, Gaylussacia, Leucothoe, Lyonia, Oxydendrum, Pieris, Satyria, and Vaccinium (subfamily Vaccinioideae) was investigated with light and scanning electron microscopy. The tetrahedral tetrads are tri-zonocolporate and range from 22.9 to 51.5 μm in diameter. Exine ornamentation (apocolpia and mesocolpia) of pollen grains is highly variable. Six exine types of apocolpia and five exine types of mesocolpia are distinguished. Viscin threads on the pollen grains of members of Gaultheria are first reported in the study. Colpus length is correlated with both pollen size and colpus maximum width. There is a weak correlation between corolla length and pollen size when the length of the corolla is less than 6 mm. Infrageneric relationships of taxa in Gaultheria are discussed on the basis of pollen data. Pollen morphology is ubiquitously variable at both the species and genus levels. Pollen data support the sister relationships between Satyria and Vaccinium and between Chamaedaphne and Eubotrys of a previously reported molecular phylogenetic analysis. The evolution of pollen characters is traced by character optimization and results discussed. An evolutionary trend of mesocolpium ornamentation within Vaccinioideae from granulate through granulate–rugulate to rugulate is apparent.

Stratigraphical position of Libby radiocarbon sample 358

On the basis of pollen data, a sample of peat from a raised bog at Clonsast, Ireland, previously assigned on stratigraphic grounds to the late Boreal period, has been found to be early Atlantic in age, which more nearly agrees with results of radiocarbon dating.