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The study, based on the examination of 70 published and unpublished pollen profiles from Poland and supplementary data from the surrounding regions, shows that an abrupt, episodic Alnus population decline at the end of the first millennium CE was a much more widespread event than has been previously reported, spanning large areas of the temperate and boreal zones in Europe. The data from Poland suggest that the decline was roughly synchronous and most likely occurred between the 9th and 10th centuries, with strong indications for the 10th century. The pollen data indicate that human impacts were not a major factor in the event. Instead, we hypothesize that one or a series of abrupt climatic shifts that caused floods and droughts at the end of the first millennium CE could have initiated this ecological disturbance, leading to a higher vulnerability of the alder trees to a pathogen outbreak. Following current observations of the decline of alder stands in Europe due to a Phytophthora outbreak, we suggest that a similar process may have occurred in the past. This study provides insight into long-term alder (mainly Alnus glutinosa) dynamics in a condition of climate change and illustrates its great resilience, enabling the natural, successful regeneration of alder stands after critical diebacks if environmental conditions improve. Our finding that the Alnus pollen decline reflects a roughly synchronous event indicates that the decline could be used as an over-regional chronostratigraphic marker for 800–1000 CE in pollen diagrams from a large part of the European Lowland. [ABSTRACT FROM AUTHOR]

Plants have always played an important role in funeral customs. To understand their true meaning, close cooperation between the archaeologist and the archaeobotanist is needed, not only during the final interpretation, but from the very beginning, at the stage of collecting materials. In the article, plants' identification, using both pollen and macroremains analysis, was described, based on one of the children's burial from the Holy Trinity Church in Byszewo (18th/19th centuries). The filling of the coffin pillow consisted of numerous hop (Humulus lupulus) macroremains, the representation of which was very low in pollen sample. This is due to the fact that only female specimens of hop were inserted into the coffin. To determine the reason for using hops in funeral practices in Byszewo, ethnobotanical data was used. The following research indicates the need for the cooperation between two methods of plant identification. It will allow misinterpretations of botanical findings to be avoided. [ABSTRACT FROM AUTHOR]

Research conducted using Airborne Laser Scanning methods in northern Poland allowed traces of a settlement from almost 2,000 years ago to be registered. The most valuable item found is a copper-alloy scallop shell-shaped plate which is still an unknown object in the cultural realities of the Roman Period in northern Poland. The results of pollen analysis of the material obtained during the cleaning of the found scallop shell-shaped plate indicate the dominance of herbaceous plants over the representation of trees in the vicinity of the archaeological site discussed. The advantage of synanthropic plants among herbaceous plants informs us about the open habitat communities formed as a result of human activity (fields, meadows, roads or ruderal areas). [ABSTRACT FROM AUTHOR]

While of higher plant origin, a specific source assignment of sedimentary leaf wax n -alkanes remains difficult. In addition, it is unknown how fast a changing catchment vegetation would be reflected in sedimentary leaf wax archives. In particular, for a quantitative interpretation of n -alkane C and H isotope ratios in terms of paleohydrological and paleoecological changes, a better understanding of transfer times and dominant sedimentary sources of leaf wax n -alkanes is required. In this study we tested to what extent compositional changes in leaf wax n -alkanes can be linked to known vegetation changes by comparison with high-resolution palynological data from the same archive. We analyzed leaf wax n -alkane concentrations and distributions in decadal resolution from a sedimentary record from Trzechowskie paleolake (TRZ, northern Poland), covering the Late Glacial to early Holocene (13 360–9940 yr BP). As an additional source indicator of targeted n -alkanes, compound-specific carbon isotopic data have been generated in lower time resolution. The results indicated rapid responses of n -alkane distribution patterns coinciding with major climatic and paleoecological transitions. We found a shift towards higher average chain length (ACL) values at the Allerød–Younger Dryas (YD) transition between 12 680 and 12 600 yr BP, coevaled with a decreasing contribution of arboreal pollen (mainly Pinus and Betula) and a subsequently higher abundance of pollen derived from herbaceous plants (Poaceae, Cyperaceae, Artemisia), shrubs, and dwarf shrubs (Juniperus and Salix). The termination of the YD was characterized by a successive increase in n -alkane concentrations coinciding with a sharp decrease in ACL values between 11 580 and 11 490 yr BP, reflecting the expansion of woodland vegetation at the YD–Holocene transition. A gradual reversal to longer chain lengths after 11 200 yr BP, together with decreasing n -alkane concentrations, most likely reflects the early Holocene vegetation succession with a decline of Betula. These results show that n -alkane distributions reflect vegetation changes and that a fast (i.e., subdecadal) signal transfer occurred. However, our data also indicate that a standard interpretation of directional changes in biomarker ratios remains difficult. Instead, responses such as changes in ACL need to be discussed in the context of other proxy data. In addition, we find that organic geochemical data integrate different ecological information compared to pollen, since some gymnosperm genera, such as Pinus , produce only a very low amount of n -alkanes and for this reason their contribution may be largely absent from biomarker records. Our results demonstrate that a combination of palynological and n -alkane data can be used to infer the major sedimentary leaf wax sources and constrain leaf wax transport times from the plant source to the sedimentary sink and thus pave the way towards quantitative interpretation of compound-specific hydrogen isotope ratios for paleohydrological reconstructions. [ABSTRACT FROM AUTHOR]

While of higher plant origin, a specific plant source assignment of sedimentary leaf wax n-alkanes remains difficult. Recent compilations of global plant data sets have demonstrated an overlapping and non-systematic production of different chain-length homologues among different classes of terrestrial vegetation. Further, n-alkane distributions can change within the same species due to environmental changes. In addition, it is unknown how fast a changing catchment vegetation would be reflected in sedimentary leaf wax archives. However, in particular for a quantitative interpretation of n-alkane C and H isotope ratios in terms of paleohydrological and paleoecological changes, a better understanding of transfer times and dominant sedimentary sources of leaf wax n-alkanes is required. In this study we aim to identify the major leaf wax contributors to a Central European lacustrine system. Therefore, we tested to what extent leaf wax n-alkane compositional changes (expressed through compound concentration ratios, such as nC27 vs. nC31, average chain length ACL, etc.) can be linked to known vegetation changes, specifically during the Younger Dryas cold period (YD), by comparison with high-resolution palynological data from the same archive. We analysed leaf wax n-alkane concentrations and distributions in decadal resolution from a sedimentary record from Trzechowskie paleolake - TRZ - (Northern Poland), covering the Late Glacial to early Holocene (13,360-9,940 yrs BP). As additional source indicator of targeted n-alkanes, compound specific carbon isotopic data have been generated in lower time resolution. The results showed rapid responses of n-alkane distribution patterns coinciding with major climatic and paleoecological transitions. We find a shift towards higher ACL values at the Allerød/YD transition between 12,680 and 12,600 yrs BP, coeval with a decreasing contribution of arboreal pollen (mainly Pinus and Betula) and a subsequently higher abundance of pollen derived from herbaceous plants (Poaceae, Cyperaceae, Artemisia), as well as shrubs and dwarf shrubs Juniperus and Salix. The termination of the YD was characterized by a successive increase of n-alkane concentrations coinciding with a sharp decrease of ACL values between 11,580-11,490 years BP, reflecting the expansion of woodland vegetation at the YD/Holocene transition. Centennial reversals to longer chain lengths during the Allerød could possibly be linked to Greenland Interstadial 1b (GI-1b). A similar pattern during the early Holocene has more likely been triggered by rapid ecological responses in course of warming, rather than to reflect a local impact of a Preboreal Oscillation or 11.4 yr event. Another gradual increase in ACL values after 11,200 yrs BP, together with decreasing n-alkane concentrations, most likely reflects the early Holocene vegetation succession with a decline of Betula. These results show, that n-alkane distributions reflect vegetation changes and that a fast (i.e. subdecadal) signal transfer occurred. However, our results also indicate that a standard interpretation of directional changes in biomarker ratios remains difficult. Instead, responses such as changes of ACL need to be discussed in context of other proxy data. In addition, we find that organic geochemical data integrate different ecological information compared to pollen, since some gymnosperm species, such as Pinus, produce only very low amount of n-alkanes and thus their contribution may be largely absent from biomarker records. Our results demonstrate that a combination of palynological and n-alkane data can be used to infer the major sedimentary leaf wax sources and constrain leaf wax transport times from the plant source to the sedimentary sink and thus pave the way towards quantitative interpretation of compound specific hydrogen isotope ratios for paleohydrological reconstructions. [ABSTRACT FROM AUTHOR]

This paper reports the archaeobotanical investigation of the early medieval lake site near Nowy Dworek, in the west of Poland, focussing on the role of plants on and around the site. The construction of a small, artificial island in a lake similar to Irish crannogs, traces of a wooden bridge and archaeological artefacts all indicate that the site was a special place for the local Slav community in the 9th–10th centuries ad. Plant macroremains and pollen also demonstrate the uniqueness of the place. A large number of the cultivated and wild plant taxa are connected with the local environment and reveal an interest in plants as an element of beliefs. Pollen from dung pellets provides information about plants used as fodder and complements the picture of plant communities on the land around the island. [ABSTRACT FROM AUTHOR]

A 2.5-m-long sediment core was retrieved from Lake Somaslampi, a small lake located in a kame field on the north slope of the Scandes Mountains in Finnish Lapland. Holocene environmental changes were inferred from the lithological, geochemical, pollen, diatom and Cladocera records stored in the lake sediment. The chronology was based on six radiocarbon AMS dates supported by a palynological control chronology. The sediment profile consists of a glacial sedimentary sequence truncated by a lacustrine one. A hiatus, tentatively correlated with climate cooling and advances of glaciers during the 8.2 ka yrs BP “Finse cooling Event”, occurs between these sequences. The glacial sequence was composed of fluvioglacial clastics, smoothly changing into glacio-lacustrine diatomaceous ooze deposited in a meromictic proglacial lake that covered the kame field. The meromixis was probably caused by the greater depth of the lake, the extended ice-cover, and the microbial mats covering large areas of the lake bottom. A distinct change in the biota of the glacio-lacustrine sediments indicates higher trophic conditions than during deposition of the fluvioglacial clastics. The late-Pleistocene vegetation was characterised by subarctic birch tundra vegetation (Betula–Salix–Ericaceae) with low biodiversity gradually changing to Betula–Pinus dominance in the early Holocene. The lake was deep and had a diatom inferred pH ~ 7 indicated also by the dominance of planktonic Cladocera. The base of the lacustrine sediment sequence (6,650–6,300 cal. BP) consisted of loess-rich sediment indicating an increase in eolian activity. This is also supported by the pollen record, which is dominated by more long-distant taxa such as Alnus and Pinus, and by the increased C/N ratio of the sediment. After the initial meromictic phase of the lake, an abrupt lowering of the water level occurred. Lake Somaslampi was isolated from the larger Pre-Lake Somas basin and became holomictic, shallow, much warmer and more productive, until the deterioration of climate around 3,000 yr BP and the increased input of clastics from the tundra soils. The vegetation followed the general climatic trend by gradually changing from the dominance of Betula and Pinus to the dominance of more tundra-related vegetation like Poaceae and Cyperaceae. However, the higher frequencies of planktonic Cladocera and centric diatoms in the most recent sediments indicates higher trophic conditions, increased turbulence and a prolonged ice-free period, which can possibly be linked to the recent climate warming especially in areas of higher altitude and latitude. [ABSTRACT FROM AUTHOR]