University of Oulu

Latałowa, M., Święta-Musznicka, J., Słowiński, M., Pędziszewska, A., Noryśkiewicz, A., Zimny, M., Obremska, M., Ott, F., Stivrins, N., Pasanen, L., Ilvonen, L., Holmström, L., Seppä, H. (2019) Abrupt Alnus population decline at the end of the first millennium CE in Europe – The event ecology, possible causes and implications. Holocene, 29 (8), 1335-1349. doi:10.1177/0959683619846978

Abrupt Alnus population decline at the end of the first millennium CE in Europe : the event ecology, possible causes and implications

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Author: Latałowa, Małgorzata1; Święta-Musznicka, Joanna1; Słowiński, Michał2;
Organizations: 1Laboratory of Palaeoecology and Archaeobotany, Department of Plant Ecology, Faculty of Biology, University of Gdańsk, Poland
2Department of Environmental Resources and Geohazards, Institute of Geography and Spatial Organization, Polish Academy of Sciences, Poland
3Institute of Archaeology, Faculty of History, Nicolaus Copernicus University in Toruń, Poland
4Institute of Geological Sciences, Polish Academy of Sciences, Poland
5Section 5.2 – Climate Dynamics and Landscape Evolution, GFZ German Research Centre for Geosciences, Germany
6Department of Archaeology, Max Planck Institute for the Science of Human History, Germany
7Department of Geography, Faculty of Geography and Earth Sciences, University of Latvia, Latvia
8Department of Geology, School of Science, Tallinn University of Technology, Estonia
9Research Unit of Mathematical Sciences, University of Oulu, Finland
10Department of Mathematics and Statistics, University of Helsinki, Finland
11Department of Geosciences and Geography, University of Helsinki, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 4.2 MB)
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Language: English
Published: SAGE Publications, 2019
Publish Date: 2019-08-13


The study, based on the examination of 70 published and unpublished pollen profiles from Poland and supplementary data from the surrounding regions, shows that an abrupt, episodic Alnus population decline at the end of the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.

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Series: The Holocene
ISSN: 0959-6836
ISSN-E: 1477-0911
ISSN-L: 0959-6836
Volume: 29
Issue: 8
Pages: 1335 - 1349
DOI: 10.1177/0959683619846978
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Funding: ML, JŚM, AP, and MZ acknowledge support from the 575 University of Gdańsk through statutory funding (530-L145-D581-18) and NS and HS the support of the 576 Academy of Finland (EBOR project).
Copyright information: © 2019 The Author(s). Reprinted by permission of SAGE Publications.