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  • 1. Aufgebauer, Anne
    et al.
    Panagiotopoulos, Konstantinos
    Wagner, Bernd
    Schaebitz, Frank
    Viehberg, Finn A.
    Vogel, Hendrik
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Zanchetta, Giovanni
    Sulpizio, Roberto
    Leng, Melanie J.
    Damaschke, Magret
    Climate and environmental change in the Balkans over the last 17 ka recorded in sediments from Lake Prespa (Albania/FYR of Macedonia/Greece)2012In: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 274, p. 122-135Article in journal (Refereed)
    Abstract [en]

    This paper presents sedimentological, geochemical, and biological data from Lake Prespa (Albania/Former Yugoslav Republic of Macedonia/Greece). The 320 cm core sequence (Co1215) covers the last 17 ka calBP and reveals significant change in climate and environmental conditions on a local and regional scale. The sediment record suggests typical stadial conditions from 17.1 to 15.7 ka calBP, documented through low lake productivity, well-mixed conditions, and cold-resistant steppe catchment vegetation. Warming is indicated from 15.7 ka calBP with slightly increased in-lake productivity, gradual expansion of trees, and decreasing erosion through disappearance of local ice caps. Between 14.5 and 11.5 ka calBP relatively stable hydrological conditions are documented. The maximum in tree taxa percentages during the Bolling/Allerod interstadial (14.5-13.2 ka calBP) indicates increased temperatures and moisture availability, whereas the increase of cold-resistant open steppe vegetation taxa percentages during the Younger Dryas (13.2-11.5 ka calBP) is coupled with distinct colder and drier conditions. The Holocene sequence from 11.5 ka calBP indicates ice-free winters, stratification of the water column, a relatively high lake trophic level and dense vegetation cover over the catchment. A strong climate related impact on the limnology and physical parameters in Lake Prespa is documented around 8.2 ka through a significant decrease in productivity, enhanced mixing, strong decomposition and soil erosion, and a coeval expansion of herbs implying cool and dry climate conditions. Intensive human activity in the catchment is indicated from around 1.9 ka calBP. This multiproxy approach improves our understanding of short- and long-term climate fluctuations in this area and their impact on catchment dynamics, limnology, hydrology, and vegetation. (C) 2012 Elsevier Ltd and INQUA. All rights reserved.

  • 2. Bazzanti, Marcello
    et al.
    Mastrantuono, Luciana
    Pilotto, Francesca
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Depth-related response of macroinvertebrates to the reversal of eutrophication in a Mediterranean lake: Implications for ecological assessment2017In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 579, p. 456-465Article in journal (Refereed)
    Abstract [en]

    A better management of nutrient inflows into lakes has led to an improvement in their conditions (i.e. reversal of eutrophication) and the effects of this on macroinvertebrate communities that inhabit different lake-depth zones is largely unknown. This paper reports a comparison of macroinvertebrate communities living in the eulittoral, infralittoral and sublittoral/profundal zones of Lake Nemi (Central Italy) before and after its natural recovery from eutrophication following the deviation of domestic Wastewater. The infralittoral zone responded more rapidly than the other two depth-zones to the improved ecological conditions, as shown by larger differences in community composition between the two periods. In the eulittoral sand, the combined effects of hydromorphological pressures and reversal of eutrophication hindered the biotic response. In the eulittoral and infralittoral zones, typical taxa of mesotrophic waters appeared or increased their abundances after the eutrophication reversal. Benthic invertebrate response was slower in the sublittoral/profundal zone due to deoxygenation that continued to prevail in the deepest area of the lake during summer. However, both tolerant and more sensitive taxa were collected there for the first time. After the reversal of eutrophication, the percentage of molluscan + large crustaceans increased in the infralittoral zone, whereas the oligochaete/chironomid ratio decreased in both sublittoral/profundal and infralittoral zones. Functional feeding metrics (percentages of filter-feeders, collector-gatherers, miners and scrapers/grazers) differently tracked the reversal of eutrophication in the three depth-zones probably according to the effects of the-reduction of nutrients on food-web structure influencing macroinvertebrates. Biological Monitoring Working Party (BMWP) and the Average Score Per Taxon (ASPT) seemed to respond to eutrophication reversal only in the sublittoral/profundal zone, where deoxygenation plays a major role as a structuring agent of the community. Our results suggest that the effects of re-. versal of eutrophication can be better assessed by examining the response of the communities belonging to each zone individually. 

  • 3.
    Becher, Marina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Börlin, Niclas
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Klaminder, Johan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    The use of terrestrial photogrammetry to estimate soil motion rates in non-sorted circlesManuscript (preprint) (Other academic)
    Abstract [en]

    Soil motion induced by cryogenic processes is known for creating soil surface structures (patterned ground) and redistributing carbon within Arctic soils. Lateral and vertical soil motion created by cryogenic processes proceeds over annual to millennial time-scales and is difficult to quantify without adopting disruptive soil sampling techniques. In this study, we evaluate the use of terrestrial close range photogrammetry to calculate soil motion rates within a patterned ground system (non-sorted circles). The measured rates of lateral and vertical motion were estimated and used to infer the importance of physical soil transport for the formation of non-sorted circles as well as the trajectories of soil carbon. Soil experiencing significant vertical displacement between years covered approximately 65% of the non-sorted circles and had surface levels fluctuating between 4 and -2.1 cm. Systematic lateral motion of surface stones allowed detection of lateral motion working outwards from the centre towards the sides, at rates ranging between 0.1 and 6.3 cm yr-1. We conclude that terrestrial close range photogrammetry can be used to identify the main soil movements within non-sorted circles and that this transport is an important factor controlling the trajectories of soil carbon over centennial to millennial timescales. 

  • 4.
    Becher, Marina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Olid, Carolina
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Buried soil organic inclusions in non-sorted circles fields in northern Sweden: Age and Paleoclimatic context2013In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 118, no 1, p. 104-111Article in journal (Refereed)
    Abstract [en]

    Although burial of surface organic soil horizons into deeper mineral soil layers helps drive the long-term buildup of carbon in arctic soils, when and why buried horizons formed as result of cryoturbation in northern Sweden remain unclear. In this study, we used C-14 and Pb-210 dating to assess when organic matter was buried within non-sorted circles fields near Abisko in northern Sweden. In addition, we used aerial photos from 1959 and 2008 to detect eventual trends in cryogenic activities during this period. We found that organic matter from former organic horizons (stratigraphically intact or partly fragmented) corresponds to three major periods: 0-100 A. D., 900-1250 A. D., and 1650-1950 A. D. The latter two periods were indicated by several dated samples, while the extent of the oldest period is more uncertainty (indicated by only one sample). The aerial photos suggest a net overgrowth by shrub vegetation of previously exposed mineral soil surfaces since 1959. This overgrowth trend was seen in most of the studied fields (92 out of 137 analyzed fields), indicating that the cryogenic activity has mainly decreased in studied non-sorted circles fields since the 1950s. This latter interpretation is also supported by the absence of buried organic layers formed during the last decades. We suggest that the organic matter was buried during the transition from longer cold periods to warmer conditions. We believe these climatic shifts could have triggered regional scale burial of soil organic matter and thus affected how these soils sequestered carbon.

  • 5.
    Bogren, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    LIDAR-analys av flygsanddyner i Västerbottens inland: Har dynmorfologi bildad under tidigare interstadialer bevarats i landskapet?2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this study was to map the prevalence of aeolian sand dunes in Västerbotten, northern Sweden to find dunes formed during earlier deglaciation phases, which was then preserved in cold-based conditions during the youngest stadial of the Weichselian glaciation. These preserved dunes were expected to be covered by a layer of till and have a rather faint morphology compared to dunes formed during the Holocene. Consequently, high resolution LIDAR-derived images from the Swedish mapping, cadastral and land registration authority (Lantmäteriet) was used to detect the dunes throughout an area covering most of Västerbotten, above the highest coastline and below the mountain range. The analysis resulted in several new findings of aeolian dunes compared to the findings in the quaternary soil map created by the Geological Survey of Sweden. Despite the fact some of the dunes at the LIDAR-derived image had a strange faint appearance, it was quickly evident during the fieldwork that the aeolian sand was not covered by till on any of the dunes visited. The common view during the last decades has been that cold-based ice will not erode or alter the morphology of the landscape beneath the ice. However, this study suggests that hypothesis may not be entirely correct, and therefore it can be hard to use geomorphological implications to reconstruct past glacial environments. Thus, it can be concluded that even under cold-based conditions, preservation of aeolian sand dunes in Västerbotten is probably not very common.

  • 6. Bonk, Alicja
    et al.
    Kinder, Małgorzata
    Enters, Dirk
    Grosjean, Martin
    Meyer-Jacob, Carsten
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Tylmann, Wojciech
    Sedimentological and geochemical responses of Lake Żabińskie (north-eastern Poland) to erosion changes during the last millennium2016In: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 56, no 2-3, p. 239-252Article in journal (Refereed)
    Abstract [en]

    Increased erosion triggered by land-use changes is a major process that influences lake sedimentation. We explored the record of erosion intensity in annually laminated sediments of Lake Żabińskie, northeast Poland. A 1000-year-long, annually resolved suite of sedimentological (varve thickness, sediment accumulation rate) and geochemical data (scanning XRF, loss on ignition, biogenic silica) was analyzed with multivariate statistics. PCA indicated erosion was a major process responsible for changes in the chemical composition of the sediments. Analysis of sedimentary facies enabled identification of major phases of erosion that influenced lake sedimentation. These phases are consistent with the history of land use, inferred from pollen analysis. From AD 1000 to 1610, conditions around and in Lake Żabińskie were relatively stable, with low erosion intensity in the catchment and a dominance of carbonate sedimentation. Between AD 1610 and 1740, higher lake productivity and increased delivery of minerogenic material were caused by development of settlements in the region and widespread deforestation. The most prominent changes were observed between AD 1740 and 1880, when further land clearance and increased agricultural activity caused intensified soil erosion and higher lake productivity. Landscape clearance also created better conditions for water column mixing, which led to changes in redox conditions in the hypolimnion. The most recent period (AD 1880–2010) was characterized by partial reforestation and a gradual decrease in the intensity of erosional processes.

  • 7. Buckland, Paul C.
    et al.
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies, Environmental Archaeology Lab.
    Insect Remains from GUS: an interim report1998In: Man, Culture and Environment in Ancient Greenland / [ed] J. Arneborg & H.C. Gulløv, Copenhagen: Danish Polar Center, Copenhagen , 1998, p. 74-79Chapter in book (Other academic)
  • 8. Buckland, Paul C.
    et al.
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    Hughes, Damian
    Palaeoecological evidence for the Vera hypothesis?2005In: Large herbivores in the wildwood and modern naturalistic grazing systems, English Nature , 2005, p. 62-116Chapter in book (Other academic)
    Abstract [en]

    This report stems from work commissioned by English Nature into the role of largeherbivores in the post-glacial landscape of Britain and the potential for using free-ranginggrazing animals to create and maintain diverse landscape mosaics in modern conditions.Some aspects may be disputed or considered controversial; it is an active field of research.Therefore we stress that the views expressed are those of the authors at the current time.Subsequent research may confirm our views or lead us to modify them.We hope they will be useful in future discussions, both within English Nature and inconservation land-management circles more generally.

  • 9. Buckland, Paul C.
    et al.
    Panagiotakopulu, Eva
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Fossil insects and the Neolithic: methods and potencial2004In: ANTAEUS 27: Annals of the Archaeological Instititute of the Hungarian Academy of Sciences, 2004, p. 235-252Conference paper (Refereed)
  • 10. Buckland, Paul C.
    et al.
    Panagiotakopulu, Eva
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    What's eating Halvdan the Black?: Fossil insects and the study of a burial mound in its landscape context2004In: Halvdanshaugen: arkeologi, historie og naturvetenskap / [ed] Jan Henning Larsen og Perry Rolfsen, Oslo: University Museum of Cultural Heritage , 2004, 1, p. 353-375Chapter in book (Other academic)
    Abstract [en]

    Although the earliest work with insects from archaeological contexts dates back to was work on Egyptian mummies in the early nineteenth century, they were not widely used in archaeological interpretation until an effective technique for concentrating their remains was developed during the 1960s by Coope and Osborne at the University of Birmingham in England. Whilst most of their research centred upon climate and environment during the Late Quaternary, Osborne in particular began to examine assemblages from archaeological sites, and his work was expanded by Kenward, initially concentrating upon Roman and early medieval deposits in the city of York and later by Robinson at Oxford, whose main interest is in the late Holocene history of the Thames valley. Funding from the Leverhulme Trust in the UK allowed Buckland to examine the origins of the insect faunas of the Atlantic islands and this work has continued until recently. Initially research was concentrated upon the Coleoptera (beetles), but Kenward added identifications of Hemiptera (true bugs), and Skidmore and Panagiotakopulu Diptera (true flies). Panagiotakopulu has also worked closely with ectoparasite remains from archaeological sites. Although identification work still relies heavily upon the availability of extensive reference collections, the development of an extensive computer-based database, BUGS, of habitat, distribution and the fossil record of Quaternary insects has made interpretation considerably easier. In Scandinavia, early work was pioneered by Henriksen and later Lindroth. More recently Lemdahl has worked extensively on Lateglacial into Holocene natural assemblages and, in association with Hellqvist, has also examined archaeological contexts. Apart from Ponel’s work in France, there has been little recent research elsewhere in Europe, and most published work concerns natural assemblages. Similarly apart from Bain’s work on post-Columbian assemblages in the eastern US and Canada, and some work by Elias in the mid-West, insects have rarely been utilised in site interpretation in the Americas and, apart from Egypt, Africa, Asia and Australasia have fared even worse. Part of the reason behind this is the scattered nature of published results, and the frequent failure of archaeologists to cost scientific aspects of work upon their sites into project design. This paper attempts to outline some of the evidence which has been obtained from the study of insect remains, as well as to outline the methods used to concentrate the fossils. The fairly extensive bibliography allows access to the published literature, particularly that relevant to the Scandinavian World.

  • 11.
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    Archaeological Field Assessment of the Proposed Borrow Pits at Staythorpe Power Station, Staythorpe, Nottinghamshire: Assessment of the fossil insects1999Report (Other academic)
  • 12.
    Buckland, Philip I.
    Department of Archaeology and Prehistory, University of Sheffield, Sheffield, UK.
    ARCUS project 220: report on palaeochannel prospection at Elvaston Castle Tarmac site, Derbyshire1995Report (Other academic)
  • 13.
    Buckland, Philip I.
    Department of Archaeology and Prehistory, University of Sheffield, Sheffield, UK.
    ARCUS: Report on a site at Walmgate, York: Report on the fossil insect fauna from a site at Walmgate, York1995Report (Other academic)
  • 14.
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Environmental Archaeology: Climate Change and E-Science2010In: Thule: Kungliga Skytteanska Samfundets Årsbok 2010, Umeå: Kungliga Skytteanska Samfundet , 2010, p. 55-69Chapter in book (Other academic)
  • 15.
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Freeing information to the people: Using the past to aid the future2011In: International Innovation Eurofocus. Disseminating Science Research and Technology, ISSN 2041-4552, no 4, p. 51-53Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    Dr Philip Buckland discusses his recent project SEAD: the web-accessible scientific database that crosses archaeological and environmental disciplines. 

    Disciplines as diverse as anthropology and palaeoecology take an interest in our environment and how we have treated it. The Strategic Environmental Archaeology Database aims to create a multi-proxy, GIS-ready database for environmental and archaeological data to aid multidisciplinary research

  • 16.
    Buckland, Philip I
    Umeå University, Faculty of Arts, Archaeology and Sami Studies, Environmental Archaeology Lab.
    Insect remains from Pástóftir, Kárahnjúkar, Iceland2006Report (Other academic)
  • 17.
    Buckland, Philip I.
    Department of Archaeology and Prehistory, University of Sheffield, Sheffield, UK.
    Lichenometry and Soil Erosion in Northwest Iceland1994In: Environmental Change in Iceland, München: nstitut für Geographie der Universität München , 1994, p. 31-40Conference paper (Other (popular science, discussion, etc.))
  • 18.
    Buckland, Philip I
    Umeå University, Faculty of Arts, Archaeology and Sami Studies, Environmental Archaeology Lab.
    Preliminary report: fossil insect remains from Karahnjukar, Iceland2006Report (Other academic)
  • 19.
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    The Bugs Coleopteran Ecology Package (BugsCEP): the development and implementation of software for palaeoenvironmental and palaeoclimatological research2009Book (Other academic)
    Abstract [en]

    This book describes the development and practical application of a unique database orientated software package, BugsCEP, for environmental, climatic and biodiversity reconstruction from beetle assemblages. BugsCEP consists of a database of ecology and distribution data for over 9400 insect taxa, and includes temperature tolerance data for 436 species. It contains abundance and summary data for over 770 sites, most of the known European Quaternary fossil coleopteran record, supported by a bibliography of over 3700 sources. Built in statistics, including a specially developed habitat classification system, provide semi-quantitative environmental reconstructions to aid in the interpretation of sites. BugsCEP's querying and reporting functions also increase the efficiency with which analyses can be undertaken, including the facility to explore the fossil record of species by searching ecology and distribution data. The Mutual Climatic Range (MCR) reconstruction method is implemented and improved upon, including predictive modelling and the graphical output of reconstructions and climate space maps. BugsCEP is available from www.bugscep.com.

  • 20.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies, Environmental Archaeology Lab.
    Buckland, Paul C.
    BugsCEP: Coleopteran Ecology Package (software)2006Other (Other (popular science, discussion, etc.))
    Abstract [en]

    BugsCEP is a research and teaching aid for palaeoentomology, entomology and ecology. As well as habitat and distribution data, it includes tools for climate and environmental reconstruction, and facilities for storing site based abundance/collection data. A variety of searching and reporting functions greatly augment the efficiency of beetle based research.

    Bugs is built around a comprehensive database of beetle ecology and European fossil records which has been accumulated over the past 20 years.

  • 21.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    Buckland, Paul C.
    How can a database full of Bugs help reconstruct the climate?2002In: Archaeological Informatics - Pushing the Envelope - CAA 2001 - Computer Applications and Quantitative Methods in Archaeology: Proceedings of the 29th Conference, Gotland, April 2001, British Archaeological Reports , 2002, p. 453-461Conference paper (Other academic)
    Abstract [en]

    The BUGS Insect Ecology Package was originally constructed (using Dbase and Clipper) to compile Coleoptera (beetle) habitat and distribution data from a myriad of sources into one, easy to use, and publicly available database. Its primary users were researchers and teachers within the palaeoentomology field. The present system, five versions and many revisions later, is built in MS Access 2000, and covers some 5300 species, 2000 references, and 240 sites (archaeological and Quaternary), and is of value to archaeologists, ecologists, and conservationists alike.

    BUGS is essentially a relational database management system constructed around three components:

    - the species data (modern ecology and distribution)

    - the bibliography

    - the site data with species lists

    Its implementation in several institutions has greatly accelerated the efficiency with which palaeoentomological investigations can be carried out, and greatly improved the teaching of the subject.

    Palaeoenvironmental reconstructions are performed by the superimposition of the ecology and distribution of modern insect populations over fossil assemblages. At the moment, this is essentially performed semi-quantitatively by cross-reference of the data (which BUGS collates for a species list and then exports as an RTF file to any word processing package). BUGS contains a wealth of ecological data which can be employed in the interpretation of archaeological sites and contexts. In natural deposits, away from the artificial heat islands created by human activity, insect distributions are essentially constrained by climatic parameters. Tim Atkinson (UEA) and Dave Perry (formerly at Birmingham University) digitally encoded the temperature range data for over 400 species into a program for the calculation of palaeoclimates through the MCR (Mutual Climatic Range) method, and this has been extensively used in the modelling of Quaternary climates from beetle remains. The aim of our present phase of BUGS development is to implement MCR functionality into the BUGS database system. From this point it should be possible to move on to other ecological variables such as habitat and vegetation types, and increase the precision of modern climatic data, thus enhancing the value of insects in archaeological interpretation and the modelling of past climates.

  • 22.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab. Umeå University, Arctic Research Centre at Umeå University.
    Buckland, Paul C.
    Species found as fossils in Quaternary sediments2012In: Checklist of Beetles of the British Isles / [ed] A.G. Duff, United Kingdom: Pemberley Books , 2012, 2nd, p. 127-130Chapter in book (Refereed)
    Abstract [en]

    This new checklist is the most up-to-date and comprehensive checklist of the beetle fauna of the British Isles, representing many man-years of effort by leading British coleopterists. The main checklist is fully annotated with detailed endnotes.

  • 23.
    Buckland, Philip I
    et al.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    Engelmark, Roger
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    Linderholm, Johan
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    Wagner, Patricia
    Environmental archaeological investigation of samples from the Kaupang 2000 excavations2001Report (Other academic)
  • 24.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Eriksson, Erik
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Linderholm, Johan
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Viklund, Karin
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Engelmark, Roger
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Palm, Fredrik
    Umeå University, Faculty of Arts, Humlab.
    Svensson, Patrik
    Umeå University, Faculty of Arts, Humlab.
    Buckland, Paul
    Panagiotakopulu, Eva
    Institute of Geography, School of GeoSciences, University of Edinburgh, UK.
    Olofsson, Johan
    Uppsala Municipal Council, Uppsala, Sweden.
    Integrating human dimensions of Arctic palaeoenvironmental science: SEAD – the strategic environmental archaeology database2011In: Journal of Archaeological Science, ISSN 0305-4403, E-ISSN 1095-9238, Vol. 38, no 2, p. 345-351Article in journal (Refereed)
    Abstract [en]

    Environmental change has a human dimension, and has had so for at least the last 10 000 years. The prehistoric impact of people on the Arctic landscape has occasionally left visible traces, such as house and field structures. More often than not, however, the only evidence available is at the microscopic or geochemical level, such as fossil insect and seed assemblages or changes in the physical and chemical properties of soils and sediments. These records are the subject of SEAD, a multidisciplinary database and software project currently underway at Umeå University, Sweden, which aims to create an online database and set of tools for investigating these traces, as part of an international research infrastructure for palaeoecology and environmental archaeology.

  • 25.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Hammarlund, Dan
    Lund University.
    Hjärthner-Holdar, Eva
    Swedish National Historical Museums.
    Lidén, Kerstin
    Stockholm University.
    Lindahl, Anders
    Lund University.
    Palm, Fredrik
    Umeå University, Faculty of Arts, Humlab.
    Possnert, Göran
    Uppsala University.
    The Strategic Environmental Archaeology Database: a resource for international, multiproxy and transdisciplinary studies of environmental and climatic change2015Conference paper (Refereed)
    Abstract [en]

    Climate and environmental change are global challenges which require global data and infrastructure to investigate. These challenges also require a multi-proxy approach, integrating evidence from Quaternary science and archaeology with information from studies on modern ecology and physical processes among other disciplines. The Strategic Environmental Archaeology Database (SEAD http://www.sead.se) is a Swedish based international research e-infrastructure for storing, managing, analysing and disseminating palaeoenvironmental data from an almost unlimited number of analysis methods. The system currently makes available raw data from over 1500 sites (>5300 datasets) and the analysis of Quaternary fossil insects, plant macrofossils, pollen, geochemistry and sediment physical properties, dendrochronology and wood anatomy, ceramic geochemistry and bones, along with numerous dating methods. This capacity will be expanded in the near future to include isotopes, multi-spectral and archaeo-metalurgical data. SEAD also includes expandable climate and environment calibration datasets, a complete bibliography and extensive metadata and services for linking these data to other resources. All data is available as Open Access through http://qsead.sead.se and downloadable software.

     

    SEAD is maintained and managed at the Environmental Archaeology Lab and HUMlab at Umea University, Sweden. Development and data ingestion is progressing in cooperation with The Laboratory for Ceramic Research and the National Laboratory for Wood Anatomy and Dendrochronology at Lund University, Sweden, the Archaeological Research Laboratory, Stockholm University, the Geoarchaeological Laboratory, Swedish National Historical Museums Agency and several international partners and research projects. Current plans include expanding its capacity to serve as a data source for any system and integration with the Swedish National Heritage Board's information systems.

     

    SEAD is partnered with the Neotoma palaeoecology database (http://www.neotomadb.org) and a new initiative for building cyberinfrastructure for transdisciplinary research and visualization of the long-term human ecodynamics of the North Atlantic funded by the National Science Foundation (NSF).

  • 26.
    Buckland, Philip I
    et al.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    Johan, Olofsson
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    Engelmark, Roger
    Umeå University, Faculty of Arts, Archaeology and Sami Studies.
    SEAD: Strategic Environmental Archaeology Database, planning report2006Report (Other academic)
    Abstract [en]

    This document lays out a strategy for the development of SEAD – A Strategic Environmental Archaeology Database, which will facilitate the digitisation and accessibility augmentation of MAL’s existing data from nearly thirty years of work in the fields of archaeology and environmental science. SEAD will also provide a framework for the entry of data from all future research and consultancy work at MAL, and allow guest researchers and external partners to contribute to, and work with the same data. The planned system will be implemented at both local and internet levels, and be designed with an aim towards broadening its scope with external partners in the future. SEAD will be made available online in order to increase the ease of access to environmental archaeology data and encourage an expansion of both the discipline and Sweden’s role in it. This is inline with current EU strategies on enhancing research infrastructure, and providing a greater insight into human-environment interactions for long term planning.

  • 27.
    Buckland, Philip I.
    et al.
    Department of Archaeology and Prehistory, University of Sheffield, Sheffield, UK.
    Jordan, Peter
    Sugden, Heather
    ARCUS Project 220: Analysis of organic deposits from trenching at Elvaston, Derbyshire. Level One Assessment1996Report (Other academic)
    Abstract [en]

    A Level One assessment was carried out to evaluate the state of preservation within the organic deposits, and to assess their potential usefulness, should further work be undertaken, for the retrieval of palaeoenvironmental information. Selected profiles within palaeochannel sequences were examined, and assessed as to whether these contained macrofossils in a state of preservation which was likely to provide data adequate for the reconstruction of past landscapes within the area. Other factors of special interest were those relating to environmental change, such as changes in sedimentation or vegetation, be they human or naturally induced. The potential for the use of three complementary data retrieval methods was reviewed.

  • 28.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Lemdahl, Geoffrey
    Linnaeus University, Sweden.
    Explaining Late Quaternary beetle extinctions in the UK using palaeoenvironmental databases for quantitative environmental reconstruction2015Conference paper (Refereed)
    Abstract [en]

    The comparison of palaeoenvironmental and archaeological records of fossil insects with modern red data books can provide a picture of local extinctions. Buckland & Buckland (2012) performed such a study on the Coleoptera of the British Isles, using the BugsCEP database for the fossil data, and looking at broad chronological divisions. The ecology of these regionally extinct beetles, all of which are extant in other parts of the World, may be used to investigate the environmental and climatic changes which may have lead to their extirpation. This process can be semi-automated and habitats quantified through the use of ecological classification and a database infrastructure which links fossil and modern ecological and climate data (Buckland & Buckland 2006; http://www.bugscep.com). Preliminary results indicate that the majority of extirpated species with mid-Holocene records were dependent on woodland environments (Buckland 2014). These investigations can be refined by using narrower time-slices, interpolating dating evidence and including more comprehensive archaeological dating evidence. The expansion of the analysis to include the full assemblages found in the samples containing the extirpated species also allows for a more comprehensive picture of the long-term relationships between biodiversity, environmental and climatic change and human activity.

  • 29.
    Buckland, Philip I.
    et al.
    Department of Archaeology and Prehistory, University of Sheffield, Sheffield, UK.
    Sadler, Jon
    Manual for the Beta test version of BUGS: a computer based palaeoentomological research aid1995Report (Other academic)
  • 30.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies, Environmental Archaeology Lab. Department of Archaeology and Prehistory, University of Sheffield, Sheffield, UK.
    Symonds, James
    Archaeological Investigation into Subsurface Features at Elvaston, Derbyshire;  A Proposal1996Report (Other academic)
  • 31.
    Buckland, Philip I.
    et al.
    Department of Archaeology and Prehistory, University of Sheffield, Sheffield, UK.
    Symonds, James
    ARCUS Project 220: archaeology at Elvaston, Derbyshire1996Report (Other academic)
  • 32.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Archaeology and Sami Studies, Environmental Archaeology Lab.
    Yuan Zhuo, Don
    University of Sheffield.
    Buckland, Paul C.
    University of Sheffield.
    Towards an Expert System in Palaeoentomology1997In: Studies in Quaternary Entomology: an Inordinate Fondness for Insects / [ed] A.C. Ashworth, P.C. Buckland & J.P. Sadler, Chichester: John Wiley & Sons Ltd. , 1997, p. 71-77Chapter in book (Other academic)
    Abstract [en]

    Studies of Quaternary insect fossils, principally of Coleoptera, the beetles, are now sufficiently frequent to warrant the construction of a database to maintain easy access to the record. BUGS, however, seeks to go beyond this and provide ecological and distributional data on the modern fauna to enable more precise reconstructions of apst environments. This paper summarizes the program and its salient features and discusses the application of intra- and intersite statistics, which the database allows.

  • 33. Chapligin, B
    et al.
    Meyer, H
    Swann, GEA
    Meyer-Jacob, Carsten
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hubberten, H-W
    A 250 ka oxygen isotope record from diatoms at Lake El'gygytgyn, far east Russian Arctic2012In: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 8, no 5, p. 1621-1636Article in journal (Refereed)
    Abstract [en]

    In 2003 sediment core Lz1024 was drilled at Lake El'gygytgyn, far east Russian Arctic, in an area of the Northern Hemisphere which has not been glaciated for the last 3.6 Ma. Biogenic silica was used for analysing the oxygen isotope composition (delta O-18(diatom)) in the upper 13m long section dating back about 250 ka with samples dominated by one taxa in the < 10 mu m fraction (Cyclotella ocellata). Downcore variations in delta O-18 values show that glacial-interglacial cycles are present throughout the core and delta O-18(diatom)-values are mainly controlled by delta O-18(precipitation). Changes reflect the Holocene Thermal Maximum, the Last Glacial Maximum (LGM) and the interglacial periods corresponding to MIS 5.5 and MIS 7 with a peak-to-peak amplitude between LGM and MIS 5.5 of Delta O-18=5.3 parts per thousand. This corresponds to a mean annual air temperature difference of about 9 degrees C. Our record is the first continuous delta O-18(diatom) record from an Arctic lake sediment core directly responding to precipitation and dating back more than 250 ka and correlates well with the stacked marine delta(18)OLR04 (r = 0.58) and delta D EPICA Dome-C record (r = 0.69). With delta O-18 results indicating strong links to both marine and ice-core records, records from Lake El'gygytgyn can be used to further investigate the sensitivity of the Arctic climate to both past and future global climatic changes.

  • 34.
    Chen, Keyao
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Influence of depositional mobility (downwashing) on the accumulation of atmospherically supplied elements in peat cores: an experimental approach2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The potential influence of downwashing on atmospherically deposited elements is of rare focus compared with other geochemical processes related to peat. Downwashing may cause a rapid downward movement of atmospherically supplied elements before they bond to the peat organic substrate and thus reduce the reliability of age-depth models that rely on atmospherically supplied radioisotopes (e.g. 210Pb, 241Am, 137Cs). However, the existence of downwashing has not been directly tested, and to which depth the deposited element can be washed down is not fully understood. To address the question of downwashing, an experiment was set up to mimic wet deposition by applying a CuBr2 solution during a three-week period in peat cores collected from Rödmossamyran. Through this, the experimental results clearly supported the existence of downward mobility. Added Cu2+ could be measured to a depth of 10 cm, similar to previous studies based on Be and Pb. As a similar metal to Cu, the age-depth model based on 210Pb dating could underestimate the ages to some extent without consideration of downwashing.

  • 35. Cui, Qiao-Yu
    et al.
    Gaillard, Marie-Jose
    Lemdahl, Geoffrey
    Sugita, Shinya
    Greisman, Annica
    Jacobson, George L.
    Olsson, Fredrik
    Umeå University, Faculty of Social Sciences, Department of Geography and Economic History, Economic history. Umeå University, Faculty of Social Sciences, Centre for Regional Science (CERUM).
    The role of tree composition in Holocene fire history of the hemiboreal and southern boreal zones of southern Sweden, as revealed by the application of the Landscape Reconstruction Algorithm: Implications for biodiversity and climate-change issues2013In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 23, no 12, p. 1747-1763Article in journal (Refereed)
    Abstract [en]

    We present a quantitative reconstruction of local forest history at two sites, Stavsakra (hemiboreal zone) and Storasjo (southern boreal zone), in southern Sweden (province of Smaland) to evaluate possible causes of contrasting Holocene fire histories in mid- and late Holocene. The Landscape Reconstruction Algorithm (LRA) is applied to evaluate between-site differences in the relative abundance of deciduous trees and Pinus (pine) and landscape/woodland openness during the Holocene. The LRA estimates of local vegetation abundance are compared with other proxies of local vegetation, that is, plant and beetle remains. The LRA results suggest that Pinus was a major tree taxon in the woodlands of Storasjo during mid- and late Holocene, while Tilia (linden) and Betula (birch) were dominant at Stavsakra. The contrasting fire histories are shown to be strongly related to between-site differences in tree composition during mid-Holocene, 4000-2000 bc in particular. The archaeological/historical and beetle data indicate contrasting land uses from c. 1000 bc (late Bronze Age/early Iron Age), grazing in open Calluna heaths at Stavsakra and woodland grazing at Storasjo. Between-site differences in fire history during late Holocene were likely due to different land-use practices. Between-site differences in tree composition in mid-Holocene are best explained by local climatic and geological/geomorphological differences between the hemiboreal and southern boreal zones of Smaland, which might also be the primary cause of between-site differences in land-use histories during late Holocene. Maintenance of biodiversity at the landscape scale in the study area requires that existing old pine woodlands and Calluna heath are managed with fire and cattle grazing. Further climate warming might lead to higher probabilities of climate-induces fire, in particular in pine-dominated woodlands.

  • 36. Ecke, Frauke
    et al.
    Christensen, Pernilla
    Rentz, Ralf
    Nilsson, Mats
    Sandström, Per
    Hörnfeldt, Birger
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Vindelfjällens forskningsstation, Ammarnäs, Sweden; Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden .
    Landscape structure and the long-term decline of cyclic grey-sided voles in Fennoscandia2010In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 25, no 4, p. 551-560Article in journal (Refereed)
    Abstract [en]

    Changes in forest landscape structure have been suggested as a likely contributing factor behind the long-term decline in the numbers of cyclic grey-sided voles (Clethrionomys rufocanus) in northern Fennoscandian lowland regions in contrast to mountain regions due to the absence of forest management in the mountains. This study, for the first time, formally explored landscape structure in 29 lowland (LF) and 14 mountain forest (MF) landscapes (each 2.5 x 2.5 km) in northern Sweden, and related the results to the cumulated spring trapping index of the grey-sided vole in 2002-2006. The grey-sided vole showed striking contrasts in dynamics close in space and time. The MF landscapes were characterized by larger patches and less fragmentation of preferred forest types. The grey-sided vole was trapped in all of 14 analyzed MF landscapes but only in three out of 29 of the LF landscapes. MF and LF landscapes with grey-sided vole occurrence were characterized by similar focal forest patch size (mean 357 ha, minimum 82 ha and mean 360 ha, minimum 79 ha, respectively). In contrast, these MF compared to the LF landscapes were characterized by larger patches of preferred forest types and less fragmented preferred forest types and by a lower proportion of clear-cut areas. The present results suggest that landscape structure is important for the abundance of grey-sided voles in both regions. However, in the mountains the change from more or less seasonal dynamics to high-amplitude cycles between the mid 1990s and 2000s cannot be explained by changes in landscape structure.

  • 37.
    Faithfull, Carolyn
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bergström, Ann-Kristin
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Vrede, Tobias
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Pelagic energy mobilization across crossed gradients of phosphorus and dissolved organic carbon in a chemostat experiment2010In: INTERNATIONAL ASSOCIATION OF THEORETICAL AND APPLIED LIMNOLOGY, VOL 30, PT 9 / [ed] Jones J, Faaborg J, 2010, Vol. 30, no 9, p. 1411-1415Conference paper (Refereed)
    Abstract [en]

    Pelagic production depends on biological energy mobilization based on both light energy mobilized by phytoplankton and imported energy bound as allochthonous organic carbon (AOC) and utilized by bacteria. Both autotrophic (phytoplankton) and heterotrophic (bacterioplankton) production form the basis of pelagic energy mobilization (PEM) in lakes (JANSSON et al. 2003). The relative importance of these two energy mobilization pathways changes with respect to phosphorus (P) and AOC availability (KARLSSON et al. 2002, JANSSON et al. 2003). Whereas heterotrophic pelagic energy mobilization (PEMhet) increases with AOC (HESSEN 1998, JANSSON et al. 2000), both autotrophic (PEMaut) and heterotrophic production increase with P (DEL GIORGIO & PETERS 1994, NURNBERG & SHAW 1999), although the proportion each contributes to PEM may change with increasing total phosphorus (TP) concentration (ROTHHAUPT & CODE 1992, KRITZRERG et al. 2006). JANSSON et al. (2003) demonstrated from whole lake data from unproductive lakes that nutrient use efficiency (PEM/TP) is lower in heterotrophic systems than in autotrophic systems. Bacteria can use AOC as a carbon and energy source, thus uncoupling bacterial production from reliance on phytoplankton carbon (JONES 1992). Because bacteria have a higher affinity for P than phytoplankton, they can out compete phytoplankton at low concentrations of P, but would be expected to mobilize less carbon (C) per unit of P because bacteria contain approximately 10 times more P per unit C (by weight) than phytoplankton (VADSTEIN 2000). Consequently, it would be expected that less energy per unit P would be available for higher trophic levels in pelagic systems dominated by heterotrophy (JANSSON et al. 2003). A second explanation for PEM/TP being lower in heterotrophic than autotrophic systems is that although a high AOC input rate is correlated with a high TP input rate (MEILI 1992), P can be tightly bound to AOC and not always be available for bacterial and phytoplankton production (JONES 1998). An increase in the bioavailability of P may be caused by UV degradation of AOC, or eutrophication (COTNER & BIDDANDA 2002). In this study we examine how the relative contributions of heterotrophic and autotrophic production change with a range of AOC and P concentrations in a chemostat environment. We hypothesise that the proportion of pelagic energy mobilisation that is heterotrophic (%PEMhet) is positively correlated with the input rate of AOC and negatively related to the input rate of inorganic P at a given dissolved organic carbon (DOC) concentration. We also hypothesise that the nutrient use efficiency (PEM/TP) will decrease as heterotrophy increases.

  • 38. Finsinger, Walter
    et al.
    Bigler, Christian
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science. NCCR Climate, Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013, Bern, Switzerland.
    Kraehenbuehl, Urs
    Lotter, Andre F
    Ammann, Brigitta
    Human impacts and eutrophication patterns during the past similar to 200 years at Lago Grande di Avigliana (N. Italy)2006In: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 36, no 1, p. 55-67Article in journal (Refereed)
    Abstract [en]

    A short sediment core from Lago Grande di Avigliana (Piedmont, Italy), the second most eutrophied lake in Italy, was analysed for pollen and diatoms to reconstruct land-use changes and to estimate baseline conditions for total phosphorus (TP) in the water column. Varve counts on sediment thin-sections and (210)Pb, (226)Ra, and (137)Cs dating provided a reliable chronology for the past similar to 200 years. The main pollen-inferred land-use changes showed a sharp decrease of hemp retting around AD 1900, as well as a gradual change to less intensive agriculture and increasing abundance of exotic plants since AD similar to 1970. Diatom-inferred TP reconstructions indicated stable TP concentrations until AD similar to 1950, revealing baseline mesotrophic conditions (TP < 25 mu g l(-1)). After AD similar to 1950, TP values increased distinctly and continuously, culminating in the late 1960s with concentrations of 150 mu g l(-1). Subsequently, diatoms implied a linear decrease of TP, with an inferred value of 40 mu g l(-1) in the surface sediment sample. Comparison with instrumental TP measurements from the water column since AD 1980 showed a rapid recovery and allowed a direct validation of the diatom TP inference. However, although the TP concentration has decreased considerably, baseline conditions have not yet been reached. When compared to the limnological effects of sewage discharges on inferred-TP concentration, our results indicated that agricultural land use played a minor role in the lake's eutrophication.

  • 39. Frank, U.
    et al.
    Nowaczyk, Norbert
    Minyuk, Pavel
    Vogel, Hendrik
    Institute of Geology and Mineralogy, University of Cologne.
    Rosen, Peter
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Melles, Martin
    A 350 ka record of climate change from Lake El'gygytgyn, Far East Russian Arctic: refining the pattern of climate modes by means of cluster analysis2013In: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 9, no 4, p. 1559-1569Article in journal (Refereed)
    Abstract [en]

    Rock magnetic, biochemical and inorganic records of the sediment cores PG1351 and Lz1024 from Lake El'gygytgyn, Chukotka peninsula, Far East Russian Arctic, were subject to a hierarchical agglomerative cluster analysis in order to refine and extend the pattern of climate modes as defined by Melles et al. (2007). Cluster analysis of the data obtained from both cores yielded similar results, differentiating clearly between the four climate modes warm, peak warm, cold and dry, and cold and moist. In addition, two transitional phases were identified, representing the early stages of a cold phase and slightly colder conditions during a warm phase. The statistical approach can thus be used to resolve gradual changes in the sedimentary units as an indicator of available oxygen in the hypolimnion in greater detail. Based upon cluster analyses on core Lz1024, the published succession of climate modes in core PG1351, covering the last 250 ka, was modified and extended back to 350 ka. Comparison to the marine oxygen isotope (delta O-18) stack LR04 (Lisiecki and Raymo, 2005) and the summer insolation at 67.5 degrees N, with the extended Lake El'gygytgyn parameter records of magnetic susceptibility (kappa(LF)), total organic carbon content (TOC) and the chemical index of alteration (CIA; Minyuk et al., 2007), revealed that all stages back to marine isotope stage (MIS) 10 and most of the substages are clearly reflected in the pattern derived from the cluster analysis.

  • 40. Fu, HS
    et al.
    Cao, JB
    Khotyaintsev, Yu V
    Sitnov, MI
    Runov, A
    Fu, SY
    Hamrin, Maria
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Andre, M
    Retino, A
    Ma, YD
    Lu, HY
    Wei, XH
    Huang, SY
    Dipolarization fronts as a consequence of transient reconnection: in situ evidence2013In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 40, no 23, p. 6023-6027Article in journal (Refereed)
    Abstract [en]

    Dipolarization fronts (DFs) are frequently detected in the Earth's magnetotail from X-GSM=-30 R-E to X-GSM=-7 R-E. How these DFs are formed is still poorly understood. Three possible mechanisms have been suggested in previous simulations: (1) jet braking, (2) transient reconnection, and (3) spontaneous formation. Among these three mechanisms, the first has been verified by using spacecraft observation, while the second and third have not. In this study, we show Cluster observation of DFs inside reconnection diffusion region. This observation provides in situ evidence of the second mechanism: Transient reconnection can produce DFs. We suggest that the DFs detected in the near-Earth region (X-GSM>-10 R-E) are primarily attributed to jet braking, while the DFs detected in the mid- or far-tail region (X-GSM<-15 R-E) are primarily attributed to transient reconnection or spontaneous formation. In the jet-braking mechanism, the high-speed flow pushes the preexisting plasmas to produce the DF so that there is causality between high-speed flow and DF. In the transient-reconnection mechanism, there is no causality between high-speed flow and DF, because the frozen-in condition is violated.

  • 41. González, Jonatan A.
    et al.
    Rodríguez-Cortés, Francisco J.
    Cronie, Ottmar
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Mateu, Jorge
    Spatio-temporal point process statistics: a review2016In: Spatial Statistics, E-ISSN 2211-6753, Vol. 18, no Part B, p. 505-544Article, review/survey (Refereed)
    Abstract [en]

    Spatio-temporal point process data have been analysed quite a bit in specialised fields, with the aim of better understanding the inherent mechanisms that govern the temporal evolution of events placed in a planar region. In particular, in the last decade there has been an acceleration of methodological developments, accompanied by a broad collection of applications as spatiotemporally indexed data have become more widely available in many scientific fields. We present a self-contained review describing statistical models and methods that can be used to analyse patterns of points in space and time when the questions of scientific interest concern both their spatial and their temporal behaviour. We revisit moment characteristics that define summary statistics, as well as conditional intensities which uniquely characterise certain spatiotemporal point processes. We make use of these concepts to describe models and associated methods of inference for spatiotemporal point process data. Three new motivating real-data examples are described and analysed throughout the paper to illustrate the most relevant techniques, discussing the pros and cons of the different considered approaches.

  • 42.
    Haei, Mahsa
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rousk, J.
    Ilstedt, Ulrik
    Öquist, Mats G.
    Bååth, E.
    Laudon, H.
    Effects of soil frost on growth, composition and respiration of the soil microbial decomposer community2011In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 43, no 10, p. 2069-2077Article in journal (Refereed)
    Abstract [en]

    Most climate change scenarios predict that the variability of weather conditions will increase in coming decades. Hence, the frequency and intensity of freeze-thaw cycles in high-latitude regions are likely to increase, with concomitant effect on soil carbon biogeochemistry and associated microbial processes. To address this issue we sampled riparian soil from a Swedish boreal forest and applied treatments with variations in four factors related to soil freezing (temperature, treatment duration, soil water content and frequency of freeze-thaw cycles), at three levels in a laboratory experiment, using a Central Composite Face-centred (CCF) experimental design. We then measured bacterial (leucine incorporation) and fungal (acetate in ergosterol incorporation) growth, basal respiration, soil microbial phospholipid fatty acid (PLFA) composition, and concentration of dissolved organic carbon (DOC). Fungal growth was higher in soil exposed to freeze-thawing perturbations and freezing temperatures of −6 °C and −12 °C, than under more constant conditions (steady 0 °C). The opposite pattern was found for bacteria, resulting in an increasing fungal-to-bacterial growth ratio following more intensive winter conditions. Soil respiration increased with water content, decreased with treatment duration and appeared to mainly be driven by treatment-induced changes in the DOC concentration. There was a clear shift in the PLFA composition at 0 °C, compared with the two lower temperatures, with PLFA markers associated with fungi as well as a number of unsaturated PLFAs being relatively more common at 0 °C. Shifts in the PLFA pattern were consistent with those expected for phenotypic plasticity of the cell membrane to low temperatures. There were small declines in PLFA concentrations after freeze-thawing and with longer durations. However, the number of freeze-thaw events had no effect on the microbiological variables. The findings

  • 43. Hahn, A
    et al.
    Kliem, P
    Ohlendorf, C
    Zolitschka, B
    Rosen, Peter
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Climate induced changes as registered in inorganic and organic sediment components from Laguna Potrok Aike (Argentina) during the past 51 ka2013In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 71, p. 154-166Article in journal (Refereed)
    Abstract [en]

    Total organic carbon, total inorganic carbon, biogenic silica content and total organic carbon/total nitrogen ratios of the Laguna Potrok Aike lacustrine sediment record are used to reconstruct the environmental history of south-east Patagonia during the past 51 ka in high resolution. High lake level conditions are assumed to have prevailed during the Last Glacial, as sediments are carbonate-free. Increased runoff linked to permafrost and reduced evaporation due to colder temperatures and reduced influence of Southern Hemispheric Westerlies (SHIN) may have caused these high lake levels with lake productivity being low and organic matter mainly of algal or cyanobacterial origin. Aquatic moss growth and diatom blooms occurred synchronously with southern hemispheric glacial warming events such as the Antarctic A-events, the postglacial warming following the LGM and the Younger Dryas chronozone. During these times, a combination of warmer climatic conditions with related thawing permafrost could have increased the allochthonous input of nutrients and in combination with warmer surface waters increased aquatic moss growth and diatom production. The SHW were not observed to affect southern Patagonia during the Last Glacial. The Holocene presents a completely different lacustrine system because (a) permafrost no longer inhibits infiltration nor emits meltwater pulses and (b) the positioning of the SHW over the investigated area gives rise to strong and dry winds. Under these conditions total organic carbon, total organic carbon/total nitrogen ratios and biogenic silica cease to be first order productivity indicators. On the one hand, the biogenic silica is influenced by dissolution of diatoms due to higher salinity and pH of the lake water under evaporative stress characterizing low lake levels. On the other hand, total organic carbon and total organic carbon/total nitrogen profiles are influenced by reworked macrophytes from freshly exposed lake level terraces during lowstands. Total inorganic carbon remains the most reliable proxy for climatic variations during the Holocene as high precipitation of carbonates can be linked to low lake levels and high autochthonous production. The onset of inorganic carbon precipitation has been associated with the southward shift of the SHW over the latitudes of Laguna Potrok Aike. The refined age-depth model of this record suggests that this shift occurred around 9.4 cal. ka BP. (c) 2012 Elsevier Ltd. All rights reserved.

  • 44. Hahn, Annette
    et al.
    Compton, John S.
    Meyer-Jacob, Carsten
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Kirsten, Kelly L.
    Lucasssen, Friedrich
    Perez Mayo, Manuel
    Schefuß, Enno
    Zabel, Matthias
    Holocene paleo-climatic record from the South African Namaqualand mudbelt: A source to sink approach2016In: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 404, no B, p. 121-135Article in journal (Refereed)
    Abstract [en]

    Variations in the sediment input to the Namaqualand mudbelt during the Holocene are assessed using an integrative terrestrial to marine, source to sink approach. Geochemical and Sr and Nd isotopic signatures are used to distinguish fluvial sediment source areas. Relative to the sediments of the Olifants River, craton outcrops in the northern Orange River catchment have a more radiogenic Sr and a more unradiogenic Nd isotopic signature. Furthermore, upper Orange River sediments are rich in heavier elements such as Ti and Fe derived from the chemical weathering of Drakensberg flood basalt. Suspension load signatures change along the Orange River's westward transit as northern catchments contribute physical weathering products from the Fish and Molopo River catchment area. Marine cores offshore of the Olifants (GeoB8323-2) and Orange (GeoB8331-4) River mouths show pulses of increased contribution of Olifants River and upper Orange River input, respectively. These pulses coincide with intervals of increased terrestrial organic matter flux and increased paleo-production at the respective core sites. We attribute this to an increase in fluvial activity and vegetation cover in the adjacent catchments during more humid climate conditions. The contrast in the timing of these wet phases in the catchment areas reflects the bipolar behavior of the South African summer and winter rainfall zones. While rainfall in the Orange River catchment is related to southward shifts in the ICTZ, rainfall in the Olifants catchment is linked to northward shifts in Southern Hemisphere Westerly storm tracks. The later may also have increased southern Benguela upwelling in the past by reducing the shedding of Agulhas eddies into the Atlantic. The high-resolution records of latitudinal shifts in these atmospheric circulation systems correspond to late Holocene centennial-millennial scale climate variability evident in Antarctic ice core records. The mudbelt cores indicate that phases of high summer rainfall zone and low winter rainfall zone humidity (at ca. 2.8 and 1 ka BP) may be synchronous with Antarctic warming events. On the other hand, dry conditions in the summer rainfall zone along with wet conditions in the winter rainfall zone (at ca 3.3, 2 and 0.5 ka BP) may be associated with Antarctic cooling events.

  • 45. Höbig, Nicole
    et al.
    Weber, Michael E.
    Kehl, Martin
    Weniger, Gerd-Christian
    Julia, Ramon
    Melles, Martin
    Fülöpb, Reka-Hajnalka
    Vogel, Hendrik
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Reicherter, Klaus
    Lake Banyoles (northeastern Spain): A Last Glacial to Holocene multi-proxy study with regard to environmental variability and human occupation2012In: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 274, p. 205-218Article in journal (Refereed)
    Abstract [en]

    Analyses of a 67-m long sediment core from Lake Banyoles (northeastern Spain) have revealed evidence for the palaeoclimate history of the northern Iberian Peninsula. Investigations have included high-resolution and non-destructive sediment-physical, geochemical, and optical methods to generate proxies indicative of sedimentologic variability and climate change. Primary stratigraphic control is based on C-14 and U-series dates of organic and inorganic material, as well as tephra from the Late Pleistocene Olot volcanic episode. While preliminary ages obtained for the core base date back to approximately 60 ka, the Last Glacial Maximum (23-19 ka) interval ends at 15 m. The top 8 m of deposits accumulated in the Holocene. Several slump events were observed in the core section, as were microtectonic structures, which constrain the movement. Evidence for palaeoclimate variations in element ratios is interpreted to represent effects of Heinrich Events H0-H5. Associated changes in environmental conditions (e.g., humidity) may have affected human occupation during the Palaeolithic-Neolithic period. Implications on human occupation in northeastern Iberia due to climate changes are discussed from archeological findings and cave sediments in neighboring areas and are analyzed with respect to the palaeolimnologic of lake Banyoles. (C) 2012 Elsevier Ltd and INQUA. All rights reserved.

  • 46. Jonsson, Christina E
    et al.
    Rosqvist, Gunhild C
    Leng, Melanie J
    Bigler, Christian
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bergman, Jonas
    Kaislahti Tillman, Päivi
    Sloane, Hilary J
    High resolution diatom δ18O records from two sub-Arctic high altitude lakes in the Swedish Scandes2010In: Journal of Quaternary Science, ISSN 0267-8179, E-ISSN 1099-1417, Vol. 25, no 6, p. 918-930Article in journal (Refereed)
    Abstract [en]

    Waters from high-altitude alpine lakes are mainly recharged by meteoric water. Because of seasonal variations in precipitation and temperature and relatively short hydraulic residence times, most high-altitude lakes have lake water isotopic compositions (δ18Olake) that fluctuate due to seasonality in water balance processes. Input from snowmelt, in particular, has a significant role in determining lake water δ18O. Here we compare two high-resolution δ18Odiatom records from lake sediments in the Swedish Scandes with instrumental data from the last century obtained from nearby meteorological stations. The time period AD 1900–1990 is characterised by an increase in winter precipitation and high winter/summer precipitation ratios and this is recorded in δ18Odiatom as decreasing trends. Lowest δ18Odiatom values and highest amount of winter precipitation are found around AD 1990 when the winter North Atlantic Oscillation index was above +2. We conclude that for the last 150 a the main factor affecting the δ18Odiatom signal in these sub-Arctic high-altitude lakes with short residence times has been changes in amount of winter precipitation and that δ18Odiatom derived from high-altitude lakes in the Swedish Scandes can be used as a winter precipitation proxy. Copyright © 2010 John Wiley & Sons, Ltd.

  • 47.
    Keskitalo, E Carina H
    et al.
    Umeå University, Faculty of Social Sciences, Department of Geography and Economic History.
    Vulturius, Gregor
    Umeå University, Faculty of Social Sciences, Department of Geography and Economic History.
    Scholten, Peter
    Umeå University, Faculty of Social Sciences, Department of Geography and Economic History.
    Adaptation to climate change in the insurance sector: examples from the UK, Germany and the Netherlands2014In: Natural Hazards, ISSN 0921-030X, E-ISSN 1573-0840, Vol. 71, no 1, p. 315-334Article in journal (Refereed)
    Abstract [en]

    Adaptation to climate change, particularly flood risks, may come to pose large challenges in the future and will require cooperation among a range of stakeholders. However, there presently exists little research especially on the integration of the private sector in adaptation. In particular, recently developed state programs for adaptation have so far been focused on the public sector. Insurance providers may have much to contribute as they offer other parts of society services to appropriately identify, assess and reduce the financial impacts of climate change-induced risks. This study aims to explore how the institutional distribution of responsibility for flood risk is being renegotiated within the UK, Germany and Netherlands. Examining how the insurance industry and the public sector can coordinate their actions to promote climate change adaptation, the study discusses how layered natural hazard insurance systems may result from attempts to deal with increasing risks due to increasing incidences of extreme events and climate change. It illustrates that concerns over the risks from extreme natural events have prompted re-assessments of the current systems, with insurance requiring long-term legislative frameworks that defines the objectives and responsibilities of insurers and the different political authorities.

  • 48.
    Klaminder, Jonatan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Appleby, P
    Crook, P
    Renberg, Ingemar
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Post-deposition diffusion of 137Cs in lake sediment: implications for radiocaesium dating2012In: Sedimentology, ISSN 0037-0746, E-ISSN 1365-3091, Vol. 59, no 7, p. 2259-2267Article in journal (Refereed)
    Abstract [en]

    Peak activities of radiocaesium (137Cs) in lake sediments have frequently been used to infer the ages of sediments deposited in the 1960s (137Cs derived from nuclear bomb testing) or in 1986 (Chernobyl derived 137Cs). Records of the vertical distribution of 137Cs in sediments can thus be used to provide accurate dates for a critical period in which palaeoecological reconstructions often overlap contemporary monitoring data. However, knowledge regarding how the distribution of 137Cs in sediments is affected by post-depositional processes is limited to interpretations based on the 137Cs distribution in sediments sampled at a single given date. This study assesses the extent to which the 137Cs record in annually laminated (varved) lake sediments is affected by post-depositional diffusion, using 11 archived sediment cores sampled between 1986 and 2007. The sediment record reveals how Chernobyl 137Cs incorporated into the 1986 varve diffused downwards in the core at a decreasing rate over time, whereas the surface sediments continued to receive inputs of 137Cs mobilized from the catchment soils or lake margin. In spite of these processes, all cores post-dating the Chernobyl accident had a clear and well-resolved peak in the 1986 varve, justifying the use of this feature as a fixed chronostratigraphic feature. Because of the very high levels of Chernobyl fallout at this site, downwards migration of Chernobyl 137Cs has, however, completely masked the nuclear weapons 137Cs fallout peak that had been clearly preserved in the 1964 varve of a pre-Chernobyl core sampled just three weeks before the Chernobyl accident. In consequence, the weapons fallout marker is likely to be of little use for determining 137Cs dates in areas strongly affected by high levels of Chernobyl fallout.

  • 49. Leng, Melanie J.
    et al.
    Wagner, Bernd
    Boehm, Anne
    Panagiotopoulos, Konstantinos
    Vane, Christopher H.
    Snelling, Andrea
    Haidon, Cheryl
    Woodley, Ewan
    Vogel, Hendrik
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Zanchetta, Gianni
    Baneschi, Ilaria
    Understanding past climatic and hydrological variability in the Mediterranean from Lake Prespa sediment isotope and geochemical record over the last glacial cycle2013In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 66, p. 123-136Article in journal (Refereed)
    Abstract [en]

    Here we present stable isotope and geochemical data from Lake Prespa (Macedonia/Albania border) over the Last Glacial cycle (Marine Isotope Stages 5-1) and discuss past lake hydrology and climate (TIC, oxygen and carbon isotopes), as well as responses to climate of terrestrial and aquatic vegetation (TOC, Rock Eval pyrolysis, carbon isotopes, pollen). The Lake Prespa sediments broadly fall into 5 zones based on their sedimentology, geochemistry, palynology and the existing chronology. The Glacial sediments suggest low supply of carbon to the lake, but high summer productivity; intermittent siderite layers suggest that although the lake was likely to have mixed regularly leading to enhanced oxidation of organic matter, there must have been within sediment reducing conditions and methanogenesis. MIS 5 and 1 sediments suggest much more productivity, higher rates of organic material preservation possibly due to more limited mixing with longer periods of oxygen-depleted bottom waters. We also calculated lakewater delta O-18 from siderite (authigenic/Glacial) and calcite (endogenic/Holocene) and show much lower lakewater delta O-18 values in the Glacial when compared to the Holocene, suggesting the lake was less evaporative in the Glacial, probably as a consequence of cooler summers and longer winter ice cover. In the Holocene the oxygen isotope data suggests general humidity, with just 2 marked arid phases, features observed in other Eastern and Central Mediterranean lakes. (C) 2012 Elsevier Ltd. All rights reserved.

  • 50.
    Lundin, Erik J
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, Stockholm, Sweden.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Giesler, Reiner
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Persson, Andreas
    Olefeldt, David
    Heliasz, Michal
    Christensen, Torben R.
    Karlsson, Jan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Is the subarctic landscape still a carbon sink?: Evidence from a detailed catchment balance2016In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, no 5, p. 1988-1995Article in journal (Refereed)
    Abstract [en]

    Climate warming raises the question whether high-latitude landscape still function as net carbon (C) sinks. By compiling an integrated C balance for an intensely studied subarctic catchment, we show that this catchment's C balance is not likely to be a strong current sink of C, a commonly held assumption. In fact, it is more plausible (71% probability) that the studied catchment functions as a C source (-1120gCm(-2)yr(-1)). Analyses of individual fluxes indicate that soil and aquatic C losses offset C sequestering in other landscape components (e.g., peatlands and aboveground forest biomass). Our results stress the importance of fully integrated catchment C balance estimates and highlight the importance of upland soils and their interaction with the aquatic network for the catchment C balance.

12 1 - 50 of 79
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