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Broström, Anna
Publications (10 of 12) Show all publications
Hellman, S., Gaillard, M.-J., Broström, A. & Sugita, S. (2008). Effects of the sampling design and selection of parameter values on pollen-based quantitative reconstructions of regional vegetation: a case study in southern Sweden using the REVEALS model.. Vegetation History and Archaeobotany, 17(5), 445-459
Open this publication in new window or tab >>Effects of the sampling design and selection of parameter values on pollen-based quantitative reconstructions of regional vegetation: a case study in southern Sweden using the REVEALS model.
2008 (English)In: Vegetation History and Archaeobotany, ISSN 0939-6314, E-ISSN 1617-6278, Vol. 17, no 5, p. 445-459Article in journal (Refereed) Published
Abstract [en]

The need for quantification of land cover from pollen data has led to the development of a Landscape Reconstruction Algorithm (LRA). The LRA includes several models of which the REVEALS model estimates regional vegetation abundance using pollen assemblages from large sites (lakes or bogs). In this paper we explore the effects of selection and number of pollen samples, and choice of pollen productivity estimates on the REVEALS results. The effect of the size of vegetation surveys is also tested. The results suggest that the differences between two sizes of vegetation surveys have little effect on the model validation. The "characteristic radius" of regional vegetation in southern Sweden was estimated as 200 km. However, the vegetation composition in a 100 x 100 km(2) square matches well with that estimated by REVEALS. Whether 25, 20 (outliers excluded) or 4 pollen samples are used does not change the REVEALS reconstructions much although the error estimates are larger when outliers are included, and very large when only four samples are used. Therefore validation of the REVEALS model and REVEALS reconstructions of past vegetation can be performed using a limited number of pollen samples, although with caution. The use of many pollen samples from multiple sites is always better whenever possible. REVEALS reconstructions are closer to the actual vegetation when the Danish Pollen Productivity Estimates (PPEs) are used instead of the Swedish PPEs for Cereals, Rumex acetosa/acetosella, Plantago lanceolata and Calluna, indicating that the Danish PPEs are more reliable than the Swedish ones for those taxa. It is recommended to test more than one set of PPEs in validation and applications of the REVEALS model for a better evaluation of the results.

National Category
Natural Sciences
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-1744 (URN)10.1007/s00334-008-0149-7 (DOI)000258317500003 ()
Available from: 2010-04-06 Created: 2010-04-06 Last updated: 2017-12-12Bibliographically approved
Mazier, F., Broström, A., Gaillard, M.-J., Sugita, S., Vittoz, P. & Buttler, A. (2008). Pollen productivity estimates and relevant source area of pollen for selected plant taxa in a pasture woodland landscape of the Jura Mountains (Switzerland).. Vegetation History and Archaeobotany, 17(5), 479-495
Open this publication in new window or tab >>Pollen productivity estimates and relevant source area of pollen for selected plant taxa in a pasture woodland landscape of the Jura Mountains (Switzerland).
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2008 (English)In: Vegetation History and Archaeobotany, ISSN 0939-6314, E-ISSN 1617-6278, Vol. 17, no 5, p. 479-495Article in journal (Refereed) Published
Abstract [en]

Relevant source area of pollen (RSAP) and pollen productivity for 11 key taxa characteristic of the pasture woodland landscape of the Jura Mountains, Switzerland, were estimated using pollen assemblages from moss polsters at 20 sites. To obtain robust pollen productivity estimates (PPEs), we used vegetation survey data at a fine spatial-resolution (1 x 1 m(2)) and randomized locations for sampling sites, techniques rarely used in palynology. Three Extended R value (ERV) submodels and three distance-weighting methods for plant abundance calculation were applied. Different combinations of the submodels and distance-weighting methods provide slightly different estimates of RSAP and PPEs. Although ERV submodel 1 using 1/d (d = distance in meters) best fits the dataset, PPE values for heavy pollen types (e.g. Abies) were sensitive to the method used for distance-weighting. Taxon-specific distance-weighting methods, such as Prentice's model, emphasize the intertaxonomic differences in pollen dispersal and deposition, and are thus theoretically sound. For the dataset obtained in this project, Prentice's model was more appropriate than other distance-weighting methods to estimate PPEs. Most of the taxa have PPEs equal to (Fagus, Plantago media and Potentilla-type), or higher (Abies, Picea, Rubiaceae and Trollius europaeus) than Poaceae (PPE = 1). Acer, Cyperaceae, and Plantago montana-type are low pollen producers. This set of PPEs will be useful for reconstructing heterogeneous, mountainous pasture woodland landscapes from fossil pollen records. The RSAP for moss polsters in this semi-open landscape region is ca. 300 m.

National Category
Natural Sciences
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-1745 (URN)10.1007/s00334-008-0143-0 (DOI)000258317500005 ()
Available from: 2010-04-06 Created: 2010-04-06 Last updated: 2017-12-12Bibliographically approved
Broström, A., Nielsen, A. B., Gaillard, M.-J., Hjelle, K., Mazier, F., Binney, H., . . . Sugita, S. (2008). Pollen productivity estimates of key European plant taxa for quantitative reconstruction of past vegetation: a review. Paper presented at 1st Joint Hite-Pollandcal Conference, NOV 13-14, 2005, Umea, SWEDEN. Vegetation History and Archaeobotany, 17(5), 461-478
Open this publication in new window or tab >>Pollen productivity estimates of key European plant taxa for quantitative reconstruction of past vegetation: a review
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2008 (English)In: Vegetation History and Archaeobotany, ISSN 0939-6314, E-ISSN 1617-6278, Vol. 17, no 5, p. 461-478Article in journal (Refereed) Published
Abstract [en]

Information on the spatial distribution of past vegetation on local, regional and global scales is increasingly used within climate modelling, nature conservancy and archaeology. It is possible to obtain such information from fossil pollen records in lakes and bogs using the landscape reconstruction algorithm (LRA) and its two models, REVEALS and LOVE. These models assume that reliable pollen productivity estimates (PPEs) are available for the plant taxa involved in the quantitative reconstructions of past vegetation, and that PPEs are constant through time. This paper presents and discusses the PPEs for 15 tree and 18 herb taxa obtained in nine study areas of Europe. Observed differences in PPEs between regions may be explained by methodological issues and environmental variables, of which climate and related factors such as reproduction strategies and growth forms appear to be the most important. An evaluation of the PPEs at hand so far suggests that they can be used in modelling applications and quantitative reconstructions of past vegetation, provided that consideration of past environmental variability within the region is used to inform selection of PPEs, and bearing in mind that PPEs might have changed through time as a response to climate change. Application of a range of possible PPEs will allow a better evaluation of the results.

Keywords
pollen productivity estimates (PPE), landscape reconstruction algorithm (LRA), tree taxa, herb taxa, moss polsters, lake sediments
National Category
Natural Sciences
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-27712 (URN)10.1007/s00334-008-0148-8 (DOI)000258317500004 ()
Conference
1st Joint Hite-Pollandcal Conference, NOV 13-14, 2005, Umea, SWEDEN
Available from: 2013-07-31 Created: 2013-07-31 Last updated: 2017-12-06Bibliographically approved
Hellman, S., Gaillard, M.-J., Broström, A. & Sugita, S. (2008). The REVEALS model, new tool to estimate past regional plant abundance from pollen data in large lakes: validation. Journal of Quaternary Science, 23(1), 21-42
Open this publication in new window or tab >>The REVEALS model, new tool to estimate past regional plant abundance from pollen data in large lakes: validation
2008 (English)In: Journal of Quaternary Science, ISSN 0267-8179, E-ISSN 1099-1417, Vol. 23, no 1, p. 21-42Article in journal (Refereed) Published
Abstract [en]

The REVEALS model was developed to reconstruct quantitatively regional vegetation abundance (in a 104–105 km2 area) from pollen assemblages in large lakes (≥100–500 ha). This model corrects for biases in pollen percentages caused by inter-taxonomic differences in pollen productivity and dispersal. This paper presents the first case study to validate REVEALS, using empirical data from southern Sweden. Percentage cover of modern regional vegetation in Skåne and Småland, two contrasting vegetation regions, was predicted with REVEALS for 26 key taxa, using pollen assemblages from surface sediments in 10 large lakes, and compared to the actual vegetation within 104 km2 compiled from satellite data, forestry inventories, crop statistics, aerial photographs, and vegetation inventories. REVEALS works well in predicting the percentage cover of large vegetation units such as total trees (wooded land), total herbs (open land), total conifers and total broad-leaved trees, and it provides reasonable estimates for individual taxa, including Pinus, Picea, Betula, Corylus, Alnus, Tilia, Salix spp., Juniperus, Poaceae, Cyperaceae, Cerealia and Secale. The results show great potential for REVEALS applications, including (1) quantitative reconstructions of past regional land cover important for palaeoclimatology and nature conservation, and (2) local-scale reconstruction of vegetation (<1 km2 up to ∼ 5 km2 area) relevant for palaeoecology and archaeology.

National Category
Natural Sciences
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-2735 (URN)10.1002/jqs.1126 (DOI)
Available from: 2010-04-23 Created: 2010-04-23 Last updated: 2017-12-12Bibliographically approved
Sugita, S., Gaillard, M.-J., Hellman, S. & Broström, A. (2007). Model-based reconstruction of vegetation and landscape using fossil pollen – implications for the interpretation of landscape openness and the role of climate change and human impacts.. In: Quaternary International 131: . Paper presented at Association (INQUA) Congress.
Open this publication in new window or tab >>Model-based reconstruction of vegetation and landscape using fossil pollen – implications for the interpretation of landscape openness and the role of climate change and human impacts.
2007 (English)In: Quaternary International 131, 2007Conference paper, Published paper (Refereed)
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-4781 (URN)
Conference
Association (INQUA) Congress
Note

Nummer:

Available from: 2010-04-28 Created: 2010-04-28 Last updated: 2016-10-25Bibliographically approved
Gaillard, M.-J., Sugita, S., Hellman, S. & Broström, A. (2006). New approach to quantitative reconstruction of past vegetation inferred from fossil pollen – implications for applications within climate research. In: EGU (European Geoscience Union) 3rd Assembly: . Vienna, Austria
Open this publication in new window or tab >>New approach to quantitative reconstruction of past vegetation inferred from fossil pollen – implications for applications within climate research
2006 (English)In: EGU (European Geoscience Union) 3rd Assembly, Vienna, Austria, 2006Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Vienna, Austria: , 2006
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-4516 (URN)
Note

Nummer:

Available from: 2010-04-27 Created: 2010-04-27 Last updated: 2016-10-25Bibliographically approved
Gaillard, M.-J., Sugita, S., Hellman, S. & Broström, A. (2005). Calibration and validation of pollen proxies: application in quantitative reconstruction of past land.cover 3000-0 yrs. BP, southern Sweden. In: EGU (European Geoscience Union) 2nd Assembly: . Vienna, Austria
Open this publication in new window or tab >>Calibration and validation of pollen proxies: application in quantitative reconstruction of past land.cover 3000-0 yrs. BP, southern Sweden
2005 (English)In: EGU (European Geoscience Union) 2nd Assembly, Vienna, Austria, 2005Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Vienna, Austria: , 2005
National Category
Natural Sciences
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-4514 (URN)
Note

Nummer:

Available from: 2010-04-27 Created: 2010-04-27 Last updated: 2016-10-25Bibliographically approved
Broström, A., Sugita, S., Gaillard, M.-J. & Petter, P. (2005). Estimating the spatial scale of pollen dispersal in the cultural landscape of southern Sweden. The Holocene, 15 (2), 252-262
Open this publication in new window or tab >>Estimating the spatial scale of pollen dispersal in the cultural landscape of southern Sweden
2005 (English)In: The Holocene, Vol. 15 (2), p. 252-262Article in journal (Refereed) Published
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-722 (URN)
Available from: 2010-04-01 Created: 2010-04-01 Last updated: 2016-10-25Bibliographically approved
Gaillard-Lemdahl, M.-J., Sugita, S., Hellman, S. & Broström, A. (2004). Pollen-based quantitative reconstruction of past vegetation using models of pollen dispersal and deposition. In: XIV IPC (International Palynological Conference). Granada, Spain
Open this publication in new window or tab >>Pollen-based quantitative reconstruction of past vegetation using models of pollen dispersal and deposition
2004 (English)In: XIV IPC (International Palynological Conference), Granada, Spain, 2004Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Granada, Spain: , 2004
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-4512 (URN)
Note
Nummer: Available from: 2010-04-27 Created: 2010-04-27 Last updated: 2016-10-25Bibliographically approved
Gaillard, M.-J., Sugita, S., Broström, A., Eklöf, E. & Pilesö, P. (2000). Long Term Land-Cover Changes on Regional to Global Scales Inferred From Fossil Pollen – How to Meet the Challenges of Climate Research?. PAGES Newsletter, 2000-3, 30-32
Open this publication in new window or tab >>Long Term Land-Cover Changes on Regional to Global Scales Inferred From Fossil Pollen – How to Meet the Challenges of Climate Research?
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2000 (English)In: PAGES Newsletter, Vol. 2000-3, p. 30-32Article in journal (Refereed) Published
Research subject
Environmental Science, Paleoecology
Identifiers
urn:nbn:se:lnu:diva-1382 (URN)
Available from: 2010-04-06 Created: 2010-04-06 Last updated: 2016-10-25Bibliographically approved

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