| 1. |
- Broström, Anna, et al.
(author)
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Pollen productivity estimates of key European plant taxa for quantitative reconstruction of past vegetation : a review
- 2008
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In: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 17:5, s. 461-478
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Journal article (peer-reviewed)abstract
- 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.
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| 2. |
- Gaillard, Marie-Jose, et al.
(author)
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The use of modelling and simulation approach in reconstructing past landscapes from fossil pollen data: a review and results from the POLLANDCAL network
- 2008
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In: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 17:5, s. 419-443
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Journal article (peer-reviewed)abstract
- Information on past land cover in terms of absolute areas of different landscape units (forest, open land, pasture land, cultivated land, etc.) at local to regional scales is needed to test hypotheses and answer questions related to climate change (e.g. feedbacks effects of land-cover change), archaeological research, and nature conservancy (e.g. management strategy). The palaeoecological technique best suited to achieve quantitative reconstruction of past vegetation is pollen analysis. A simulation approach developed by Sugita (the computer model POLLSCAPE) which uses models based on the theory of pollen analysis is presented together with examples of application. POLLSCAPE has been adopted as the central tool for POLLANDCAL (POLlen/LANdscape CALibration), an international research network focusing on this topic. The theory behind models of the pollen-vegetation relationship and POLLSCAPE is reviewed. The two model outputs which receive greatest attention in this paper are the relevant source area of pollen (RSAP) and pollen loading in mires and lakes. Six examples of application of POLLSCAPE are presented, each of which explores a possible use of the POLLANDCAL tools and a means of validating or evaluating the models with empirical data. The landscape and vegetation factors influencing the size of the RSAP, the importance of pollen productivity estimates (PPEs) for the model outputs, the detection of small and rare patches of plant taxa in pollen records, and quantitative reconstructions of past vegetation and landscapes are discussed on the basis of these examples. The simulation approach is seen to be useful both for exploring different vegetation/landscape scenarios and for refuting hypotheses.
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| 3. |
- Meltsov, Vivika, et al.
(author)
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The role of landscape structure in determining palynological and floristic richness
- 2013
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In: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 22:1, s. 39-49
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Journal article (peer-reviewed)abstract
- The associations between floristic and palynological richness and landscape structure were studied based on modern pollen-vegetation data from a patchy cultural landscape in southern Estonia (northern temperate vegetation zone). Nine study sites (small lakes and their surrounding vegetation) represent land cover gradient from closed forest to semi-open vegetation. Floristic richness (number of species) and floristic richness of pollen types (number of pollen-equivalent taxa) were used to describe the vegetation within the radius of 250 m from the pollen sampling sites. Palynological richness was calculated to describe the modern pollen samples diversity. Landscape structure was estimated on the basis of landscape openness and three landscape diversity measures: richness of community patches, Simpson evenness of community patches and Simpson diversity of community patches. To study the effect of the spatial scale of landscapes on the vegetation-landscape and pollen-landscape associations, landscape structure was estimated within eight radii (250-2,000 m) around each lake. The results showed that landscape openness was the most important determinant of both floristic richness and palynological richness in southern Estonia and that landscape diversity estimated by Simpson diversity index was also significantly associated with the richness estimates. Floristic and palynological richness were significantly positively correlated with landscape structure within the radii greater than 1,000 m from the pollen sampling sites, which is similar to the estimated Relevant Source Area of Pollen in southern Estonia. We conclude that within one floristic or climatic region, palynological richness gives reliable estimates about the variation in floristic richness and landscape structure; however, caution must be taken when comparing pollen-inferred vegetation diversities from different regions or when interpreting fossil pollen records from times with highly different vegetation associations.
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| 4. |
- Väli, Vivika, et al.
(author)
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Pollen richness : a reflection of vegetation diversity or pollen-specific parameters?
- 2022
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In: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 31:6, s. 611-622
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Journal article (peer-reviewed)abstract
- Our study aims to increase the understanding about the impacts of potential drivers of pollen richness by using a pollen-vegetation modelling approach. We used the Sutton-Prentice dispersal model implemented in the HUMPOL software suite to explore the effects of factors commonly associated with pollen richness: vegetation diversity (plant richness and evenness), land-cover characteristics (patch richness, evenness and size, and basin size) and pollen-related parameters (productivity and fall speed). The impact of the factors was tested using modelling scenarios involving all combinations of the included factors and their values. All tested factors had a statistically significant impact on modelled pollen richness. Pollen-type based plant richness was the dominant determinant of pollen richness; however, pollen productivity became co-dominant at higher plant richness levels, effectively limiting the detection of species with low pollen productivity. The fall speed of pollen and sedimentary basin size had moderate impact, but gained importance in simulations with elevated plant richness. In patchy land-cover, patch richness was the most significant determinant of pollen richness, while patch evenness and size were the least important factors. Our modelling approach provides insights into the significance of common factors in determining pollen richness and its connection to plant diversity, as well as a theoretical basis for understanding the substantial variation among earlier empirical pollen-plant richness studies. The estimation of plant richness from pollen richness in past vegetation diversity studies could be improved by the separation of taxa with low and high pollen productivity and an awareness of the pollen source area.
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