Giesecke, Thomas

[["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.journal","Review of Palaeobotany and Palynology"],["dc.bibliographiccitation.lastpage","25"],["dc.bibliographiccitation.volume","228"],["dc.contributor.author","Birks, H. John B."],["dc.contributor.author","Felde, Vivian A."],["dc.contributor.author","Bjune, Anne E."],["dc.contributor.author","Grytnes, John-Arvid"],["dc.contributor.author","Seppa, Heikki"],["dc.contributor.author","Giesecke, Thomas"],["dc.date.accessioned","2018-11-07T10:15:04Z"],["dc.date.available","2018-11-07T10:15:04Z"],["dc.date.issued","2016"],["dc.description.abstract","Current interest and debate on pollen-assemblage richness as a proxy for past plant richness have prompted us to review recent developments in assessing whether modern pollen-assemblage richness reflects contemporary floristic richness. We present basic definitions and outline key terminology. We summarise four basic needs in assessing pollen-plant richness relationships - modern pollen data, modern vegetation data, pollen-plant translation tables, and quantification of the co-variation between modern pollen and vegetation compositional data. We discuss three key estimates and one numerical tool - richness estimation, evenness estimation, diversity estimation, and statistical modelling. We consider the inherent problems and biases in assessing pollen-plant richness relationships - taxonomic precision, pollen-sample:pollen-population ratios, pollen-representation bias, and underlying concepts of evenness and diversity. We summarise alternative approaches to studying pollen plant richness relationships. We show that almost all studies which have compared modern pollen richness with contemporary site-specific plant richness reveal good relationships between palynological richness and plant richness. We outline future challenges and research opportunities - interpreting past pollen-richness patterns, estimating richness from macrofossils, studying pollen richness at different scales, partitioning diversity and estimating beta diversity, estimating false, hidden, and dark richness, and considering past functional and phylogenetic diversity from pollen data. We conclude with an assessment of the current state-of-knowledge about whether pollen richness reflects floristic richness and explore what is known and unknown in our understanding of pollen-plant richness relationships. (C) 2016 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.revpalbo.2015.12.011"],["dc.identifier.isi","000374424800001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/40739"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1879-0615"],["dc.relation.issn","0034-6667"],["dc.title","Does pollen-assemblage richness reflect floristic richness? A review of recent developments and future challenges"],["dc.type","review"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","209"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","The Holocene"],["dc.bibliographiccitation.lastpage","220"],["dc.bibliographiccitation.volume","19"],["dc.contributor.author","Seppa, Heikki"],["dc.contributor.author","Alenius, Teija"],["dc.contributor.author","Muukkonen, Petteri"],["dc.contributor.author","Giesecke, Thomas"],["dc.contributor.author","Miller, Paul A."],["dc.contributor.author","Ojala, Antti E. K."],["dc.date.accessioned","2018-11-07T08:32:08Z"],["dc.date.available","2018-11-07T08:32:08Z"],["dc.date.issued","2009"],["dc.description.abstract","Recent investigations show that the pollen accumulation rate (PAR) of the common tree taxa is directly related to the biomass and, by inference, to the population size of the taxa around the study site. Fossil PAR records preserved in lakes provide therefore a potential proxy for quantitative biomass and population reconstructions. We use the high-resolution PAR records obtained from two accurately dated lake sediment cores in Finland to generate quantitative Holocene biomass records for Pinus, Picea and Betula, the most common tree taxa of the European Boreal forest. PAR values were calibrated to biomass values by comparing the modern PAR values with the modern biomass values and assuming a linear relationship between the past PAR and biomass values. The obtained PAR and biomass values and trends are remarkably coherent between the two records. Pinus has a stable Holocene biomass size and its modern biomass, about 20 t/ha corresponds with the natural Pinus biomass in the study regions. In contrast, Picea immigrated from the East during the mid Holocene, had a maximum biomass, 50-60 t/ha, at 3500-1000 cal. yr BP, and declined strongly during the last 1500-1000 years as a result of increased human activity and related rise of fire frequency. Thus, the modern Picea biomass in the study regions, about 22 t/ha, is only 35-40% of the natural Picea biomass. The results of this pilot study demonstrate the potential of the calibrated PAR data in quantitative biomass and population reconstructions. Such reconstructions can provide fresh insights into the structure of past plant communities and, when combined with records reflecting palaeoclimates, natural disturbances, and human activity, can help to disentangle the long-term importance of different enviromental drivers to changes in plants populations and ecosystems."],["dc.description.sponsorship","Academy of Finland; European Science Foundation [2003-980409]"],["dc.identifier.doi","10.1177/0959683608100565"],["dc.identifier.isi","000264239900004"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/13075"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/17274"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Sage Publications Ltd"],["dc.relation.issn","0959-6836"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Calibrated pollen accumulation rates as a basis for quantitative tree biomass reconstructions"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","53"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","The Holocene"],["dc.bibliographiccitation.lastpage","63"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Seppa, Heikki"],["dc.contributor.author","Schurgers, Guy"],["dc.contributor.author","Miller, Paul A."],["dc.contributor.author","Bjune, Anne E."],["dc.contributor.author","Giesecke, Thomas"],["dc.contributor.author","Kuehl, Norbert"],["dc.contributor.author","Renssen, Hans"],["dc.contributor.author","Salonen, J. Sakari"],["dc.date.accessioned","2018-11-07T10:04:12Z"],["dc.date.available","2018-11-07T10:04:12Z"],["dc.date.issued","2015"],["dc.description.abstract","Palaeoecological records provide a rich source of information to explore how plant distribution ranges respond to climate changes, but their use is complicated by the fact that, especially when based on pollen data, they are often spatially too inaccurate to reliably determine past range limits. To solve this problem, we focus on hazel (Corylus avellana), a tree species with large and heavy fruits (nuts), which provide firm evidence of the local occurrence of species in the past. We combine the fossil nut records of hazel from Fennoscandia, map its maximum distribution range during the Holocene thermal maximum (HTM) and compare the fossil record with the Holocene hazel range shift as simulated by the LPJ-GUESS dynamic vegetation model. The results show that the current northern range limit of hazel in central and eastern Fennoscandia is constrained by too short growing seasons and too long and cold winters and demonstrate that the species responded to the HTM warming of about 2.5 degrees C (relative to the present) by shifting its range limit up to 63-64 degrees N, reached a rough equilibrium with the HTM climatic conditions and retreated from there to about 60 degrees N during the last 4000 years in response to the late-Holocene cooling. Thus, the projected future warming of about 2.5 degrees C would reverse the long-term southward retraction of species' northern range limit in Europe and is likely to lead to hazel being a common, regeneratively reproductive species up to 63-64 degrees N. In addition to the accuracy of the projected warming, the likelihood of this scenario will depend on inter-specific competition with other tree taxa and the potential of hazel to migrate and its population to grow in balance with the warming. In general, the range dynamics from the HTM to the present suggest a tight climatic control over hazel's range limit in Fennoscandia."],["dc.identifier.doi","10.1177/0959683614556377"],["dc.identifier.isi","000346178000005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/38643"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Sage Publications Ltd"],["dc.relation.issn","1477-0911"],["dc.relation.issn","0959-6836"],["dc.title","Trees tracking a warmer climate: The Holocene range shift of hazel (Corylus avellana) in northern Europe"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1394"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Journal of Biogeography"],["dc.bibliographiccitation.lastpage","1405"],["dc.bibliographiccitation.volume","37"],["dc.contributor.author","Giesecke, Thomas"],["dc.contributor.author","Miller, Paul A."],["dc.contributor.author","Sykes, Martin T."],["dc.contributor.author","Ojala, Antti E. K."],["dc.contributor.author","Seppa, Heikki"],["dc.contributor.author","Bradshaw, Richard H. W."],["dc.date.accessioned","2018-11-07T08:41:46Z"],["dc.date.available","2018-11-07T08:41:46Z"],["dc.date.issued","2010"],["dc.description.abstract","Aim The northern limits of temperate broadleaved species in Fennoscanndia are controlled by their requirements for summer warmth for successful regeneration and growth as well as by the detrimental effects of winter cold on plant tissue. However, occurrences of meteorological conditions with detrimental effects on individual species are rare events rather than a reflection of average conditions. We explore the effect of changes in inter-annual temperature variability on the abundances of the tree species Tilia cordata, Quercus robur and Ulmus glabra near their distribution limits using a process-based model of ecosystem dynamics. Location A site in central Sweden and a site in southern Finland were used as examples for the ecotone between boreal and temperate forests in Fennoscandia. The Finnish site was selected because of the availability of varve-thickness data. Methods The dynamic vegetation model LPJ-GUESS was run with four scenarios of inter-annual temperature forcing for the last 10,000 years. In one scenario the variability in the thickness of summer and winter varves from the annually laminated lake in Finland was used as a proxy for past inter-annual temperature variability. Two scenarios were devised to explore systematically the effect of stepwise changes in the variance and shape parameter of a probability distribution. All variability scenarios were run both with and without the long-term trend in Holocene temperature change predicted by an atmospheric general circulation model. Results Directional changes in inter-annual temperature variability have significant effects on simulated tree distribution limits through time. Variations in inter-annual temperature variability alone are shown to alter vegetation composition by magnitudes similar to the magnitude of changes driven by variation in mean temperatures. Main conclusions The varve data indicate that inter-annual climate variability has changed in the past. The model results show that past changes in species abundance can be explained by changes in the inter-annual variability of climate parameters as well as by mean climate. Because inter-annual climatic variability is predicted to change in the future, this component of climate change should be taken into account both when making projections of future plant distributions and when interpreting vegetation history."],["dc.identifier.doi","10.1111/j.1365-2699.2010.02296.x"],["dc.identifier.isi","000278923500019"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/19544"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","0305-0270"],["dc.title","The effect of past changes in inter-annual temperature variability on tree distribution limits"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1662"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Journal of Ecology"],["dc.bibliographiccitation.lastpage","1677"],["dc.bibliographiccitation.volume","107"],["dc.contributor.author","Reitalu, Triin"],["dc.contributor.author","Bjune, Anne E."],["dc.contributor.author","Blaus, Ansis"],["dc.contributor.author","Giesecke, Thomas"],["dc.contributor.author","Helm, Aveliina"],["dc.contributor.author","Matthias, Isabelle"],["dc.contributor.author","Peglar, Sylvia M."],["dc.contributor.author","Salonen, J. Sakari"],["dc.contributor.author","Seppa, Heikki"],["dc.contributor.author","Väli, Vivika"],["dc.contributor.author","Birks, H. John B."],["dc.contributor.editor","de Lafontaine, Guillaume"],["dc.date.accessioned","2020-03-16T09:38:18Z"],["dc.date.available","2020-03-16T09:38:18Z"],["dc.date.issued","2019"],["dc.description.abstract","Sedimentary pollen offers excellent opportunities to reconstruct vegetation changes over past millennia. Number of different pollen taxa or pollen richness is used to characterise past plant richness. To improve the interpretation of sedimentary pollen richness, it is essential to understand the relationship between pollen and plant richness in contemporary landscapes. This study presents a regional‐scale comparison of pollen and plant richness from northern Europe and evaluates the importance of environmental variables on pollen and plant richness. We use a pollen dataset of 511 lake‐surface pollen samples ranging through temperate, boreal and tundra biomes. To characterise plant diversity, we use a dataset formulated from the two largest plant atlases available in Europe. We compare pollen and plant richness estimates in different groups of taxa (wind‐pollinated vs. non‐wind‐pollinated, trees and shrubs vs. herbs and grasses) and test their relationships with climate and landscape variables. Pollen richness is significantly positively correlated with plant richness (r = 0.53). The pollen plant richness correlation improves (r = 0.63) when high pollen producers are downweighted prior to estimating richness minimising the influence of pollen production on the pollen richness estimate. This suggests that methods accommodating pollen‐production differences in richness estimates deserve further attention and should become more widely used in Quaternary pollen diversity studies. The highest correlations are found between pollen and plant richness of trees and shrubs (r = 0.83) and of wind‐pollinated taxa (r = 0.75) suggesting that these are the best measures of broad‐scale plant richness over several thousands of square kilometres. Mean annual temperature is the strongest predictor of both pollen and plant richness. Landscape openness is positively associated with pollen richness but not with plant richness. Pollen richness values from extremely open and/or cold areas where pollen production is low should be interpreted with caution because low local pollen production increases the proportion of extra‐regional pollen. Synthesis. Our results confirm that pollen data can provide insights into past plant richness changes in northern Europe, and with careful consideration of pollen‐production differences and spatial scale represented, pollen data make it possible to investigate vegetation diversity trends over long time‐scales and under changing climatic and habitat conditions."],["dc.identifier.doi","10.1111/1365-2745.13134"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/63335"],["dc.language.iso","en"],["dc.relation.issn","0022-0477"],["dc.relation.issn","1365-2745"],["dc.title","Patterns of modern pollen and plant richness across northern Europe"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","483"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","CLIMATE OF THE PAST"],["dc.bibliographiccitation.lastpage","499"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","Gaillard, M.-J."],["dc.contributor.author","Sugita, Shinya"],["dc.contributor.author","Mazier, Florence"],["dc.contributor.author","Trondman, A.-K."],["dc.contributor.author","Brostrom, A."],["dc.contributor.author","Hickler, Thomas"],["dc.contributor.author","Kaplan, Jed O."],["dc.contributor.author","Kjellstrom, E."],["dc.contributor.author","Kokfelt, U."],["dc.contributor.author","Kunes, Petr"],["dc.contributor.author","Lemmen, C."],["dc.contributor.author","Miller, P."],["dc.contributor.author","Olofsson, J."],["dc.contributor.author","Poska, Anneli"],["dc.contributor.author","Rundgren, M."],["dc.contributor.author","Smith, B."],["dc.contributor.author","Strandberg, G."],["dc.contributor.author","Fyfe, Ralph M."],["dc.contributor.author","Nielsen, A. B."],["dc.contributor.author","Alenius, Teija"],["dc.contributor.author","Balakauskas, L."],["dc.contributor.author","Barnekow, L."],["dc.contributor.author","Birks, H. John B."],["dc.contributor.author","Bjune, Anne E."],["dc.contributor.author","Bjorkman, L."],["dc.contributor.author","Giesecke, Thomas"],["dc.contributor.author","Hjelle, K."],["dc.contributor.author","Kalnina, Laimdota"],["dc.contributor.author","Kangur, Mikhel"],["dc.contributor.author","van der Knaap, Willem O."],["dc.contributor.author","Koff, T."],["dc.contributor.author","Lageras, P."],["dc.contributor.author","Latalowa, Malgorzata"],["dc.contributor.author","Leydet, Michelle"],["dc.contributor.author","Lechterbeck, J."],["dc.contributor.author","Lindbladh, M."],["dc.contributor.author","Odgaard, B. V."],["dc.contributor.author","Peglar, S. M."],["dc.contributor.author","Segerstrom, U."],["dc.contributor.author","von Stedingk, H."],["dc.contributor.author","Seppa, Heikki"],["dc.date.accessioned","2018-11-07T08:47:21Z"],["dc.date.available","2018-11-07T08:47:21Z"],["dc.date.issued","2010"],["dc.description.abstract","The major objectives of this paper are: (1) to review the pros and cons of the scenarios of past anthropogenic land cover change (ALCC) developed during the last ten years, (2) to discuss issues related to pollen-based reconstruction of the past land-cover and introduce a new method, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites), to infer long-term records of past land-cover from pollen data, (3) to present a new project (LANDCLIM: LAND cover - CLIMate interactions in NW Europe during the Holocene) currently underway, and show preliminary results of REVEALS reconstructions of the regional land-cover in the Czech Republic for five selected time windows of the Holocene, and (4) to discuss the implications and future directions in climate and vegetation/land-cover modeling, and in the assessment of the effects of human-induced changes in land-cover on the regional climate through altered feedbacks. The existing ALCC scenarios show large discrepancies between them, and few cover time periods older than AD 800. When these scenarios are used to assess the impact of human land-use on climate, contrasting results are obtained. It emphasizes the need for methods such as the REVEALS model-based land-cover reconstructions. They might help to fine-tune descriptions of past land-cover and lead to a better understanding of how long-term changes in ALCC might have influenced climate. The REVEALS model is demonstrated to provide better estimates of the regional vegetation/land-cover changes than the traditional use of pollen percentages. This will achieve a robust assessment of land cover at regional- to continental-spatial scale throughout the Holocene. We present maps of REVEALS estimates for the percentage cover of 10 plant functional types (PFTs) at 200 BP and 6000 BP, and of the two open-land PFTs 'grassland' and 'agricultural land' at five time-windows from 6000 BP to recent time. The LANDCLIM results are expected to provide crucial data to reassess ALCC estimates for a better understanding of the land suface-atmosphere interactions."],["dc.description.sponsorship","Swedish Council; Nordic Research Council"],["dc.identifier.doi","10.5194/cp-6-483-2010"],["dc.identifier.isi","000281433300007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/20930"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Copernicus Gesellschaft Mbh"],["dc.relation.issn","1814-9332"],["dc.relation.issn","1814-9324"],["dc.title","Holocene land-cover reconstructions for studies on land cover-climate feedbacks"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","629"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Journal of Ecology"],["dc.bibliographiccitation.lastpage","640"],["dc.bibliographiccitation.volume","97"],["dc.contributor.author","Seppa, Heikki"],["dc.contributor.author","Alenius, Teija"],["dc.contributor.author","Bradshaw, Richard H. W."],["dc.contributor.author","Giesecke, Thomas"],["dc.contributor.author","Heikkila, Maija"],["dc.contributor.author","Muukkonen, Petteri"],["dc.date.accessioned","2018-11-07T08:28:14Z"],["dc.date.available","2018-11-07T08:28:14Z"],["dc.date.issued","2009"],["dc.description.abstract","1. Norway spruce (Picea abies), one of the dominant tree species in Eurasia, has spread slowly westward in northern Europe, invading eastern Finland about 6500 calibrated years ago (cal. years BP), eastern central Sweden about 2700 cal. years BP and southern Norway about 1000 cal. years BP. Its spread is the most recent and best constrained invasion of a main tree species in northern Europe and allows an assessment of colonization patterns and associated competitive replacement processes. 2. We analysed five selected high-resolution pollen accumulation rate (PAR)-records along a 700-km long transect in the direction of P. abies invasion from eastern Finland to central Sweden across the present P. abies- and Pinus sylvestris-dominated southern boreal zone. 3. Our results show that the P. abies population increased in size from the time of the initial expansion to levels comparable with the modern in 100-550 years. At each site P. abies invaded a dense, intact Pinus-Betula-Alnus forest, mixed with temperate deciduous taxa, particularly Tilia cordata and Corylus avellana. The resident mixed forest provided no or weak resistance to the colonization of P. abies, and the variable population growth rate was therefore not caused by compositional differences in the resident forest but by other, possibly local edaphic factors. 4. Of the taxa that formed the resident forest, T. cordata responded most strongly to the invasion of P. abies. This suggests that the mid-Holocene T. cordata population decline was not directly climate-induced but resulted from competitive replacement due to overlapping ecological niches with P. abies, a stronger competitor. 5. Synthesis. The rise to dominance of P. abies was caused not only by its rapid population growth but by associated competitive suppression of other taxa, leading to a major ecosystem change from a mixed conifer-deciduous forest to the modern P. abies- and P. sylvestris-dominated boreal conifer forest in central Fennoscandia. This competitive suppression by P. abies is still reflected in the scattered occurrence and generally weak performance of T. cordata in the boreal zone of Europe and may influence its distribution and abundance patterns under predicted future climate scenarios."],["dc.description.sponsorship","European Commission [ERAS-CT-2003980409]"],["dc.identifier.doi","10.1111/j.1365-2745.2009.01505.x"],["dc.identifier.isi","000267071500004"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/16375"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell Publishing, Inc"],["dc.relation.issn","0022-0477"],["dc.title","Invasion of Norway spruce (Picea abies) and the rise of the boreal ecosystem in Fennoscandia"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2805"],["dc.bibliographiccitation.issue","19-20"],["dc.bibliographiccitation.journal","Quaternary Science Reviews"],["dc.bibliographiccitation.lastpage","2814"],["dc.bibliographiccitation.volume","30"],["dc.contributor.author","Giesecke, Thomas"],["dc.contributor.author","Bennett, K. D."],["dc.contributor.author","Birks, H. John B."],["dc.contributor.author","Bjune, Anne E."],["dc.contributor.author","Bozilova, Elisaveta"],["dc.contributor.author","Feurdean, Angelica"],["dc.contributor.author","Finsinger, Walter"],["dc.contributor.author","Froyd, Cynthia"],["dc.contributor.author","Pokorny, Petr"],["dc.contributor.author","Roesch, Manfred"],["dc.contributor.author","Seppa, Heikki"],["dc.contributor.author","Tonkov, Spasimir"],["dc.contributor.author","Valsecchi, V. G."],["dc.contributor.author","Wolters, Steffen"],["dc.date.accessioned","2018-11-07T08:52:02Z"],["dc.date.available","2018-11-07T08:52:02Z"],["dc.date.issued","2011"],["dc.description.abstract","Mid to high latitude forest ecosystems have undergone several major compositional changes during the Holocene. The temporal and spatial patterns of these vegetation changes hold potential information to their causes and triggers. Here we test the hypothesis that the timing of vegetation change was synchronous on a sub-continental scale, which implies a common trigger or a step-like change in climate parameters. Pollen diagrams from selected European regions were statistically divided into assemblage zones and the temporal pattern of the zone boundaries analysed. The results show that the temporal pattern of vegetation change was significantly different from random. Times of change cluster around 8.2, 4.8, 3.7, and 1.2 ka, while times of higher than average stability were found around 2.1 and 5.1 ka. Compositional changes linked to the expansion of Corylus avellana and Alnus glutinosa centre around 10.6 and 9.5 ka, respectively. A climatic trigger initiating these changes may have occurred 0.5 to 1 ka earlier, respectively. The synchronous expansion of C avellana and A. glutinosa exemplify that dispersal is not necessarily followed by population expansion. The partly synchronous, partly random expansion of A. glutinosa in adjacent European regions exemplifies that sudden synchronous population expansions are not species specific traits but vary regionally. (C) 2011 Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","German Research Foundation [GI 732/1-1]; Royal Society"],["dc.identifier.doi","10.1016/j.quascirev.2011.06.014"],["dc.identifier.isi","000295387000029"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22073"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0277-3791"],["dc.title","The pace of Holocene vegetation change - testing for synchronous developments"],["dc.type","review"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","199"],["dc.bibliographiccitation.journal","Quaternary Science Reviews"],["dc.bibliographiccitation.lastpage","216"],["dc.bibliographiccitation.volume","90"],["dc.contributor.author","Marquer, Laurent"],["dc.contributor.author","Gaillard, Marie-Jose"],["dc.contributor.author","Sugita, Shinya"],["dc.contributor.author","Trondman, Anna-Kari"],["dc.contributor.author","Mazier, Florence"],["dc.contributor.author","Nielsen, Anne Birgitte"],["dc.contributor.author","Fyfe, Ralph M."],["dc.contributor.author","Odgaard, B. V."],["dc.contributor.author","Alenius, Teija"],["dc.contributor.author","Birks, H. John B."],["dc.contributor.author","Bjune, Anne E."],["dc.contributor.author","Christiansen, Joerg"],["dc.contributor.author","Dodson, John"],["dc.contributor.author","Edwards, Kevin J."],["dc.contributor.author","Giesecke, Thomas"],["dc.contributor.author","Herzschuh, Ulrike"],["dc.contributor.author","Kangur, Mihkel"],["dc.contributor.author","Lorenz, Sebastian"],["dc.contributor.author","Poska, Anneli"],["dc.contributor.author","Schult, Manuela"],["dc.contributor.author","Seppa, Heikki"],["dc.date.accessioned","2018-11-07T09:41:14Z"],["dc.date.available","2018-11-07T09:41:14Z"],["dc.date.issued","2014"],["dc.description.abstract","We present pollen-based reconstructions of the spatio-temporal dynamics of northern European regional vegetation abundance through the Holocene. We apply the Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model using fossil pollen records from eighteen sites within five modern biomes in the region. The eighteen sites are classified into four time-trajectory types on the basis of principal components analysis of both the REVEALS-based vegetation estimates (RVs) and the pollen percentage (PPs). The four trajectory types are more clearly separated for RVs than PPs. Further, the timing of major Holocene shifts, rates of compositional change, and diversity indices (turnover and evenness) differ between RVs and PPs. The differences are due to the reduction by REVEALS of biases in fossil pollen assemblages caused by different basin size, and inter-taxonomic differences in pollen productivity and dispersal properties. For example, in comparison to the PPs, the RVs show an earlier increase in Corylus and Ulmus in the early-Holocene and a more pronounced increase in grassland and deforested areas since the mid-Holocene. The results suggest that the influence of deforestation and agricultural activities on plant composition and abundance from Neolithic times was stronger than previously inferred from PPs. Relative to PPs, RVs show a more rapid compositional change, a largest decrease in turnover, and less variable evenness in most of northern Europe since 5200 cal yr BP. All these changes are primarily related to the strong impact of human activities on the vegetation. This study demonstrates that RV-based estimates of diversity indices, timing of shifts, and rates of change in reconstructed vegetation provide new insights into the timing and magnitude of major human distribution on Holocene regional, vegetation, feature that are critical in the assessment of human impact on vegetation, land-cover, biodiversity, and climate in the past. (C) Elsevier Ltd.All tights reserved."],["dc.identifier.doi","10.1016/j.quascirev.2014.02.013"],["dc.identifier.isi","000336466800014"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33685"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0277-3791"],["dc.title","Holocene changes in vegetation composition in northern Europe: why quantitative pollen-based vegetation reconstructions matter"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","676"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Global Change Biology"],["dc.bibliographiccitation.lastpage","697"],["dc.bibliographiccitation.volume","21"],["dc.contributor.author","Trondman, A.-K."],["dc.contributor.author","Gaillard, M.-J."],["dc.contributor.author","Mazier, Florence"],["dc.contributor.author","Sugita, Shinya"],["dc.contributor.author","Fyfe, Ralph M."],["dc.contributor.author","Nielsen, A. B."],["dc.contributor.author","Twiddle, C."],["dc.contributor.author","Barratt, P."],["dc.contributor.author","Birks, H. John B."],["dc.contributor.author","Bjune, Anne E."],["dc.contributor.author","Bjorkman, L."],["dc.contributor.author","Brostrom, A."],["dc.contributor.author","Caseldine, C."],["dc.contributor.author","David, R."],["dc.contributor.author","Dodson, J."],["dc.contributor.author","Doerfler, Walter"],["dc.contributor.author","Fischer, Elisabeth"],["dc.contributor.author","van Geel, Michel"],["dc.contributor.author","Giesecke, Thomas"],["dc.contributor.author","Hultberg, T."],["dc.contributor.author","Kalnina, Laimdota"],["dc.contributor.author","Kangur, Mikhel"],["dc.contributor.author","van der Knaap, P."],["dc.contributor.author","Koff, T."],["dc.contributor.author","Kunes, Petr"],["dc.contributor.author","Lageras, P."],["dc.contributor.author","Latalowa, Malgorzata"],["dc.contributor.author","Lechterbeck, J."],["dc.contributor.author","Leroyer, C."],["dc.contributor.author","Leydet, Michelle"],["dc.contributor.author","Lindbladh, M."],["dc.contributor.author","Marquer, Laurent"],["dc.contributor.author","Mitchell, Fraser J. G."],["dc.contributor.author","Odgaard, B. V."],["dc.contributor.author","Peglar, S. M."],["dc.contributor.author","Persson, T."],["dc.contributor.author","Poska, Anneli"],["dc.contributor.author","Roesch, Manfred"],["dc.contributor.author","Seppa, Heikki"],["dc.contributor.author","Veski, Siim"],["dc.contributor.author","Wick, L."],["dc.date.accessioned","2018-11-07T10:01:35Z"],["dc.date.available","2018-11-07T10:01:35Z"],["dc.date.issued","2015"],["dc.description.abstract","We present quantitative reconstructions of regional vegetation cover in north-western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present (bp)] at a 1 degrees x1 degrees spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records from lakes and bogs to reconstruct the past cover of 25 plant taxa grouped into 10 plant-functional types and three land-cover types [evergreen trees, summer-green (deciduous) trees, and open land]. The model corrects for some of the biases in pollen percentages by using pollen productivity estimates and fall speeds of pollen, and by applying simple but robust models of pollen dispersal and deposition. The emerging patterns of tree migration and deforestation between 6k bp and modern time in the REVEALS estimates agree with our general understanding of the vegetation history of Europe based on pollen percentages. However, the degree of anthropogenic deforestation (i.e. cover of cultivated and grazing land) at 3k, 0.5k, and 0.2k bp is significantly higher than deduced from pollen percentages. This is also the case at 6k in some parts of Europe, in particular Britain and Ireland. Furthermore, the relationship between summer-green and evergreen trees, and between individual tree taxa, differs significantly when expressed as pollen percentages or as REVEALS estimates of tree cover. For instance, when Pinus is dominant over Picea as pollen percentages, Picea is dominant over Pinus as REVEALS estimates. These differences play a major role in the reconstruction of European landscapes and for the study of land cover-climate interactions, biodiversity and human resources."],["dc.identifier.doi","10.1111/gcb.12737"],["dc.identifier.isi","000348652400016"],["dc.identifier.pmid","25204435"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/38051"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1365-2486"],["dc.relation.issn","1354-1013"],["dc.title","Pollen-based quantitative reconstructions of Holocene regional vegetation cover (plant-functional types and land-cover types) in Europe suitable for climate modelling"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]