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Flemming Skov - One of the best experts on this subject based on the ideXlab platform.
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Postglacial migration supplements climate in determining plant species ranges in Europe
Proceedings of the Royal Society B: Biological Sciences, 2011Co-Authors: Signe Normand, Jesper Bladt, Oliver Tackenberg, Flemming Skov, Robert E Ricklefs, Jens-christian SvenningAbstract:The influence of dispersal limitation on species ranges remains controversial. Considering the dramatic impacts of the last glaciation in Europe, species might not have tracked climate changes through time and, as a consequence, their present-day ranges might be in disequilibrium with current climate. For 1016 European plant species, we assessed the relative importance of current climate and limited Postglacial migration in determining species ranges using regression modelling and explanatory variables representing climate, and a novel species-specific hind-casting-based measure of accessibility to Postglacial colonization. Climate was important for all species, while Postglacial colonization also constrained the ranges of more than 50 per cent of the species. On average, climate explained five times more variation in species ranges than accessibility, but accessibility was the strongest determinant for one-sixth of the species. Accessibility was particularly important for species with limited long-distance dispersal ability, with southern glacial ranges, seed plants compared with ferns, and small-range species in southern Europe. In addition, accessibility explained one-third of the variation in species' disequilibrium with climate as measured by the realized/potential range size ratio computed with niche modelling. In conclusion, we show that although climate is the dominant broad-scale determinant of European plant species ranges, constrained dispersal plays an important supplementary role.
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Postglacial dispersal limitation of widespread forest plant species in nemoral europe
Ecography, 2008Co-Authors: Jens-christian Svenning, Signe Normand, Flemming SkovAbstract:Climate is often singled out as the primary range limiting factor at large scales, while other environmental factors, notably soil, are thought to predominate at smaller scales. However, the Postglacial migrational lag hypothesis controversially suggests that many species are strongly dispersal-limited and still expanding from their ice age refugia. We investigated the importance of Postglacial migrational lag, climate, and soil as range determinants for 47 widespread forest plant species across nemoral Europe (47.0–60.0°N, west of 24.0°E) using regression modeling, information-theoretic model selection, multi-model inference, and variation partitioning. Migrational lag was represented by a measure of accessibility to recolonization from ice age refugia. Twelve species were largely ubiquitous and not analyzed further. For the remaining species, there was strong support for climate, soil, and accessibility to Postglacial recolonization. Accessibility accounted for a small to moderate amount of variation, but its model-averaged regression coefficient was stronger than those for climate or soil for 11 species and the second or third strongest coefficient for an additional 10 species. The resulting odds ratios were greater than one for 33 out of 35 species, i.e. adjusted for climate and soil, prevalence for the far majority of the 35 non-ubiquitous species increased with increasing accessibility. There were no differences among growth forms in the importance of accessibility. In contrast, compared to non-boreal species, accessibility had little importance for species with wide boreal distributions, as expected from their more widespread, northern glacial distributions. In conclusion, even the ranges of many widespread forest plant species are probably still moderately to strongly limited by Postglacial migrational lag. Therefore, although species ranges are also strongly influenced by climate, we cannot expect most forest plant species to closely track the expected 21st century climatic changes.
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could the tree diversity pattern in europe be generated by Postglacial dispersal limitation
Ecology Letters, 2007Co-Authors: Jens-christian Svenning, Flemming SkovAbstract:The relative importance of contemporary climate and history as controls of geographical diversity patterns is intensely debated. A key example is the controversy over the extent to which temperate tree distributions and diversity patterns reflect Postglacial dispersal limitation. Here, we focus on Central and Northern Europe, and show that recent estimates of tree migration rates < 100 m year−1 imply that many species have probably not reached equilibrium with climate in this region. We then demonstrate that geographical accessibility from glacial refuges explains 78% of the geographical variation in the region's tree diversity and is a much stronger diversity predictor than climate. Finally, we show that realistic estimates of migration rates can be derived from the observed tree diversity pattern by assuming it to be purely dispersal driven. In conclusion, the tree diversity pattern in Central and Northern Europe could, to a large extent, be a result of Postglacial dispersal limitation.
Jens-christian Svenning - One of the best experts on this subject based on the ideXlab platform.
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Postglacial migration supplements climate in determining plant species ranges in Europe
Proceedings of the Royal Society B: Biological Sciences, 2011Co-Authors: Signe Normand, Jesper Bladt, Oliver Tackenberg, Flemming Skov, Robert E Ricklefs, Jens-christian SvenningAbstract:The influence of dispersal limitation on species ranges remains controversial. Considering the dramatic impacts of the last glaciation in Europe, species might not have tracked climate changes through time and, as a consequence, their present-day ranges might be in disequilibrium with current climate. For 1016 European plant species, we assessed the relative importance of current climate and limited Postglacial migration in determining species ranges using regression modelling and explanatory variables representing climate, and a novel species-specific hind-casting-based measure of accessibility to Postglacial colonization. Climate was important for all species, while Postglacial colonization also constrained the ranges of more than 50 per cent of the species. On average, climate explained five times more variation in species ranges than accessibility, but accessibility was the strongest determinant for one-sixth of the species. Accessibility was particularly important for species with limited long-distance dispersal ability, with southern glacial ranges, seed plants compared with ferns, and small-range species in southern Europe. In addition, accessibility explained one-third of the variation in species' disequilibrium with climate as measured by the realized/potential range size ratio computed with niche modelling. In conclusion, we show that although climate is the dominant broad-scale determinant of European plant species ranges, constrained dispersal plays an important supplementary role.
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Postglacial dispersal limitation of widespread forest plant species in nemoral europe
Ecography, 2008Co-Authors: Jens-christian Svenning, Signe Normand, Flemming SkovAbstract:Climate is often singled out as the primary range limiting factor at large scales, while other environmental factors, notably soil, are thought to predominate at smaller scales. However, the Postglacial migrational lag hypothesis controversially suggests that many species are strongly dispersal-limited and still expanding from their ice age refugia. We investigated the importance of Postglacial migrational lag, climate, and soil as range determinants for 47 widespread forest plant species across nemoral Europe (47.0–60.0°N, west of 24.0°E) using regression modeling, information-theoretic model selection, multi-model inference, and variation partitioning. Migrational lag was represented by a measure of accessibility to recolonization from ice age refugia. Twelve species were largely ubiquitous and not analyzed further. For the remaining species, there was strong support for climate, soil, and accessibility to Postglacial recolonization. Accessibility accounted for a small to moderate amount of variation, but its model-averaged regression coefficient was stronger than those for climate or soil for 11 species and the second or third strongest coefficient for an additional 10 species. The resulting odds ratios were greater than one for 33 out of 35 species, i.e. adjusted for climate and soil, prevalence for the far majority of the 35 non-ubiquitous species increased with increasing accessibility. There were no differences among growth forms in the importance of accessibility. In contrast, compared to non-boreal species, accessibility had little importance for species with wide boreal distributions, as expected from their more widespread, northern glacial distributions. In conclusion, even the ranges of many widespread forest plant species are probably still moderately to strongly limited by Postglacial migrational lag. Therefore, although species ranges are also strongly influenced by climate, we cannot expect most forest plant species to closely track the expected 21st century climatic changes.
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could the tree diversity pattern in europe be generated by Postglacial dispersal limitation
Ecology Letters, 2007Co-Authors: Jens-christian Svenning, Flemming SkovAbstract:The relative importance of contemporary climate and history as controls of geographical diversity patterns is intensely debated. A key example is the controversy over the extent to which temperate tree distributions and diversity patterns reflect Postglacial dispersal limitation. Here, we focus on Central and Northern Europe, and show that recent estimates of tree migration rates < 100 m year−1 imply that many species have probably not reached equilibrium with climate in this region. We then demonstrate that geographical accessibility from glacial refuges explains 78% of the geographical variation in the region's tree diversity and is a much stronger diversity predictor than climate. Finally, we show that realistic estimates of migration rates can be derived from the observed tree diversity pattern by assuming it to be purely dispersal driven. In conclusion, the tree diversity pattern in Central and Northern Europe could, to a large extent, be a result of Postglacial dispersal limitation.
Timo Ruskeeniemi - One of the best experts on this subject based on the ideXlab platform.
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Earthquake-induced deformation structures in glacial sediments—evidence on fault reactivation and instability at the Vaalajärvi fault in northern Fennoscandia
Journal of Seismology, 2020Co-Authors: Antti E.k. Ojala, Jukka Pekka Palmu, Timo Ruskeeniemi, Jussi Mattila, M. Middleton, N. Nordbäck, M. Kirsch, S. Lorenz, R. Zimmermann, L. AndreaniAbstract:Late and Postglacial reverse faults and seismically-induced landslides are characteristic features of deglaciated terrain in the northern Fennoscandia. The main focus of this study was to investigate the rupturing history of the reverse Vaalajärvi fault complex in Sodankylä, Finland, based on remote sensing, on-site geophysics and sedimentology in excavations trenched across the faulted terrain. In addition to the previously known NNW–SSE-trending Vaalajärvi segment, we discovered six new SW–NE-trending fault segments that probably belong to the same Vaalajärvi ‘Postglacial’ fault complex. Our analysis indicate that the Vaalajärvi fault segment was triggered by stress change caused by ruptures on the surrounding SW–NE-trending reverse faults. In total, at least two to three slip events have taken place in different segments of the Vaalajärvi complex since the Early Weichselian with the most recent event(s) being Postglacial in timing. By using the scaling laws of fault surface rupture length and offset and under different scenarios of which segments or systems ruptured in a single or separate event, we estimate that the Vaalajärvi complex potentially hosted an earthquake that ranged between M _ w ≈ 6.7–7.0. This magnitude is comparable to the landslide-inferred magnitudes in the Vaalajärvi area.
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Distribution and morphology of landslides in northern Finland: An analysis of Postglacial seismic activity
Geomorphology, 2017Co-Authors: Antti E.k. Ojala, Jukka Pekka Palmu, Timo Ruskeeniemi, Jussi Mattila, Mira Markovaara-koivisto, Raimo SutinenAbstract:Abstract The ages and sizes of landslides occurring in seismically active areas can be used to reconstruct the seismic history of the area and estimate the maximum moment magnitudes of past earthquakes. Here, we present a data set of 121 landslides discovered in northern Finland that were analyzed for their morphometric characteristics. We show that 89 debris slide type landslides in the data set are clustered close to known Postglacial faults (PGFs) and thus provide information on the characteristics of Postglacial paleoseismic events. By using empirical correlations between the landslide volume–area data and earthquake moment magnitude, we estimate maximum moment magnitudes M w ≈ 6.9–7.7 for Postglacial earthquakes in the Suasselka, Isovaara–Riikonkumpu, Venejarvi, and Vaalajarvi areas, where earlier estimates based on fault length and displacement have yielded magnitudes varying between M w ≈ 6.5 and 7.5. We also show that the landslides in northern Finland are located within a radius of 35 km from the closest known PGF and that sizes of the landslides decrease as a function of distance from PGFs, hence providing strong empirical evidence for their seismic origin. As far as we are aware, this is the first use of landside data in quantifying Postglacial seismicity within the Fennoscandian Shield area.
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lidar dem detection and classification of Postglacial faults and seismically induced landforms in finland a paleoseismic database
Gff, 2015Co-Authors: Jukka Pekka Palmu, Antti E.k. Ojala, Timo Ruskeeniemi, Raimo Sutinen, Jussi MattilaAbstract:AbstractDuring the last decades, Postglacial faults (PGFs) have been found in northern Fennoscandia, the first fault scarps being discovered in western Finnish Lapland in the 1960s. With LiDAR-based digital elevation models (DEMs), a new and accurate remote sensing mapping methodology has been acquired. It allows the relatively rapid and low-cost detection and mapping of late- or PGFs and, for instance, mapping of landslides from areas where they have not previously been recognized. We describe the approach of the Geological Survey of Finland to the systematic search for (screening) and mapping of PGFs, paleolandslides, and other morphological features of Quaternary deposits related to post- and late-glacial seismic activity in Finland. The observations have been collected and classified into a file geodatabase with ArcGis (© ESRI) using a procedure that includes several steps. We also provide examples from western and northern Finland of how sites of late- and Postglacial fault scarps and landslides have...
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LiDAR DEM detection and classification of Postglacial faults and seismically-induced landforms in Finland: a paleoseismic database
GFF, 2015Co-Authors: Jukka Pekka Palmu, Antti E.k. Ojala, Timo Ruskeeniemi, Raimo Sutinen, Jussi MattilaAbstract:AbstractDuring the last decades, Postglacial faults (PGFs) have been found in northern Fennoscandia, the first fault scarps being discovered in western Finnish Lapland in the 1960s. With LiDAR-based digital elevation models (DEMs), a new and accurate remote sensing mapping methodology has been acquired. It allows the relatively rapid and low-cost detection and mapping of late- or PGFs and, for instance, mapping of landslides from areas where they have not previously been recognized. We describe the approach of the Geological Survey of Finland to the systematic search for (screening) and mapping of PGFs, paleolandslides, and other morphological features of Quaternary deposits related to post- and late-glacial seismic activity in Finland. The observations have been collected and classified into a file geodatabase with ArcGis (? ESRI) using a procedure that includes several steps. We also provide examples from western and northern Finland of how sites of late- and Postglacial fault scarps and landslides have been detected and described from LiDAR DEM data.
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Airborne LiDAR detection of Postglacial faults and Pulju moraine in Palojärvi, Finnish Lapland
Global and Planetary Change, 2014Co-Authors: Raimo Sutinen, Eija Hyvönen, Maarit Middleton, Timo RuskeeniemiAbstract:Postglacial faults (PGFs) are indicative of young tectonic activity providing crucial information for nuclear repository studies. Airborne LiDAR (Light Detection And Ranging) data revealed three previously unrecognized late- or Postglacial faults in northernmost Finnish Lapland. Under the canopies of mountain birch (Betula pubescens ssp. czerepanovii) we also found clusters of the Pulju moraine, typically found on the ice-divide zone of the former Fennoscandian ice sheet (FIS), to be spatially associated with the fault-scarps. Tilt derivative (TDR) filtered LiDAR data revealed the previously unknown Palojärvi fault that, by the NE-SW orientation parallels with the well documented Lainio-Suijavaara PGF in northern Sweden. This suggests that PGFs are more extensive features than previously recognized. Two inclined diamond drill holes verified the fractured system of the Palojärvi fault and revealed clear signs of Postglacial reactivation. Two other previously unrecognized PGFs, the W-E trending Paatsikkajoki fault and the SE-NW trending Kultima fault, differ from the Palojärvi faulting in orientation and possibly also with regard to age. The Pulju moraine, a morphological feature showing transitions from shallow (
John M Sinton - One of the best experts on this subject based on the ideXlab platform.
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Effects of deglaciation on the petrology and eruptive history of the Western Volcanic Zone, Iceland
Bulletin of Volcanology, 2015Co-Authors: Deborah E. Eason, John M Sinton, Karl Gronvold, Mark D. KurzAbstract:New observations and geochemical analyses of volcanic features in the 170-km-long Western Volcanic Zone (WVZ) of Iceland constrain spatial and temporal variations in volcanic production and composition associated with the last major deglaciation. Subglacial eruptions represent a significant portion of the late Quaternary volcanic budget in Iceland. Individual features can have volumes up to ∼48 km^3 and appear to be monogenetic. Subaqueous to subaerial transition zones provide minimum estimates of ice sheet thickness at the time of eruption, although water-magma interactions and fluctuating lake levels during eruption can lead to complex lithological sequences. New major and trace element data for 36 glacial and Postglacial eruptive units, combined with observations of lava surface quality, passage zone heights, and ^3He exposure ages of some glacial units, indicate a maximum in volcanic production in the WVZ during the last major ice retreat. Anomalously high volcanic production rates continue into the early Postglacial period and coincide with significant incompatible element depletions and slightly higher CaO and SiO_2 and lower FeO content at a given MgO. Subglacial units with strong incompatible element depletions also have lava surfaces that lack evidence of subsequent glaciation. These units likely formed after the onset of deglaciation, when rapidly melting ice sheets increased decompression rates in the underlying mantle, leading to anomalously high melting rates in the depleted upper mantle. This process also can explain the eruption of extremely depleted picritic lavas during the early Postglacial period. These new observations indicate that the increased volcanic activity associated with glacial unloading peaked earlier than previously thought, before Iceland was completely ice free.
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Postglacial eruptive history of the western volcanic zone iceland
Geochemistry Geophysics Geosystems, 2005Co-Authors: John M Sinton, Karl Gronvold, Kristjan SaemundssonAbstract:New field observations, age constraints, and extensive chemical analyses define the complete Postglacial eruptive history of the 170-km-long Western Volcanic Zone (WVZ) of Iceland, the ultraslow-spreading western boundary of the south Iceland microplate. We have identified 44 separate eruptive units, 10 of which are small-volume eruptions associated with the flanking Grimsnes system. Overall chemical variations are consistent with very simplified models of melting of a source approximating primitive mantle composition. The 17 eruptions in the first 3000 years of Postglacial time account for about 64% of the total Postglacial production and are incompatible-element depleted compared to younger units, consistent with enhanced melting as a consequence of rebound immediately following deglaciation. Steadily declining eruption rates for the last 9000 years also correlate with changes in average incompatible element ratios that appear to reflect continued decline in melting extents to the present day. This result is not restricted to the WVZ, however, and may herald a decline in melting throughout all of western Iceland during later Postglacial time. Lavas from the northern part of the WVZ are depleted in incompatible elements relative to those farther south at all times, indicating either a long-wavelength gradient in mantle source composition or variations in the melting process along axis. We find no evidence in the Postglacial volcanic record for current failure of the WVZ, despite evidence for continued propagation of the eastern margin of the microplate. The dominance of lava shields in the eruptive history of the WVZ contrasts with the higher number of fissure eruptions in other Icelandic volcanic zones. WVZ shields represent long-duration, low-effusion rate eruptions fed by recharge magma arising out of the mantle. Average effusion rate is the key variable distinguishing shield and fissure eruptions, both within the WVZ and between different volcanic zones. High effusion rate, large-volume eruptions require the presence of large crustal magma reservoirs, which have been rare or absent in the WVZ throughout Postglacial time.
Signe Normand - One of the best experts on this subject based on the ideXlab platform.
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Postglacial migration supplements climate in determining plant species ranges in Europe
Proceedings of the Royal Society B: Biological Sciences, 2011Co-Authors: Signe Normand, Jesper Bladt, Oliver Tackenberg, Flemming Skov, Robert E Ricklefs, Jens-christian SvenningAbstract:The influence of dispersal limitation on species ranges remains controversial. Considering the dramatic impacts of the last glaciation in Europe, species might not have tracked climate changes through time and, as a consequence, their present-day ranges might be in disequilibrium with current climate. For 1016 European plant species, we assessed the relative importance of current climate and limited Postglacial migration in determining species ranges using regression modelling and explanatory variables representing climate, and a novel species-specific hind-casting-based measure of accessibility to Postglacial colonization. Climate was important for all species, while Postglacial colonization also constrained the ranges of more than 50 per cent of the species. On average, climate explained five times more variation in species ranges than accessibility, but accessibility was the strongest determinant for one-sixth of the species. Accessibility was particularly important for species with limited long-distance dispersal ability, with southern glacial ranges, seed plants compared with ferns, and small-range species in southern Europe. In addition, accessibility explained one-third of the variation in species' disequilibrium with climate as measured by the realized/potential range size ratio computed with niche modelling. In conclusion, we show that although climate is the dominant broad-scale determinant of European plant species ranges, constrained dispersal plays an important supplementary role.
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Postglacial dispersal limitation of widespread forest plant species in nemoral europe
Ecography, 2008Co-Authors: Jens-christian Svenning, Signe Normand, Flemming SkovAbstract:Climate is often singled out as the primary range limiting factor at large scales, while other environmental factors, notably soil, are thought to predominate at smaller scales. However, the Postglacial migrational lag hypothesis controversially suggests that many species are strongly dispersal-limited and still expanding from their ice age refugia. We investigated the importance of Postglacial migrational lag, climate, and soil as range determinants for 47 widespread forest plant species across nemoral Europe (47.0–60.0°N, west of 24.0°E) using regression modeling, information-theoretic model selection, multi-model inference, and variation partitioning. Migrational lag was represented by a measure of accessibility to recolonization from ice age refugia. Twelve species were largely ubiquitous and not analyzed further. For the remaining species, there was strong support for climate, soil, and accessibility to Postglacial recolonization. Accessibility accounted for a small to moderate amount of variation, but its model-averaged regression coefficient was stronger than those for climate or soil for 11 species and the second or third strongest coefficient for an additional 10 species. The resulting odds ratios were greater than one for 33 out of 35 species, i.e. adjusted for climate and soil, prevalence for the far majority of the 35 non-ubiquitous species increased with increasing accessibility. There were no differences among growth forms in the importance of accessibility. In contrast, compared to non-boreal species, accessibility had little importance for species with wide boreal distributions, as expected from their more widespread, northern glacial distributions. In conclusion, even the ranges of many widespread forest plant species are probably still moderately to strongly limited by Postglacial migrational lag. Therefore, although species ranges are also strongly influenced by climate, we cannot expect most forest plant species to closely track the expected 21st century climatic changes.
