Holocene changes in vegetation composition in northern Europe: why quantitative pollen-based vegetation reconstructions matter

Abstract

International audienceWe 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 humandisturbance on Holocene regional vegetation, features that are critical in the assessment of humanimpact on vegetation, land-cover, biodiversity, and climate in the past

Approaches to quantitative reconstruction of woody vegetation in managed woodlands from pollen records

“…Recent advances in reconstruction approaches at the regional scale (considering vegetation composition in areas with radii 50-100km) show the potential of these methods (Marquer, et al 2014, Trondman, et al 2015, but by averaging a large number of small sites or using large (500ha plus In this paper, we show that linear regression of pollen influx from Tauber traps against distance weighted plant abundance generates RPP Quercus values for eight tree taxa which are comparable with previous European studies (e.g. Sugita, et al 1999;Mazier, et al 2012), whilst ERV analysis results were unreliable.…”

Constraining the Deforestation History of Europe: Evaluation of Historical Land Use Scenarios with Pollen-Based Land Cover Reconstructions

“…However, the issues described above present a problem: few independent observations have been available at appropriate spatial and temporal resolution with which to evaluate continental-and global-scale ALCC scenarios. Fortunately, recent developments in the quantitative reconstruction of land cover using paleoecological archives [37,38] and efforts to apply these methods in a synthetic way at continental scales [39][40][41] provide new opportunities for evaluating ALCC models and their scenarios.…”

“…While the theory for the quantitative reconstruction of land cover based on pollen records has existed for decades [42][43][44][45], large-scale reconstructions only became possible more recently with the development of computer programs [37,38,46], and the intensive field studies were needed to parameterize these models regionally [39,47,48]. The REVEALSmethod of quantitative pollen-based land cover reconstruction [37], has been applied in a number of regional studies in Europe [41,46,47,49] and in sub-continental syntheses for northwestern and northern Central Europe [40,50]. This large-scale synthesis provides, for the first time, an independent estimate of land cover at a spatial and temporal scale suitable for the evaluation of ALCC scenarios.…”

Vegetation dynamics and fire history at the southern boundary of the forest vegetation zone in European Russia during the middle and late Holocene

“…Although many palaeoecological studies have been undertaken in this general region, most of these have focused on the north-western and central parts of the East European Plain, Fennoscandia and eastern Baltic region (Khotinsky and Klimanov, 1997;Krementski et al, 2000, Seppä andBirks, 2001;Seppä and Poska, 2004;Saarse et al, 2010) with many fewer at the southern margin and little explicit consideration of the dynamics of the forest-steppe ecotone . At this ecotone there is evidence for a long history of human occupation which has driven change in vegetation in concert with climate (Marquer et al, 2014).…”