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This study aims to estimate relative pollen productivity (PPEs) of major pollen types and the relevant source area of pollen (RSAP) in a semi-open landscape in western Norway. Extended R-value (ERV) models are used to analyse a data set consisting of surface pollen assemblages from 34 lakes and vegetation survey around each site. Ordination techniques indicate relatively short gradients (<2.3 SD) both in the vegetation and pollen data sets. The lake sizes vary from 0.4 ha to 19.0 ha (mean=5.7 ha, sd=4.3 ha) but follow a normal distribution – a departure from the assumption of the ERV models that the lake size should be constant among sites. Simulations demonstrate that, if the sizes of circular-shaped lakes follow a normal distribution, the ERV model-based methods provide the expected PPE and RSAP values using a standardized lake radius. If the distribution is highly skewed or equally random around the mean, the results are not reliable. We apply the analytical strategy implied from the simulations to obtain relative PPEs and the RSAP in western Norway. PPEs for ten taxa (Alnus, Fagus, Picea, Pinus, Quercus, Juniperus, Salix, Calluna, Cyperaceae, Rumex) relative to Poaceae are comparable with some of those previously obtained in different parts of Europe, indicating that there are general patterns of high and low pollen producers that will be useful for reconstruction purposes. The RSAP estimate is the area within a radius of 900–1100 m. This study demonstrates the importance of careful evaluation of the extent to which the departures from the model assumptions affect the outcomes from the ERV model-based analysis. [ABSTRACT FROM PUBLISHER]

AbstractA biomization method, which objectively assigns individual pollen assemblages to biomes (Prentice et al., 1996), was tested using modern pollen data from Japan and applied to fossil pollen data to reconstruct palaeovegetation patterns 6000 and 18,000 14C yr bp Biomization started with the assignment of 135 pollen taxa to plant functional types (PFTs), and nine possible biomes were defined by specific combinations of PFTs. Biomes were correctly assigned to 54% of the 94 modern sites. Incorrect assignments occur near the altitudinal limits of individual biomes, where pollen transport from lower altitudes blurs the local pollen signals or continuous changes in species composition characterizes the range limits of biomes. As a result, the reconstructed changes in the altitudinal limits of biomes at 6000 and 18,000 14C yr bp are likely to be conservative estimates of the actual changes. The biome distribution at 6000 14C yr bp was rather similar to today, suggesting that changes in the bioclimate of Japan have been small since the mid-Holocene. At 18,000 14C yr bp the Japanese lowlands were covered by taiga and cool mixed forests. The southward expansion of these forests and the absence of broadleaved evergreen/warm mixed forests reflect a pronounced year-round cooling. [ABSTRACT FROM AUTHOR]

This study aims to evaluate a reconstruction method of past storminess using aeolian sand influx (ASI) in peat deposits. We use high-resolution records of ASI from four peat bogs along the Estonian coast and compare those with local instrumentally-recorded storminess data since 1920 AD and with historical climatic records around the Baltic Sea over the last two centuries. Potential effects of local changes in forest cover and anthropogenic disturbances on the ASI signals are also evaluated with historical maps available for the study sites. Diameter of all sand grains >65 μm is measured with an image analysis system to detect temporal changes in the grain-size distribution. Our results demonstrate two major periods of high ASI over the last centuries in the region: during the 19th century and since the 1950s with highest values in 1980–2000 AD. Cross-correlations between the changes in ASI and the instrumentally-recorded storm days during the last century are positive and significant. High ASI values recorded during the 19th century correspond to the positive NAO indices and high cyclonic activity reconstructed in southern Sweden. We find that sand grains <250 μm in diameter add additional information for detecting changes in storminess. Temporal shifts in grain-size distribution and median diameter of mineral grains occur in every core, showing changes in the source materials through time. • Validity of aeolian sand influx (ASI) as an index of past storminess is evaluated. • ASI records in peat correspond well to the overall trend of storminess since 1800s. • Sand fractions <250 μm in peat are reliable to depict past storminess trends. • Shifts in grain-size distribution of sands suggest changes in the source material. [ABSTRACT FROM AUTHOR]

Presents an introduction to articles related to paleoecology that appear in the July 2005 issue of the journal "Ecology."

In this study we estimate relative pollen productivity (RPP) for plant taxa characteristic of human-induced vegetation in ancient cultural landscapes of the low mountain ranges of Shandong province in eastern temperate China. RPP estimates are required to achieve pollen-based reconstructions of Holocene plant cover using modelling approaches based on Prentice's and Sugita's theoretical background and models (REVEALS and LOVE). Pollen counts in moss samples and vegetation data from 36 sites were used in the Extended R-Value (ERV) model to estimate the relevant source area of pollen (RSAP) of moss polsters and RPP of major plant taxa. The best results were obtained with the ERV sub-model 3 and Prentice's taxon-specific method (using a Gaussian Plume dispersal model) to distance weight vegetation data. RSAP was estimated to 145 m using the maximum likelihood method. RPP was obtained for 18 taxa of which two taxa had unreliable RPP (Amaranthaceae/Chenopodiaceae and Vitex negundo). RPPs for Castanea, Cupressaceae, Robinia/ Sophora, Aster/ Anthemis-type, Cannabis/ Humulus, Caryophyllaceae, Brassicaceae and Galium-type are the first ones for China. Trees, except Robinia/ Sophora (RPP = 0.78 ± 0.03) have larger RPPs than herbs other than Artemisia (RPP = 24.7 ± 0.36). The RPPs for Quercus, Pinus and Artemisia are comparable with other RPPs obtained in China, the RPPs for Pinus, Quercus, Ulmus, Cyperaceae and Galium-type with the mean RPPs obtained in Europe, and RPP for Cupressaceae with that for Juniperus in Europe. The values for Aster/ Anthemis-type, Caryophyllaceae, Asteraceae SF Cichorioideae and Juglans differ from the few RPPs available in China and/or Europe. [ABSTRACT FROM AUTHOR]

Early agriculture can be detected in palaeovegetation records, but quantification of the relative importance of climate and land use in influencing regional vegetation composition since the onset of agriculture is a topic that is rarely addressed. We present a novel approach that combines pollen-based REVEALS estimates of plant cover with climate, anthropogenic land-cover and dynamic vegetation modelling results. This is used to quantify the relative impacts of land use and climate on Holocene vegetation at a sub-continental scale, i.e. northern and western Europe north of the Alps. We use redundancy analysis and variation partitioning to quantify the percentage of variation in vegetation composition explained by the climate and land-use variables, and Monte Carlo permutation tests to assess the statistical significance of each variable. We further use a similarity index to combine pollen-based REVEALS estimates with climate-driven dynamic vegetation modelling results. The overall results indicate that climate is the major driver of vegetation when the Holocene is considered as a whole and at the sub-continental scale, although land use is important regionally. Four critical phases of land-use effects on vegetation are identified. The first phase (from 7000 to 6500 BP) corresponds to the early impacts on vegetation of farming and Neolithic forest clearance and to the dominance of climate as a driver of vegetation change. During the second phase (from 4500 to 4000 BP), land use becomes a major control of vegetation. Climate is still the principal driver, although its influence decreases gradually. The third phase (from 2000 to 1500 BP) is characterised by the continued role of climate on vegetation as a consequence of late-Holocene climate shifts and specific climate events that influence vegetation as well as land use. The last phase (from 500 to 350 BP) shows an acceleration of vegetation changes, in particular during the last century, caused by new farming practices and forestry in response to population growth and industrialization. This is a unique signature of anthropogenic impact within the Holocene but European vegetation remains climatically sensitive and thus may continue to respond to ongoing climate change. [ABSTRACT FROM AUTHOR]

In this paper we test the performance of the Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model using pollen records from multiple small sites. We use Holocene pollen records from large and small sites in southern Sweden to identify what is/are the most significant variable(s) affecting the REVEALS-based reconstructions, i.e. type of site (lakes and/or bogs), number of sites, site size, site location in relation to vegetation zones, and/or distance between small sites and large sites. To achieve this objective we grouped the small sites according to (i) the two major modern vegetation zones of the study region, and (ii) the distance between the small sites and large lakes, i.e. small sites within 50, 100, 150, or 200 km of the large lakes. The REVEALS-based reconstructions were performed using 24 pollen taxa. Redundancy analysis was performed on the results from all REVEALS-model runs using the groups within (i) and (ii) separately, and on the results from all runs using the groups within (ii) together. The explanatory power and significance of the variables were identified using forward selection and Monte Carlo permutation tests. The results show that (a) although the REVEALS model was designed for pollen data from large lakes, it also performs well with pollen data from multiple small sites in reconstructing the percentage cover of groups of plant taxa (e.g. open land taxa, summer-green trees, evergreen trees) or individual plant taxa; however, in the case of this study area, the reconstruction of the percentage cover of Calluna vulgaris, Cyperaceae, and Betula may be problematic when using small bogs; (b) standard errors of multiple small-site REVEALS estimates will generally be larger than those obtained using pollen records from large lakes, and they will decrease with increasing size of pollen counts and increasing number of small sites; (c) small lakes are better to use than small bogs if the total number of small sites is low; and (d) the size of small sites and the distance between them do not play a major role, but the distance between the small sites and landscape/vegetation boundaries is a determinant factor for the accuracy of the vegetation reconstructions. [ABSTRACT FROM AUTHOR]

We present the first gridded and temporally continuous quantitative pollen-based plant-cover reconstruction for temperate and northern subtropical China over the Holocene (11.7 ka to present) obtained by applying the Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model. The objective is to provide a dataset of pollen-based land cover for the last ca. 12 millennia that is suitable for palaeoclimate modelling and for the evaluation of simulated past vegetation cover from dynamic vegetation models and anthropogenic land-cover change (ALCC) scenarios. The REVEALS reconstruction was achieved using 94 selected pollen records from lakes and bogs at a 1 ∘ × 1 ∘ spatial scale and a temporal resolution of 500 years between 11.7 and 0.7 ka and in three recent time windows (0.7–0.35 ka, 0.35–0.1 ka, and 0.1 ka to present). The dataset includes REVEALS estimates of cover and their standard errors (SEs) for 27 plant taxa in 75 1 ∘ × 1 ∘ grid cells distributed within the study region. The 27 plant taxa were also grouped into 6 plant functional types and 3 land-cover types (coniferous trees CT, broadleaved trees BT, and C 3 herbs/open land (C 3 H/OL)), and their REVEALS estimates of cover and related SEs were calculated. We describe the protocol used for the selection of pollen records and the REVEALS application (with parameter settings) and explain the major rationales behind the protocol. As an illustration, we present, for eight selected time windows, gridded maps of the pollen-based REVEALS estimates of cover for the three land-cover types (CT, BT, and C 3 H/OL). We then discuss the reliability and limitations of the Chinese dataset of Holocene gridded REVEALS plant cover, and its current and potential uses. The dataset is available at the National Tibetan Plateau Data Center (TPDC; Li, 2022; 10.11888/Paleoenv.tpdc.272292). [ABSTRACT FROM AUTHOR]

Pollen productivity estimate (PPE) is one of the parameters necessary for pollen-based quantitative reconstruction of vegetation in the past. This paper summarizes and reviews the absolute PPEs (aPPEs) that were obtained with the area-based flower counting approach since the 1970s. The data for 23 species of trees are available from Japan and for 22 species of Poaceae from Japan, Spain, and Morocco. The aPPE values vary from 1 to 60 [1012 grains·ha−1·year−1], and are comparable to those previously reported in Europe and using different methods and approaches. The mean aPPEs of temperate conifers, such as Sciadopitys verticillata , Cryptomeria japonica , and Chamaecyparis obtusa , are as high as those of some of the common broadleaved trees, Castanea mollissima , Castanopsis cuspidata , and Alnus spp. The mean aPPEs of Abies firma , Fagus crenata , and Betula platyphylla are low, and those of Pinus densiflora , Quercus spp., Juglans ailanthifolia , Carpinus tchonoskii , Aesculus turbinata , and Poaceae spp. are intermediate. The relative PPE (rPPE) values of the arboreal taxa (relative to Poaceae), calculated using the aPPEs presented here, are smaller than those obtained in Western Europe and China based on the Extended R-value model approach. Differences in the sampling and analytical methods, as well as the interregional differences in Poaceae pollen productivity, might have contributed to the discrepancies observed. Although further studies are necessary, the flower counting approach is practical and informative for species-specific estimates of absolute pollen productivity and provides critical parameters for quantitatively reconstructing past vegetation in absolute units using the rates of pollen accumulation in sediments. [ABSTRACT FROM AUTHOR]

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 disturbance on Holocene regional vegetation, features that are critical in the assessment of human impact on vegetation, land-cover, biodiversity, and climate in the past. [Copyright &y& Elsevier]

Aim To assess statistically the relative importance of climate and human impact on forest composition in the late Holocene. Location Estonia, boreonemoral Europe. Methods Data on forest composition (10 most abundant tree and shrub taxa) for the late Holocene (5100-50 calibrated years before 1950) were derived from 18 pollen records and then transformed into land-cover estimates using the REVEALS vegetation reconstruction model. Human impact was quantified with palaeoecological estimates of openness, frequencies of hemerophilous pollen types (taxa growing in habitats influenced by human activities) and microscopic charcoal particles. Climate data generated with the ECBilt- CLIO- VECODE climate model provided summer and winter temperature data. The modelled data were supported by sedimentary stable oxygen isotope (δ18O) records. Redundancy analysis ( RDA), variation partitioning and linear mixed effects ( LME) models were applied for statistical analyses. Results Both climate and human impact were statistically significant predictors of forest compositional change during the late Holocene. While climate exerted a dominant influence on forest composition in the beginning of the study period, human impact was the strongest driver of forest composition change in the middle of the study period, c. 4000-2000 years ago, when permanent agriculture became established and expanded. The late Holocene cooling negatively affected populations of nemoral deciduous taxa ( Tilia, Corylus, Ulmus, Quercus, Alnus and Fraxinus), allowing boreal taxa ( Betula, Salix, Picea and Pinus) to succeed. Whereas human impact has favoured populations of early-successional taxa that colonize abandoned agricultural fields ( Betula, Salix, Alnus) or that can grow on less fertile soils ( Pinus), it has limited taxa such as Picea that tend to grow on more mesic and fertile soils. Main conclusions Combining palaeoecological and palaeoclimatological data from multiple sources facilitates quantitative characterization of factors driving forest composition dynamics on millennial time-scales. Our results suggest that in addition to the climatic influence on forest composition, the relative abundance of individual forest taxa has been significantly influenced by human impact over the last four millennia. [ABSTRACT FROM AUTHOR]

Abstract: The vegetation of Europe has undergone substantial changes during the course of the Holocene epoch, resulting from range expansion of plants following climate amelioration, competition between taxa and disturbance through anthropogenic activities. Much of the detail of this pattern is understood from decades of pollen analytical work across Europe, and this understanding has been used to address questions relating to vegetation-climate feedback, biogeography and human impact. Recent advances in modelling the relationship between pollen and vegetation now make it possible to transform pollen proportions into estimates of vegetation cover at both regional and local spatial scales, using the Landscape Reconstruction Algorithm (LRA), i.e. the REVEALS (Regional Estimates of VEgetation Abundance from Large Sites) and the LOVE (LOcal VEgetation) models. This paper presents the compilation and analysis of 73 pollen stratigraphies from the British Isles, to assess the application of the LRA and describe the pattern of landscape/woodland openness (i.e. the cover of low herb and bushy vegetation) through the Holocene. The results show that multiple small sites can be used as an effective replacement for a single large site for the reconstruction of regional vegetation cover. The REVEALS vegetation estimates imply that the British Isles had a greater degree of landscape/woodland openness at the regional scale than areas on the European mainland. There is considerable spatial bias in the British Isles dataset towards wetland areas and uplands, which may explain higher estimates of landscape openness compared with Europe. Where multiple estimates of regional vegetation are available from within the same region inter-regional differences are greater than intra-regional differences, supporting the use of the REVEALS model to the estimation of regional vegetation from pollen data. [Copyright &y& Elsevier]

Abstract: Estimates of relevant source area of pollen (RSAP) and relative pollen productivity (PPE) are critical parameters for quantitative reconstructions of past vegetation and land cover. This study provides estimates for PPE relative to Poaceae for ten taxa, characterizing the cultural landscape of south Estonia and the RSAP for 40 lakes with an average radius of approximately 100m (22–274m, average 101m) in the region. We evaluate the effects on those estimates of various combinations of factors, such as the analytical methods (i.e. three Extended R value (ERV) sub-models), the distance-weighting methods used to determine plant abundance, and alternative classification schemes of vegetation and land cover data around study sites. Different combinations of ERV sub-models and distance-weighting methods lead to estimates of RSAP varying between 1500m and 2000m. The differences in the estimated RSAP are strongly related to the patch size of the vegetation data. According to ERV sub-model 1, which shows the highest log-likelihood among the three sub-models, most of the taxa have PPE that are higher (Picea, Pinus, Quercus), slightly higher (Salix, Artemisia, Filipendula) or similar (Betula, Cerealia, Cypreraceae) to that of Poaceae. The three ERV sub-models produce only slightly different PPE. However, the selection of distance-weighting method for vegetation has considerable influence on the PPE values. The inverse distance-weighting methods, which do not consider inter-taxonomic differences in pollen dispersal, tend to underestimate PPE for taxa with heavy pollen grains and overestimate PPE for taxa with light pollen grains, compared to the results obtained using other methods that consider taxon specific pollen-dispersal. General land-cover data, based on the classification scheme similar to the CORINE (COoRdination of Information on the Environment) database, could be used for estimating the RSAP and PPE, although some potential problems remain when the classification is too simplified and consolidated. [Copyright &y& Elsevier]

• Concentration reduction theory is the leading theory regarding the mechanism of competition for nutrients in soils among plants, yet it has not been rigorously tested.• Here we used a spatially explicit, fine-scale grid-based model that simulated diffusion and plant uptake of nutrients by plants in soil to test whether concentration reduction theory was appropriate for terrestrial plant competition for nutrients.• In the absence of competition, increasing the rate of diffusion allows a plant to maintain positive growth rates below the lowest average concentration to which it can reduce nutrients in soil solution (R*). As such, differences among plants in the reduction of soil moisture, which here primarily affects nutrient diffusion, can causeR* to predict competitive success incorrectly. The stronger competitor for nutrients captures the largest proportion of the nutrient supply by ensuring nutrients contact its roots before those of a competitor.• Although the metric derived from concentration reduction theory,R*, might have predictive power for competitive outcomes in terrestrial ecosystems, this evidence suggests that plants outcompete other plants for nutrients by pre-empting the supply, not reducing the average concentration.New Phytologist(2005)doi: 10.1111/j.1469-8137.2005.01386.x© New Phytologist(2005) [ABSTRACT FROM AUTHOR]

Quantitative reconstructions of past land cover are necessary to determine the processes involved in climate–human–land-cover interactions. We present the first temporally continuous and most spatially extensive pollen-based land-cover reconstruction for Europe over the Holocene (last 11 700 cal yr BP). We describe how vegetation cover has been quantified from pollen records at a 1 ∘ × 1 ∘ spatial scale using the "Regional Estimates of VEgetation Abundance from Large Sites" (REVEALS) model. REVEALS calculates estimates of past regional vegetation cover in proportions or percentages. REVEALS has been applied to 1128 pollen records across Europe and part of the eastern Mediterranean–Black Sea–Caspian corridor (30–75 ∘ N, 25 ∘ W–50 ∘ E) to reconstruct the percentage cover of 31 plant taxa assigned to 12 plant functional types (PFTs) and 3 land-cover types (LCTs). A new synthesis of relative pollen productivities (RPPs) for European plant taxa was performed for this reconstruction. It includes multiple RPP values (≥2 values) for 39 taxa and single values for 15 taxa (total of 54 taxa). To illustrate this, we present distribution maps for five taxa (Calluna vulgaris, Cerealia type (t)., Picea abies, deciduous Quercus t. and evergreen Quercus t.) and three land-cover types (open land, OL; evergreen trees, ETs; and summer-green trees, STs) for eight selected time windows. The reliability of the REVEALS reconstructions and issues related to the interpretation of the results in terms of landscape openness and human-induced vegetation change are discussed. This is followed by a review of the current use of this reconstruction and its future potential utility and development. REVEALS data quality are primarily determined by pollen count data (pollen count and sample, pollen identification, and chronology) and site type and number (lake or bog, large or small, one site vs. multiple sites) used for REVEALS analysis (for each grid cell). A large number of sites with high-quality pollen count data will produce more reliable land-cover estimates with lower standard errors compared to a low number of sites with lower-quality pollen count data. The REVEALS data presented here can be downloaded from 10.1594/PANGAEA.937075 (Fyfe et al., 2022). [ABSTRACT FROM AUTHOR]

Aims: The morphological traits of fine roots change with forest succession and soil weathering. However, low tree species diversity in boreal forests may limit plastic responses of the roots to soil nutrient loss. We tested whether pine trees (Pinus sylvestris L.) exhibit root plasticity to change fine root allocation to deeper soil horizons in response to varying degree of podzolization. Methods: We compared root biomass in two sand dune chronosequences (aluminium (Al)/iron (Fe) oxide-poor coarse-textured sand vs. oxide-rich fine-textured sand) in Estonia. Results: We found that faster podzolization in coarse-textured soil promotes migration of Al/Fe oxides and phosphorus (P) into deeper horizons and reshapes the depth distribution of fine root biomass. A decrease in P availability in the coarse-textured soil profile increases fine root biomass and length in both the organic and mineral horizons. In the fine-textured old soil, fine root distribution increases in the mineral soil (especially, spodic horizon) rich in oxide-bonded P. Conclusion: Pine roots exhibit two forms of plasticity in low-diversity boreal forests – changing root morphological traits and changing depth distribution of root biomass, depending on the abundance of Al and Fe oxides and the depth distribution and dominant form of P. [ABSTRACT FROM AUTHOR]

Long-term perspectives on climate- and human-induced shifts in plant communities and tree line in mountains are often inferred from fossil pollen records. However, various factors, such as complex patterns of orographic wind fields and abundant insect-pollinated plants in higher altitudes, make pollen-based reconstruction in mountain regions difficult. Over the last decade the Landscape Reconstruction Algorithm (LRA) - a model-based approach in reconstruction of vegetation – has been successfully applied in various parts of the globe. However, evaluation of its effectiveness in mountain ranges is still limited. The present study assesses the extent to which the LRA approach helps quantify the local changes in vegetation cover at Vicdessos valley in northern French Pyrenees as a case study. In the study area well-dated sediment cores are available from eight bogs and ponds, 6–113 m in radius, located above the current tree line. We first use a simple simulation experiment to evaluate the way how pollen records from "landscape islands" (mountain tops and plateaus) would represent local vegetation and to clarify important factors affecting the LRA-based reconstruction in a mountainous region. This study then uses pollen records from these sites and vegetation and land-cover data both within a 50-km radius around the Vicdessos valley and within a 2-km radius from each site for evaluation of the REVEALS- and LOVE-based reconstruction of the regional and local plant cover, respectively, in the LRA approach. The land-cover data are complied for coniferous trees, broadleaved trees and non-forested areas from the CORINE and historical maps in three time windows: 1960–1970, 1990–2000 and 2000–2013. Major findings are as follows. (1) Accuracy of the regional vegetation estimates affects the reliability of the LRA-based reconstruction of vegetation within a 2-km radius; use of the CORINE data as input to the LOVE model improves reliability of the results over the use of the REVEALS-based estimates of regional vegetation. This implies that a systematic selection of pollen data only from sites above the tree line is problematic for estimating regional vegetation, and thus the entire LRA process. (2) Selection of the dispersal models for pollen transport (i.e. the Langrangian Stochastic Model vs. Gaussian Plume Model) does not affect significantly the LRA-based estimates at both the regional and local scales in the study area. (3) The LRA approach improves the pollen-based reconstruction of local vegetation compared to pollen percentage alone in northern Pyrenees. Although further empirical and simulation studies are necessary, our results emphasize the importance of site selection for the LRA-based reconstruction of vegetation in mountain regions. • Pollen-based reconstruction of Holocene land-cover in mountain regions. • The LRA approach is effective in mountain regions. • The REVEALS-based estimates are influenced by the systematic selection of pollen sites. • Pollen proportions alone are not useful for the local reconstruction. • New horizons for answering questions about human impact on upland vegetation. [ABSTRACT FROM AUTHOR]

Abstract: Questions: How open was the landscape prior to agriculture? Did agriculture start earlier in the south than in the north? How did the vegetation change in different regions after the introduction of agriculture? Location: Coast of SW and W Norway. Methods: The REVEALS (Regional Estimates of VEgetation Abundance from Large Sites) model is applied for pollen‐based vegetation reconstruction in 19 time windows over the last 9,000 years. Pollen data from 63 sites (lakes and bogs) are compiled and systematically used for data analysis so that the structure of vegetation change in space and time is captured. Results: Estimated cover of selected trees, shrubs, Calluna, graminids and herbs indicate a partly open outer coast throughout the Holocene. The highest tree cover is estimated for 8,200–6,200 cal. BP. Broad‐leaved trees (Fraxinus, Quercus, Tilia and Ulmus) spread from south to north and were present in the whole region at the end of the Mesolithic (5,950 cal. BP). Larger spatial variation in tree cover and a step‐wise reduction in deciduous trees after 5,700 cal. BP is concordant with increases in open‐land taxa indicating human activity. Vegetation changes caused by agriculture are indicated in the very south from ca. 5,950 cal. BP. Distinct human‐induced vegetation changes with spatial differentiation took place from 4,200 to 1,700 cal. BP, when most of the areas earlier covered by deciduous woodland had been transformed to cultivated fields, grasslands and heathlands. Increased Poaceae cover from 1,700 cal. BP probably reflects the expansion of mown meadows in addition to pastures. Conclusions: Capturing continuous changes of vegetation structure in space and time elucidates open areas along the western coast prior to the introduction of agriculture. Agriculture started earliest in the very south and spread rapidly along the whole coast prior to the Late Neolithic. Differences within the study area have existed in all time periods, reflecting different land‐use practices adapted to different natural conditions. [ABSTRACT FROM AUTHOR]

Bogs comprise various niches that are ideal habitats for diatoms. Even though diatoms are widely used bioindicators in many aquatic ecosystems, little is known about their within-site distribution and versatility in bogs. The abundance of bogs in hemiboreal region offers a good opportunity to study the variability of diatom assemblages in different bog habitats and factors influencing it. This study aims to describe the diatom assemblages (1) in the most common bog ecotopes and (2) along the microtopography, and (3) to evaluate the extent to which abiotic environmental parameters (i.e. water table, electric conductivity, pH, moisture and shading) affect the diatom assemblages. According to our results, the most widespread and abundant species are typical bog-inhabiting acidophilic taxa, such as Eunotia paludosa, Kobayasiella parasubtillissima and E. bilunaris. Multivariate analyses showed that some patterns in different microhabitats and ecotopes can be distinguished according to diatom assemblages. In this study, the diatom assemblages were affected by moisture, shading and pH. The study demonstrates the potential usefulness of diatom assemblages as bioindicators to provide additional information about the microsite conditions in bogs. [ABSTRACT FROM AUTHOR]

Long-term records of environmental history at decadal to millennial time-scales enable an assessment of ecosystem variability and responses to past anthropogenic disturbances and are fundamental for the development of environmental management strategies. This study examines the local variability of land-use history in the South Swedish Uplands over the last 200 years based on pollen records from three lake-sediment successions. Temporal changes in the proportional cover of 14 plant taxa were quantified as percentages using the landscape reconstruction algorithm (LRA). The LRA-based estimates of the extent of four land-use categories (cropland, meadows/grassland, wetland, outland/woodland) were compared to corresponding estimates based on historical maps and aerial photographs from ad 1769-1823, 1837-1895, 1946 and 2005. Although the LRA approach tends to overestimate grassland cover by 10-30 % for the two earliest time periods, the reconstructed vegetation composition is generally in good agreement with estimates based on the historical records. Subsequently, the LRA approach was used to reconstruct the 200-year history of local land-use dynamics at 20-year intervals around two small lakes. The qualitative assessment of difference approach, which requires fewer assumptions and parameters than LRA for objective evaluation of between-site differences in plant abundances, provides consistent results in general. Significant differences exist in the land-use history between the sites. Local catchment characteristics, such as soil conditions and wetland cover, appear important for the development of human impact on the landscape. Quantifications of past vegetation dynamics provide information on the amplitude, frequency and duration of the land-use changes and their effects on terrestrial and aquatic ecosystems, and should be taken into account when nature conservation strategies are developed. [ABSTRACT FROM AUTHOR]

Quantitative estimates of past vegetation with a clearly defined spatial scale are a critical step to better understand the patterns and processes of changes in vegetation and land-cover over time and space. However, such estimates are difficult to obtain from pollen data due to their lack of spatial dimension and the inter-taxonomic differences in pollen production, dispersal, and deposition mechanisms. This study assesses the potential of the Landscape Reconstruction Algorithm (LRA) to reconstruct the spatial and temporal patterns of upland vegetation in the Bassiès Valley, northern Pyrenees over the last 200 years, a period characterised by a decline of traditional pastoral activities. We used well-dated pollen records from eight bogs and ponds and vegetation and land-cover data within a 1-km radius from each site to evaluate the LRA-based reconstruction of local land-cover. The LRA approach was then used to reconstruct the 200-year history of local land-cover dynamics at 10 to 20-year intervals around each site in relation to land-abandonment. Our study shows that in addition to allowing long-term reconstruction, LRA estimates (1) are more sensitive to vegetation composition changes over time and space compared to historical land-cover maps and pollen percentages, and (2) improve the reconstruction of past local vegetation compared to pollen percentages alone. The LRA results reveal site-specific land-cover trajectories within the small-sized study area over 200 years. Some sites exhibit changes in land-cover composition with heathland and tree cover increase (ESC, EM), while others are found to be more stable, dominated 1) exclusively by heathland (LEG, W1652), 2) heathland with intermediate proportions of grassland (FOUZ, SIG), or 3) exclusively by grassland (OT). This land-cover composition variability over space and time may be related both to local topography and past grazing activity. The quantification of past vegetation dynamics provides opportunities for bridging the gap between researchers, policy makers and practitioners, and should be taken into account to further investigate the effect of long-term grazing activities on the past and modern plant and landscape diversity. • Landscape Reconstruction Algorithm (LRA) estimates of mountain land-cover changes over 200 years. • LRA estimates are more sensitive to vegetation changes compared to historical land-cover maps and pollen percentages. • LRA estimates revealed site-specific land-cover trajectories within the study area. • Some sites show increase in woody land-covers, others have more stable trajectories with different dominant types. • Spatio-temporal variability of land-cover composition may be related to past grazing activity. [ABSTRACT FROM AUTHOR]

Abstract: We collected two sediment cores and modern submerged aquatic plants and phytoplankton from two sub-basins of Lake Christina, a large shallow lake in west-central Minnesota, and used stable isotopic and elemental proxies from sedimentary organic matter to explore questions about the pre- and post-settlement ecology of the lake. The two morphologically distinct sub-basins vary in their sensitivities to internal and external perturbations offering different paleoecological information. The record from the shallower and much larger western sub-basin reflects its strong response to internal processes, while the smaller and deeper eastern sub-basin record primarily reflects external processes including important post-settlement land-use changes in the area. A significant increase in organic carbon accumulation (3–4 times pre-settlement rates) and long-term trends in δ13C, organic carbon to nitrogen ratios (C/N), and biogenic silica concentrations shows that primary production has increased and the lake has become increasingly phytoplankton-dominated in the post-settlement period. Significant shifts in δ15N values reflect land-clearing and agricultural practices in the region and support the idea that nutrient inputs have played an important role in triggering changes in the trophic status of the lake. Our examination of hydroclimatic data for the region over the last century suggests that natural forcings on lake ecology have diminished in their importance as human management of the lake increased in the mid-1900s. In the last 50years, three chemical biomanipulations have temporarily shifted the lake from the turbid, algal-dominated condition into a desired clear water regime. Two of our proxies (δ13C and BSi) measured from the higher resolution eastern basin record responded significantly to these known regime shifts. [Copyright &y& Elsevier]

Abstract: Quantitative vegetation reconstruction models have been developed to allow more faithful accounts of changes in vegetation structure to be attained. Widespread application of these models is encouraged, however for this to be realised necessary parameter values, such as pollen productivity estimates require further investigation. This study shows results of tests undertaken to detect the influence of a homogenous vegetation structure and sampling strategy upon the calculation of PPEs from contemporary data. Using a collection of contemporary moss samples, sub-groups were created using defined sampling strategies (random or systematic) and nearest neighbour distance thresholds to investigate the influence of these conditions upon PPE generation. Results suggest that a random sampling strategy achieves the most reliable values, but using a systematic strategy is possible. Furthermore, in areas where vegetation patterning is non-stationary, a large degree of variation is incorporated into the values obtained, and the use of quantitative models in such situations could be problematic. [Copyright &y& Elsevier]

• Poleward Pleistocene plant migration has been an important process structuring modern temperate and boreal plant communities, but the contribution of equatorward migration remains poorly understood. Paleobotanical evidence suggests Miocene or Pleistocene origin for temperate 'sky island' plant taxa in Mexico. These 'rear edge' populations situated in a biodiversity hotspot may be an important reserve of genetic diversity in changing climates. • We used mtDNA sequences, cpDNA sequences and chloroplast microsatellites to test hypotheses of Miocene vs Pleistocene colonization of temperate Douglasfir in Mexico, explore geographic patterns of molecular variation in relation to Pleistocene climate history using ecological niche models, and assess the taxonomic and conservation implications. • We found strong evidence for Pleistocene divergence of Douglas-fir in Mexico (958 thousand yr before present (ka) with the 90% highest posterior density interval ranging from 1.6 million yr before present (Ma) to 491 ka), consistent with the southward Pleistocene migration hypothesis. Genetic diversity was high and strongly partitioned among populations. Spatial patterns of molecular variation and ecological niche models suggest a complex late Pleistocene history involving periods of isolation and expansion along mountain corridors. • These results highlight the importance of southward Pleistocene migration in establishing modern high-diversity plant communities and provide critical insights into proposals to conserve the unique biodiversity of Mexican Douglas-fir and associated taxa. [ABSTRACT FROM AUTHOR]

Applying the concept of sustainability to invasive species management (ISM) is challenging but necessary, given the increasing rates of invasion and the high costs of invasion impacts and control. To be sustainable, ISM must address environmental, social, and economic factors (or “pillars”) that influence the causes, impacts, and control of invasive species across multiple spatial and temporal scales. Although these pillars are generally acknowledged, their implementation is often limited by insufficient control options and significant economic and political constraints. In this paper, we outline specific objectives in each of these three “pillars” that, if incorporated into a management plan, will improve the plan’s likelihood of sustainability. We then examine three case studies that illustrate how these objectives can be effectively implemented. Each pillar reinforces the others, such that the inclusion of even a few of the outlined objectives will lead to more effective management that achieves ecological goals, while generating social support and long-term funding to maintain projects to completion. We encourage agency directors and policy-makers to consider sustainability principles when developing funding schemes, management agendas, and policy. [Copyright &y& Elsevier]

Holocene relative sea level changes and palaeogeography of the uplifting Tihu ridge-swale beach system in the functionally tideless Baltic Sea were reconstructed using airborne LiDAR elevation data, ground-penetrating radar surveys, sedimentological proxies, recent models of Fennoscandian uplift due to glacial isostatic adjustment, and GIS-based terrain modelling. Considering that aeolian contribution to the ridge growth was relatively small and uniform along the studied profiles, it was possible to utilize an age estimation method based on terrain elevation and pre-determined RSL curves. The tested relative sea level curves converged around a linear trend during the past 7 ka, the rate of which (3.1–3.2 mm/a) is strongly correlated with relative-to-geoid uplift model output. We found that the Tihu system started to emerge from the sea ~5.4 ka ago. In its older part, it includes a complex of elevated barrier spits where both the isostatic uplift and gradual sediment aggradation due to longshore transport contributed to its nucleation and initial progradation. In its lower (younger) section, a forced progradation "staircase" of palaeocoastlines was formed in a regime of sediment deficit and low-energy hydrodynamic conditions. Analysis of near-cyclic occurrences of beach/foredune ridges and larger ridge sets within the Tihu ridgeplain revealed time intervals of enhanced storminess during 5.4–4.9, 4.8–4.5, 4.6–4.3, 4.1–3.8, 3.7–3.4, 3.2–2.9, 2.7–2.4, and 2.2–1.9 ka BP. Serving as a new independent proxy for past storminess and high sea level events in Estonia, these phases match well with some previous European Atlantic storminess reconstructions for Mid- to- Late Holocene. • Evolution of the Tihu ridgeplain studied based on relative sea level modelling • The palaeospit emerged ~5400 years ago, it has grown due to 3.1 mm/a postglacial uplift and beach ridge/foredune build-up • The ridgeplain consists of ~100 low ridges, and scattered between, higher ridge groups reflecting palaeostorminess episodes • Eight major stormy periods identified at the eastern coast of the Baltic Sea [ABSTRACT FROM AUTHOR]

Land-cover changes have a clear impact on local climates via biophysical effects. European land cover has been affected by human activities for at least 6000 years, but possibly longer. It is thus highly probable that humans altered climate before the industrial revolution (AD1750–1850). In this study, climate and vegetation 6000 years (6 ka) ago is investigated using one global climate model, two regional climate models, one dynamical vegetation model, pollen-based reconstruction of past vegetation cover using a model of the pollen-vegetation relationship and a statistical model for spatial interpolation of the reconstructed land cover. This approach enables us to study 6 ka climate with potential natural and reconstructed land cover, and to determine how differences in land cover impact upon simulated climate. The use of two regional climate models enables us to discuss the robustness of the results. This is the first experiment with two regional climate models of simulated palaeo-climate based on regional climate models. Different estimates of 6 ka vegetation are constructed: simulated potential vegetation and reconstructed vegetation. Potential vegetation is the natural climate-induced vegetation as simulated by a dynamical vegetation model driven by climate conditions from a climate model. Bayesian spatial model interpolated point estimates of pollen-based plant abundances combined with estimates of climate-induced potential un-vegetated land cover were used for reconstructed vegetation. The simulated potential vegetation is heavily dominated by forests: evergreen coniferous forests dominate in northern and eastern Europe, while deciduous broadleaved forests dominate central and western Europe. In contrast, the reconstructed vegetation cover has a large component of open land in most of Europe. The simulated 6 ka climate using reconstructed vegetation was 0–5 °C warmer than the pre-industrial (PI) climate, depending on season and region. The largest differences are seen in north-eastern Europe in winter with about 4–6 °C, and the smallest differences (close to zero) in southwestern Europe in winter. The simulated 6 ka climate had 10–20% more precipitation than PI climate in northern Europe and 10–20% less precipitation in southern Europe in summer. The results are in reasonable agreement with proxy-based climate reconstructions and previous similar climate modelling studies. As expected, the global model and regional models indicate relatively similar climates albeit with regional differences indicating that, models response to land-cover changes differently. The results indicate that the anthropogenic land-cover changes, as given by the reconstructed vegetation, in this study are large enough to have a significant impact on climate. It is likely that anthropogenic impact on European climate via land-use change was already taking place at 6 ka. Our results suggest that anthropogenic land-cover changes at 6 ka lead to around 0.5 °C warmer in southern Europe in summer due to biogeophysical forcing. • First simulation of paleoclimate using more than one regional climate model. • Mid-Holocene vegetation constructed both by dynamical vegetation model and pollen records and statistical methods. • Differences between modelled and reconstructed vegetation, and the response to land-cover changes in regional climate models. • Anthropogenic land-cover changes are large enough to have a significant impact on European climate already at Mid-Holocene. [ABSTRACT FROM AUTHOR]

Models based on generalized plant physiological theory represent a promising approach for describing vegetation responses to environmental drivers on large scales but must be tested for their ability to reproduce features of real vegetation. We tested the capability of a generalized vegetation model (LPJ-GUESS) to simulate vegetation structural and compositional dynamics under various disturbance regimes at the transition between prairie, northern hardwoods, and boreal forest in the Great Lakes region of the United States. LPJ-GUESS combines detailed representations of population dynamics as commonly used in forest gap models with the same mechanistic representations of plant physiological processes as adopted by a dynamic global vegetation model (the Lund-Potsdam-Jena [LPJ] model), which has been validated from the stand to the global scale. The model does not require site-specific calibration. The required input data are information on climate, atmospheric CO2 concentration, and soil texture class, as well as information on generally recognized species traits (broad-leaved vs. needle-leaved, general climatic range, two fire- resistance classes, shade-tolerance class, and maximum longevity). Model predictions correspond closely to observed patterns of vegetation dynamics and standing biomass at an old-growth eastern hemlock (Tsuga canadensis)/hardwood forest (Sylvania Wilderness, Michigan), an old-growth forest remnant from the "Great Lakes Pines Forest" (Itasca State Park, Minnesota), and a presettlement savanna (Cedar Creek Natural History Area, Minnesota). At all three sites, disturbance (wind or fire) strongly controls species composition and stand biomass. The model could be used to simulate vegetation dynamics on a regional basis or under past or future climates and atmospheric CO2 levels, without a need for reparameterization. [ABSTRACT FROM AUTHOR]

In an attempt to quantify Holocene anthropogenic land-cover change in temperate China, we 1) applied the REVEALS model to estimate plant-cover change using 94 pollen records and relative pollen productivity for 27 plant taxa, 2) reviewed earlier interpretation of pollen studies in terms of climate- and human-induced vegetation change, and 3) reviewed information on past land use from archaeological studies. REVEALS achieved a more realistic reconstruction of plant-cover change than pollen percentages in terms of openland versus woodland. The study suggests successive human-induced changes in vegetation cover. The first signs of human- induced land-cover change (crop cultivation, otherwise specified) are found c. 7 ka BP in the temperate deciduous forest, and S and NE Tibetan Plateau (mainly grazing, possibly crop cultivation), 6.5–6 ka BP in the temperate steppe and temperate desert (grazing, uncertain), and 5.5–5 ka BP in the coniferous-deciduous mixed forest, NE subtropical region, and NW Tibetan Plateau (grazing). Further intensification of anthropogenic land-cover change is indicated 5–4.5 ka BP in the E temperate steppe, and S and NE Tibetan Plateau (grazing, cultivation uncertain), 3.5–3 ka BP in S and NE Tibetan Plateau, W temperate steppe, temperate desert (grazing), and NW Tibetan Plateau (probably grazing), and 2.5–2 ka BP in the temperate deciduous forest, N subtropical region, and temperate desert (grazing). These changes generally agree with increased human activity as documented by archaeological studies. REVEALS reconstructions have a stronger potential than biomization to evaluate scenarios of anthropogenic land-cover change such as HYDE, given they are combined with information from archaeological studies. [ABSTRACT FROM AUTHOR]

The Landscape Reconstruction Algorithm (LRA) is regarded as the soundest approach for quantifying taxon-specific plant cover from pollen data. The reliability of relative pollen productivity (RPP) estimates is fundamental in the accuracy of quantitative vegetation reconstruction using the LRA approach. Inconsistent RPP estimates produced by different studies can cast doubt on the reliability and applicability of quantitative vegetation reconstruction. Therefore, it is crucial that the RPP estimates are evaluated before being applied for quantitative vegetation reconstruction. We have tested two alternative approaches, namely, a leave-one-out cross-validation (LOO) method and a splitting-by-subregion strategy, using surface pollen assemblages and the REVEALS model-the first step in the LRA-to evaluate the reliability of RPPs estimates of 10 target taxa obtained in the cultural landscape of Shandong. We compared the REVEALS estimates (RVs) with observations of regional vegetation abundance (OBVs) and pollen proportions (PPs). The RVs of all taxa are generally closer to OBVs than PPs, and the degree of similarity depends strongly on the abundance of individual taxa in plant and pollen; taxa dominant in the region show the highest similarity between RVs and OBVs, such as Artemisia , Poaceae, and Humulus . The RVs of all herb taxa except Humulus and Asteraceae SF Cichorioideae are slightly overrepresented, and the RVs of all tree taxa are underrepresented except for Castanea . The comparison of RVs with OBVs collected from different spatial extents shows that the RVs of all herb taxa are more similar to OBVs collected from shorter distances (100 km and 75 km for the entire region and the subregion, respectively), whereas the RVs of all tree taxa are more similar to OBVs collected from longer distances (150 km and 100 km for the entire region and the subregion, respectively). Furthermore, our findings highlight the importance to test different sizes of area for vegetation surveys for evaluation of the RVs given that the appropriate size of vegetation survey may vary between low pollen producers (mainly herbs) and high pollen producers (mainly trees). We consider that the LOO strategy is the best approach in this case study for evaluating the RPP estimates from surface moss polsters. The evaluation confirms the reliability of the obtained RPP estimates for their potential application in quantitative reconstruction of vegetation abundance in temperate China., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer SZ declared a past co-authorship with the author M-JG to the handling editor., (Copyright © 2023 Li, Gaillard, Xie, Huang, Cui, Fyfe, Marquer and Sugita.)

Protein function is coupled to its structural changes, for which stimulus-induced difference Fourier-transform infrared (FTIR) spectroscopy is a powerful method. By optimizing the attenuated total reflection (ATR)-FTIR analysis on sodium-pumping rhodopsin KR2 in aqueous solution, we first measured the accurate difference spectra upon sodium binding in the whole IR region (4000-1000 cm -1 ). The new spectral window allows the analysis of not only the fingerprint region (1800-1000 cm -1 ) but also the hydrogen-bonding donor region (4000-1800 cm -1 ), revealing an unusually strong hydrogen bond of Tyr located in the sodium binding site of KR2. Progress in ATR-FTIR difference spectroscopy provides an approach to investigating stimulus-induced structural changes of membrane proteins under physiological aqueous conditions.