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The study of the pollen rain from modern vegetation has greatly improved the interpretation of pollen diagrams and our understanding of ancient plant communities. In this study, 76 pollen samples were studied from various vegetation types in Cantabria, northern Iberian Peninsula. The pollen signals of the main taxa were compared to their estimated spatial coverage at various scales (100 m, 1 km and 5 km from the sampling point) using vegetation maps. Additionally, we investigated whether there were similar modern vegetation types to past ones interpreted from the pollen record from La Molina peatland, Cantabria. Our results revealed that the pollen rain from the laurel-evergreen oak community (Lauro nobilis-Quercetum ilicis) was mainly evergreen Quercus pollen (59-77%), with Laurus nobilis being very under-represented. The representation of Fagus sylvatica pollen varied according to its local presence. In the modern vegetation, two sample sites with over 95% cover of Fagus within a 100 m radius had a pollen content below 3%. Pine demonstrated high dispersal capability, with pollen values exceeding 20% even in samples with little or no pine cover within 1 and 5 km. Poaceae had limited representation, with up to 60% even in samples lacking tree cover within a 5 km radius. Mixed deciduous woodlands were dominated by deciduous Quercus and Corylus, and their resemblance to woods in the northern Iberian Peninsula during the mid Holocene is discussed. While a principal component analysis linked modern vegetation to the most recent part of the pollen diagram from La Molina, no clear parallels emerged between present-day and ancient vegetation. Finally, it was found that there were no differences in pollen concentrations trapped by acrocarpous and pleurocarpous mosses.

Pollen records from archaeological sites provide a direct reflection of the vegetation in the immediate vicinity, enabling an accurate depiction of anthropogenic impacts on vegetation. In this study, we applied the biomization technique to fossil pollen data to reconstruct human impact on the biome at the Chengzishan archaeological site in western Liaoning, China, and hence to explore the response of temperate forest vegetation to human activities. The results indicate that the original vegetation at Chengzishan was warm temperate coniferous and broadleaved mixed forest (TEDE). The findings suggest a shift in biome dominance over time, with cool temperate steppe (STEP) replacing TEDE as the dominant biome in response to human activities. Combined with archaeobotanical records, we conclude that the observed vegetation changes in the pollen record were closely linked to deforestation, fire use, and agricultural activities.

This research focuses on the recent pollen image of several vegetation types in NW Italy. In 201 arboreal, shrubby, and herbaceous plant populations, pollen samples were taken from moss polsters, and the corresponding vegetation was recorded using the phytosociological method. Since studies on recent pollen rain in the Mediterranean mountains and coast are rare, this research aims to provide new data and tools to better interpret fossil pollen spectra. Pollen analysis provided data for the comparison between surface spectra and vegetation. Davis indices, fidelity, dispersion, and the relation with vegetation data were calculated for each taxon, and PCA was carried out. Most vegetation types are identifiable through the taxa dominating the pollen spectra, as frequently happens in woodlands (e.g., beech woods, chestnut woods, etc.). Characterizing shrubland and certain tree-dominated vegetation types (e.g., Larix forests) through pollen data is more complex. In this regard, Davis indices are particularly useful for identifying pollen/plant association, over- and underrepresentation of pollen, and taxa indicating vegetation types. Pollen threshold values were calculated which allow the assessment of the local presence of a plant. Overall, the achieved results partially confirm those of previous research carried out in the region, greatly expanding the comparisons between several different plant communities and the database in view of future sharing through the EMPD.

Recently, the evolutionary history of the Caribbean mangroves has been reconsidered using partial palynological databases organized by the time intervals of interest, namely Late Cretaceous to Eocene for the origin, the Eocene–Oligocene transition for major turnover and Neogene to Quaternary for diversification. These discussions have been published in a set of sequential papers, but the raw information remains unknown. This paper reviews all the information available and provides the first comprehensive and updated compilation of the abovementioned partial databases. This compilation is called CARMA-F (CARibbean MAngroves-Fossil) and includes nearly 90 localities from the present and past Caribbean coasts, ranging from the Late Cretaceous to the Pliocene. Details on the Quaternary localities (CARMA-Q) will be published later. CARMA-F lists and illustrates the fossil pollen from past mangrove taxa and their extant representatives, and includes a map of the studied localities and a conventional spreadsheet with the raw data. The compilation is the most complete available for the study of the origin, evolution and diversification of Caribbean mangroves, and is open to modifications for adapting it to the particular interests of each researcher.

The Late Holocene fossil pollen records from the Zemu glacier, located in Yabuk, North Sikkim, in the eastern Himalayas, effectively generated quantitative climate reconstructions based on the transfer function model. The transfer function model was developed by establishing a modern pollen–climate calibration set from the temperate alpine belt of North Sikkim. A redundancy analysis was carried out to detect the pattern of variation of climatic variables in the modern pollen datasets. The mean annual precipitation (MAP) and mean temperature of the warming month (MTWA) had the strongest influence on the composition of the modern pollen samples among the climatic variables considered in the analysis. Proxy data in the form of fossil pollen records were analyzed for reconstructing past climate based upon the relationships between modern pollen vegetation assemblages and climatic patterns. Transfer functions for MAP and MTWA were developed with the partial least squares (PLS) approach, and model performance was assessed using leave-one-out cross-validation. The validated model was used to reconstruct MAP and MTWA for the last 2992 cal years BP (1042 BC) in North Sikkim. The variability observed in the reconstructions was analyzed for past global climatic events. It was further compared with the available regional and hemispheric proxy-based climate reconstructions. The reconstructions captured comparable Medieval Warm Period (MWP) and Little Ice Age (LIA)-like events from the Zemu glacier region. The fossil pollen data and climate reconstructions were further compared with the mineral magnetism data of the subsurface sediment profile.

The two major aims of this study are (1) To test the performance of the Landscape Reconstruction Algorithm (LRA) to quantify past landscape changes using historical maps and related written sources, and (2) to use the LRA and map reconstructions for a better understanding of the origin of landscape diversity and the recent loss of species diversity. Southern Sweden, hemiboreal vegetation zone. The LRA was applied on pollen records from three small bogs for four time windows between AD 1700 and 2010. The LRA estimates of % cover for woodland/forest, grassland, wetland, and cultivated land were compared with those extracted from historical maps within 3‐km radius around each bog. Map‐extracted land‐use categories and pollen‐based LRA estimates (in % cover) of the same land‐use categories show a reasonable agreement in several cases; when they do not agree, the assumptions used in the data (maps)‐model (LRA) comparison are a better explanation of the discrepancies between the two than possible biases of the LRA modeling approach. Both the LRA reconstructions and the historical maps reveal between‐site differences in landscape characteristics through time, but they demonstrate comparable, profound transformations of the regional and local landscapes over time and space due to the agrarian reforms in southern Sweden during the 18th and 19th centuries. The LRA was found to be the most reasonable approach so far to reconstruct quantitatively past landscape changes from fossil pollen data. The existing landscape diversity in the region at the beginning of the 18th century had its origin in the long‐term regional and local vegetation and land‐use history over millennia. Agrarian reforms since the 18th century resulted in a dramatic loss of landscape diversity and evenness in both time and space over the last two centuries leading to a similarly dramatic loss of species (e.g., beetles). We studied the last three centuries of land‐use history in central Småland (Southern Sweden) using historical maps, pollen records from three small bogs and models of the relationship between pollen and vegetation (the Landscape Reconstruction Algorithm, LRA). The aims of the study is to (1) evaluate the performance of the LRA for quantitative pollen‐based reconstructions of past landscape and (2) discuss the impact of recent land‐use changes (over the last three centuries) on changes in biodiversity (mainly landscape diversity and beetle fauna). The results indicate that the LRA is a robust modelling approach to translate pollen data into vegetation/plant cover, and that the transformation of the landscape since the 18th century strongly diminished biodiversity both at the landscape and species level.

Proxy-based reconstructions and modeling of Holocene spatiotemporal precipitation patterns for China and Mongolia have hitherto yielded contradictory results indicating that the basic mechanisms behind the East Asian Summer Monsoon and its interaction with the westerly jet stream remain poorly understood. We present quantitative reconstructions of Holocene precipitation derived from 101 fossil pollen records and analyse them with the help of a minimal empirical model. We show that the westerly jet-stream axis shifted gradually southward and became less tilted since the middle Holocene. This was tracked by the summer monsoon rain band resulting in an early-Holocene precipitation maximum over most of western China, a mid-Holocene maximum in north-central and northeastern China, and a late-Holocene maximum in southeastern China. Our results suggest that a correct simulation of the orientation and position of the westerly jet stream is crucial to the reliable prediction of precipitation patterns in China and Mongolia. The basic mechanisms behind the East Asian Summer Monsoon remain poorly understood. Using proxy-based reconstructions and simulations, here the authors show that changes in the orientation and position of the westerly jet stream resulted in regionally asynchronous Holocene precipitation maxima.

Analysis of pollen records from North America and Europe reveals a warming trend over the Holocene, consistent with climate-model simulations. Preserved pollen presents climate past In spite of decades of work, climate trends over the Holocene—the past 11,700 years—remain extensively debated. For example, climate models forced by known changes in insolation tend to simulate warming while reconstructions using proxies such as marine records often reveal cooling over the late Holocene, before sharp warming in the industrial era. Now, Jeremiah Marsicek and colleagues re-analyse extensive pollen records from North America and Europe and show a warming trend over the Holocene, consistent with climate model simulations. Evidence for cooling appears to be constrained to the North Atlantic region, rather than being a global signal. Cooling during most of the past two millennia has been widely recognized 1 , 2 and has been inferred to be the dominant global temperature trend of the past 11,700 years (the Holocene epoch) 3 . However, long-term cooling has been difficult to reconcile with global forcing 4 , and climate models consistently simulate long-term warming 4 . The divergence between simulations and reconstructions emerges primarily for northern mid-latitudes, for which pronounced cooling has been inferred from marine and coastal records using multiple approaches 3 . Here we show that temperatures reconstructed from sub-fossil pollen from 642 sites across North America and Europe closely match simulations, and that long-term warming, not cooling, defined the Holocene until around 2,000 years ago. The reconstructions indicate that evidence of long-term cooling was limited to North Atlantic records. Early Holocene temperatures on the continents were more than two degrees Celsius below those of the past two millennia, consistent with the simulated effects of remnant ice sheets in the climate model Community Climate System Model 3 (CCSM3) 5 . CCSM3 simulates increases in ‘growing degree days’—a measure of the accumulated warmth above five degrees Celsius per year—of more than 300 kelvin days over the Holocene, consistent with inferences from the pollen data. It also simulates a decrease in mean summer temperatures of more than two degrees Celsius, which correlates with reconstructed marine trends and highlights the potential importance of the different subseasonal sensitivities of the records. Despite the differing trends, pollen- and marine-based reconstructions are correlated at millennial-to-centennial scales, probably in response to ice-sheet and meltwater dynamics, and to stochastic dynamics similar to the temperature variations produced by CCSM3. Although our results depend on a single source of palaeoclimatic data (pollen) and a single climate-model simulation, they reinforce the notion that climate models can adequately simulate climates for periods other than the present-day. They also demonstrate that amplified warming in recent decades increased temperatures above the mean of any century during the past 11,000 years.

Aim: To quantify the effect of Pleistocene climate fluctuations on habitat connectivity across páramos in the Northern Andes. Location: Northern Andes. Methods: The unique páramos habitat underwent dynamic shifts in elevation in response to changing climate conditions during the Pleistocene. The lower boundary of the páramos is defined by the upper forest line, which is known to be highly responsive to temperature. Here, we reconstruct the extent and connectivity of páramos over the last 1 million years (Myr) by reconstructing the upper forest line from the long fossil pollen record of Funza09, Colombia, and applying it to spatial mapping on modern topographies across the Northern Andes for 752 time slices. Data provide an estimate of how often and for how long different elevations were occupied by páramos and estimate their connectivity to provide insights into the role of topography in biogeographical patterns of páramos. Results: Our findings show that connectivity amongst páramos of the Northern Andes was highly dynamic, both within and across mountain ranges. Connectivity amongst páramos peaked during extreme glacial periods but intermediate cool stadials and mild interstadials dominated the climate system. These variable degrees of connectivity through time result in what we term the ‘flickering connectivity system’. We provide a visualization (video) to showcase this phenomenon. Patterns of connectivity in the Northern Andes contradict patterns observed in other mountain ranges of differing topographies. Main conclusions: Pleistocene climate change was the driver of significant elevational and spatial shifts in páramos causing dynamic changes in habitat connectivity across and within all mountain ranges. Some generalities emerge, including the fact that connectivity was greatest during the most ephemeral of times. However, the timing, duration and degree of connectivity varied substantially among mountain ranges depending on their topographical configuration. The flickering connectivity system of the páramos uncovers the dynamic settings in which evolutionary radiations shaped the most diverse alpine biome on Earth.

About 250 fossil pollen types related to 113 extant angiospermous families from the Cretaceous and the Tertiary in China are discussed in the first part of this article. In the second part, comparisons of early records of fossil pollen in and outside China are made to trace the oldest fossil records. Based on these data, we conclude that many plants may have originated in China, a finding that may be important for the study of the origin and early development of angiosperms.