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A contribution to the PAGES Focus 4 Land Use and Cover Theme ABSTRACT: We present quantitative reconstructions of regional vegetation cover in north western Europe western Europe north of the Alps and eastern Europe for five time windows in the Holocene [around 6k 3k 0.5k 0.2k and 0.05k calendar years before present (bp)] at a 1° × 1° spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records from lakes and bogs to reconstruct the past cover of 25 plant taxa grouped into 10 plant functional types and three land cover types [evergreen trees summer green (deciduous) trees and open land]. The model corrects for some of the biases in pollen percentages by using pollen productivity estimates and fall speeds of pollen and by applying simple but robust models of pollen dispersal and deposition. The emerging patterns of tree migration and deforestation between 6k bp and modern time in the REVEALS estimates agree with our general understanding of the vegetation history of Europe based on pollen percentages. However the degree of anthropogenic deforestation (i.e. cover of cultivated and grazing land) at 3k 0.5k and 0.2k bp is significantly higher than deduced from pollen percentages. This is also the case at 6k in some parts of Europe in particular Britain and Ireland. Furthermore the relationship between summer green and evergreen trees and between individual tree taxa differs significantly when expressed as pollen percentages or as REVEALS estimates of tree cover. For instance when Pinus is dominant over Picea as pollen percentages Picea is dominant over Pinus as REVEALS estimates. These differences play a major role in the reconstruction of European landscapes and for the study of land cover–climate interactions biodiversity and human resources.

The island of Mauritius offers the opportunity to study the poorly understood vegetation response to climate change on a small tropical oceanic island. A high-resolution pollen record from a 10 m long peat core from Kanaka Crater (560 m elevation, Mauritius, Indian Ocean) shows that vegetation shifted from a stable open wet forest Last Glacial state to a stable closed-stratified-tall-forest Holocene state. An ecological threshold was crossed at ∼11.5 cal ka BP, propelling the forest ecosystem into an unstable period lasting ∼4000 years. The shift between the two steady states involves a cascade of four abrupt (

International audience; A high-resolution sedimentary charcoal record from Lago dell'Accesa in southern Tuscany reveals numerous changes in fire regime over the last 11.6 kyr cal. BP and provides one of the longest gap-free series from Italy and the Mediterranean region. Charcoal analyses are coupled with gamma density measurements, organic-content analyses, and pollen counts to provide data about sedimentation and vegetation history. A comparison between fire frequency and lake-level reconstructions from the same site is used to address the centennial variability of fire regimes and its linkage to hydrological processes. Our data reveal strong relationships among climate, fire, vegetation, and land-use and attest to the paramount importance of fire in Mediterranean ecosystems. The mean fire interval (MFI) for the entire Holocene was estimated to be 150 yr, with a minimum around 80 yr and a maximum around 450 yr. Between 11.6 and 3.6 kyr cal. BP, up to eight high-frequency fire phases lasting 300–500 yr generally occurred during shifts towards low lake-level stands (ca 11,300, 10,700, 9500, 8700, 7600, 6200, 5300, 3400, 1800 and 1350 cal. yr BP). Therefore, we assume that most of these shifts were triggered by drier climatic conditions and especially a dry summer season that promoted ignition and biomass burning. At the beginning of the Holocene, high climate seasonality favoured fire expansion in this region, as in many other ecosystems of the northern and southern hemispheres. Human impact affected fire regimes and especially fire frequencies since the Neolithic (ca 8000–4000 cal. yr BP). Burning as a consequence of anthropogenic activities became more frequent after the onset of the Bronze Age (ca 3800–3600 cal. yr BP) and appear to be synchronous with the development of settlements in the region, slash-and-burn agriculture, animal husbandry, and mineral exploitation. The anthropogenic phases with maximum fire activity corresponded to greater sensitivity of the vegetation and triggered significant changes in vegetational communities (e.g. temporal declines of Quercus ilex forests and expansion of shrublands and macchia). The link between fire and climate persisted during the mid- and late Holocene, when human impact on vegetation and the fire regime was high. This finding suggests that climatic conditions were important for fire occurrence even under strongly humanised ecosystem conditions.

International audience; After a review of the first steps in marine palynology, we show that the understanding of the northwest African setting is crucial to evaluate the potential of marine palynological studies elsewhere. We studied distribution patterns of pollen grains in recent marine sediments off NW Africa and were able to clearly relate patterns to modern pollen source areas (vegetation belts) and operating transport systems (wind belts and ocean currents). In particular patterns of Quercus, Artemisia, Chenopodiaceae-Amaranthaceae, Ephedra, Gramineae, and wet forest trees are very indicative of the position of the vegetation belts on the adjacent continent. Aeolian pollen transport is carried out by the northeast trade winds and the African Easterly Jet (AEJ). In the rain forest belt transport of pollen and fern spores also occurs by rivers. A detailed comparison between recent pollen rain samples from terrestrial and marine sites between 21 and 12°N showed that the latitudinal range of vegetation belts is clearly reflected in the pollen samples of both environments. A migration of the southern border of the Sahara is reflected by the changing ratio between Chenopodiaceae-Amaranthaceae pollen from the desert and Gramineae pollen from the savannah belt. Distribution patterns of pollen for 9000 and 18,000 14C yr BP (last glacial maximum) time-slices, based on pollen records from eleven marine cores between Portugal and the Gulf of Guinea show significant latitudinal migrations of vegetation belts, but a stable position of the main wind trajectories. The AEJ had a stable position around 21°N. The belt with trade winds had a stable position from Morocco southwards. Changing vigour of the trade winds is clearly reflected by the patterns of isopollen contours and by changes in pollen influx records.

Event stratigraphy is used to help characterise the Anthropocene as a chronostratigraphic concept, based on analogous deep-time events, for which we provide a novel categorization. Events in stratigraphy are distinct from extensive, time-transgressive ‘episodes’ – such as the global, highly diachronous record of anthropogenic change, termed here an Anthropogenic Modification Episode (AME). Nested within the AME are many geologically correlatable events, the most notable being those of the Great Acceleration Event Array (GAEA). This isochronous array of anthropogenic signals represents brief, unique events evident in geological deposits, e.g.: onset of the radionuclide ‘bomb-spike’; appearance of novel organic chemicals and fuel ash particles; marked changes in patterns of sedimentary deposition, heavy metal contents and carbon/nitrogen isotopic ratios; and ecosystem changes leaving a global fossil record; all around the mid-20th century. The GAEA reflects a fundamental transition of the Earth System to a new state in which many parameters now lie beyond the range of Holocene variability. Globally near-instantaneous events can provide robust primary guides for chronostratigraphic boundaries. Given the intensity, magnitude, planetary significance and global isochroneity of the GAEA, it provides a suitable level for recognition of the base of the Anthropocene as a series/epoch. Contributing authors are members of the Anthropocene Working Group (AWG), of the Subcommission on Quaternary Stratigraphy (SQS), a component body of the International Commission on Stratigraphy (ICS). The paper was inspired by a publication by Gibbard et al. (2021), which initiated our critical enquiry into the Anthropocene as a geological event. The authors thank the anonymous referees and editor, Alessandra Negri, whose comments helped improve this manuscript. We are also grateful to Lucy E. Edwards for alerting us at the proof stage to the NASC requirements for defining episodes formally

The long term response of ancient societies to climate change has been a matter of global debate. Until recently, the lack of integrative studies between archaeological, palaeoecological, and palaeoclimatological data had prevented an evaluation of the relationship between climate change, distinct subsistence strategies, and cultural transformations across the largest rainforest of the world, Amazonia. Here, we review the most relevant cultural changes seen in the archaeological record of six different regions within Greater Amazonia during late pre-Columbian times. We compare the chronology of those cultural transitions with high-resolution regional palaeoclimate proxies, showing that, while some societies faced major reorganisation during periods of climate change, others were unaffected and even flourished. We propose that societies with intensive, specialised land-use systems were vulnerable to transient climate change. In contrast, land-use systems that relied primarily on polyculture agroforestry, resulting in the formation of enriched forests and fertile Amazonian Dark Earths in the long term, were more resilient to climate change.

International audience; Plant architecture strongly influences ecological performance, yet its role in plant evolution has been weakly explored. By testing both phylogenetic and environmental signals, it is possible to separate architectural traits into four categories: development constraints (phylogenetic signal only); convergences (environmental dependency only); key confluences to the environmental driver (both); unknown (neither).We analysed the evolutionary history of the genus Euphorbia, a model clade with both high architectural diversity and a wide environmental range. We conducted comparative analyses of 193 Euphorbia species worldwide using 73 architectural traits, a dated phylogeny, and climate data.We identified 14 architectural types in Euphorbia based on trait combinations. We found 22 traits and three types representing convergences under climate groups; 21 traits and four types showing phylogenetic signal but no relation to climate; and 16 traits and five types with both climate and phylogenetic signals. Major drivers of architectural trait evolution likely include water stress in deserts (selected for succulence, continuous branching), frost disturbance in temperate systems (selected for simple, prostrate, short‐lived shoots) and light competition (selected for arborescence). Simple architectures allowed resilience to disturbance, and frequent transitions into new forms. Complex architectures with functional specialisation developed under stable climates but have low evolvability.

Facial compartmentalization in the skull of extant pygmy whales (Kogiidae) is a unique feature among cetaceans that allows for the housing of a wide array of organs responsible for echolocation. Recent fossil findings indicate a remarkable disparity of the facial bone organization in Miocene kogiids, but the significance of such a rearrangement for the evolution of the clade has been barely explored. Here we describe Kogia danomurai sp. nov., a late Miocene (c. 5.8 Ma) taxon from the Pisco Formation (Peru), based on a partially preserved skull with a new facial bone pattern. Phylogenetic analysis recovers K. danomurai as the most basal representative of the extant genus Kogia, displaying a combination of derived (incipiently developed and excavated sagittal facial crest) and plesiomorphic features (high position of the temporal fossa, and antorbital notch not transformed into a narrow slit). Furthermore, when compared with the extant Kogia, the facial patterning found in K. danomurai indicates differential development among the facial organs, implying different capabilities of sound production relative to extant Kogia spp. Different facial bone patterns are particularly notable within the multi-species kogiid assemblage of the Pisco Formation, which suggests causal connections between different patterns and feeding ecologies (e.g. nekton piscivory and benthic foraging). At c. 5.8 Ma, K. danomurai was part of a cetacean community composed of clades typical of the late Miocene, and of other early representatives of extant taxa, a mixture probably representing an initial shift of the coastal faunas toward the ecosystem dynamics of the present-day south-eastern Pacific. © 2021 The Palaeontological Association

International audience; The biological processes involved in the preservation, viability, and revival of long‐term dormant dinoflagellate cysts buried in sediments remain unknown. Based on studies of plant seed physiology, we tested whether the revival of ancient cysts preserved in century‐old sediments from the Bay of Brest (France) could be stimulated by melatonin and gibberellic acid, two molecules commonly used in seed priming. Dinoflagellates were revived from sediments dated to approximately 150 years ago (156 ± 27, 32 cm depth), extending the known record age of cyst viability previously established as around one century. A culture suspension of sediments mixed with melatonin and gibberellic acid solutions as biostimulants exhibited germination of 11 dinoflagellate taxa that could not be revived under controlled culture conditions. The biostimulants revived some dinoflagellates from century‐old sediments, including the potentially toxic species Alexandrium minutum. The biostimulants showed positive effects on germination on even more ancient cysts, showing dose‐dependent effects on the germination of Scrippsiella acuminata. Concentrations of 1, 10, and 100 µM melatonin and gibberellic acid promoted germination. In contrast, 1000 µM solutions, particularly for melatonin, drastically decreased germination, suggesting a potential noxious effect of high doses of these molecules on dinoflagellate revival. Our findings suggest that melatonin and gibberellic acid are involved in the stimulation of germination of dinoflagellate cysts. These biostimulants can be used to germinate long‐term stored dinoflagellate cysts, which may promote studies of ancient strains in the resurrection ecology research field.

International audience; Mountain ombrotrophic peatlands in Central Europe are an important stock of transboundary contamination both of natural and anthropogenic origin. The Snie _ zka Mountain (West Sudetes) forms a significant orographic barrier and receives aerosols from broadly-recognized anthropogenic sources (production and use of stainless steel, processing of uranium, coal combustion, nuclear weapon tests, and Chernobyl accident). The main objective of the study was to assess the pattern of distribution and origin of trace elements and to distinguish the long-range transport vs. local signals in two 210 Pb and 14 C e dated peat cores from the highest summit of the Karkonosze (West Sudetes) spanning the last 280 years. Maximum values and accumulations of almost all investigated elements (Pb, Zn, Cu, Ni, Cr, Ti, Al, U, Sc, and REE) were identified around the 1970s. The analysis of peat using scanning electron microscopy (SEM) confirmed the occurrence of spheroidal aluminosilicate fly ash particles (SAP) in the topmost 40 cm (from AD 1938) together with a maximum of mullite (3Al 2 O 3 $2SiO 2), an anthropogenic marker originating from coal-based power plants. The overall 206 Pb/ 207 Pb signature ranges from 1.160 to 1.173, indicating a predominant contribution of anthropogenic Pb. Human activities promote the release of mobile 234 U, due to the weaker bonds to mineral structure, and cause the radiogenic disequilibrium between 238 U and its daughter 234 U.

Wildfire occurrence is influenced by climate, vegetation and human activities. A key challenge for understanding the risk of fires is quantifying the mediating effect of vegetation on fire regimes. Here, we explore the relative importance of Holocene land cover, land use, dominant functional forest type, and climate dynamics on biomass burning in temperate and boreo-nemoral regions of central and eastern Europe over the past 12 kyr. We used an extensive data set of Holocene pollen and sedimentary charcoal records, in combination with climate simulations and statistical modelling. Biomass burning was highest during the early Holocene and lowest during the mid-Holocene in all three ecoregions (Atlantic, continental and boreo-nemoral) but was more spatially variable over the past 3–4 kyr. Although climate explained a significant variance in biomass burning during the early Holocene, tree cover was consistently the highest predictor of past biomass burning over the past 8 kyr. In temperate forests, biomass burning was high at ∼45 % tree cover and decreased to a minimum at between 60 % and 70 % tree cover. In needleleaf-dominated forests, biomass burning was highest at ∼ 60 %–65 % tree cover and steeply declined at >65 % tree cover. Biomass burning also increased when arable lands and grasslands reached ∼ 15 %–20 %, although this relationship was variable depending on land use practice via ignition sources, fuel type and quantities. Higher tree cover reduced the amount of solar radiation reaching the forest floor and could provide moister, more wind-protected microclimates underneath canopies, thereby decreasing fuel flammability. Tree cover at which biomass burning increased appears to be driven by warmer and drier summer conditions during the early Holocene and by increasing human influence on land cover during the late Holocene. We suggest that long-term fire hazard may be effectively reduced through land cover management, given that land cover has controlled fire regimes under the dynamic climates of the Holocene.

In the Mediterranean region, Corsica represents one of the most important hotspots of biodiversity, partly due to the high number of endemics species. This region is also one of the most affected by forest fires worldwide. The present vegetation is adapted to a wide range of disturbance regimes, but a change in fire frequency or intensity in the future may severely affect ecological resources and other socio-economical aspects. Here, we study the dynamics of vegetation–human–fire interactions for the past 12,000 years as recorded by Lake Bastani (Corsica, France). We used well-dated sedimentary records of charcoal, pollen and fungal spores to infer past fire regime, land cover and pastoral activities, respectively, and we compared our results with charcoal records from two other Corsican lakes (Nino and Creno, respectively). Our results suggest that climate and natural fires were the main factors shaping the landscape before 5000 cal. BP. Then, the extraordinary diversity of the current Corsican vegetation has been mainly promoted by human activities on the island (i.e. deforestation and pastoralism) at least from the Bronze Age (3500 cal. BP). The top of our record shows a sharp decrease in fungal remains ( Sporormiella-type), usually associated with pastoral activities, which could be attributed to the land abandonment occurring since a few decades.

International audience; Instrumental records of temperature and hydrological regimes in East Africa evidence frequent droughts with dramatic effects on population and ecosystems. Sources of these climatic variations remain largely unconstrained, partly because of a paucity of Late Holocene records. Here, we present a multi-proxy analysis of a 4-m continuous sediment core collected in the Kyambangunguru crater marsh, in southwest Tanzania, covering the last 4000 yrs (cal. BP). We used microscopic (macro-remains, microfossils, palynofacies, pollen), elemental (carbon, nitrogen contents), molecular (br GDGTs, n-alkanes) and compound-specific isotopic (δ2H n-alkanes) investigations to reconstruct the environmental history of the marsh. The multi proxy record reveals that, 2500 years ago, the marsh underwent a major ecological transition from a lake to a peatland. Temperature and hydrological reconstructions evidence warmer and drier conditions between 2200 and 860 cal. BP, which probably triggered the establishment of a perennial peatland. This study is one of the first combined temperature and precipitation record of Late Holocene in the region and highlights changes in the spatial distribution of the East African climate regimes. Several cold periods are observed, between 3300 and 2000 cal. BP and since 630 cal. BP, the latter corresponding to the Little Ice Age. Moreover, wetter conditions are reported during the Medieval Climate Anomaly in contrast to other north-eastern African records suggesting that Tanzania is located at the transition between two hydro-climatic zones (north-eastern versus southern Africa) and has experienced variable contributions of these two zones over the last millennium.

International audience; A 4 m core was extracted from the center of a peatland located in the Drugeon valley (France). Thirteen radiocarbon dates were used to build a robust age model. Testate amoebae were used for reconstructing mire surface wetness. High-resolution pollen analysis of the sequence reconstructed 9 millennia of development of the peatland and its surrounding vegetation. During the early/middle Holocene (9500 to 5800 cal BP), warm conditions led to high evapotranspiration and low water levels. The vegetation history is characterized by the development of a Pinus and a mixed Quercus forest. From 5800 cal BP, testate amoebae show wetter conditions, indicating the onset of the cooler Neoglacial period. The cooling is also evidenced by the development of Abies and Fagus trees, replacing the oak forest. The first indicators of human impact appear at about 4800 cal BP, and indicators of farming activity remains very rare until ca. 2600 cal BP, at the beginning of the Iron Age. The development of the peatland responded to climatic fluctuation until 2600 cal BP, after which human impact became the main driver. The last millennium has been characterized by sudden drying and the spread of pine on the peatland.

International audience

International audience; Reconstructing the past vegetation conventionally uses pollen percentages (PPs) or pollen accumulation rates (PARs). Qualitative interpretation of PPs and PARs is based on insights gained from modern analogues of the pollen-vegetation relationship or on the comparative approach that compares past and modern pollen assemblages. Quantifying past vegetation/ land cover using pollen data requires other approaches that can correct the non-linear relationship with vegetation and biases due to inter-taxonomic differences in pollen productivity, dispersion and deposition. Relative Pollen Productivity (RPP) can be estimated using the Extended R-Value (ERV) model (Prentice and Parsons, 1983), provided modern pollen assemblages and distance weighted vegetation abundance (DWPA) around the pollen sampling point are available from actual field measurements (e.g. Li et al., 2017). We present for the first time RPPs of some of the key pollen taxa retrieved from the fossil pollen sequences located within the broader Acacia–Albizia biogeographic zone in the drier parts of south-east India along the Coromandel coast, falling in the rain shadow of the southwest or summer monsoon. To achieve this, surface soil samples for pollen analysis and distance-weighted vegetation data were collected from 14 sites in the current mosaic landscape of this biogeographic zone using the Crackles Vegetation Survey protocol (Bunting et al., 2013). RPPs of 6 key pollen taxa, viz.,. Poaceae, Acacia/Albizia, Dodonaea, Justicia, Melastomataceae/ Combretaceae, and Randia were estimated with the ERV model (sub-model 3) for which the best likelihood function curve was obtained using the Prentice Bog (dispersion) model. Results indicate a Relevant Source Area of Pollen (sensu Sugita, 1994) of 164 m radius for the modern pollen samples. The estimated RPPs relative to Poaceae (RPP set to 1) are highest for Acacia/Albizia, Dodonaea, and Justicia (>10), and are

International audience; Pollen-based quantitative reconstruction of regional land cover is an essential step to infer past landscape dynamics and to produce vegetation descriptions useful in Earth-system modelling. In this study, we test the REVEALS (Regional Estimates of VEgetation Abundance from Large Sites) model (Sugita, 2007a) for the first time tropical south east India to reconstruct Holocene regional land-cover change. We use three fossil pollen records from the Coromandel coast, falling in the rain shadow of the southwest or summer monsoon and characterized by Tropical Dry Evergreen Forests (TDEFs). One of the pollen records is from a site located in the same region as sites used to estimate Relative Pollen Productivity (RPP) needed for the application of the REVEALS model. The two other pollen records are from the same biogeographic zone, ~150 km south of the primary site. The REVEALS reconstructions are achieved for consecutive 500-year time windows up to 0.7 ka BP and time windows of decreasing length up to present following the protocol of PAGES LandCover6k (Gaillard et al. 2018). In addition to RPPs estimated for six key taxa of SE India, Poaceae, Acacia/Albizia, Dodonaea, Justicia, Melastomataceae/Combretaceae, and Randia, we applied RPPs from China (Li, et al., 2017) for Aster/Anthemis-t. (known as Compositae Echinate in India), Amaranthaceae/Chenopodiaceae, and Cyperaceae, assuming that RPPs in temperate China and SE India are comparable. The REVEALS reconstructions suggest that, except for Cyperaceae, all other taxa are over-represented in the pollen record. Fluctuations in the quantitative estimates of key pollen markers of the TDEF vegetation through time indicate that the present mosaic vegetation of the region may have existed for a long time, and that the land cover of SE India was a scrubland with grasses and patches of TDEFs through most of the Holocene.

International audience; Resumen. La Ingeniería de requisitos es un enfoque sistemático y disciplinado para la especificación y gestión de requisitos de software; uno de sus objetivos es transformar las necesidades de los interesados en especificaciones formales con el fin de implementar un sistema. Estas necesidades por lo general se manifiestan y articulan en lenguaje natural, esto debido a la universalidad y facilidad que presenta el lenguaje natural para la comunicación de los requisitos. Para facilitar los procesos de transformación y para mejorar la calidad de los requisitos resultantes, varios autores han propuesto plantillas para la escritura de requisitos en lenguaje natural estructurado. Sin embargo, esas plantillas no permiten escribir ciertos requisitos funcionales, no funcionales y restricciones, y no se adaptan correctamente a ciertos tipos de sistemas como los adaptativos, los basados en líneas de productos y los embebidos. Este artículo (i) presenta algunas evidencias de las debilidades de la plantilla recomendada por el IREB® (International Requirements Engineering Institute) conocida como plantilla Rupp, y (ii) sienta las bases para la construcción de una mejor plantilla que facilite el trabajo de los ingenieros de requisitos y que a la larga mejore la calidad de los nuevos productos. Para ello, la plantilla Rupp fue empleada en la especificación de requisitos de un producto de software para la gestión de recursos humanos de una compañía de tecnología en la ciudad de Medellín-Colombia. En esta experiencia encontramos que algunos requisitos no podrían ser escritos correctamente usando dicha plantilla. Basados en la evidencia recolectada en este caso, este artículo presenta una versión mejorada de la plantilla Rupp que permite escribir correctamente todos los requisitos analizados. A pesar de los resultados prometedores de la validación de esta nueva plantilla, es aún un trabajo preliminar y no concluyente con respecto a su cobertura o al nivel de calidad de los requisitos que se pueden escribir con ella. Palabras Clave: Requisitos, Ingeniería de requisitos, lenguaje natural, plantilla. 1. Introducción Los requisitos son quizás la base más importante en la construcción de productos de software porque a través de éstos se puede lograr un entendimiento común entre las partes interesadas sobre el sistema que se va a implementar. Según Wiegers & Beatty [1], los dos objetivos más importantes en la especificación de un requisito son (i) que cuando varias personas lean el requisito lleguen a la misma interpretación; y (ii) la interpretación de cada lector coincida con lo que el autor del requisito intentaba comunicar. En este sentido, Pohl [2] sostiene que el Lenguaje Natural (LN) es la forma más común de comunicar y documentar los requisitos de un sistema, puesto que el LN es universal y está al alcance de cualquier individuo en cualquier ámbito; además, no

Wind erosion is an important soil degradation process on agricultural fields in the Sahel and is strongly affected by scattered woody vegetation. This paper analyses the effect of scattered vegetation on sediment transport in agricultural fields in northern Burkina Faso. A model was developed to simulate the changes in wind speed and sediment transport around shrubs and trees. The model was applied by using field measurements on wind speed, wind direction, and sediment transport, obtained from two farmers' fields during the rainy season of 2003. Vegetation characteristics and the density of vegetation elements differed per field. The model was used for scenario studies to test the effect of height, number, element type and spatial arrangement of vegetation elements on aeolian sediment transport. The local effects of vegetation elements on wind speed and sediment transport are small compared with the effects caused by the changes in the aerodynamic roughness length and changing wind speed at a larger scale. With relatively small changes in the characteristics of scattered woody vegetation, sediment transport can change considerably. An optimal arrangement of vegetation elements in an area in itself does not exist; it is an interrelation between the number of vegetation elements, the silhouette area and the type of vegetation elements present. This interrelation makes the use of scattered vegetation as a wind erosion control strategy attractive, as it fits in a variety of farming systems and can easily be adapted to specific needs of farmers. Therefore, scattered woody vegetation can be used to reduce sediment transport. Copyright © 2014 John Wiley & Sons, Ltd.

Dune slacks are important habitats, with many endangered plant species. A series of eleven dune slacks of 1–42 years old was studied in SW-Texel, the Netherlands, with the EU-habitat directive species Liparis loeselii present in all except the youngest and oldest. Analysis of aerial photographs revealed that new slacks are currently formed every 4–5 years. In each slack, topsoil and vegetation data were collected in 2010 and 2014–2015. During succession, vegetation changed from brackish pioneer stages to dune slacks with L. loeselii and Parnassia palustris and ultimately grassland species. Differences between dune slacks and sampling periods were mostly significant. Herb cover and soil C increased with slack age, and over the five year study period, while bare sand, bulk density and pH decreased. The annual pH-decrease was 0.055 and 0.075 for pH-H2O and pH-KCl respectively, and annual C-increase 0.16% and 35 g m-2. Liparis loeselii was only present between pHH2O 5.8–7.5 and pHKCl 5.6–7.6, and only occurred at C-content below 4.3%. In lime-poor dunes, environmental conditions thus become unsuitable approximately 34 years after the start of succession. In the dune slacks, Liparis loeselii established within 6 years, showed peak values after 11–16 years, and declined until conditions became unsuitable. Rejuvenation may occur after large storms with fresh sand deposits. However, even with further succession, the present populations are not endangered and probably last until 2040. With new dune slacks every 5 years, L. loeselii occurs in approximately eight different dune slacks at the same time, ensuring viable populations also in the future. This shows that adverse effects of succession can be counteracted by dynamics on local and landscape scale.

A paucity of empirical non‐marine data means that uncertainty surrounds the impact of climate change on terrestrial ecosystems in tropical regions beyond the last glacial period. The sedimentary fill of the Bosumtwi impact crater (Ghana) provides the longest continuous Quaternary terrestrial archive of environmental change in West Africa, spanning the last ∼1.08 million years. Here we explore the drivers of change in ecosystem and climate in tropical West Africa for the past ∼540 000 years using pollen analysis and the nitrogen isotope composition of bulk organic matter preserved in sediments from Lake Bosumtwi. Variations in grass pollen abundance (0−99%) indicate transitions between grassland and forest. Coeval variations in the nitrogen isotopic composition of organic matter indicate that intervals of grassland expansion coincided with minimum lake levels and low regional moisture availability. The observed changes responded to orbitally paced global climate variations on both glacial–interglacial and shorter timescales. Importantly, the magnitude of ecosystem change revealed by our data exceeds that previously determined from marine records, demonstrating for the first time the high sensitivity of tropical lowland ecosystems to Quaternary climate change.

Three restoration strategies on agricultural fields with acid sandy soil were evaluated after 18 and 25 years: conversion to heathland, rangeland and forest. Changes in soil microstructure, chemical characteristics, availability of N and P, and vegetation composition were analyzed in agricultural soils, three undisturbed reference sites and five types of restored former agricultural fields.Agricultural soils were characterized by organic slurry without much soil life. Soil nutrients were especially high for P, mostly in mineral form, and P-desorption rates were high. Partial and complete topsoil removal, aiming at heathland restoration, led to (much) lower soil organic matter and nutrients, but not to recovery of soil life, nor to P-limited soils. Heather was accompanied by many grassland species, even with complete topsoil removal. Conversion to rangeland did not decrease nutrient stocks, but led to improved soil life, although different from reference grasslands due to the higher pH. P-availability remained high, but net N-mineralization and plant N-content were clearly lower after 25 than after 18 years. Plant diversity was relatively high, and cover of eutrophic grasses decreased to 8–39% in intermediate and productive rangelands. Nutrient-poor species remained absent, but the slightly higher pH improved conditions for many grassland herbs. Afforestation did also not lead to nutrient-poor conditions, but soil life clearly increased and nutrients were used for rapid tree growth. Undergrowth species however remained eutrophic.It was impossible to retrieve the P-limited reference ecosystems within 25 years of restoration, not even with complete topsoil removal. Differences in plant diversity between expensive topsoil removal and much cheaper conversion to rangeland were also relatively small. For restoration on a landscape scale, it may thus be better to focus on conversion to semi-natural grasslands and afforestation. The half-open, nutrient-, mineral-, and species-rich landscape offers opportunities for large grazers, but also for many insects and birds.

The Uddelermeer is a unique lake for The Netherlands, containing a sediment record that continuously registered environmental and climatic change from the late Pleistocene on to the present. A 15.6-m-long sediment record was retrieved from the deepest part of the sedimentary basin and an age–depth model was developed using radiocarbon dating, 210Pb dating, and Bayesian modeling. Lake-level change was reconstructed using a novel combination of high-resolution palaeoecological proxies (e.g. pollen, non-pollen palynomorphs, chironomids), quantitative determinations of lake-level change (ground-penetrating radar), and estimates of changes in precipitation (lipid biomarker stable isotopes). We conclude that lake levels were at least as high as present-day water levels from the late glacial to 3150 cal. yr BP, with the exception of at least one lake-level lowstand during the Preboreal period. Lake levels were ca. 2.5 m lower than at present between 3150 and 2800 cal. yr BP, which might have been the result of a change in moisture source region prior to the so-called 2.8-kyr event. Increasing precipitation amounts around 2800 cal. yr BP resulted in a lake-level rise of about 3.5–4 m to levels that were 1–1.5 m higher than at present, in line with increased precipitation levels as inferred for the 2.8-kyr event from nearby raised bog areas as well as with reconstructions of higher lake levels in the French Alps, all of which have been previously attributed to a phase of decreased solar activity. Lake levels decreased to their present level only during recent times, although the exact timing of the drop in lake levels is unclear.

Plaggic Anthrosols are the result of historical forms of land management in cultural landscapes on chemically poor sandy substrates. Application of plaggic manure was responsible for the development of the plaggic horizons of these agricultural soils. Pollen diagrams reflect aspects of the environmental development but the interpretation of the pollen spectra is complicated due to the mix of the aeolian pollen influx of crop species and species in the surroundings, and of pollen occurring in the used stable fillings. Pollen diagrams and radiocarbon dates of plaggic Anthrosols suggested a development period of more than a millennium. Calluna is present in almost all the pollen spectra, indicating the presence of heath in the landscape during the whole period of soil development. Optically stimulated luminescence dating of the plaggic horizon made clear that the deposition of plaggic covers started in the 16th century and accelerated in the 18th century. The stable fillings, used for the production of plaggic manure and responsible for the rise of the soil surface, cannot be identified with pollen diagrams alone. Biomarker analyses provide more evidence about the sources of stable fillings. The oldest biomarker spectra of the plaggic horizons of three typical plaggic Anthrosols examined in this study were dominated by biomarkers of forest species such as Quercus and Betula while the spectra of middle part of the plaggic horizons were dominated by biomarkers of stem tissue of crop species such as Secale and Avena. Only the youngest spectra of the plaggic horizons were dominated by biomarkers of Calluna. This indicates that the use of heath sods as stable filling was most likely introduced very late in the development of the Anthrosols. Before the 19th century the mineral component in plaggic manure cannot be explained by the use of heath sods. We conclude that other sources of materials, containing mineral grains must have been responsible for the raise of the plaggic horizon.

1. Little is known regarding the long‐term stability or instability of Amazonian plant communities.2. We assessed whether the most abundant species, hyperdominants, may have risen to prominence at the Pleistocene–Holocene transition, following subsequent changes in moisture regimes, or as a result of human activity later in the Holocene.3. The fossil pollen history of the commonest western Amazonian tree, Iriartea deltoidea (hereafter Iriartea), is investigated using fossil pollen data from 13 lakes. Iriartea is a monospecific genus with diagnostic pollen. It is also considered a ‘useful’ plant, and its abundance could have been enriched by human action.4. Iriartea pollen was found to have increased in abundance in the last 3000 years, but did not show a consistent relationship with human activity.5. The suggestion that the hyperdominants in modern Amazonian forests are a legacy of pre‐Columbian people is unsupported.6. The abundance of Iriartea pollen is related to increasing precipitation, not human activity over the last 3000 years. This member of the hyperdominant category of Amazonian trees has only recently acquired this status.7. Synthesis. Our findings are consistent with the observation that communities in complex systems are ephemeral. The populations of even the most abundant species can change over a few tens of generations. The relative abundance of tree species, even in relatively stable systems such as those of Amazonian floodplains, changes on ecological not evolutionary timescales.

Presented here is the first chironomid calibration data set for tropical South America. Surface sediments were collected from 59 lakes across Bolivia (15 lakes), Peru (32 lakes), and Ecuador (12 lakes) between 2004 and 2013 over an altitudinal gradient from 150mabove sea level (a.s.l) to 4655ma.s.l, between 0-17° S and 64-78°W. The study sites cover a mean annual temperature (MAT) gradient of 25 °C. In total, 55 chironomid taxa were identified in the 59 calibration data set lakes. When used as a single explanatory variable, MAT explains 12.9% of the variance (λ1=λ2 =1.431). Two inference models were developed using weighted averaging (WA) and Bayesian methods. The best-performing model using conventional statistical methods was a WA (inverse) model (R2 jack =0.890; RMSEPjack =2.404 °C, RMSEP-root mean squared error of prediction; mean biasjack =-0.017 °C; max biasjack =4.665 °C). The Bayesian method produced a model with R2 jack =0.909, RMSEPjack =2.373 °C, mean biasjack =0.598 °C, and max biasjack =3.158 °C. Both models were used to infer past temperatures from a ca. 3000-year record from the tropical Andes of Ecuador, Laguna Pindo. Inferred temperatures fluctuated around modern-day conditions but showed significant departures at certain intervals (ca. 1600 cal yr BP; ca. 3000-2500 cal yr BP). Both methods (WA and Bayesian) showed similar patterns of temperature variability; however, the magnitude of fluctuations differed. In general the WA method was more variable and often underestimated Holocene temperatures (by ca.-7±2.5 °C relative to the modern period). The Bayesian method provided temperature anomaly estimates for cool periods that lay within the expected range of the Holocene (ca.-3±3.4 °C). The error associated with both reconstructions is consistent with a constant temperature of 20 °C for the past 3000 years. We would caution, however, against an over-interpretation at this stage. The reconstruction can only currently be deemed qualitative and requires more research before quantitative estimates can be generated with confidence. Increasing the number, and spread, of lakes in the calibration data set would enable the detection of smaller climate signals. © 2016 Author(s)., Funding was provided by the Natural Environment Research Council (NERC) UK, and the National Aeronautics and Space Administration (NASA) NNX14AD31G. NERC grants were awarded to E. Montoya (ref: NE/J018562/1) and F. Matthews-Bird (ref: NE/J500288/1). This work was supported by the NERC Radiocarbon Facility NRCF010001 (allocation number 1682.1112)

Land-use change occurs nowhere more rapidly than in the tropics, where the imbalance between deforestation and forest regrowth has large consequences for the global carbon cycle(1). However, considerable uncertainty remains about the rate of biomass recovery in secondary forests, and how these rates are influenced by climate, landscape, and prior land use(2-4). Here we analyse aboveground biomass recovery during secondary succession in 45 forest sites and about 1,500 forest plots covering the major environmental gradients in the Neotropics. The studied secondary forests are highly productive and resilient. Aboveground biomass recovery after 20 years was on average 122 megagrams per hectare (Mg ha(-1)), corresponding to a net carbon uptake of 3.05 Mg C ha(-1) yr(-1), 11 times the uptake rate of old-growth forests. Aboveground biomass stocks took a median time of 66 years to recover to 90% of old-growth values. Aboveground biomass recovery after 20 years varied 11.3-fold ( from 20 to 225 Mg ha(-1)) across sites, and this recovery increased with water availability (higher local rainfall and lower climatic water deficit). We present a biomass recovery map of Latin America, which illustrates geographical and climatic variation in carbon sequestration potential during forest regrowth. The map will support policies to minimize forest loss in areas where biomass resilience is naturally low (such as seasonally dry forest regions) and promote forest regeneration and restoration in humid tropical lowland areas with high biomass resilience.

Pollen and non-pollen palynomorphs (NPP) from the Early Neolithic settlement of La Draga have provided new palaeoenvironmental data concerning the establishment of the first farming societies in NE Iberian Peninsula. The analysis of samples from the archaeological profiles allowed the comprehension of several processes involved in the formation of this archaeological site and the reconstruction of environmental conditions in the different phases of occupation, in addition to obtaining new data about the ecological significance of NPP in archaeological levels. New NPP have been described, illustrated, and discussed.The first farming societies settled at La Draga in a humid and densely forested area, with the predominance of deciduous trees (deciduous Quercus and Corylus) and Pinus and Abies in the surrounding mountains. Following their establishment at the site, abrupt changes in vegetation are recorded, in terms of deforestation of oak and riparian forests. Sedimentation dynamics involved in the formation of the archaeological site influenced the composition of the NPP spectra, reflected in the contraposition between waterlogged and subaerial layers, but especially, between organic peaty layers formed at local level and sediments transported by erosive processes in the layers belonging to the second phase of occupation.

Bacteria and fungi are important micro-organisms in the soil, but may differ in their impact on net N-mineralization. The hypothesis was tested that fungi are characterized by low microbial activity, but also low immobilization, and bacteria by high activity and high immobilization. A one-month laboratory incubation experiment with selective inhibition of fungi (cycloheximide) or bacteria (streptomycin) was conducted with samples of organic layer and mineral topsoil (0-10. cm) from neutral, bacteria-dominated and acidic, fungi-dominated Luxembourg beech forests. In the control treatment, respiration was higher in neutral than in acidic soil, but net N-mineralization was lower, due to higher immobilization. In the antibiotic treatments, differences in nitrification suggest that selective inhibition indeed occurred; in all soils and horizons, nitrification was especially limited by bactericide. Besides as inhibitor of the target group, antibiotics may also serve as source of C and N for the non-target group. For both bactericide and fungicide, acidic soils showed higher net recovery of C and N from antibiotics than neutral soil, which suggests that uptake or sorption of antibiotics is higher in the latter. Clear differences between neutral and acidic soils arose when the main micro-organisms were stimulated. In bacteria-dominated neutral soil, application of fungicide led to increased microbial respiration. In fungi-dominated acidic soil, however, application of bactericide did not lead to higher respiration, but to increased net N-mineralization per unit respiration, which supports a lower immobilization. Differences between antibiotics were consistent for organic layer and mineral topsoil, with increase in activity with fungicide, and lower immobilization with bactericide. The results provide correlative and experimental evidence that reduced immobilization by fungi compensates for their lower rates of activity with respect to N-availability to the vegetation.

Highlights: • 18 southern European charcoal records document 16,000 years of fire regime changes. • Since the Neolithic, land uses have artificially maintained high fire frequencies. • Human-induced decreases in forest cover led to a reduction in the biomass burned. • Human-modified landscapes affected ecological processes more meaningly than expected. Abstract: Variability in fire regime at the continental scale has primarily been attributed to climate change, often overshadowing the widely potential impact of human activities. However, human ignition modifies the rhythm of fire episodes occurrence (fire frequency), whereas land use alters vegetation composition and fuel load, and thus the amount of biomass burned. It is unclear, however, whether and how humans have exercised a significant influence over fire regimes at continental and millennial scales. Based on sedimentary charcoal records, we use new alternative estimate of fire frequency and biomass burned for the last 16000 years (here after 16 ky) that we evaluate with outputs from climate, vegetation, land use and population models. We find that pronounced regional-scale land use changes in southern Europe at the beginning of the Neolithic (8–6 ky), during the Bronze Age (5–4 ky) and the medieval period (1 ky) caused a doubling of fire frequency compared to the Holocene average (the last 11.5 ky). Despite anthropogenic influences, southern European biomass burned decreased from 7 ky, which is in line both with changes in orbital parameters leading climate cooling and also reductions in biomass availability because of land use. Our study underscores the role of elevation-dependent parameters, and particularly biomass and land management, as major drivers of fire regime variability. Results attest a determinant anthropogenic driving-force on fire regime and a decrease in fire-carbon emissions since 7 ky in Southern Europe.

The newly updated inventory of palaeoecological research in Latin America offers an important overview of sites available for multi-proxy and multi-site purposes. From the collected literature supporting this inventory, we collected all available age model metadata to create a chronological database of 5116 control points (e.g. 14C, tephra, fission track, OSL, 210Pb) from 1097 pollen records. Based on this literature review, we present a summary of chronological dating and reporting in the Neotropics. Difficulties and recommendations for chronology reporting are discussed. Furthermore, for 234 pollen records in northwest South America, a classification system for age uncertainties is implemented based on chronologies generated with updated calibration curves. With these outcomes age models are produced for those sites without an existing chronology, alternative age models are provided for researchers interested in comparing the effects of different calibration curves and age–depth modelling software, and the importance of uncertainty assessments of chronologies is highlighted. Sample resolution and temporal uncertainty of ages are discussed for different time windows, focusing on events relevant for research on centennial- to millennial-scale climate variability. All age models and developed R scripts are publicly available through figshare, including a manual to use the scripts.

We present a record of environmental and climatic changes in the northern Andes during the penultimate interglacial-glacial cycle based on integrated information from pollen and grain size distributions (GSDs). The record reflects the 58.33-26.21 m interval of a new sediment core from Lake Fúquene (2540 m elevation; 5°N) in the Colombian Andes. The age model is mainly based on cyclostyratigraphy and shows that this core interval reflects the period from 284 to 130 ka. The 1 cm sample increments yield a resolution of ~ 60 yr. In 2553 samples we analyzed 66 selected pollen and spore taxa with the best known ecological ranges. We reconstructed upper forest line (UFL) positions between ~ 2000 and ~ 3400 m elevation and the most abrupt temperature shifts ranged up to 10 °C/100 yr at Terminations II and III. Regional vegetation change is mainly driven by eccentricity (100 kyr) and obliquity (41 kyr) cycles, while changes in local aquatic vegetation show variability in the obliquity and precession (21 kyr) bands. Millennial-scale climate variability reflecting Dansgaard-Oeschger (DO) climate cycles in the upper part of the record, continues in this penultimate intergalcial-glacial cycle strongly suggesting that this variability has a persistent character in Pleistocene vegetation and climate dynamics. Short-lived upslope excursions of the UFL reflect 20 DO-style cycles during marine isotope stages (MIS) 7 and 6. Changes in species composition of montane forest are evident, and trees with most pioneer qualities (Alnus, Morella, Quercus and Weinmannia) migrated at the forefront. Other arboreal taxa like Podocarpus, Miconia, and Hedyosmum mostly followed later. Changes in regional vegetation distribution and forest composition, as well as in local aquatic vegetation and GSD of sediments supplied to the lake, allowed the development of an integrated reconstruction of the biotic and abiotic environments in the drainage basin.

The uniform morphology of different species of Poaceae (grass) pollen means that identification to below family level using light microscopy is extremely challenging. Poor taxonomic resolution reduces recoverable information from the grass pollen record, for example, species diversity and environmental preferences cannot be extracted. Recent research suggests Fourier Transform Infra-red Spectroscopy (FTIR) can be used to identify pollen grains based on their chemical composition. Here, we present a study of twelve species from eight subfamilies of Poaceae, selected from across the phylogeny but from a relatively constrained geographical area (tropical West Africa) to assess the feasibility of using this chemical method for identification within the Poaceae family. We assess several spectral processing methods and use K-nearest neighbour (k-nn) analyses, with a leave-one-out cross-validation, to generate identification success rates at different taxonomic levels. We demonstrate we can identify grass pollen grains to subfamily level with an 80% success rate. Our success in identifying Poaceae to subfamily level using FTIR provides an opportunity to generate high taxonomic resolution datasets in research areas such as palaeoecology, forensics, and melissopalynology quickly and at a relatively low cost.

Soil studies commonly comprise the uppermost meter for tracing, e.g., soil development. However, the maximum rooting depth of various plants significantly exceeds this depth. We hypothesized that deeper parts of the soil, soil parent material and especially paleosols provide beneficial conditions in terms of, e.g., nutrient contents, thus supporting their utilization and exploitation by deep roots. We aimed to decipher the different phases of soil formation in Dutch drift sands and cover sands. The study site is located at Bedafse Bergen (southeastern Netherlands) in a 200-year-old oak stand. A recent Podzol developed on drift sand covering a Plaggic Anthrosol that was piled up on a relict Podzol on Late Glacial eolian cover sand. Root-free soil and sediment samples, collected in 10–15 cm depth increments, were subjected to a multi-proxy physical and geochemical approach. The Plaggic Anthrosol revealed low bulk density and high phosphorous and organic carbon contents, whereas the relict Podzol was characterized by high iron and aluminum contents. Frequencies of fine (diameter ≤ 2 mm) and medium roots (2–5 mm) were determined on horizontal levels and the profile wall for a detailed pseudo-three-dimensional insight. On horizontal levels, living roots were most abundant in the uppermost part of the relict Podzol with ca. 4450 and 220 m−2, significantly exceeding topsoil root abundances. Roots of oak trees thus benefited from the favorable growth conditions in the nutrient-rich Plaggic Anthrosol, whereas increased compactness and high aluminum contents of the relict Podzol caused a strong decrease of roots. The approach demonstrated the benefit of comprehensive root investigation to support interpretation of soil profiles, as fine roots can be significantly underestimated when quantified at the profile wall. The possible rooting of soil parent material and paleosols long after their burial confirmed recent studies on the potential influence of rooting to overprint sediment–(paleo)soil sequences of various ages, sedimentary and climatic settings. Potential consequences of deep rooting for terrestrial deep carbon stocks, located to a relevant part in paleosols, remain largely unknown and require further investigation.

In the Quaternary palynological literature, the name Diporotheca rhizophila has come to be applied for fungal spores labelled in the Hugo de Vries-Laboratory (HdV) in Amsterdam (The Netherlands) as Type HdV-143. The widespread occurrence of this taxon in palynological preparations was difficult to understand as the species is definitely known only from Solanum species in Washington State in the USA. Comparison of spores found in palaeoecological and forensic samples with those of the original material (holotype) of D. rhizophila established that the name had been misapplied. Type HdV-143 is distinguished from the holotype by the shape, size, and ornamentation of the ascospores. The spores in the palaeoecological material are navicular to fusiform, and not oval when mature. They develop robust, dark brown, anastomosed ridges from an early stage, and are much longer, measuring 44–59 μm and not 25–37 μm in length. Similarities in spore structure and development indicate that both can be accommodated in the same genus, but as different species. The specimens from palynological preparations are described here as D. webbiae sp. nov. Circumstantial evidence, gained from palaeoecological analysis, suggests that the new species may be associated with the fern genus Thelypteris, and today occurs most commonly in wet Alnus carr. Similar spores have been reported from the pre-Quaternary fossil record under the generic name Striadiporites.

International audience; Progresses in reconstructing Earth's history of biomass burning has motivated the development of a modern charcoal dataset covering the last decades through a community-based initiative called the Global Modern Charcoal Dataset (GMCD). As the frequency, intensity and spatial scale of fires are predicted to increase regionally and globally in conjunction with changing climate, anthropogenic activities and land-use patterns, there is an increasing need to further understand, calibrate and interrogate recent and past fire regimes as related to changing fire emissions and changing carbon sources and sinks. Discussions at the PAGES Global Paleofire Working Group workshop 2015, including paleoecologists, numerical modelers, statisticians, paleoclimatologists, archeologists, and anthropologists, identified an urgent need for an open, standardized, quality-controlled and globally representative dataset of modern sedimentary charcoal and other sediment-based fire proxies. This dataset fits into a gap between metrics of biomass burning indicators, current fire regimes and land cover, and carbon emissions inventories. The dataset will enable the calibration of paleofire data with other modern datasets including: data of satellite derived fire occurrence, vegetation patterns and species diversity, land cover change, and a range of sources capturing biochemical cycling. Standardized protocols are presented for collecting and analyzing sediment-based fire proxies, including charcoal, levoglucosan, black carbon, and soot. The GMCD will provide a publically-accessible repository of modern fire sediment surface samples in all terrestrial ecosystems. Sample collection and contributions to the dataset will be solicited from lacustrine, peat, marine, glacial, or other sediments, from a wide variety of ecosystems and geographic locations.

The research was funded by a grant from the National Science Centre (Poland) (No 2015/17/B/ST10/01656). The work was also made in the framework of the National Programme of Development of Humanities project (No 2bH15015483) as well as budgetary sources for scientific activity in 2016–2019, project number 0342/IP1/2016/74. V.E.J.J. was supported by the French National Research Agency (MIXOPEAT project, grant number ANR-17-CE01–0007). We thank Julie Loisel help with the calculation of the peat carbon accumulation rates. We thank also Jerzy Sikora and Pawel Zawilski for defining the chronology of the potsherd found during field surveys in the Gleboczek vicinity, and Sambor Czerwinski for constructing the lidar terrain map of the study area.

The importance of human impacts on Earth has led to the proposal of a new geologic epoch called the Anthropocene. However markers, recognizable in all records, are required to define this period. Here we combine elemental geochemistry with stable lead (Pb) isotopes and mineralogical analyses to decipher the sources of lead in two exploited ombrotrophic peat bogs (Puścizna Mala and Puścizna Krauszowska) from Southern Poland. The most disturbed parts of the cores, distinguished using bulk density and age–depth models (22–45 cm in PM and 22–46 cm in PK), were excluded from the interpretation. The two studied cores record ca. 2000 years of variations in lead accumulation rates and isotopic compositions. In the lowest part of the cores (2nd to 4th century AD for Puścizna Mala and 2nd century BC to 2nd century AD for Puścizna Krauszowska), the 206Pb/207Pb ratios (1.188) are consistent with natural supplies from the erosion of the nearby Tatra Mountains. From the 9th to the 19th century AD, 206Pb/207Pb ratios (1.176–1.179) are similar to the signatures obtained from Polish galena ores. The highest Pb accumulation rates are found around 1950 AD and reflect the primary influence of bituminous coal combustion together with the secondary influence of leaded gasoline. This result agrees with the occurrence and abundance of spheroidal aluminosilicates, an unambiguous marker of human industrial activity and coal burning as well as with the acceleration of Zn, Cd and Fe accumulation rate. Our results provide evidence that similar geochemical patterns exist in both analysed cores despite differences in the history of peatland exploitation. Therefore, given that extra care is taken to identify the disturbed peat layers, exploited peatlands can be used to record past changes in lead isotopic signature during the Anthropocene.

Patterns of fire are changing across African savannahs, rainforests, fynbos, woodlands, and Afroalpine and montane forests, with direct environmental and socio-ecological consequences. Fire variability has implications for biodiversity (Beale et al. 2018), vegetation patterns, grazing quality, carbon emissions, protected area management, and landscape heterogeneity. Fire is a crucial component of savannah functioning and structure and is essential for maintaining its biodiversity. Long-term records are key to understanding drivers of fire variability and contextualize recent and ongoing land-use changes that altered fire responses to climate and vegetation changes (e.g. Ekblom and Gillson 2010, Colombaroli et al. 2014). As indigenous forest loss continues and modification through selective harvesting and land-use encroachment accelerate forest changes, the importance of historical disturbance regimes is increasingly relevant for assessing past ranges of variability and to define management targets that support more resilient socioecological systems (Whitlock et al. 2018). But how can the research community engage and integrate with land-management practitioners and policy developers? And how can we promote knowledge transfer and collaborative capacity between the international community and the next generation of African scientists?

Typically for the geomorphology of the Luxembourger Gutland is the occurrence of mardels, a local name for small closed depressions. They occur on various substrates and can have a natural or anthropogenic genesis. In general, mardels on the Strassen marls are abandoned quarries, related to historical clay extraction, and mardels on the Luxembourger sandstone are sinkholes, related to joint patterns. Probably, most of the mardels on the Keuper marls are also abandoned quarries but some of them have a natural genesis as subsidence basins related to subsurface dissolutions of gypsum lenses, present in the marl deposits. During the Late Holocene the mardels became filled with colluvial deposits. The pollen records documented in these deposits can be correlated to Subatlantic climatic oscillations and correspond to changes in the rate of soil erosion and land management. In particular, the Little Ice Age stands out as a period with increased denudation and temporary extension of arable land.

The Oregon white oak savanna, once common in Oregon's Willamette Valley, has been reduced to less than 1% of its former extent. For ecological restoration purposes, we used phytolith analysis to establish both historical vegetation composition and structure at the Jim's Creek research site in Oregon, USA. We sampled the soil at 47 selected plots, extracted the phytoliths, and determined the composition of the phytolith assemblages. Based on the ratios of grass and tree phytoliths in the samples, each site was assigned to one of three ecotopes that, through phytoliths, describe the historic vegetation mosaic. By reconstructing the spatial distribution of historic vegetation types, we were able to confirm the pattern of conifer encroachment on former savanna as suggested by other studies.

Sabinaria magnifica is so far the only known species in the recently discovered tropical palm genus Sabinaria (Arecaceae). Here we present a complete description of the pollen morphology of this palm species based on light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We also made SEM-based comparisons of Sabinaria with other genera within the tribe Cryosophileae. Pollen grains of Sabinaria magnifica resemble the other genera in the heteropolar, slightly asymmetric monads, and the monosulcate and tectate exine with perforate surface. Nevertheless, there are some clear differences with Thrinax, Chelyocarpus and Cryosophila in terms of aperture and exine. S. magnifica differs from its closest relative, Itaya amicorum, in the exine structure. This study shows that a combination of microscope techniques is essential for the identification of different genera within the Cryosophileae and may also be a necessary when working with other palynologically less distinct palm genera.

This paper presents the result of palynological research of peat relicts, found in the Westerkoggepolder (North-Holland, The Netherlands). In general, such relicts of peat in the actual landscape point to an extensive peat cover in the past that disappeared due to land reclamation and agricultural management. Improvement of the drainage in historical time resulted in shrinkage and bio-oxidation of peat. This caused a land surface lowering of at least 3 m and a transformation of Histosols in original peat deposits into eluvial clay covers with Mollic Gleysols. Similar processes occur in other regions in the world were people settled in areas with histosols and reclaimed land for food production. The last relicts of the former peat cover are valuable parts of the national soil archives and deserve the status of geoheritage.

Podzolation is the dominant soil forming process in chemical poor sandy soils. It is well studied how iron concentrations of podzols are effected by translocation of active iron from eluvial to illuvial horizons and leaching to the aquifer. Iron stocks of Podzols, in contrasts, have not been widely studied for comparison purposes of individual soil horizons or between soils. In this study we provide an analysis of the iron stocks for two buried Podzols developed in Late-Glacial aeolian coversands. Chemical analyses of the active and immobile iron fractions in each of the horizons in both profiles show that more iron has been involved in the podzolation process, than the amount which can be derived by chemical weathering of minerals in the overlying soil horizons. This deficit in endogenic iron therefore requires exogenic enrichment to explain the observed iron concentrations during podzolation. The contribution of exogenic iron was studied using micrometeorites as a proxy for atmospheric deposition. These particles of cosmic origins are part of a continuous flux of iron-rich materials into the Earth's atmosphere and they are deposited over time on every square meter of land surface. Their extraction from ectorganic F horizon of initial Podzols helped illustrate that atmospheric deposition in the form of aerosol and aeolian (e.g. Sahara) dust, micrometeorites and other hydrolysable particles are a relevant iron contribution in soil development. The requisite active iron for podzolation can therefore be derived from chemical weathering of atmospheric iron sources in the acidic soil environment.

We present a phytosociological overview of the arid and semi-arid montane vegetation of the province of Arequipa in southern Peru. The xerophytic vegetation was studied after extreme rainfall had promoted exceptionally lush vegetation and a high aboveground floristic diversity. We used TWINSPAN for classification and Detrended Correspondence Analysis for gradient analysis of our relevés. PC-ORD was used to show the hierarchical similarity structure of the syntaxa, and to compare them with related communities in Peru and surrounding countries from literature. We present a synoptic table, and describe the physiognomy, floristic composition, ecology and spatial distribution of the plant communities. In total, we recorded 187 plant species, including 50 endemics, in 196 phytosociological relevés distributed over 2030 km2 at an elevation between 2020 and 3260 m a. s. l. The relevés were assigned to three alliances in the class Opuntietea sphaericae. The vegetation consists mainly of native species of trees, shrubs, grasses, succulents, annual herbs, and ferns. The most diverse families were Asteraceae, Cactaceae, Solanaceae, Malvaceae, Boraginaceae, Fabaceae, Poaceae, Amaranthaceae and Pteridaceae. Within the class Opuntietea sphaericae, three alliances have been distinguished of which two are new. The Ambrosio artemisioidis-Weberbauerocerion weberbaueri comprising six associations was recorded on barren hillsides between 2000 and 2900 m a. s. l. in the Arequipa city boundary zones. The Corryocaction brevistyli defines xerophytic scrub between 2700 and 3200 m a. s. l. in semi-dry regions bordering the puna grasslands. It contains the Balbisio weberbaueri-Ambrosietum artemisioidis and the Aloysio spathulatae-Corryocactetum brevistyli, all in need of further investigation as they lack diagnostic species. A unit clearly distinguished by Weberbauerocereus rauhii and Neoraimondia arequipensis is here described as a new alliance, Neoraimondio arequipensis-Weberbauerocerion rauhii. It grows in inter-Andean valleys in dry regions (1100– 2200 m a. s. l.), with abundant cacti accompanied by few xerophytes.

article i nfo In this study, we present a record spanning the last 4000 years from a Baltic bog (Kusowskie Bagno) in northern Poland. Using numerous biotic and abiotic proxies, such as testate amoebae (depth to water table reconstruc- tions), stable carbon isotopes ( 13 C), plant macrofossils (proxies for local vegetation and mire surface wetness), pollen and spores (proxies for regional vegetation and human impact), we reconstructed and identified the re- gional hydro-climatic signal of Kusowskie Bagno bog and compared it to other bog records around the Baltic Sea. Our aims were to: 1) combine the species traits of bryophytes and testate amoebae, and more common proxies (isotopes, plant micro-and macro-remains) to infer past peatland development, 2) compare the hydro- climatic signal of Kusowskie Bagno bog to existing records around the Baltic Sea. We found that Kusowskie Bagno bog was very wet during the last 4000 years, and even drainage and peat exploitation had not disturbed its hydrology in northern part in the last 200 years. Carbon isotopes and plant macrofossils were significantly re- latedtospecifictraitsoftestateamoebae,whichinturnreflectedthewatertablechangesoverthelast4000years. Kusowskie Bagno recorded at least the following wet shifts: AD 250, 550, 850, 1250 and 1700, while wet condi- tions occurred during the Migration period at ca AD 550. Furthermore, the testate amoeba-based quantitative wetness reconstruction in Kusowskie Bagno bog resembles the pattern observed in other sites around the Baltic, i.e.,Estonia,Finland,Ireland,northernBritainandthe7500-yearrecordfromthe Stązkibog,northern Poland.Our results provided statistically validated evidence that interactions between plant and microbe need to be more considered further to reconstruct past hydrological. This is the first study of past hydro-climatic changes in peatlands based upon a trait-based approach.

The phytosociology and ecology of puna vegetation in twelve localities at an altitude of 3750–4500 m in northern Moquegua (south Peru) have been studied. The study area has a pluviseasonal climate with summer rainfall. Using TWINSPAN, Detrended Correspondence Analysis and Farthest Neighbor Clustering, 157 phytosociological relevés were analyzed. For each community, the syntaxonomy, floristic diversity and relation with environmental variables are discussed. 210 vascular plant species belonging to 131 genera and 52 families were recorded. Three main vegetation types were distinguished: 1. chasmophyte vegetation composed of a great diversity of shrubs, dwarf shrubs, ferns and annuals, 2. Puya raimondii stands characterized by considerable species richness in shrubs, grasses and herbs, and 3. extensive puna grasslands influenced by grazing. The zonal vegetation of the supratropical and orotropical bioclimatic belts was represented by two phytosociological classes: Argyrochosmetea niveae (chasmophytes) and Calamagrostietea vicunarum (Puya raimondii and puna grasslands). Within the Argyrochosmetea niveae and Salpichroetalia glandulosae, the new alliances Argyrochosmo niveae-Neowerdermannion peruvianae and Hypochaerido mucidae-Loricarion graveolentis were distinguished, including six associations consisting of steep rock and crevice shrublands on lithosols. Within the Azorello compactae-Festucion orthophyllae (Calamagrostietea vicunarum) two associations with four subassociations and two communities were distinguished comprising grasslands and Puya raimondii stands. One association was described in the Calamagrostion minimae. The puna vegetation of Moquegua hosts rare, endangered and/or protected plant species in Peru. The vulnerability of the flora and vegetation in the mountains of Moquegua is briefly discussed.

Since the re-establishment of a more natural water regime is considered by water management in wetlands with artificially stable water levels, the biogeochemical and ecological effects of water level fluctuation with different nutrient loads should be investigated. This is particularly important for biodiverse mesotrophic fens, sensitive to acidification and eutrophication. Mesocosm experiments were conducted to study the interactive effects of water level fluctuation and P-enrichment under controlled summer conditions, using peat cores including vegetation from three fens differing in biogeochemical characteristics. The effects of fluctuating water levels on biogeochemistry and vegetation appeared to be highly dependent on peat chemistry, and more important than the effects of P-enrichment. Only when plant growth was stimulated by a favorable water level regime, P-enrichment led to increased P-consumption by plants. In rich fens with a high soil Ca-content, 7 weeks of lowered water table (−15 cm) did not lead to a drop in pH. However, soil subsidence, increased N-availability and decline of the rich fen bryophyte Scorpidium scorpioides give cause to concern. 7 weeks of inundation (+15 cm) offered possibilities for restoration in these fens, since alkalinity and Ca-concentrations increased, while soil P-mobilization did not occur. Even P-enrichment did not result in increased P-availability, presumably due to Ca-related precipitation of P. In rich fens with a high soil Fe-content, water table lowering should be avoided as well, because of soil subsidence, increased N-availability, decline of the rich fen bryophyte Calliergon giganteum , plus acidification due to Fe-oxidation. Shallow inundation, however, is also harmful, especially after mowing and with P-rich water, because plant growth was hampered, presumably by toxicity of NH 4 + and/or Fe(II). In mineral-poor fens with a high soil P- and S-content, shallow inundation should be avoided, because of tremendous internal P-mobilization. Vitality of the dominant bryophyte Sphagnum palustre , however, was not affected. Low water tables affected neither vegetation, nor biogeochemistry, showing resistance to short-term drought in these fens. Given the strong mediating effect of soil chemistry, risks and benefits of re-establishment of fluctuating water levels with clean or P-rich water need to be considered for different fen types separately in water and nature management.

We compare eight pollen records reflecting climatic and environmental change from the tropical Andes. Our analysis focuses on the last 50 ka, with particular emphasis on the Pleistocene to Holocene transition. We explore ecological grouping and downcore ordination results as two approaches for extracting environmental variability from pollen records. We also use the records of aquatic and shoreline vegetation as markers for lake level fluctuations, and precipitation change. Our analysis focuses on the signature of millennial-scale variability in the tropical Andes, in particular, Heinrich stadials and Greenland interstadials. We identify rapid responses of the tropical vegetation to this climate variability, and relate differences between sites to moisture sources and site sensitivity.