How Joannites’ economy eradicated primeval forest and created anthroecosystems in medieval Central Europe

During European states’ development, various past societies utilized natural resources, but their impact was not uniformly spatially and temporally distributed. Considerable changes resulted in landscape fragmentation, especially during the Middle Ages. Changes in state advances that affected the local economy significantly drove trajectories of ecosystems’ development. The legacy of major changes from pristine forest to farming is visible in natural archives as novel ecosystems. Here, we present a high-resolution densely dated multi-proxy study covering the last 1500 years from a peatland located in CE Europe. The economic activity of medieval societies was highly modified by new rulers—the Joannites (the Order of St. John of Jerusalem, Knights Hospitaller). We studied the record of these directorial changes noted in the peat profile. Our research revealed a rapid critical land-use transition in the late Middle Ages and its consequences on the peatland ecosystem. The shift from the virgin forest with regular local fires to agriculture correlates well with the raising of local economy and deforestations. Along with the emerging openness, the wetland switched from alkaline wet fen state to acidic, drier Sphagnum-dominated peatland. Our data show how closely the ecological state of wetlands relates to forest microclimate. We identified a significant impact of the Joannites who used the novel farming organization. Our results revealed the surprisingly fast rate of how feudal economy eliminated pristine nature from the studied area and created novel anthroecosystems

Integrating fire-scar, charcoal and fungal spore data to study fire events in the boreal forest of northern Europe

Fire is a major disturbance agent in the boreal forest, influencing many current and future ecosystem conditions and services. Surprisingly few studies have attempted to improve the accuracy of fire-event reconstructions even though the estimates of the occurrence of past fires may be biased, influencing the reliability of the models employing those data (e.g. C stock, cycle). This study aimed to demonstrate how three types of fire proxies - fire scars from tree rings, sedimentary charcoal and, for the first time in this context, fungal spores of Neurospora - can be integrated to achieve a better understanding of past fire dynamics. By studying charcoal and Neurospora from sediment cores from forest hollows, and the fire scars from tree rings in their surroundings in the southern Fennoscandian and western Russian boreal forest, we produced composite fire-event data sets and fire-event frequencies, and estimated fire return intervals. Our estimates show that the fire return interval varied between 126 and 237 years during the last 11,000 years. The highest fire frequency during the 18th-19th century can be associated with the anthropogenic influence. Importantly, statistical tests revealed a positive relationship between other fire event indicators and Neurospora occurrence allowing us to pinpoint past fire events at times when the sedimentary charcoal was absent, but Neurospora were abundant. We demonstrated how fire proxies with different temporal resolution can be linked, providing potential improvements in the reliability of fire history reconstructions from multiple proxies.Peer reviewe

Regional variability in peatland burning at mid- to high-latitudes during the Holocene

Acknowledgements This work developed from the PAGES (Past Global Changes) C-PEAT (Carbon in Peat on EArth through Time) working group. PAGES has been supported by the US National Science Foundation, Swiss National Science Foundation, Swiss Academy of Sciences and Chinese Academy of Sciences. We acknowledge the following financial support: UK Natural Environment Research Council Training Grants NE/L002574/1 (T.G.S.) and NE/S007458/1 (R.E.F.); Dutch Foundation for the Conservation of Irish Bogs, Quaternary Research Association and Leverhulme Trust RPG-2021-354 (G.T.S); the Academy of Finland (M.V); PAI/SIA 80002 and FONDECYT Iniciación 11220705 - ANID, Chile (C.A.M.); R20F0002 (PATSER) ANID Chile (R.D.M.); Swedish Strategic Research Area (SRA) MERGE (ModElling the Regional and Global Earth system) (M.J.G.); Polish National Science Centre Grant number NCN 2018/29/B/ST10/00120 (K.A.); Russian Science Foundation Grant No. 19-14-00102 (Y.A.M.); University of Latvia Grant No. AAp2016/B041/Zd2016/AZ03 and the Estonian Science Council grant PRG323 (TrackLag) (N.S. and A.M.); U.S. Geological Survey Land Change Science/Climate Research & Development Program (M.J., L.A., and D.W.); German Research Foundation (DFG), grant MA 8083/2-1 (P.M.) and grant BL 563/19-1 (K.H.K.); German Academic Exchange Service (DAAD), grant no. 57044554, Faculty of Geosciences, University of Münster, and Bavarian University Centre for Latin America (BAYLAT) (K.H.K). Records from the Global Charcoal Database supplemented this work and therefore we would like to thank the contributors and managers of this open-source resource. We also thank Annica Greisman, Jennifer Shiller, Fredrik Olsson and Simon van Bellen for contributing charcoal data to our analyses. Any use of trade, firm, or product name is for descriptive purposes only and does not imply endorsement by the U.S. Government.Peer reviewedPostprin

The Reading Palaeofire Database : an expanded global resource to document changes in fire regimes from sedimentary charcoal records

Sedimentary charcoal records are widely used to reconstruct regional changes in fire regimes through time in the geological past. Existing global compilations are not geographically comprehensive and do not provide consistent metadata for all sites. Furthermore, the age models provided for these records are not harmonised and many are based on older calibrations of the radiocarbon ages. These issues limit the use of existing compilations for research into past fire regimes. Here, we present an expanded database of charcoal records, accompanied by new age models based on recalibration of radiocarbon ages using IntCal20 and Bayesian age-modelling software. We document the structure and contents of the database, the construction of the age models, and the quality control measures applied. We also record the expansion of geographical coverage relative to previous charcoal compilations and the expansion of metadata that can be used to inform analyses. This first version of the Reading Palaeofire Database contains 1676 records (entities) from 1480 sites worldwide. The database (RPDv1b - Harrison et al., 2021) is available at https://doi.org/10.17864/1947.000345.Peer reviewe

The Eurasian Modern Pollen Database (EMPD), version 2

The Eurasian (nee European) Modern Pollen Database (EMPD) was established in 2013 to provide a public database of high-quality modern pollen surface samples to help support studies of past climate, land cover, and land use using fossil pollen. The EMPD is part of, and complementary to, the European Pollen Database (EPD) which contains data on fossil pollen found in Late Quaternary sedimentary archives throughout the Eurasian region. The EPD is in turn part of the rapidly growing Neotoma database, which is now the primary home for global palaeoecological data. This paper describes version 2 of the EMPD in which the number of samples held in the database has been increased by 60% from 4826 to 8134. Much of the improvement in data coverage has come from northern Asia, and the database has consequently been renamed the Eurasian Modern Pollen Database to reflect this geographical enlargement. The EMPD can be viewed online using a dedicated map-based viewer at https://empd2.github.io and downloaded in a variety of file formats at https://doi.pangaea.de/10.1594/PANGAEA.909130 (Chevalier et al., 2019).Peer reviewe

The Medieval Climate Anomaly in South America

The Medieval Climate Anomaly (MCA) is a climatic perturbation with a core period of 1000-1200 AD that is well-recognized in the Northern Hemisphere (NH). Its existence in the Southern Hemisphere (SH) and the level of synchronicity with the NH is still a matter of debate. Here we present a palaeotemperature synthesis for South America encompassing the past 1500 years based on multiproxy data from 76 published land and marine sites. The data sets have been thoroughly graphically correlated and the MCA trends palaeoclimatologically mapped. The vast majority of all South American land sites suggest a warm MCA. Andean vegetation zones moved upslope, glaciers retreated, biological productivity in high altitude lakes increased, the duration of cold season ice cover on Andean lakes shortened, and trees produced thicker annual rings. Similar MCA warming occurred in coastal seas, except in the year-round upwelling zones of Peru, northern Chile and Cabo Frio (Brazil) where upwelling processes intensified during the MCA due to changes in winds and ocean currents. MCA warming in South America and the NH appears to have occurred largely synchronous, probably reaching comparable intensities. Future studies will have to address major MCA data gaps that still exist outside the Andes in the central and eastern parts of the continent. The most likely key drivers for the medieval climate change are multicentennial Pacific and Atlantic ocean cycles, probably linked to solar forcing

Attribution of modern Andean glacier mass loss requires successful hindcast of pre-industrial glacier changes

Andean glaciers have been shrinking due to long-term climatic warming during the past 100 years. Stuart-Smith et al. (2021) used observations and numerical models to evaluate the anthropogenic contribution to the centennial retreat of the Palcaraju Glacier in the Peruvian Cordillera Blanca. According to their central estimate, the glacier retreat is thought to be entirely the result of the observed 1 °C warming since 1880 in this region, of which they consider 85–105% as human-induced warming. However, this attribution must be questioned because the numerical models used by the authors fail to replicate the well-documented Andean temperature and glacier history of the Common Era. In a recent literature synthesis we have demonstrated that Andean glaciers retreated significantly during the Medieval Climate Anomaly (MCA, 1000–1200 CE) when the vast majority of all South American land sites experienced a warm phase, recorded as a near-global natural event, that is not linked with human activity (Lüning et al., 2019a). The MCA was followed by the Little Ice Age (LIA, 1300–1850 CE) when many Andean glaciers advanced significantly, some of them even reaching their maximum Holocene down-valley extension. In contrast, the “hindcast” of Stuart-Smith et al. (2021) erroneously suggests hardly any glacier length fluctuations for pre-industrial times. Given the unsuccessful “hindcast”, we do not consider the attribution results of the study as robust.Fil: Lüning, Sebastian. Institute for Hydrography, Geoecology and Climate Sciences; SuizaFil: Galka, Mariusz. University Of Lodz; ArgentinaFil: Bamonte, Florencia Paula. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Paleoecología y Palinologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Garcia Rodriguez, Felipe. Universidade Federal do Rio Grande; BrasilFil: Vahrenholt, Fritz. Universitat Hamburg; Alemani