84,243 research outputs found

    Understanding evolutionary processes during past Quaternary climatic cycles: Can it be applied to the future?

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    Climate change affected ecological community make-up during the Quaternary which was probably both the cause of, and was caused by, evolutionary processes such as species evolution, adaptation and extinction of species and populations

    Global late Quaternary megafauna extinctions linked to humans, not climate change

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    The late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. To date, focus has been on the extinction chronology of individual or small groups of species, specific geographical regions or macroscale studies at very coarse geographical and taxonomic resolution, limiting the possibility of adequately testing the proposed hypotheses. We present, to our knowledge, the first global analysis of this extinction based on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132 000 years BP and the late Holocene 1000 years BP, testing the relative roles played by glacial–interglacial climate change and humans. We show that the severity of extinction is strongly tied to hominin palaeobiogeography, with at most a weak, Eurasia-specific link to climate change. This first species-level macroscale analysis at relatively high geographical resolution provides strong support for modern humans as the primary driver of the worldwide megafauna losses during the late Quaternary

    Application of the biomization technique in the Eastern Colombian Andes

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    Two pollen records (Lake Fuquene and Pantano de Martos) are analyzed in order to test the usefulness of the Biomization technique to management on forest adaptation to climate change. This work focuses on Biomes and Plant Functional Types response to climate changes on specific dates (18, 14, 12.5, 8 and 6 Kyr) along the Late Quaternary, as deduced from the pollen composition. Results show different responses of vegetation to changes in past environmental conditions, which can be attributed to the different altitudes of the two study sites. While biomes in Lake Fuquene (2500 m a.s.l.) shift from Cool Grassland at 18 Kyr to Cool Mixed Forest and Cool evergreen Forest at 6 Kyr ago, no biome shift is detected in Pantano de Martos (3200 m a.s.l.) through the Late Quaternary. A look to the different Plant Functional Types taking part on the surroundings of the study sites at different ages, together with the analyses of Arboreal / Non Arboreal pollen percentages, give a detailed idea of the ecosystem response to past climate changes. This study shows the potential of the Biomization technique as a simple and powerful tool to analyze ecosystem responses at local and regional scales

    Empirical Predictability of Community Responses to Climate Change

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    Robust predictions of ecosystem responses to climate change are challenging. To achieve such predictions, ecology has extensively relied on the assumption that community states and dynamics are at equilibrium with climate. However, empirical evidence from Quaternary and contemporary data suggest that species communities rarely follow equilibrium dynamics with climate change. This discrepancy between the conceptual foundation of many predictive models and observed community dynamics casts doubts on our ability to successfully predict future community states. Here we used community response diagrams (CRDs) to empirically investigate the occurrence of different classes of disequilibrium responses in plant communities during the Late Quaternary, and bird communities during modern climate warming in North America. We documented a large variability in types of responses including alternate states, suggesting that equilibrium dynamics are not the most common type of response to climate change. Bird responses appeared less predictable to modern climate warming than plant responses to Late Quaternary climate warming. Furthermore, we showed that baseline climate gradients were a strong predictor of disequilibrium states, while ecological factors such as species’ traits had a substantial, but inconsistent effect on the deviation from equilibrium. We conclude that (1) complex temporal community dynamics including stochastic responses, lags, and alternate states are common; (2) assuming equilibrium dynamics to predict biodiversity responses to future climate changes may lead to unsuccessful predictions

    Influence of Climate Change on Obligatory Interactions in the Ecosystem: Predicting the Future

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    Obligatory interactions in the ecosystem are sensitive to climate fluctuations. The study of how   mutualistic and parasitic associations which are obligatory for the partners, respond to past climate change especially in the Quaternary, would help deepen the understanding and provide clues to how ecosystems would respond to current and future climate changes. Data was obtained by searching through articles from different scientific databases spanning from 1990 to 2022.  The focus was on decoupling of partners, changes of the distributional limits of partner species and response to sudden climate change by the interacting partner species. From this review, data on response of obligate interactions to past climate change is limited and all constraints should be removed to allow for sufficient and appropriate data. Efficient calibration of demographic events from genetic data coupled with use of suitable biological models; including enhanced number of models from the tropics to help resolve the difficulty of timing biological events may be the way forward. Keywords: obligate; interactions; Quaternary; climate change; ecosystem: DOI: 10.7176/JEES/13-5-04 Publication date:July 31st 202

    Consistent role of Quaternary climate change in shaping current plant functional diversity patterns across European plant orders

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    Current and historical environmental conditions are known to determine jointly contemporary species distributions and richness patterns. However, whether historical dynamics in species distributions and richness translate to functional diversity patterns remains, for the most part, unknown. The geographic patterns of plant functional space size (richness) and packing (dispersion) for six widely distributed orders of European angiosperms were estimated using atlas distribution data and trait information. Then the relative importance of late-Quaternary glacial-interglacial climate change and contemporary environmental factors (climate, productivity, and topography) as determinants of functional diversity of evaluated orders was assesed. Functional diversity patterns of all evaluated orders exhibited prominent glacial-interglacial climate change imprints, complementing the influence of contemporary environmental conditions. The importance of Quaternary glacial-interglacial climate change factors was comparable to that of contemporary environmental factors across evaluated orders. Therefore, high long-term paleoclimate variability has imposed consistent supplementary constraints on functional diversity of multiple plant groups, a legacy that may permeate to ecosystem functioning and resilience. These findings suggest that strong near-future anthropogenic climate change may elicit long-term functional disequilibria in plant functional diversity

    Signature of Obliquity and Eccentricity in Soil Chronosequences

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    Periodic shifts in Earth\u27s orbit alter incoming solar radiation and drive Quaternary climate cycles. However, unambiguous detection of these orbitally driven climatic changes in records of terrestrial sedimentation and pedogenesis remains poorly defined, limiting our understanding of climate change‐landscape feedbacks, impairing our interpretation of terrestrial paleoclimate proxies, and limiting linkages among pedogenesis, sedimentation, and paleoclimatic change. Using a meta‐analysis, we show that Quaternary soil ages preserved in the modern record have periodicities of 41 and 98 kyr, consistent with orbital cycles. Further, soil ages predominantly date to periods of low rates of climatic change following rapid climate shifts associated with glacial‐to‐interglacial transitions. Soil age appears linked to orbital cycles via climate‐modulated sediment deposition, which may largely constrain soil formation to distinct climate periods. These data demonstrate a record of widespread orbital cyclicity in sediment deposition and subsequent pedogenesis, providing a key insight into soil‐landscape evolution and terrestrial paleo‐environment changes

    Drivers of ecosystem and climate change in tropical West Africa over the past ∼540 000 years

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    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

    Quaternary global change: review and issues(Special issue in memory of Hugues Faure)

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    The French National Committee of INQUA, the IGCP Project n° 459 (Carbon Cycle and Hydrology in the Paleo Terrestrial Environments),the CNRS (Centre National de la Recherche Scientifique), the CCGM (Commission de la Carte Géologique du Monde), the IRD (Institut de Recherche pour le Développement), and the BRGM (Bureau de Recherches Géologiques et Minières) have organized in June 2004 a special International Colloquium dedicated to the memory of Hugues Faure who passed away in May 2003. It was the occasion to make a review and to emphasize new results and issues on the different topics initiated by Hugues and his collaborators. It was also a chance for all his colleagues and friends to remember a rare human being and a great scientist, passionately involved in the observation and understanding of the planet, which he called “the real world”, and assuming his destiny up to the end. The Scientific committee of this colloquium has decided to publish a special issue of Global and Planetary Change with some selected papers presented during this colloquium. This GPC special issue includes some of the papers presented at this colloquium and some invited papers from scientific personalities who wished to contribute to this special volume. The general theme of the special publication in honour to Hugues Faure is the Quaternary and the Global Changes. It will focus on the global cycles and Quaternary climate (3 papers), sea-level fluctuations, tectonics and climate variations (3 papers), climate changes in terrestrial records (9 papers), and man, environment and global change (4 papers). A total of 20 contributions, including a foreword on Hugues Faure, are proposed by the participants of this colloquium

    Римо-католицизм в Україні

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    This special issue focuses on the interactions between Quaternary Geology and Archaeology and results from the INQUA-NL Symposium: ‘Late Quaternary Climate Change: a Human Perspective’ held on April 14th2009, KNAW Trippenhuis, Amsterdam. The symposium was attended by over 125 scientists and students with interest in the fields of Quaternary Geology and Archaeology. The symposium was organized for the INQUA Netherlands commission (INQUA-NL) by Wim Hoek, Faculty of Geosciences, Utrecht University (UU), Henry Hooghiemstra, Faculty of Science, University of Amsterdam (UvA), and Jos Deeben, National Service for Cultural Heritage (RCE). The INQUA Netherlands commission (INQUA-NL) is the Netherlands' national representation in INQUA, the International Union for Quaternary Research (see furtherwww.geo.uu.nl/inqua-nl).The Netherlands is a country made by humans, but before the large-scale impact of humans that formed the typical Dutch landscape, people inhabited our area and needed to be able to deal with natural disasters like climate change, river floods or sea-level change. In the field of archaeology, there is increasingly more space to include the environmental changes that partly determined the behaviour of prehistoric communities. The interactions between quaternary geology and archaeology are not only restricted to provide stratigraphical information during archaeological prospection or on exposures during excavations. Quaternary geology is increasingly applied to gain insight in the landscape development and environmental setting where people have lived in the past. Above this, predictive models can be improved by the interaction of archaeological and geological/palaeogeographical research (see also Deeben et al., 2010).</jats:p
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