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[hal-05269703] Long-term forest-line dynamics in the French Pyrenees: an accelerating upward shift related to forest context, global warming and pastoral abandonment
<div><p>Worldwide, the upper forest line has climbed over the past decades, shaping mountain landscapes in response to global changes. In European mountains, this recent trend is a continuation of the forest transition initiated in the mid-19 th century, when forest extent was minimal. This study aimed to (1) reconstruct the forest-line dynamics for the entire French Pyrenees from the mid-19 th century until today and (2) investigate the influence of human and environmental drivers on the spatio-temporal variations in forest-line shift. To ascertain the forest-line elevational shift for the 114 municipalities studied, three digital land-use maps (dated 1851, 1993 and 2010) were employed. The forest-line shift velocity was calculated for the two periods delineated by these maps. We applied linear mixed-effect models to analyse the role of human and environmental drivers on the forest-line shift. The mean upward shift was 0.9 m.yr -1 during the 1851-1993 period but was four-fold higher during the 1993-2010 period (3.5 m.yr -1 ). During the first period, the forest line shifted upward seven times faster in the eastern Pyrenees, where the mountain pine, a pioneer species, formed the ecotone and pastoral abandonment occurred earlier, than in the western Pyrenees (1.3 vs. 0.2 m.yr -1 ). Conversely, in the following period, the shift occurred three times as fast in the western Pyrenees, where abandonment became widespread, as in the eastern Pyrenees (5.6 vs. 2.1 m.yr -1 ). In addition, during the second period, the closed forest line climbed twice as fast as the forest line (5.6 m.yr -1 ), indicating a pronounced densification of the subalpine forest. Our original approach integrates a large spatial scale and temporal depth and sheds new light on the interrelationships between global warming, pastoral abandonment and the forest-line upward shift.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Noémie Delpouve) 19 Sep 2025
https://hal.science/hal-05269703v1
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[hal-05168750] Framing the relationship between justice and ecosystem services: A systematic review
Ecosystem services (ES) are integral to environmental justice, in particular because they unevenly contribute to the well-being of different communities. Effective ES management and governance can promote equitable access and ensure that marginalized groups are not excluded from ES benefits, while recognizing the interests of multiple stakeholders and fostering fair decision making. Although environmental justice is a multifaceted concept that encompasses distributive, procedural, and recognition dimensions, most of the research on justice in ES has focused primarily on distributional aspects. Recent reviews indicate a growing interest in integrating environmental justice concerns with ES, but also highlight gaps in understanding how the relationship between justice and ES is framed and studied in different contexts. We conducted a systematic review of the scientific literature to identify the predominant framings of the relationship between ES and justice. Through a qualitative and quantitative analysis of 217 articles, examined from an environmental justice perspective, we identified five distinct framings, i.e. particular conceptualizations of the relationship between ES and justice that ultimately influence what (in)justices can be rendered visible or invisible. Each of the framings 'Space', 'Access', 'Values', 'PES' (Payment for ES), and 'Management' is associated with specific research questions and methods on ES, as well as specific perspectives and findings on justice. The plurality of framings identified in this review underscores the conceptual complexity of environmental justice and highlights the importance of engaging with diverse perspectives when addressing justice in relation to ES.
ano.nymous@ccsd.cnrs.fr.invalid (Bruno Locatelli) 18 Jul 2025
https://hal.science/hal-05168750v1
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[hal-05055736] Changing the decision context to enable social learning for climate adaptation
Successful adaptation often involves changes to the decision context to enable new ways of thinking and acting on climate change. Using 16 adaptation initiatives the authors were engaged with, we analysed how and why decision contexts changed to identify ways to improve adaptation as a process of collective deliberation and social learning. We used the scope of the adaptation issue and governance arrangements to classify initiatives into four types and scored changes in the decision context using three frameworks: (1) the values, rules and knowledge (VRK) perspective to identify changes to adaptation decision‐making; (2) the five dimensions of futures consciousness to identify the building of adaptation capabilities and (3) the social learning cycle to reveal evidence of reflexive learning. Initiatives using novel governance arrangements for discrete problems (‘problem governance’) or complex, systemic issues (‘systems governance’) scored highest for influences of VRK, futures consciousness and the social learning cycle on the decision context. Initiatives using existing management for discrete problems (‘problem management’) scored moderately for change in the decision context, while those using existing management for systemic issues (‘systems management’) scored low because change was often impeded by existing rules. All three frameworks influenced decision contexts in systems governance initiatives. Problem governance initiatives revealed interactions of VRK and futures consciousness but limited influence of VRK on the social learning cycle. Scope and governance arrangements differ with the adaptation issue and initiatives adapt over time: some small‐scale ones became more systemic, developed novel governance arrangements and changed the decision context. Our findings do not show that some adaptation initiatives are better or more transformative than others; just that their scope and appropriate governance arrangements are different. This questions the notion that successful adaptation requires building generic transformative adaptation approaches and capabilities. There is a diversity of arrangements that work. What is important is to align the approach to the adaptation problem. We suggest two directions for improving adaptation initiatives: first, by influencing how they can shift between problem and systems focus and between standard management and novel governance, and secondly, by using methods to diagnose and direct change in the decision context. Read the free Plain Language Summary for this article on the Journal blog.
ano.nymous@ccsd.cnrs.fr.invalid (Matthew J Colloff) 05 May 2025
https://agroparistech.hal.science/hal-05055736v1
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[tel-05324805] Dynamique des forêts subalpines dans le contexte des changements globaux : patrons, déterminants (abiotiques, paysagers et socioéconomiques) et conséquences sur la diversité floristique
Depuis le minimum forestier atteint vers 1850 en France, une expansion générale des forêts est observée. Dans les montagnes, l'expansion peut se traduire par une remontée de la limite supérieure des forêts, transition entre les étages subalpin et alpin. Le réchauffement global, la répartition des essences forestières, l'abandon pastoral, et le développement du tourisme interagissent pour moduler la dynamique de la limite des forêts. La remontée de la limite des forêts modifie les anciennes pelouses alpines et ses communautés végétales patrimoniales. Les plantes forestières peuvent coloniser la forêt nouvellement installée avec retard, alors que les plantes des pelouses alpines peuvent s'éteindre plus ou moins rapidement. Le premier objectif de cette thèse est de quantifier le déplacement altitudinal de la limite des forêts à l'échelle des Pyrénées et des Alpes du Nord françaises depuis 1850. Un second objectif est de comprendre les effets des facteurs climatiques, socio-économiques, paysagers et forestiers, déterminant les variations de la dynamique de la limite des forêts depuis 150 ans. Un troisième objectif est de quantifier les effets de la remontée de la limite des forêts sur la diversité taxonomique et fonctionnelle des communautés végétales. Pour retracer la dynamique, la limite des forêts a été estimée par commune à l'aide de cartes d'usage des sols historiques et récentes, qui ont permis de délimiter deux périodes dans les Pyrénées (1851-1993 et 1993-2010) et trois périodes dans les Alpes (1860-1951, 1951-1995 et 1995-2007). Nous avons comparé les altitudes des limites des forêts entre les dates et les communes pour explorer les patrons spatio-temporels. Les effets des facteurs topographiques, climatiques, socio-économiques, paysagers et forestiers sur ces patrons spatio-temporels ont également été explorés. Enfin, nous avons analysé la distribution de la diversité taxonomique et fonctionnelle des communautés végétales des forêts anciennes jusqu'aux pelouses alpines grâce à des relevés stationnels et botaniques, effectués pendant l'été 2023 dans la vallée de la Maurienne. Les résultats montrent une dynamique contrastée : la limite des forêts s'est élevée de 174 m entre 1851 et 2010 dans les Pyrénées, avec une accélération entre 1993 et 2010, alors qu'elle s'est élevée de 166 m uniquement entre 1951 et 1995 dans les Alpes du Nord, donc de façon plus tardive mais plus rapide. La dynamique temporelle coïncide avec celle du réchauffement global dans les Pyrénées, mais avec un délai de réponse. Au contraire dans les Alpes, la remontée est limitée entre 1995 et 2007, et la limite des forêts s'est même abaissée de 5 m.an⁻¹ en Haute-Savoie. Les variations spatiales de la dynamique coïncident avec celles de l'abandon pastoral en France. De plus, l'hétérogénéité spatiale récente dans les Alpes est liée aux variations de pressions pastorales et touristiques contemporaines. Le contexte forestier joue également un rôle majeur. Dans les Pyrénées notamment, la remontée observée est plus rapide à l'Est de la chaîne, où la limite est formée par le pin à crochets, une espèce pionnière présentant de bonnes capacités de colonisation. L'analyse de la diversité floristique par groupe écologique montre un crédit (ou lag) de colonisation de 30% des espèces spécialistes de forêt ancienne dans les forêts récentes. Une dette d'extinction pour 27% des espèces de pelouses est observée dans les landes, et descend à 8% dans les forêts établies depuis plus de 70 ans. La dette d'extinction des espèces de pelouses est payée plus vite que le crédit de colonisation des espèces de forêts anciennes. Cette étude régionale à une profondeur temporelle inédite montre comment les facteurs globaux et régionaux interagissent sur le long terme pour modeler les paysages au niveau des écotones entre la forêt subalpine et les pelouses alpines, et souligne les compromis à y trouver entre conservation de la biodiversité et exploitation des ressources.
ano.nymous@ccsd.cnrs.fr.invalid (Noémie Delpouve) 21 Oct 2025
https://hal.univ-lorraine.fr/tel-05324805v1
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[hal-04918197] Remote-sensing-based forest canopy height mapping: some models are useful, but might they provide us with even more insights when combined?
The development of high-resolution mapping models for forest attributes based on remote sensing data combined with machine or deep learning techniques has become a prominent topic in the field of forest observation and monitoring. This has resulted in the availability of multiple, sometimes conflicting, sources of information, but, at face value, it also makes it possible to learn about forest attribute uncertainty through the joint interpretation of multiple models. This article seeks to endorse the latter by utilizing the Bayesian model averaging approach to diagnose and interpret the differences between predictions from different models. The predictions in our case are forest canopy height estimations for metropolitan France arising from five different models. An independent reference dataset, containing four different definitions of forest height (dominant, mean, maximum, and Lorey's) was established based on around 5500 plots of the French National Forest Inventory (NFI), distributed across the entire area of interest. In this study, we evaluate models with respect to their probabilities of correctly predicting measurements or estimations obtained from NFI plots, highlighting the spatial variability in respective model probabilities across the study area. We observed sig-nificant variability in these probabilities depending on the forest height definition used, implying that the different models inadvertently predict different types of canopy height. We also present the respective inter-model and intra-model variance estimations, enabling us to grasp where the employed models have comparable contributions but contrasting predictions. We show that topography has an important impact on the models spread. Moreover, we observed that the forest stand vertical structure, the dominant tree species, and the type of forest ownership systematically emerge as statistically significant factors influencing the model divergences. Finally, we observed that the fitted higher-order mixtures, which enabled the presented analyses, do not necessarily reduce bias or prevent the saturation of the predicted heights observed in the individual models.
ano.nymous@ccsd.cnrs.fr.invalid (Nikola Besic) 29 Jan 2025
https://hal.science/hal-04918197v1
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[hal-05168783] Intertwined people–nature relations are central to nature-based adaptation to climate change
Adaptation to climate change is a social-ecological process: it is not solely a result of natural processes or human decisions but emerges from multiple relations within social systems, within ecological systems and between them. We propose a novel analytical framework to evaluate social-ecological relations in nature-based adaptation, encompassing social (people-people), ecological (nature-nature) and social-ecological (people-nature) relations. Applying this framework to 25 case studies, we analyse the associations among these relations and identify archetypes of social adaptation. Our findings revealed that adaptation actions with more people-nature relations mobilise more social and ecological relations. We identified four archetypes, with distinct modes of adaptation along a gradient of people-nature interaction scores, summarised as: 1) nature control; 2) biodiversity-based; 3) ecosystem services-based; and 4) integrated approaches. This study contributes to a nuanced understanding of nature-based adaptation, highlighting the importance of integrating diverse relations across social and ecological systems. Our findings offer valuable insights for informing the design and implementation of adaptation strategies and policies.
ano.nymous@ccsd.cnrs.fr.invalid (Bruno Locatelli) 18 Jul 2025
https://hal.science/hal-05168783v1
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[hal-05290167] Poster X-RISKS
Analyse et gestion des risques multiples pour les socio-écosystèmes forestiers Responsables du projet : Marielle BRUNETTE et Eric RIGOLOT CONTEXTE : X-RISKS part du constat que les risques en forêt sont souvent considérés en silo, indépendamment les uns des autres. Or, dans un contexte de changements globaux, les interactions entre risques doivent être prises en compte pour mieux protéger les forêts.
ano.nymous@ccsd.cnrs.fr.invalid (Marielle Brunette) 30 Sep 2025
https://hal.inrae.fr/hal-05290167v1
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[hal-04959397] NUM-DATA - Développer le partage, l'accessibilité et l'exploitation numérique des données des socio-écosystèmes forestiers (SEF) tempérés et tropicaux
Avec l'ambition d'appuyer la recherche du Programme FORESTT sur la résilience des forêts tempérées et tropicales, le projet NUM-DATA répond à un besoin transverse dans le domaine des données et du numérique, en soutien aux projets ciblés du programme FORESTT et aux projets lauréats de l'appel à projets.
ano.nymous@ccsd.cnrs.fr.invalid (Sophie Fortuno) 20 Feb 2025
https://hal.science/hal-04959397v1
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[hal-04616188] Préserver l’avenir de nos forêts : ce que peut apporter la recherche
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ano.nymous@ccsd.cnrs.fr.invalid (Arnaud Sergent) 20 Jun 2024
https://hal.science/hal-04616188v1
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[hal-04503573] FORESTT - FORESTs and global environmental changes: social-ecological systems in Transition
Forest social ecological systems play a determinant role in adaptation to global change and mitigation processes. However, managers and decision-makers are faced with many uncertainties due to the major threats to the maintenance of the ecological and social functions of these systems. In this context, FORESTT proposes an ambitious research program addressing the scientific barriers to the multiscale functioning of temperate and tropical forest social ecological systems and the services they provide, the assessment and management of risks relating to global change, and the often-conflicting interdependences between different uses and management strategies in the short and long term. FORESTT aims to build, structure and lead an interdisciplinary, participatory and transformative forest science oriented towards action and the implementation of innovative and sustainable solutions, promoting the sustainability of forest social ecological systems. FORESTT will achieve these goals with support from a national scientific community of recognized excellence, international networks, and the various stakeholders involved in the forest-based sector and training in the field of forest sciences. FORESTT is structured around four scientific challenges dedicated to increasing knowledge and addressing (1) the societal challenges of the social ecological transition of forests, (2) the development of a circular and agile wood-based bioeconomy, (3) the adaptation and resilience of forest ecosystems for mitigating the negative effects of global climate change, and (4) the use of smart monitoring systems to foster scientific discoveries, and to guide forest management and political decisions. Both the already identified focal projects (five in total), structuring and strengthening the national scientific community and focusing efforts on priorities in line with the general objectives of the PEPR, and one open call for collaborative research projects will enable us to address the research objectives defined in these four scientific challenges. FORESTT will promote interdisciplinarity, linking social and economic sciences, environmental sciences, plant and animal sciences, and materials sciences. The program will also establish structures facilitating open and co constructed innovations concerning societal issues relating to forest management and planning. FORESTT will, thus, contribute to the objectives of the national low-carbon and biodiversity strategies, and the “forest” roadmap for the national ecological planning, and will support the implementation of the new European forestry strategy and the national anti-imported deforestation strategy in a context of diversified forest social ecological systems. FORESTT also aims to provide operational tools for negotiation, consultation and decision support for the preservation of biodiversity and maintenance of the correct functioning of forest ecosystems, and support for the development of a bioeconomy of high social, economic, and environmental value. FORESTT will capitalize on the vibrant and diverse French scientific community, with its international insertion and research facilities in France (both mainland France and overseas territories) and in the tropics. FORESTT aims to raise France's scientific leadership to the highest international level for this strategic theme and to provide expertise and support for national, European, and international public policies, by actively seeking contributions from stakeholders and through knowledge transfer.
ano.nymous@ccsd.cnrs.fr.invalid (Christophe Plomion) 13 Mar 2024
https://hal.science/hal-04503573v1
