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Climate and ungulate browsing impair regeneration dynamics in spruce-fir-beech forests in the French Alps / Mithila Unkule in Annals of Forest Science, vol 79 n° 1 (2022)  

Public [article]  inAnnals of Forest Science > vol 79 n° 1 (2022) . - n° 11 Titre : Climate and ungulate browsing impair regeneration dynamics in spruce-fir-beech forests in the French Alps Type de document : Article/Communication Auteurs : Mithila Unkule, Auteur ; Christian Piedallu, Auteur ; Philippe Balandier, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 11 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Abies alba [Termes IGN] Alpes (France) [Termes IGN] Cervidae [Termes IGN] Fagus sylvatica [Termes IGN] faune locale [Termes IGN] hauteur des arbres [Termes IGN] humidité du sol [Termes IGN] Jura, massif du [Termes IGN] Picea abies [Termes IGN] placette d'échantillonnage [Termes IGN] régénération (sylviculture) [Termes IGN] sécheresse [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) Key message: Different components of water balance and temperature reduce density and height growth of saplings of Picea abies (L.) H. Karst (Norway spruce), Abies alba Mill. (silver fir) and Fagus sylvatica L. (European beech) in mixed uneven-aged forests in the French Alps and Jura mountains. Ungulate browsing is an additional pressure on fir and beech that could jeopardise the renewal of these species in the future. Context: The uncertainty in tree recruitment rates raises questions about the factors affecting regeneration processes in forests. Factors such as climate, light, competition and ungulate browsing pressure may play an important role in determining regeneration, forest structures and thus future forest composition. Aims: The objective of this study was to quantify sapling densities and height increments of spruce, fir and beech and to identify dominant environmental variables influencing them in mixed uneven-aged forests in the French Alps and Jura mountains. Methods: Sapling height increment and density were recorded in 152 plots, and non-linear mixed models were obtained to establish relations between them and environmental factors known to affect regeneration, namely altitude, slope, aspect, canopy openness, soil characteristics, temperature, precipitation and ungulate browsing. Results: Regeneration density, varying from 0 to 7 saplings per m 2, decreased with sapling height and was also negatively affected for spruce by PET, but positively for fir by precipitation and for beech by mean annual soil water content. Height increment reached up to 50 cm annually, increasing with sapling height and canopy openness and decreasing under high maximum summer temperatures for spruce and beech. The statistical effect of different environmental variables varied slightly among species but trends were quite similar. Additionally, ungulate browsing was high, with fir being the most intensely browsed, followed closely by beech, while spruce was rarely browsed. Conclusions: All these results suggest that more temperature warming and a decrease in water availability could negatively impact sapling growth and density in the three species, with possible reduction of forest renewal fluxes. The observed increase of ungulate populations leading to increased browsing could be particularly detrimental to fir saplings. Numéro de notice : A2022-509 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1186/s13595-022-01126-y Date de publication en ligne : 23/03/2022 En ligne : https://doi.org/10.1186/s13595-022-01126-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101045 [article]

Multi-method monitoring of rockfall activity along the classic route up Mont Blanc (4809 m a.s.l.) to encourage adaptation by mountaineers / Jacques Mourey in Natural Hazards and Earth System Sciences, vol 22 n° 2 (February 2022)  

Public [article]  inNatural Hazards and Earth System Sciences > vol 22 n° 2 (February 2022) . - pp 445 - 460 Titre : Multi-method monitoring of rockfall activity along the classic route up Mont Blanc (4809 m a.s.l.) to encourage adaptation by mountaineers Type de document : Article/Communication Auteurs : Jacques Mourey, Auteur ; Pascal Lacroix, Auteur ; Pierre-Allain Duvillard, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 445 - 460 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] capteur actif [Termes IGN] capteur non-imageur [Termes IGN] carte thématique [Termes IGN] détection de changement [Termes IGN] éboulement [Termes IGN] modèle numérique de terrain [Termes IGN] Mont-Blanc, massif du [Termes IGN] onde sismique [Termes IGN] pergélisol [Termes IGN] prévention des risques [Termes IGN] risque naturel [Termes IGN] saison [Termes IGN] sismologie [Termes IGN] surveillance géologique [Termes IGN] température de l'air Résumé : (auteur) There are on average 35 fatal mountaineering accidents per summer in France. On average, since 1990, 3.7 of them have occurred every summer in the Grand Couloir du Goûter, on the classic route up Mont Blanc (4809 m a.s.l.). Rockfall is one of the main factors that explain this high accident rate and contribute to making it one of the most accident-prone areas in the Alps for mountaineers. In this particular context, the objective of this study is to document the rockfall activity and its triggering factors in the Grand Couloir du Goûter in order to disseminate the results to mountaineers and favour their adaptation to the local rockfall hazard. Using a multi-method monitoring system (five seismic sensors, an automatic digital camera, three rock subsurface temperature sensors, a traffic sensor, a high-resolution topographical survey, two weather stations and a rain gauge), we acquired a continuous database on rockfalls during a period of 68 d in 2019 and some of their potential triggering factors (precipitation, ground and air temperatures, snow cover, frequentation by climbers). At the seasonal scale, our results confirm previous studies showing that rockfalls are most frequent during the snowmelt period in permafrost-affected rockwalls. Furthermore, the unprecedented time precision and completeness of our rockfall database at high elevation thanks to seismic sensors allowed us to investigate the factors triggering rockfalls. We found a clear correlation between rockfall frequency and air temperature, with a 2 h delay between peak air temperature and peak rockfall activity. A small number of rockfalls seem to be triggered by mountaineers. Our data set shows that climbers are not aware of the variations in rockfall frequency and/or cannot/will not adapt their behaviour to this hazard. These results should help to define an adaptation strategy for climbers. Therefore, we disseminated our results within the mountaineering community thanks to the full integration of our results into the management of the route by local actors. Knowledge built during this experiment has already been used for the definition and implementation of management measures for the attendance in summer 2020. Numéro de notice : A2022-181 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : 10.5194/nhess-22-445-2022 En ligne : https://doi.org/10.5194/nhess-22-445-2022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99859 [article]

A method to produce metadata describing and assessing the quality of spatial landmark datasets in mountain area / Marie-Dominique Van Damme (2022)  

Public Titre : A method to produce metadata describing and assessing the quality of spatial landmark datasets in mountain area Type de document : Article/Communication Auteurs : Marie-Dominique Van Damme , Auteur ; Ana-Maria Olteanu-Raimond , Auteur Editeur : Göttingen : Copernicus publications Année de publication : 2022 Projets : CHOUCAS / Olteanu-Raimond, Ana-Maria Conférence : AGILE 2022, 25th international AGILE Conference on Geographic Information Science, Artificial intelligence in the service of geospatial technologies 14/06/2022 17/06/2022 Vilnius Lithuanie OA Proceedings Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Infrastructure de données [Termes IGN] Alpes (France) [Termes IGN] appariement de données localisées [Termes IGN] données localisées [Termes IGN] données ouvertes [Termes IGN] jeu de données localisées [Termes IGN] loisir [Termes IGN] métadonnées géographiques [Termes IGN] montagne [Termes IGN] norme ISO [Termes IGN] ontologie [Termes IGN] qualité des données Résumé : (auteur) The increase of recreational activities in the mountains and a growing amount of websites proposing geographic data, offer new opportunities for societal needs such as mountain rescue, biodiversity monitoring, outdoor activities. However, the main issue with the websites data is the lack of metadata that minimizes its reuse outside the community that produced the data. The goal of this paper is to study and generate quality and descriptive metadata using ISO standards. To this end, we propose a method based on a common vocabulary such as an ontology and a data matching process. The first one allows to associate to each type of feature from an available geographic dataset an ontology class that will facilitate data matching, reproducibility of results and minimize semantic heterogeneity. The second one allows to define matching links between features representing the same entity in the real world and compute quality indicators based on the validated links. Finally, at the end of this process, we are able to generate descriptive and quality metadata. By following ISO standards and using the QualityML dictionary for measures, the metadata is serialized to XML and can finally be published as open source. Our approach was applied to five different landmark datasets in the French Alps region. New insights were acquired regarding positional accuracy and semantic granularity. Numéro de notice : C2022-027 Affiliation des auteurs : UGE-LASTIG (2020- ) Thématique : GEOMATIQUE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.5194/agile-giss-3-17-2022 Date de publication en ligne : 10/06/2022 En ligne : https://doi.org/10.5194/agile-giss-3-17-2022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100928

Regeneration of spruce - fir - beech mixed forests under climate and ungulate pressure / Mithila Unkule (2022)  

Public Titre : Regeneration of spruce - fir - beech mixed forests under climate and ungulate pressure Titre original : Régénération des forêts mixtes épicéa - sapin - hêtre sous la pression du climat et des ongulés Type de document : Thèse/HDR Auteurs : Mithila Unkule, Auteur ; Benoît Courbaud, Directeur de thèse ; Philippe Balandier, Directeur de thèse Editeur : Grenoble [France] : Université Grenoble Alpes Année de publication : 2022 Importance : pp 207 Format : 21 x 30 cm Note générale : bibliographie Thèse pour obtenir le grade de Docteur de l'Université Grenoble Alpes, Spécialité Biodiversité, Ecologie, Environnement Langues : Anglais (eng) Descripteur : [Termes IGN] Abies alba [Termes IGN] Alpes (France) [Termes IGN] altitude [Termes IGN] aménagement forestier [Termes IGN] Cervidae [Termes IGN] dynamique de la végétation [Termes IGN] écologie forestière [Termes IGN] Fagus sylvatica [Termes IGN] forêt inéquienne [Termes IGN] gestion forestière durable [Termes IGN] jeune arbre [Termes IGN] Jura, massif du [Termes IGN] pente [Termes IGN] Picea abies [Termes IGN] régénération (sylviculture) [Vedettes matières IGN] Végétation et changement climatique Index. décimale : THESE Thèses et HDR Résumé : (auteur) Global environmental changes are affecting tree population demography with potentially significant impacts on forest biodiversity and wood industry. Forest regeneration processes include seed production, growth and survival of saplings to the recruitment sizes at which trees are considered in forest inventories. Changes in regeneration dynamics directly affect forest composition and structure and can jeopardize the sustainability of forest management. This is especially the case in mountain forests where environmental gradients are strong and where forests are often uneven-aged, i.e. combining trees of all ages in a single stand. Regeneration processes are difficult to monitor. Large data sets often give only fixed pictures of sapling densities with little information on demographic processes. In this thesis, we quantified the effects of different biotic and abiotic factors on regeneration dynamics of Picea abies (spruce), Abies alba (fir) and Fagus sylvatica (beech) in the French Alps and Jura mountains. We also predicted changes in tree recruitment fluxes in these forests, for potential climate change situations. We recorded sapling height increment and density of spruce, fir and beech in 152 plots across the French Alps and Jura mountains. We then analysed how biotic and abiotic factors known to affect regeneration, namely altitude, slope, aspect, light availability, soil characteristics, ungulate browsing, temperature, precipitation and evapotranspiration, affected sapling density and growth using non-linear mixed models. We showed that temperature has a positive non-linear effect on sapling height growth and water resource availability has a positive effect on sapling density. Terminal shoot browsing, which prevents sapling height growth, is especially frequent on fir. In a second analysis, we built a more comprehensive model of regeneration dynamics, representing explicitly the process of new seedling production, sapling growth, browsing and survival, and finally their recruitment into adult trees. We predicted parameters for these processes in combination, using Approximate Bayesian Computation (ABC), based on the field data collected earlier. The results imply that more frequent and intense heat and drought events could negatively influence sapling growth and survival of the three species, with probable reduction of forest renewal fluxes. An increase of ungulate populations leading to increased browsing could be especially detrimental to fir and possibly also to beech saplings. We also predicted the potential tree recruitment fluxes for different IPCC climate projection scenarios for the year 2100, and showed that a reduction in tree recruitments is highly likely. This study shows that the ABC method can be efficiently used to estimate regeneration dynamic processes, based on sapling density, height increment and browsing data. It highlights the vulnerability of future forest regeneration to water availability and ungulate presence, urging researchers and forest managers alike to anticipate future potential important changes in mountain forest dynamics. Note de contenu : 1- Introduction 2- Theoretical framework 3- Spruce-fir-beech regeneration in French Alps 4- Estimating regeneration processes and tree recruitment rates 5- Discussion and perspectives 6- Conclusions Numéro de notice : 15288 Affiliation des auteurs : non IGN Thématique : FORET Nature : Thèse française Note de thèse : Thèse de Doctorat : Biodiversité, Ecologie, Environnement : Grenoble : 2022 Organisme de stage : Laboratoire des EcoSystèmes et des Sociétés en Montagne DOI : sans En ligne : https://tel.archives-ouvertes.fr/tel-03722811 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101511

Le Mont-Blanc mesuré au LiDAR héliporté / Mathieu Peyréga in XYZ, n° 169 (décembre 2021)

Public [article]  inXYZ > n° 169 (décembre 2021) . - pp 33 - 40 Titre : Le Mont-Blanc mesuré au LiDAR héliporté Type de document : Article/Communication Auteurs : Mathieu Peyréga, Auteur Année de publication : 2021 Article en page(s) : pp 33 - 40 Langues : Français (fre) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] calotte glaciaire [Termes IGN] données altimétriques [Termes IGN] données GNSS [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] hélicoptère [Termes IGN] modèle numérique de terrain [Termes IGN] Mont-Blanc, massif du [Termes IGN] précision des données [Termes IGN] sommet (relief) [Termes IGN] télémétrie laser aéroporté Résumé : (Auteur) Nous présentons une mesure de l’altitude du sommet du mont Blanc et du volume de sa calotte par méthode LiDAR héliporté de très haute densité. Cette méthode alternative aux expéditions d’alpinistes et aux techniques topographiques classiques permet une mesure de précision équivalente. Le bilan d’incertitude est présenté et rappelle que la source d’erreur principale est la propagation troposphérique, commune à la méthode GNSS terrestre mise en œuvre depuis une vingtaine d’années pour le suivi de ce sommet emblématique. Cette mesure réalisée à une quinzaine de jours d’intervalle de l’expédition traditionnelle permet également de donner une indication sur la stabilité à court terme des valeurs calculées. Numéro de notice : A2021-849 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueNat DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99179 [article]

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