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Termes IGN > sciences naturelles > sciences de la Terre et de l'univers > géosciences > géographie physique > géomorphologie > relief > pente
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Forest age and topographic position jointly shape the species richness and composition of vascular plants in karstic habitats / Zoltán Bátori in Annals of Forest Science, vol 80 n° 1 (2023)
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Titre : Forest age and topographic position jointly shape the species richness and composition of vascular plants in karstic habitats Type de document : Article/Communication Auteurs : Zoltán Bátori, Auteur ; Csaba Tölgyesi, Auteur ; Gábor Li, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 16 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] âge du peuplement forestier
[Termes IGN] changement climatique
[Termes IGN] gestion forestière
[Termes IGN] habitat d'espèce
[Termes IGN] karst
[Termes IGN] pente
[Termes IGN] topographie locale
[Termes IGN] Tracheophyta
[Vedettes matières IGN] SylvicultureRésumé : (auteur) Key message: Dolines may provide important safe havens for many plant species and play a key role in maintaining biodiversity. The combined effects of forest age and topographic position influence the biodiversity patterns of these unique habitats. Forest managers, conservationists, and researchers need to work together in order to maintain the species richness and composition of these habitats under environmental changes.
Context: Dolines are the most prominent geomorphological features in many karst landscapes that may provide important microhabitats for many species.
Aims: We aim to contribute to a better understanding of how forest age and topographic position influence the plant species richness and composition of vascular plants within doline habitats.
Methods: We studied the effects of forest age (four age classes: from 5- to 10-year-old stands to more than 90-year-old stands), topographic position (south-facing slope, bottom, and north-facing slope), and their interaction on the distribution of vascular plants and mean Ellenberg indicator values in dolines using detrended correspondence analysis and mixed-effects models. Diagnostic species for the forest age classes and topographic positions were also determined.
Results: Different groups of vascular plant species usually showed significant preferences for certain topographic positions and/or forest age classes in dolines. In general, the number of species in all studied groups of plants increased after a few years of canopy removal. The number of plant species in almost all groups was lowest in dolines covered with 40–45-year-old forests. The moist and nutrient-rich doline bottoms covered with 90–120-year-old forests harboured many climate change vulnerable plant species.
Conclusions: Forest age and topographic position considerably influence the species richness and composition of vascular plants in dolines; therefore, forest managers and conservationists need to consider their potential impacts when evaluating the effects of climate warming on karst landscapes.Numéro de notice : A2023-188 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1186/s13595-023-01183-x Date de publication en ligne : 31/03/2023 En ligne : https://doi.org/10.1186/s13595-023-01183-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102967
in Annals of Forest Science > vol 80 n° 1 (2023) . - n° 16[article]Discrete element analysis of deformation features of slope controlled by karst fissures under the mining effect: a case study of Pusa landslide, China / Qian Zhao in Geomatics, Natural Hazards and Risk, vol 14 n° 1 (2023)
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Titre : Discrete element analysis of deformation features of slope controlled by karst fissures under the mining effect: a case study of Pusa landslide, China Type de document : Article/Communication Auteurs : Qian Zhao, Auteur ; Zhongping Yang, Auteur ; Yuanwen Jiang, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : pp 1 - 32 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] Chine
[Termes IGN] effondrement de terrain
[Termes IGN] faille géologique
[Termes IGN] géomorphologie locale
[Termes IGN] karst
[Termes IGN] pente
[Termes IGN] prospection minéraleRésumé : (auteur) Karst landforms are widely distributed in the southwestern mountain areas of China, and the continuous underground mining activities lead to frequent occurrence of catastrophic collapses and landslides. Revealing the relationship between the development characteristics of the controlling karst fissures and the slope deformation process is crucial to understand the collapse and landslide phenomena. The Pusa landslide is selected as the geological prototype of discrete element analysis, and the universal distinct element code (UDEC) is applied to simulate the overall deformation response of the mountain containing extensive karst fissure during the mining process. The results show that under the action of mining, the roof above the goaf bends and subsides, and the middle of the roof even breaks and collapses. The separation fractures effectively block the upward transmission of the collapse state of the rock stratum. The bottom of the karst fissure is susceptible to cracking first in the process of coal seam mining due to stress concentration, and the area of severe deformation in the slope coincides with the mining pressurization area. The morphology of the karst fissure controls and determines the deformation characteristics of the rock mass at the slope top, and only the karst fissure located within the mining influence range is the object to be considered in the slope stability analysis. The limit karst fracture depth, about 1/3 of the slope height, is the limit value to determine whether the rock mass at the slope top is toppled or slipped. The relationship between the karst fissure and the free surface gradually changes from the directional or co-directional to the reverse, the motion state of the rock mass at the slope top changes from slipping to toppling, and the role of karst fissure changes from a potential slip surface to the cracking boundary. Although the deformation damage of the reverse structural slope is not very serious, the influence of the karst fissure on the stability of the slope still cannot be ignored. This study aims to provide basic theoretical support for the subsequent research on the failure mechanism of karst mountains under the combined action of multi-structural planes. Numéro de notice : A2023-036 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/19475705.2022.2158376 Date de publication en ligne : 29/12/2023 En ligne : https://doi.org/10.1080/19475705.2022.2158376 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102305
in Geomatics, Natural Hazards and Risk > vol 14 n° 1 (2023) . - pp 1 - 32[article]Multi‑constellation GNSS interferometric reflectometry for the correction of long-term snow height retrieval on sloping topography / Wei Zhou in GPS solutions, vol 26 n° 4 (October 2022)
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Titre : Multi‑constellation GNSS interferometric reflectometry for the correction of long-term snow height retrieval on sloping topography Type de document : Article/Communication Auteurs : Wei Zhou, Auteur ; Liangke Huang, Auteur ; Bing Ji, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 140 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] hauteur (coordonnée)
[Termes IGN] manteau neigeux
[Termes IGN] pente
[Termes IGN] Ransac (algorithme)
[Termes IGN] rapport signal sur bruit
[Termes IGN] réflectométrie par GNSS
[Termes IGN] signal GNSS
[Termes IGN] système de référence altimétrique
[Termes IGN] topographie locale
[Termes IGN] transformation en ondelettes
[Termes IGN] valeur aberrante
[Vedettes matières IGN] AltimétrieRésumé : (auteur) Snow is a key parameter for global climate and hydrological systems. Global Navigation Satellite System interferometric reflectometry (GNSS-IR) has been applied to accurately monitor snow height (SH) with low cost and high temporal–spatial resolution. We proposed an improved GNSS-IR method using detrended signal-to-noise ratio (δSNR) arcs corresponding to multipath reflection tracks with different azimuths. After using wavelet decomposition and random sample consensus, noise with various frequencies for SNR arcs and outliers of reflector height (RH) estimations have been sequentially mitigated to enhance the availability of the proposed method. Thus, a height datum based on the ground RHs retrieved from multi-GNSS SNR data is established to compensate for the influence of topography variation with different azimuths in SH retrieval. The approximately 3-month δSNR datasets collected from three stations deployed on sloping topography were used to retrieve SH and compared with the existing method and in situ measurements. The results show that the root mean square errors of the retrievals derived from the proposed method for the three sites are between 4 and 8 cm, and the corresponding correlation surpasses 0.95 when compared to the reference SH datasets. Additionally, we compare the performance of a retrieval with the existing GNSS-IR Web App, and it shows an improvement in RMSE of about 7 cm. Furthermore, because topography variation has been considered, the average correction of SH retrievals is between 2 and 4 cm. The solution with the proposed method helps develop the applications of the GNSS-IR technique on complex topography. Numéro de notice : A2022-712 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-022-01333-0 Date de publication en ligne : 15/09/2022 En ligne : https://doi.org/10.1007/s10291-022-01333-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101590
in GPS solutions > vol 26 n° 4 (October 2022) . - n° 140[article]Predicting the variability in pedestrian travel rates and times using crowdsourced GPS data / Michael J. Campbell in Computers, Environment and Urban Systems, vol 97 (October 2022)
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Titre : Predicting the variability in pedestrian travel rates and times using crowdsourced GPS data Type de document : Article/Communication Auteurs : Michael J. Campbell, Auteur ; Philip E. Dennison, Auteur ; Matthew Thompson, Auteur Année de publication : 2022 Article en page(s) : n° 101866 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique
[Termes IGN] base de données localisées
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] chemin le moins coûteux, algorithme du
[Termes IGN] données issues des réseaux sociaux
[Termes IGN] durée de trajet
[Termes IGN] mobilité urbaine
[Termes IGN] navigation pédestre
[Termes IGN] pente
[Termes IGN] planification urbaine
[Termes IGN] trace GPS
[Termes IGN] Utah (Etas-Unis)Résumé : (auteur) Accurately predicting pedestrian travel times is critically valuable in emergency response, wildland firefighting, disaster management, law enforcement, and urban planning. However, the relationship between pedestrian movement and landscape conditions is highly variable between individuals, making it difficult to estimate how long it will take broad populations to get from one location to another on foot. Although functions exist for predicting travel rates, they typically oversimplify the inherent variability of pedestrian travel by assuming the effects of landscapes on movement are universal. In this study, we present an approach for predicting the variability in pedestrian travel rates and times using a large, crowdsourced database of GPS tracks. Acquired from the outdoor recreation website AllTrails, these tracks represent nearly 2000 hikes on a diverse range of trails in Utah and California, USA. We model travel rates as a function of the slope of the terrain by generating a series of non-linear percentile models from the 2.5 th to the 97.5 th by 2.5 percentiles. The 50 th percentile model, representing the hiking speed of the typical individual, demonstrates marked improvement over existing slope-travel rate functions when compared to an independent test dataset. Our results demonstrate novel capacity to estimate travel time variability, with modeled percentiles being able to predict actual percentiles with less than 10% error. Travel rate functions can also be applied to least cost path analysis to provide variability in travel times. Numéro de notice : A2022-599 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.compenvurbsys.2022.101866 Date de publication en ligne : 20/08/2022 En ligne : https://doi.org/10.1016/j.compenvurbsys.2022.101866 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101452
in Computers, Environment and Urban Systems > vol 97 (October 2022) . - n° 101866[article]Assessing road accidents in spatial context via statistical and non-statistical approaches to detect road accident hotspot using GIS / Yegane Khosravi in Geodetski vestnik, vol 66 n° 3 (September - November 2022)
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Titre : Assessing road accidents in spatial context via statistical and non-statistical approaches to detect road accident hotspot using GIS Type de document : Article/Communication Auteurs : Yegane Khosravi, Auteur ; Farhad Hosseinali, Auteur ; Mostafa Adresi, Auteur Année de publication : 2022 Article en page(s) : pp 412 - 431 Note générale : bibliographie Langues : Anglais (eng) Slovène (slv) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] accident de la route
[Termes IGN] analyse de groupement
[Termes IGN] autocorrélation spatiale
[Termes IGN] classification par nuées dynamiques
[Termes IGN] corrélation automatique de points homologues
[Termes IGN] distance de Manhattan
[Termes IGN] estimation par noyau
[Termes IGN] Iran
[Termes IGN] méthode statistique
[Termes IGN] pente
[Termes IGN] processus de hiérarchisation analytique
[Termes IGN] regroupement de données
[Termes IGN] système d'information géographiqueRésumé : (auteur) Road accidents are among the most critical causes of fatality, personal injuries, and financial damage worldwide. Identifying accident hotspots and the causes of accidents and improving the condition of these hotspots is an economical way to improve road traffic safety. In this study, to identify the accident hotspots of “Dehbala” road located in Yazd province-Iran, statistical and non-statistical clustering methods were used. First, the weighting of the criteria was performed by an expert using the AHP method. Hence, the spatial correlation of slope and curvature was calculated by Global Moran’I. Anselin Local Moran index and Getis-Ord Gi* and Kernel Density Estimation were used to identify accident hotspots based on accident location due to the density of points. As a result, four accident hotspots were obtained by the Anselin Local Moran index, three accident hotspots by Getis-Ord Gi*and one accident-prone area were obtained by Kernel Density Estimation method. Three algorithms, k-means, k-medoids, and DBSCAN, were used to identify accident-prone areas or points using non-statistical methods. The dense cluster of each method was considered as an accident-prone cluster. Then the results of statistical and non- statistical methods were intersected with each other and the final accident-prone area was obtained. This study revealed the effect of geometric charcateristics of the road (slope and curvature) on the occurance of accidents. Numéro de notice : A2022-781 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.15292/geodetski-vestnik.2022.03.412-431 Date de publication en ligne : 04/08/2022 En ligne : https://doi.org/10.15292/geodetski-vestnik.2022.03.412-431 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101864
in Geodetski vestnik > vol 66 n° 3 (September - November 2022) . - pp 412 - 431[article]Réservation
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