Résumé
We predict stand basal area (BA) from small footprint LiDAR data in 129 one-ha tropical forest plots across four sites in French Guiana and encompassing a great diversity of forest structures resulting from natural (soil and geological substrate) and anthropogenic effects (unlogged and logged forests). We use predictors extracted from the Canopy Height Model to compare models of varying complexity: single or multiple regressions and nested models that predict BA by independent estimates of stem density and quadratic mean diameter. Direct multiple regression was the most accurate, giving a 9.6% Root Mean Squared Error of Prediction (RMSEP). The magnitude of the various errors introduced during the data collection stage is evaluated and their contribution to MSEP is analyzed. It was found that these errors accounted for less than 10% of model MSEP, suggesting that there is considerable scope for model improvement. Although site-specific models showed lower MSEP than global models, stratification by site may not be the optimal solution. The key to future improvement would appear to lie in a stratification that captures variations in relations between LiDAR and forest structure.
Auteurs, date et publication :
Auteurs G. Vincent , D. Sabatier , L. Blanc , J. Chave , E. Weissenbacher , R. Pélissier , E. Fonty , J.-F. Molino , P. Couteron
Publication : Remote Sensing of Environment
Date : 2012
Volume : 125
Pages : 23–33
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouAuteurs, date et publication :
Auteurs Jérôme Sueur , Almo Farina , Amandine Gasc , Nadia Pieretti , Sandrine Pavoine
Publication : Acta Acustica united with Acustica
Date : 2025
Volume : 100
Issue : 4
Pages : 772-781
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Max Ringler , Georgine Szipl , Walter Hödl , Leander Khil , Barbara Kofler , Michael Lonauer , Christina Provin , Eva Ringler
Publication : Behavioral Ecology and Sociobiology
Date : 2025
Volume : 71
Issue : 8
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Ecosystems support the adaptation of societies to global changes through their contributions to people's quality of life. Ecosystem-based adaptation (EBA) implementation remains a challenge and will require changes of practices, structures and processes underpinning human and nature interactions, also considered as co-production of nature’s contributions to adaptation (NCA). We analysed the levers required to implement EBA to reach a future desired by stakeholders of a mountain social-ecological system in the French Alps. Using a participatory backcasting scenario approach and a serious game, local stakeholders were invited to design a desired vision for their region in 2040 and reflect on strategies and levers for reaching it. We analysed co-production actions required to achieve adaptation objectives aligned with the vision. We then assessed how local communities can leverage these actions to navigate a desired adaptation pathway. EBA and landscape multifunctionality are critical to achieve stakeholders’ vision. EBA require substantial adjustments, transformations, or new co-production actions, but natural capital was not a limiting factor for adaptation. Synergies among multiple co-production actions create windows of opportunity for local communities to achieve their vision through the combination of social levers. However, most powerful levers, like collaborative decision-making or common strategy design, appeared the most difficult to activate. EBA is mainly constrained here by social barriers reflecting the lack of collaboration and communication among stakeholders. Recognizing potential contributions of ecosystems to adaptation by maintaining and developing NCA supply can help communities to re-structure and re-think their local social-ecological system to achieve desired and sustainable pathways.
Auteurs, date et publication :
Auteurs Enora Bruley , Bruno Locatelli , Matt J. Colloff , Nicolas Salliou , Thibault Métris , Sandra Lavorel
Publication : Environmental Science & Policy
Date : 2021
Volume : 124
Pages : 567-579
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Snow depth estimation derived from high-resolution digital elevation models (DEMs) can lead to improved understanding of the spatially highly heterogeneous nature of snow distribution, as well as help us improve our knowledge of how snow patterns influence local geomorphic processes. Slope deformation processes such as permafrost creep can make it challenging to acquire a snow-free DEM that matches the sub-snow topography at the time of the associated snow-covered DEM, which can cause errors in the computed snow depths. In this study, we illustrate how modelling changes in the sub-snow topography can reduce errors in snow depths derived from DEM differencing in an area of permafrost creep. To model the sub-snow topography, a surface deformation model was constructed by performing non-rigid registration based on B-splines of two snow-free DEMs. Seasonal variations in creep were accounted for by using an optimization approach to find a suitable value to scale the deformation model based on in-situ snow depth measurements or the presence of snow-free areas corresponding to the date of the snow-covered DEM. This scaled deformation model was used to transform one of the snow-free DEMs to estimate the sub-snow topography corresponding to the date of the snow-covered DEM. The performance of this method was tested on an active rock glacier in the southern French Alps for two surveys dates, which were conducted in the winter and spring of 2017.
Auteurs, date et publication :
Auteurs Jason Goetz , Paul Fieguth , Keyvan Kasiri , Xavier Bodin , Marco Marcer , Alexander Brenning
Publication : Remote Sensing of Environment
Date : 2025
Volume : 231
Pages : 111275
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Demographic compensation arises when vital rates change in opposite directions across populations, buffering the variation in population growth rates, and is a mechanism often invoked to explain the stability of species geographic ranges. However, studies on demographic compensation have disregarded the effects of temporal variation in vital rates and their temporal correlations, despite theoretical evidence that stochastic dynamics can affect population persistence in temporally varying environments. We carried out a seven-year-long demographic study on the perennial plant Arabis alpina (L.) across six populations encompassing most of its elevational range. We discovered demographic compensation in the form of negative correlations between the means of plant vital rates, but also between their temporal coefficients of variation, correlations and elasticities. Even if their contribution to demographic compensation was small, this highlights a previously overlooked, but potentially important, role of stochastic processes in stabilising population dynamics at range margins.
Auteurs, date et publication :
Auteurs Marco Andrello , Pierre de Villemereuil , Marta Carboni , Delphine Busson , Marie-Josée Fortin , Oscar E. Gaggiotti , Irène Till‐Bottraud
Publication : Ecology Letters
Date : 2025
Volume : 23
Issue : 5
Pages : 870-880
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs Jérôme Chave , Jean Olivier , Frans Bongers , Patrick Châtelet , Pierre-Michel Forget , Peter van der Meer , Natalia Norden , Bernard Riéra , Pierre Charles-Dominique
Publication : Journal of Tropical Ecology
Date : 2025
Volume : 24
Issue : 4
Pages : 355
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Marie-Anne Félix , Christian Braendle , Asher D Cutter
Publication : PloS one
Date : 2025
Volume : 9
Issue : 4
Pages : e94723
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs MARCELY Valois , FERNANDO Z Vaz-de-Mello , Fernando AB Silva
Publication : Zootaxa
Date : 2025
Volume : 4027
Issue : 2
Pages : 205-226
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Michael D Pirie , Lars W Chatrou , Paul JM Maas
Publication : PhytoKeys
Date : 2025
Issue : 112
Pages : 1