Résumé
Altitude lakes are weakly impacted by human activities. This makes them choice ecosystems to understand how biological communities are impacted by natural factors. This question was addressed to littoral benthic diatoms, a largely used ecological indicator. We wanted to know if benthic diatoms in lakes are more impacted by local varying factors (altitude, lake depth...) or regional varying factors (geology). The study area takes place in the Northern French Alps. Littoral benthic diatoms of 63 natural lakes situated between 1350 and 2700 m · a.s.l. were sampled. Two categories of communities were observed: one of deep and lower altitude lakes and one of higher altitude and shallower lakes. In each category, communities were characterized and were corresponding to particular lake types: lakes dominated by a particular geology, lakes with a water level fluctuation, turbid lakes,... Communities did not show a spatial structure. We observed that local factors were more important than regional factors. Indeed, the study area displayed a mixed geology even at a local level. On another hand, altitude a local varying factor determines freezing period a determining item of high-altitude lake functioning.
Auteurs, date et publication :
Auteurs Léa Feret , Agnès Bouchez , Frédéric Rimet
Publication : Annales de Limnologie - International Journal of Limnology
Date : 2025
Volume : 53
Pages : 411-423
Catégorie(s)
#INRAE #OLARésumé
Finding suitable models of canopy reflectance in forward simulation mode is a prerequisite for their use in inverse mode to characterize canopy variables of interest, such as leaf area index (LAI) or chlorophyll content. In this study, the accuracy of the three-dimensional reflectance model DART (Discrete Anisotropic Radiative Transfer) was assessed for canopies of different genotypes of Eucalyptus, having distinct biophysical and biochemical characteristics, to improve the knowledge on how these characteristics are influencing the reflectance signal as measured by passive orbital sensors. The first step was to test the model suitability to simulate reflectance images in the visible and near infrared. We parameterized DART model using extensive measurements from Eucalyptus plantations including 16 contrasted genotypes. Forest inventories were conducted and leaf, bark, and forest floor optical properties were measured. Simulation accuracy was evaluated by comparing the mean top of canopy (TOC) bidirectional reflectance of DART with TOC reflectance extracted from a Pleiades very high resolution satellite image. Results showed a good performance of DART with mean reflectance absolute error lower than 2%. Intergenotype reflectance variability was correctly simulated, but the model did not succeed at catching the slight spatial variation for a given genotype, excepted when large gaps appeared due to tree mortality. The second step consisted of sensitivity analysis to explore which biochemical or biophysical characteristics influenced more the canopy reflectance between genotypes. Perspectives for using DART model in inversion mode in these ecosystems were discussed. (Résumé d'auteur)
Auteurs, date et publication :
Auteurs Julianne de Castro Oliveira , Jean Baptiste Feret , Flávio Jorge Ponzoni , Yann Nouvellon , Jean-Philippe Gastellu Etchegorry , Otávio Camargo Campoe , Jose Luiz Stape , Luiz Carlos Estraviz Rodriguez , Guerric Le Maire
Publication : IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date : 2025
Volume : 10
Issue : 11
Pages : 4844-4852
Catégorie(s)
#CIRAD #FORET Itatinga #INRAERésumé
Our knowledge of the rhizosphere bacterial communities in deep soils and the role of Eucalyptus and Acacia on the structure of these communities remains very limited. In this study, we targeted the bacterial community along a depth profile (0 to 800 cm) and compared community structure in monospecific or mixed plantations of Acacia mangium and Eucalyptus grandis. We applied quantitative PCR (qPCR) and sequence the V6 region of the 16S rRNA gene to characterize composition of bacterial communities. We identified a decrease in bacterial abundance with soil depth, and differences in community patterns between monospecific and mixed cultivations. Sequence analysis indicated a prevalent effect of soil depth on bacterial communities in the mixed plant cultivation system, and a remarkable differentiation of bacterial communities in areas solely cultivated with Eucalyptus. The groups most influenced by soil depth were Proteobacteria and Acidobacteria (more frequent in samples between 0 and 300 cm). The predominant bacterial groups differentially displayed in the monospecific stands of Eucalyptus were Firmicutes and Proteobacteria. Our results suggest that the addition of an N2-fixing tree in a monospecific cultivation system modulates bacterial community composition even at a great depth. We conclude that co-cultivation systems may represent a key strategy to improve soil resources and to establish more sustainable cultivation of Eucalyptus in Brazil. (Résumé d'auteur)
Auteurs, date et publication :
Auteurs Arthur Prudêncio de Araujo Pereira , Pedro Avelino Maia de Andrade , Daniel Bini , Ademir Durrer , Agnès Robin , Jean-Pierre Bouillet , Fernando Dini Andreote , Elke Jurandy Bran Nogueira Cardoso
Publication : PloS One
Date : 2025
Volume : 12
Issue : 7
Pages : e0180371 (15 p.)
Catégorie(s)
#CIRAD #FORET Itatinga #FORET Rubberflux #INRAEAuteurs, date et publication :
Auteurs Chiara Pistocchi , Federica Tamburini , Gerard Gruau , André Ferhi , Dominique Trevisan , Jean-Marcel Dorioz
Publication : Water Research
Date : 2025
Volume : 111
Pages : 346-356
Catégorie(s)
#INRAE #OLAAuteurs, date et publication :
Auteurs Édouard Jurkevitch , Stéphan Jacquet
Publication : Médecine Sciences
Date : 2025
Volume : 33
Issue : 5
Pages : 519-527
Catégorie(s)
#INRAE #OLARésumé
Background and aims Legumes are used in forage agriculture to replace mineral N fertilizer by biological N fixation. We hypothesised that N addition through biological N fixation may have different effects on soil organic matter (SOM)112 quantity and composition compared to mineral N fertilization. In this study we introduced lucerne into grasslands and aimed to examine the resulting effects on C stocks and the molecular C signatures of roots and soil.
Auteurs, date et publication :
Auteurs Alexandra Creme , Abad Chabbi , François Gastal , Cornelia Rumpel
Publication : Plant and Soil
Date : 2025
Volume : 415
Issue : 1-2
Pages : 189-201
Catégorie(s)
#ACBB #ACBB Lusignan #INRAERésumé
Artificial stocking practices are widely used by resource managers worldwide, in order to sustain fish populations exploited by both recreational and commercial activities, but their benefits are controversial. Former practices involved exotic strains, although current programs rather consider artificial breeding of local fishes (supportive breeding). Understanding the complex genetic effects of these management strategies is an important challenge with economic and conservation implications, especially in the context of population declines. In this study, we focus on the declining Arctic charr (Salvelinus alpinus) population from Lake Geneva (Switzerland and France), which has initially been restocked with allochtonous fishes in the early eighties, followed by supportive breeding. In this context, we conducted a genetic survey to document the evolution of the genetic diversity and structure throughout the last 50 years, before and after the initiation of hatchery supplementation, using contemporary and historical samples. We show that the introduction of exotic fishes was associated with a genetic bottleneck in the 1980–1990s, a break of Hardy–Weinberg Equilibrium (HWE), a reduction in genetic diversity, an increase in genetic structure among spawning sites, and a change in their genetic composition. Together with better environmental conditions, three decades of subsequent supportive breeding using local fishes allowed to re-e stablish HWE and the initial levels of genetic variation. However, current spawning sites have not fully recovered their original genetic composition and were extensively homogenized across the lake. Our study demonstrates the drastic genetic consequences of different restocking tactics in a comprehensive spatiotemporal framework and suggests that genetic alteration by nonlocal stocking may be partly reversible through supportive breeding. We recommend that conservation-based programs consider local diversity and implement adequate protocols to limit the genetic homogenization of this Arctic charr population.
Auteurs, date et publication :
Auteurs Romain Savary , Christophe Dufresnes , Alexis Champigneulle , Arnaud Caudron , Sylvain Dubey , Nicolas Perrin , Luca Fumagalli
Publication : Ecology and Evolution
Date : 2025
Volume : 7
Issue : 14
Pages : 5201-5211
Catégorie(s)
#INRAE #OLAAuteurs, date et publication :
Auteurs Eric Capo , Didier Debroas , Fabien Arnaud , Marie-Elodie Perga , Cécile Chardon , Isabelle Domaizon
Publication : Environmental Microbiology
Date : 2025
Volume : 19
Issue : 7
Pages : 2873-2892
Catégorie(s)
#INRAE #OLAAuteurs, date et publication :
Auteurs Eric Capo , Isabelle Domaizon , Dominique Maier , Didier Debroas , Christian Bigler
Publication : Journal of Paleolimnology
Date : 2025
Volume : 58
Issue : 4
Pages : 479-495
Catégorie(s)
#INRAE #OLAAuteurs, date et publication :
Auteurs Lorenzo Brilli , Luca Bechini , Marco Bindi , Marco Carozzi , Daniele Cavalli , Richard Conant , Cristopher D. Dorich , Luca Doro , Fiona Ehrhardt , Roberta Farina , Roberto Ferrise , Nuala Fitton , Rosa Francaviglia , Peter Grace , Ileana Iocola , Katja Klumpp , Joël Léonard , Raphaël Martin , Raia Silvia Massad , Sylvie Recous
Publication : Science of The Total Environment
Date : 2025
Volume : 598
Pages : 445-470