Résumé
Soil fauna is a key control of the decomposition rate of leaf litter, yet its interactions with litter quality and the soil environment remain elusive. We conducted a litter decomposition experiment across different topographic levels within the landscape replicated in two rainforest sites providing natural gradients in soil fertility to test the hypothesis that low nutrient availability in litter and soil increases the strength of fauna control over litter decomposition. We crossed these data with a large dataset of 44 variables characterizing the biotic and abiotic microenvironment of each sampling point and found that microbe-driven carbon (C) and nitrogen (N) losses from leaf litter were 10.1 and 17.9% lower, respectively, in the nutrient-poorest site, but this among-site difference was equalized when meso- and macrofauna had access to the litterbags. Further, on average, soil fauna enhanced the rate of litter decomposition by 22.6%, and this contribution consistently increased as nutrient availability in the microenvironment declined. Our results indicate that nutrient scarcity increases the importance of soil fauna on C and N cycling in tropical rainforests. Further, soil fauna is able to equalize differences in microbial decomposition potential, thus buffering to a remarkable extent nutrient shortages at an ecosystem level.
Auteurs, date et publication :
Auteurs Guille Peguero , Jordi Sardans , Dolores Asensio , Marcos Fernández-Martínez , Albert Gargallo-Garriga , Oriol Grau , Joan Llusià , Olga Margalef , Laura Márquez , Romà Ogaya , Ifigenia Urbina , Elodie A. Courtois , Clément Stahl , Leandro Van Langenhove , Lore T. Verryckt , Andreas Richter , Ivan A. Janssens , Josep Peñuelas
Publication : Proceedings of the Royal Society B: Biological Sciences
Date : 2019
Volume : 286
Issue : 1910
Pages : 20191300
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
Soil nutrient availability and functional traits interact in complex ways during the assembly of tree communities hindering our understanding of the implications that this may have for their phylogenetic and functional diversity. We combined abundance, taxonomic, phylogenetic and functional trait data of 222 tree species distributed along nutrient concentration gradients at 24 plots in two tropical forest study sites. We analysed micro and macronutrient concentration in organic and topsoil horizons and tested for the following: (1) nutrient-based species sorting due to contrasting trait–environment relationships, (2) whether nutrient filtering has consequences for phylogenetic and functional diversity, and functional space size and occupancy and (3) we mapped trait distributions across the phylogeny of tree species to track the evolutionary signature of nutrient availability. We found that total nitrogen (N), available phosphorus and total potassium in soil accounted for 68% of the variation in tropical tree species community composition, with strong associations with nutrient concentration for 89% of the tree species included in the analysis. This nutrient-based species selection was mediated by interactions between the three soil nutrient concentrations with leaf nitrogen, leaf thickness and wood density. Soil N concentration was positively associated with the functional space at site level. At plot level, soil N concentration positively correlated with functional evenness and it was negatively associated with the functional space not occupied by any species in the tree community. Despite the phylogenetic conservatism of leaf N across tree lineages even when not considering legumes, many sister-species pairs show contrasting values which match with their habitat preferences thus indicating the evolutionary lability of this trait, particularly within recently diversified clades. Synthesis. Our results demonstrate that soil nutrient-based species selection is a prevalent driver of community assembly in tropical forests, a process mediated by key functional traits within the leaf and wood economics spectrum. Functional space size and its filling increase with soil nutrient concentration, whereas niche vacancy decreases. This selection process has likely influenced tropical tree species diversification patterns via habitat specialization.
Auteurs, date et publication :
Auteurs Guille Peguero , Fernando Coello , Jordi Sardans , Dolores Asensio , Oriol Grau , Joan Llusià , Romà Ogaya , Ifigenia Urbina , Leandro Van Langenhove , Lore T. Verryckt , Clément Stahl , Laëtitia Bréchet , Elodie A. Courtois , Jérôme Chave , Bruno Hérault , Ivan A. Janssens , Josep Peñuelas
Publication : Journal of Ecology
Date : 2025
Volume : 111
Issue : 6
Pages : 1218-1230
Catégorie(s)
#ANR-Citation #CIRAD #CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Oriol Grau , Josep Peñuelas , Bruno Ferry , Vincent Freycon , Lilian Blanc , Mathilde Desprez , Christopher Baraloto , Jérôme Chave , Laurent Descroix , Aurélie Dourdain , Stéphane Guitet , Ivan A. Janssens , Jordi Sardans , Bruno Hérault
Publication : Scientific Reports
Date : 2017
Volume : 7
Pages : 45017
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
Human activities are transforming grassland biomass via changing climate, elemental nutrients, and herbivory. Theory predicts that food-limited herbivores will consume any additional biomass stimulated by nutrient inputs (‘consumer-controlled’). Alternatively, nutrient supply is predicted to increase biomass where herbivores alter community composition or are limited by factors other than food (‘resource-controlled’). Using an experiment replicated in 58 grasslands spanning six continents, we show that nutrient addition and vertebrate herbivore exclusion each caused sustained increases in aboveground live biomass over a decade, but consumer control was weak. However, at sites with high vertebrate grazing intensity or domestic livestock, herbivores consumed the additional fertilization-induced biomass, supporting the consumer-controlled prediction. Herbivores most effectively reduced the additional live biomass at sites with low precipitation or high ambient soil nitrogen. Overall, these experimental results suggest that grassland biomass will outstrip wild herbivore control as human activities increase elemental nutrient supply, with widespread consequences for grazing and fire risk.
Auteurs, date et publication :
Auteurs E. T. Borer , W. S. Harpole , P. B. Adler , C. A. Arnillas , M. N. Bugalho , M. W. Cadotte , M. C. Caldeira , S. Campana , C. R. Dickman , T. L. Dickson , I. Donohue , A. Eskelinen , J. L. Firn , P. Graff , D. S. Gruner , R. W. Heckman , A. M. Koltz , K. J. Komatsu , L. S. Lannes , A. S. MacDougall
Publication : Nature Communications
Date : 2020
Volume : 11
Issue : 1
Pages : 6036
Catégorie(s)
#CEREEP #CNRS #ENSAuteurs, date et publication :
Auteurs Stephan Böhm
Publication : Chelonian Conservation and Biology
Date : 2025
Volume : 12
Issue : 1
Pages : 112-118
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Dominance often indicates one or a few species being best suited for resource capture and retention in a given environment. Press perturbations that change availability of limiting resources can restructure competitive hierarchies, allowing new species to capture or retain resources and leaving once dominant species fated to decline. However, dominant species may maintain high abundances even when their new environments no longer favour them due to stochastic processes associated with their high abundance, impeding deterministic processes that would otherwise diminish them. Here, we quantify the persistence of dominance by tracking the rate of decline in dominant species at 90 globally distributed grassland sites under experimentally elevated soil nutrient supply and reduced vertebrate consumer pressure. We found that chronic experimental nutrient addition and vertebrate exclusion caused certain subsets of species to lose dominance more quickly than in control plots. In control plots, perennial species and species with high initial cover maintained dominance for longer than annual species and those with low initial cover respectively. In fertilized plots, species with high initial cover maintained dominance at similar rates to control plots, while those with lower initial cover lost dominance even faster than similar species in controls. High initial cover increased the estimated time to dominance loss more strongly in plots with vertebrate exclosures than in controls. Vertebrate exclosures caused a slight decrease in the persistence of dominance for perennials, while fertilization brought perennials' rate of dominance loss in line with those of annuals. Annual species lost dominance at similar rates regardless of treatments. Synthesis. Collectively, these results point to a strong role of a species' historical abundance in maintaining dominance following environmental perturbations. Because dominant species play an outsized role in driving ecosystem processes, their ability to remain dominant—regardless of environmental conditions—is critical to anticipating expected rates of change in the structure and function of grasslands. Species that maintain dominance while no longer competitively favoured following press perturbations due to their historical abundances may result in community compositions that do not maximize resource capture, a key process of system responses to global change.
Auteurs, date et publication :
Auteurs Peter A. Wilfahrt , Eric W. Seabloom , Jonathan D. Bakker , Lori Biederman , Miguel N. Bugalho , Marc W. Cadotte , Maria C. Caldeira , Jane A. Catford , Qingqing Chen , Ian Donohue , Anne Ebeling , Nico Eisenhauer , Sylvia Haider , Robert W. Heckman , Anke Jentsch , Sally E. Koerner , Kimberly J. Komatsu , Ramesh Laungani , Andrew MacDougall , Jason P. Martina
Publication : Journal of Ecology
Date : 2025
Volume : n/a
Issue : n/a
Catégorie(s)
#CEREEP #CNRS #ENSRésumé
To identify novel epigenetic signatures that could provide predictive information that is complementary to promoter methylation status of the O-6-methylguanine-DNA methyltransferase (MGMT) gene for predicting temozolomide (TMZ) response, among glioblastomas (GBMs) without glioma-CpGs island methylator phenotype (G-CIMP)
Auteurs, date et publication :
Auteurs An-An Yin , Ya-Long He , Amandine Etcheverry , Yu-He Liu , Marc Aubry , Jill Barnholtz-Sloan , Bo-Lin Liu , Jean Mosser , Zi-Fan Lu , Xiang Zhang
Publication : Clinical Epigenetics
Date : 2019
Volume : 11
Issue : 1
Pages : 76
Catégorie(s)
#CNRS #EcoGenO #Université de RennesRésumé
Declines in grassland diversity in response to nutrient addition are a general consequence of global change. This decline in species richness may be driven by multiple underlying processes operating at different time-scales. Nutrient addition can reduce diversity by enhancing the rate of local extinction via competitive exclusion, or by reducing the rate of colonization by constraining the pool of species able to colonize under new conditions. Partitioning net change into extinction and colonization rates will better delineate the long-term effect of global change in grasslands. We synthesized changes in richness in response to experimental fertilization with nitrogen, phosphorus and potassium with micronutrients across 30 grasslands. We quantified changes in local richness, colonization, and extinction over 8–10 years of nutrient addition, and compared these rates against control conditions to isolate the effect of nutrient addition from background dynamics. Total richness at steady state in the control plots was the sum of equal, relatively high rates of local colonization and extinction. On aggregate, 30%–35% of initial species were lost and the same proportion of new species were gained at least once over a decade. Absolute turnover increased with site-level richness but was proportionately greater at lower-richness sites relative to starting richness. Loss of total richness with nutrient addition, especially N in combination with P or K, was driven by enhanced rates of extinction with a smaller contribution from reduced colonization. Enhanced extinction and reduced colonization were disproportionately among native species, perennials, and forbs. Reduced colonization plateaued after the first few (<5) years after nutrient addition, while enhanced extinction continued throughout the first decade. Synthesis. Our results indicate a high rate of colonizations and extinctions underlying the richness of ambient communities and that nutrient enhancement drives overall declines in diversity primarily by exclusion of previously established species. Moreover, enhanced extinction continues over long time-scales, suggesting continuous, long-term community responses and a need for long-term study to fully realize the extinction impact of increased nutrients on grassland composition.
Auteurs, date et publication :
Auteurs Andrew J. Muehleisen , Carmen R. E. Watkins , Gabriella R. Altmire , E. Ashley Shaw , Madelon F. Case , Lina Aoyama , Alejandro Brambila , Paul B. Reed , Marina LaForgia , Elizabeth T. Borer , Eric W. Seabloom , Jonathan D. Bakker , Carlos Alberto Amillas , Lori Biederman , Qingqing Chen , Elsa E. Cleland , Philip A. Fay , Nicole Hagenah , Stan Harpole , Yann Hautier
Publication : Journal of Ecology
Date : 2025
Volume : n/a
Issue : n/a
Catégorie(s)
#CEREEP #CNRS #ENSAuteurs, date et publication :
Auteurs Elizabeth T. Borer , Carly J. Stevens
Publication : Trends in Ecology & Evolution
Date : 2022
Volume : 37
Issue : 6
Pages : 541-552
Catégorie(s)
#CEREEP #CNRS #ENSRésumé
Explaining the evolutionary origin and maintenance of color polymorphisms is a major challenge in evolutionary biology. Such polymorphisms are commonly thought to reflect the existence of alternative behavioral or life-history strategies under negative frequency-dependent selection. The European common wall lizard Podarcis muralis exhibits a striking ventral color polymorphism that has been intensely studied and is often assumed to reflect alternative reproductive strategies, similar to the iconic “rock–paper–scissors” system described in the North American lizard Uta stansburiana. However, available studies so far have ignored central aspects in the behavioral ecology of this species that are crucial to assess the existence of alternative reproductive strategies. Here, we try to fill this gap by studying the social behavior, space use, and reproductive performance of lizards showing different color morphs, both in a free-ranging population from the eastern Pyrenees and in ten experimental mesocosm enclosures. In the natural population, we found no differences between morphs in site fidelity, space use, or male–female spatial overlap. Likewise, color morph was irrelevant to sociosexual behavior, space use, and reproductive success within experimental enclosures. Our results contradict the commonly held hypothesis that P. muralis morphs reflect alternative behavioral strategies, and suggest that we should instead turn our attention to alternative functional explanations.
Auteurs, date et publication :
Auteurs Javier Abalos , Guillem Pérez i de Lanuza , Alicia Bartolomé , Océane Liehrmann , Hanna Laakkonen , Fabien Aubret , Tobias Uller , Pau Carazo , Enrique Font
Publication : Ecology and Evolution
Date : 2025
Volume : 10
Issue : 20
Pages : 10986-11005