Résumé
The recovery of soil conditions is crucial for successful ecosystem restoration and, hence, for achieving the goals of the UN Decade on Ecosystem Restoration. Here, we assess how soils resist forest conversion and agricultural land use, and how soils recover during subsequent tropical forest succession on abandoned agricultural fields. Our overarching question is how soil resistance and recovery depend on local conditions such as climate, soil type and land-use history. For 300 plots in 21 sites across the Neotropics, we used a chronosequence approach in which we sampled soils from two depths in old-growth forests, agricultural fields (i.e. crop fields and pastures), and secondary forests that differ in age (1–95 years) since abandonment. We measured six soil properties using a standardized sampling design and laboratory analyses. Soil resistance strongly depended on local conditions. Croplands and sites on high-activity clay (i.e. high fertility) show strong increases in bulk density and decreases in pH, carbon (C) and nitrogen (N) during deforestation and subsequent agricultural use. Resistance is lower in such sites probably because of a sharp decline in fine root biomass in croplands in the upper soil layers, and a decline in litter input from formerly productive old-growth forest (on high-activity clays). Soil recovery also strongly depended on local conditions. During forest succession, high-activity clays and croplands decreased most strongly in bulk density and increased in C and N, possibly because of strongly compacted soils with low C and N after cropland abandonment, and because of rapid vegetation recovery in high-activity clays leading to greater fine root growth and litter input. Furthermore, sites at low precipitation decreased in pH, whereas sites at high precipitation increased in N and decreased in C : N ratio. Extractable phosphorus (P) did not recover during succession, suggesting increased P limitation as forests age. These results indicate that no single solution exists for effective soil restoration and that local site conditions should determine the restoration strategies.This article is part of the theme issue ‘Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration'.
Auteurs, date et publication :
Auteurs Masha T. van der Sande , Jennifer S. Powers , Thom W. Kuyper , Natalia Norden , Beatriz Salgado-Negret , Jarcilene Silva de Almeida , Frans Bongers , Diego Delgado , Daisy H. Dent , Géraldine Derroire , Mario Marcos do Espirito Santo , Juan Manuel Dupuy , Geraldo Wilson Fernandes , Bryan Finegan , Mayra E. Gavito , José Luis Hernández-Stefanoni , Catarina C. Jakovac , Isabel L. Jones , Maria das Dores Magalhães Veloso , Jorge A. Meave
Publication : Philosophical Transactions of the Royal Society B: Biological Sciences
Date : 2025
Volume : 378
Issue : 1867
Catégorie(s)
#CIRAD #FORET ParacouRésumé
The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from $sim$1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers.
Auteurs, date et publication :
Auteurs Jingjing Liang , Javier G P Gamarra , Nicolas Picard , Mo Zhou , Bryan Pijanowski , Douglass F Jacobs , Peter B Reich , Thomas W Crowther , Gert-Jan Nabuurs , Sergio De-Miguel , Jingyun Fang , Christopher W Woodall , Jens-Christian Svenning , Tommaso Jucker , Jean-Francois Bastin , Susan K Wiser , Ferry Slik , Bruno Hérault , Giorgio Alberti , Gunnar Keppel
Publication : Nature Ecology & Evolution
Date : 2025
Catégorie(s)
#CIRAD #FORET ParacouRésumé
Abstract
Biogeochemical niche (BN) hypothesis aims to relate species/genotype elemental composition with its niche based on the fact that different elements are involved differentially in distinct plant functions. We here test the BN hypothesis through the analysis of the 10 foliar elemental concentrations and 20 functional‐morphological of 60 tree species in a French Guiana tropical forest. We observed strong legacy (phylogenic + species) signals in the species‐specific foliar elemental composition (elementome) and, for the first time, provide empirical evidence for a relationship between species‐specific foliar elementome and functional traits. Our study thus supports the BN hypothesis and confirms the general niche segregation process through which the species‐specific use of bio‐elements drives the high levels of α‐diversity in this tropical forest. We show that the simple analysis of foliar elementomes may be used to test for BNs of co‐occurring species in highly diverse ecosystems, such as tropical rainforests. Although cause and effect mechanisms of leaf functional and morphological traits in species‐specific use of bio‐elements require confirmation, we posit the hypothesis that divergences in functional‐morphological niches and species‐specific biogeochemical use are likely to have co‐evolved.
Auteurs, date et publication :
Auteurs Jordi Sardans , Joan Llusià , Romà Ogaya , Helen Vallicrosa , Iolanda Filella , Albert Gargallo‐Garriga , Guille Peguero , Leandro Van Langenhove , Lore T. Verryckt , Clément Stahl , Elodie A. Courtois , Laëtitia M. Bréchet , Akash Tariq , Fanjiang Zeng , Abdulwahed Fahad Alrefaei , Weiqi Wang , Ivan A. Janssens , Josep Peñuelas
Publication : Ecology
Date : 2025
Volume : 104
Issue : 11
Pages : e4118
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
Estimating consistent large-scale tropical forest height using remote sensing is essential for understanding forest-related carbon cycles. The Global Ecosystem Dynamics Investigation (GEDI) light detection and ranging (LiDAR) instrument employed on the International Space Station has collected unique vegetation structure data since April 2019. Our study shows the potential value of using remote-sensing (RS) data (i.e., optical Sentinel-2, radar Sentinel-1, and radar PALSAR-2) to extrapolate GEDI footprint-level forest canopy height model (CHM) measurements. We show that selected RS features can estimate vegetation heights with high precision by analyzing RS data, spaceborne GEDI LiDAR, and airborne LiDAR at four tropical forest sites in South America and Africa. We found that the GEDI relative height (RH) metric is the best at 98% (RH98), filtered by full-power shots with a sensitivity greater than 98%. We found that the optical Sentinel-2 indices are dominant with respect to radar from 77 possible features. We proposed the nine essential optical Sentinel-2 and the radar cross-polarization HV PALSAR-2 features in CHM estimation. Using only ten optimal indices for the regression problems can avoid unimportant features and reduce the computational effort. The predicted CHM was compared to the available airborne LiDAR data, resulting in an error of around 5 m. Finally, we tested cross-validation error values between South America and Africa, including around 40% from validation data in training to obtain a similar performance. We recommend that GEDI data be extracted from all continents to maintain consistent performance on a global scale. Combining GEDI and RS data is a promising method to advance our capability in mapping CHM values.
Auteurs, date et publication :
Auteurs Yen-Nhi Ngo , Dinh Ho Tong Minh , Nicolas Baghdadi , Ibrahim Fayad
Publication : Remote Sensing
Date : 2023
Volume : 15
Issue : 4
Pages : 975
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics.
Auteurs, date et publication :
Auteurs Edwin Pos , Luiz de Souza Coelho , Diogenes de Andrade Lima Filho , Rafael P. Salomão , Iêda Leão Amaral , Francisca Dionízia de Almeida Matos , Carolina V. Castilho , Oliver L. Phillips , Juan Ernesto Guevara , Marcelo de Jesus Veiga Carim , Dairon Cárdenas López , William E. Magnusson , Florian Wittmann , Mariana Victória Irume , Maria Pires Martins , Daniel Sabatier , José Renan da Silva Guimarães , Jean François Molino , Olaf S. Bánki , Maria Teresa Fernandez Piedade
Publication : Scientific Reports
Date : 2023
Volume : 13
Issue : 1
Pages : 1–11
Catégorie(s)
#CIRAD #FORET ParacouRésumé
Reconstructing past ecological population dynamics and demographic events is crucial for understanding the dynamics of ecological processes, evaluating the impact of environmental changes and making informed conservation decisions. In forest ecosystems, retrodiction (i.e. the backward projection of ecological populations) plays a pivotal role in understanding historical forest carbon levels and the factors that have influenced their variation over time, because forest demography is a major determinant of the amount of carbon stored in forest ecosystems. The persistent lack of quantitative methods has been a significant obstacle in retrodicting forest demography, especially in applications of a broad geographical scale. While there is a wealth of models for predicting future forest conditions, models that can project these conditions backward in time are scarce. This study presents reverse matrix model (RMM), an innovative retrodiction modelling approach grounded in the principles of transition matrix models. RMM is designed to deduce past demographic characteristics of ecological populations using current data, making it one of the first models capable of projecting the fine-scale dynamics of forest demography into the past. We assessed the retrodictive performance of RMM by fitting it to a dataset of a disturbed tropical rainforest in French Guiana in 2001–2023, then comparing the retrodictions to observations back to 1983 when the disturbance occurred. We further empirically evaluated the viability of retrodiction over a defined duration by inverting the density-dependent matrix model by Lin et al. (1996), which predicts the dynamics of northern hardwoods in the United States. The case studies demonstrate significant potential for RMM application in various domains of forestry and conservation, including ecosystem management and conservation planning, global change impact assessment and biodiversity monitoring.
Auteurs, date et publication :
Auteurs Nicolas Picard , Jack Andrew Hansen , Nancy Harris , Jingjing Liang
Publication : Methods in Ecology and Evolution
Date : 2025
Volume : 15
Issue : 11
Pages : 2024-2037
Catégorie(s)
#CIRAD #FORET ParacouRésumé
Fine roots mediate plant nutrient acquisition and growth. Depending on soil nutrient availability, plants can regulate fine root biomass and morphological traits to optimise nutrient acquisition. Little is known, however, about the importance of these parameters influencing forest functioning. In this study, we measured root responses to nutrient additions to gain a mechanistic understanding of plant adaptations to nutrient limitation in two tropical forests in French Guiana, differing twofold in their soil nutrient statuses. We analysed the responses of root biomass, mean root diameter (RD), specific root length (SRL), specific root area (SRA), root tissue density (RTD) and carbon (C), nitrogen (N) and phosphorus (P) concentrations in roots down to 15 cm soil depth after three years of N and P additions. At the lower-fertility site Paracou, no changes in root biomass or morphological traits were detected with either N or P addition, although P concentrations in roots increased with P addition. In the higher fertility site, Nouragues, root biomass and P concentrations in roots increased with P addition, with no changes in morphological traits. In contrast, N addition shifted root traits from acquisitive to more conservative by increasing RTD. A significant interaction between N and P in Nouragues pointed to stronger responses to P addition in the absence of N. Our results suggest that the magnitude and direction of root biomass and trait expression were regulated by soil fertility, corroborated by the response to N or P additions. At low fertility sites, we found lower plasticity in root trait expression compared to more fertile conditions, where N and P additions caused stronger and antagonistic responses. Identifying the exact role of mechanisms affecting root nutrient uptake in Amazon forests growing in different soils will be crucial to foresee if and how rapid global changes can affect their carbon allocation.
Auteurs, date et publication :
Auteurs Laynara F. Lugli , Lucia Fuchslueger , Helena Vallicrosa , Leandro Van Langenhove , Christian Ranits , Pere Roc Fernandez Garberi , Lore Verryckt , Oriol Grau , Laëtitia Bréchet , Guille Peguero , Joan Llusia , Romà Ogaya , Laura Marquez , Miguel Portillo-Estrada , Irene Ramirez-Rojas , Elodie Courtois , Clement Stahl , Jordi Sardans , Josep Penuelas , Erik Verbruggen
Publication : Oikos
Date : 2025
Volume : 2024
Issue : 4
Pages : e10412
Catégorie(s)
#ANR-Citation #CNRS #FORET Nouragues #FORET ParacouRésumé
Climate extremes and biotic interactions at the neighbourhood scale affect tropical forest dynamics with long-term consequences for biodiversity, global carbon cycling and climate change mitigation. However, forest disturbance may change crowding intensity, and thus the relative contribution of climate extremes and neighbourhood interactions on tree growth, thereby influencing tropical forest resistance and resilience to climate change. Here, we aim to evaluate the separate and interactive effects of climate and neighbours on tree growth in old-growth and disturbed tropical forests. We used 30 years of growth measurements for over 300 tropical tree species from 15 forest plots in French Guiana to investigate the separate and interactive effects of climate anomalies (in solar radiation, maximum temperature, vapour pressure deficit and climatic water deficit) and neighbourhood crowding on individual tree growth. Contrasting old-growth and selectively logged forests, we also examined how disturbance history affects tree growth sensitivity to climate and neighbours. Finally, for the most abundant 100 species, we evaluated the role of 12 functional traits pertaining to water relations, light and carbon use in mediating tree growth sensitivity to climate anomalies, neighbourhood crowding and their interactions. Climate anomalies tied to heat and drought stress and neighbourhood crowding independently reduced tree growth, and showed positive interactive effects which attenuated their separate effects on tree growth. Their separate and interactive effects were stronger in disturbed than undisturbed forests. Fast-growing species (i.e. higher intrinsic growth rates) were more abundant in disturbed forests and more sensitive to climate anomalies and neighbourhood crowding. Traits related to water relations, light and carbon use captured species sensitivities to different climate anomalies and neighbourhood crowding levels but were weak predictors of their interactions. Synthesis: Our results demonstrate that climate anomalies and neighbourhood crowding can interact to shape tropical tree growth, suggesting that considering the biotic context may improve predictions of tropical forest dynamics facing altered climate regimes. Furthermore, species traits can capture tree growth sensitivity to the separate effects of climate and neighbours, suggesting that better representing leading functional dimensions in tropical tree strategies offers a promising way towards a better understanding of the underlying ecological mechanisms that govern tropical forest dynamics.
Auteurs, date et publication :
Auteurs Daniela Nemetschek , Géraldine Derroire , Eric Marcon , Mélaine Aubry-Kientz , Johanna Auer , Vincyane Badouard , Christopher Baraloto , David Bauman , Quentin Le Blaye , Marion Boisseaux , Damien Bonal , Sabrina Coste , Elia Dardevet , Patrick Heuret , Peter Hietz , Sébastien Levionnois , Isabelle Maréchaux , Sean M. McMahon , Clément Stahl , Jason Vleminckx
Publication : Journal of Ecology
Date : 2025
Volume : 112
Issue : 3
Pages : 590-612
Catégorie(s)
#CIRAD #FORET ParacouRésumé
One foundational assumption of trait-based ecology is that traits can predict species demography. However, the links between traits and demographic rates are, in general, not as strong as expected. These weak associations may be due to the use of traits that are distantly related to performance, and/or the lack of consideration of size-related variations in both traits and demographic rates. Here, we examined how wood traits were related to demographic rates in 19 tree species from a lowland forest in eastern Amazonia. We measured 11 wood traits (i.e. structural, anatomical and chemical traits) in sapling, juvenile and adult wood; and related them to growth and mortality rates (MR) at different ontogenetic stages. The links between wood traits and demographic rates changed during tree development. At the sapling stage, relative growth rates (RGR) were negatively related to wood specific gravity (WSG) and total parenchyma fractions, while MR decreased with radial parenchyma fractions, but increased with vessel lumen area (VA). Juvenile RGR were unrelated to wood traits, whereas juvenile MR were negatively related to WSG and axial parenchyma fractions. At the adult stage, RGR scaled with VA and wood potassium concentrations. Adult MR were not predicted by any trait. Overall, the strength of the trait-demography associations decreased at later ontogenetic stages. Our results indicate that the associations between traits and demographic rates can change as trees age. Also, wood chemical or anatomical traits may be better predictors of growth and MR than WSG. Our findings are important to expand our knowledge on tree life-history variations and community dynamics in tropical forests, by broadening our understanding on the links between wood traits and demography during tree development.
Auteurs, date et publication :
Auteurs Andrés González-Melo , Juan Manuel Posada , Jacques Beauchêne , Romain Lehnebach , Sébastian Levionnois , Géraldine Derroire , Bruno Clair , Juliana Medeiros
Publication : AoB PLANTS
Date : 2024
Volume : 16
Issue : 1
Pages : plad090
Catégorie(s)
#CIRAD #CNRS #FORET Nouragues #FORET ParacouRésumé
Predictions of climate change over land indicate drying trends in the form of ecological and agricultural droughts over many regions (1-6), and increased flooding in others (7). Globally, evapotranspiration (ET) from vegetated areas consumes about 63% of annual precipitation8, which is expected to increase with global warming (9,10), and can approach 100% in drylands (11) beyond which ecosystems are unsustainable. As global climate change progresses, it remains unknown what fraction of the precipitation will remain available for runoff, recharge of aquifers and consumption, or prevent ecosystems’ collapse in dry regions (7,12). Here, we show using a global dataset that evapotranspiration from ecosystems displays a conservative ‘saturation effect’ at ~460 mm across climates with a precipitation range of ~4000 mm. This implies that changes in precipitation are preferentially reflected in ecosystem water yield (WY; the residual between precipitation and evapotranspiration). Consequently, changes in WY are greatly enhanced compared with precipitation changes, both in observations and model-based future projections. In dry regions, ecosystems will reach the unsustainable state (negative WY) faster than expected based on predicted changes in precipitation alone, imposing land cover changes and impacting water availability for ecological and societal needs.
Auteurs, date et publication :
Auteurs Fedor Tatrinov , Jonathan Müller , Eyal Rotenberg
Date : 2024