Etant donné le rôle clé des grands herbivores sur la diversité végétale spécifique et fonctionnelle, notre objectif était de mieux comprendre la relation entre l'herbivorie et les communautés végétales principalement à une échelle spatiale fine, afin de concilier des objectifs de gestions des populations et de conservation de la flore. Pour cela, nous avons abordé cette problématique en intégrant des approches taxonomiques et fonctionnelles, et en étudiant les interactions aux niveaux inter- et intra-spécifiques. Nous avons combiné les informations de trois bases de données : (1) des données de régime alimentaire issus d'analyses d'ADN metabarcoding réalisées sur des faeces de chamois (Rupicapra rupicapra), chevreuil (Capreolus capreolus) et mouflons (Ovis gmelini musimon) du Massif des Bauges, (2) des données sur les caractéristiques des communautés végétales (composition floristique, biomasse, phénologie), (3) des données de traits fonctionnels des plantes. L'analyse de variabilité intra-spécifique des trois grands herbivores nous a permis de valider l'hypothèse de variation de niche (NVH) de Van Valen au niveau intra-spécifique mais aussi au niveau inter-spécifique, soit une relation positive entre la largeur de niche de l'espèce et sa variabilité intra-spécifique. Ensuite, grâce à deux populations de chamois d'alpage, l'une vivant en sympatrie avec le mouflon et l'autre vivant en allopatrie, nous avons pu mettre en évidence l'absence d'effets négatifs de la population introduite de mouflon sur le régime alimentaire de la population native de chamois, autant au niveau de la niche alimentaire taxonomique que fonctionnelle. L'analyse des critères de sélection alimentaire nous a finalement permis de mettre en avant des différences de critères de choix entre les deux espèces à certaines saisons, expliquant ainsi partiellement le partitionnement des niches taxonomiques et fonctionnelles entre les deux espèces. Par ailleurs, les scénarios proposés d'évolution de la sélection alimentaire au cours de l'année pour les deux espèces concordaient avec les caractéristiques morphologiques spécifiques à l'espèce d'ongulé. Finalement, contrairement à la littérature où aucune étude n'était capable de discriminer les effets directs et indirects des traits fonctionnels à cause de corrélations, nous avons pu, grâce à des analyses de pistes, démontrer que, dans la plupart des cas, les traits biomécaniques avaient un effet direct sur le choix alimentaire alors que les traits chimiques n'avaient qu'un effet indirect. Enfin, d'un point de vue méthodologique, nous conseillons l'utilisation d'indices d'azote fécaux uniquement dans l'étude de la variation à long terme de la qualité des régimes de manière spécifique à chaque espèce et chaque site, et non pas pour comparer des qualités de régime entre espèces ni pour étudier les variations fines à l'échelle intra-saisonnière. La complémentarité des approches nous a permis de mieux appréhender la structuration des communautés d'herbivores, et devrait nous aider à mieux évaluer l'état actuel et l'évolution des relations entre individus, entre espèces et avec leur environnement.Mots-clés : ongulés, interactions intra- et inter-spécifiques, approche taxonomique et fonctionnelle, ADN metabarcoding, NIRS, massif des Bauges, sélection alimentaire / Given the key role of large herbivores on species and functional plant diversity, we aimed at better understanding the relationship between herbivory and plant communities mainly at a fine-scale, in order to reconcile objectives of population management and plant conservation. For this purpose, we used both taxonomic and functional approaches, and studied interactions at the inter- and intra-specific levels. We combined information coming from three databases: (1) diet data from DNA-metabarcoding applied on chamois (Rupicapra rupicapra), roe deer (Capreolus capreolus) and mouflon (Ovis gmelini musimon) faeces from the Bauges Massif, (2) characteristics of plant communities (plant composition, biomass, phenology), (3) plant functional traits. Analyses of intra-specific variability of the three large herbivores allowed us to upscale the niche variation hypothesis (NVH) of Van Valen from the intra- to the inter-specific level, i.e. we observed a positive relationship between the species niche breadth and among-individual variation. Then, based on two chamois subpopulations living in pastures, one living in sympatry with the mouflon and the other living in allopatry, we revealed the absence of negative effects of the introduced mouflon population on native chamois population diet, both for the taxonomic and functional dietary niche. Analyses of diet selection criteria allowed us to highlight differences in choice criteria between chamois and mouflon in some seasons, which helped to explain the taxonomic and functional niche partitioning of the two species. Furthermore, the proposed scenario of the evolution of diet selection over the year for both species were consistent with ungulate-specific morpho-physiological features. Finally, contrary to the literature where no studies could discriminate the direct and indirect effects of functional traits on diet selection because of correlations, we used path analyses, which allowed us to show that in most cases, biomechanical traits had a direct effect on diet choices, whereas chemical traits had an indirect effect. Furthermore, from a methodological point of view, we advised to use nitrogen fecal indices only to study the evolution of species-specific and location-specific population long-term diet quality, but not to compare diet quality between species, nor to study slight fluctuations at the intra-seasonal level. The complementarity of the approaches allowed us to better account for the structuration of herbivore communities, which should help to better assess the actual state and the evolution of relationships among individuals, species and their environment.Key-words: ungulates, intra- and inter-specific interactions, taxonomic and functional approach, DNA metabarcoding, NIRS, Bauges Massif, diet selection

Les changements globaux affectent la biodiversité à tous les niveaux de l’espace, du temps et d’organisation biologique. Afin de limiter notre impact sur le monde naturel, il est nécessaire de concilier nos activités avec les dynamiques de la biodiversité. Dans ce but, l’écologie scientifique a pour rôle d’apporter les connaissances scientifiques nécessaires à la compréhension et à la prédiction des réponses de la biodiversité lorsqu’elle est confrontée à de tels changements environnementaux. Or, la compréhension des processus par lesquels les activités humaines influent sur la diversité écologique est limité par la compartimentation de la discipline dans les échelles spatiales, temporelles, et entre les niveaux d’organisations.Partant de ce constat, ce travail de thèse s’est intéressé aux réponses des communautés d’oiseaux communs au changement climatique, en proposant une vision intégrative de l’écologie des changements globaux. J’ai notamment cherché à montrer comment la prise en compte des interactions entre les différentes échelles nous permettaient de lever le voile sur les processus mis en jeu dans les réponses des communautés précédemment décrites sur de larges échelles. En analysant des données issus de suivis à long-terme des oiseaux nicheurs communs en Europe (France, Suède) et en Amérique du Nord, j’ai proposé une navigation dans les dimensions spatiales, temporelles et les niveaux d’organisations. En confrontant les différentes échelles, mes travaux ont notamment montré que :(i) la recomposition thermique des communautés est une réponse non-linéaire aux variations de température déterminée à l’échelle locale, probablement via des processus démographiques influencés par les anomalies de températures.(ii) la présence d’aires protégées, la diversité en habitat et la topographie du paysage facilite la réponse des oiseaux communs aux variations de températures locales.(iii) la réponse à l’échelle des communautés est le fruit d’une interaction entre les dynamiques des espèces et les caractéristiques de leur niche thermique : les espèces abondantes ainsi que les espèces plus rares aux niches thermiques froides sont responsables des dynamiques de communautés observées.(v) le changement climatique joue un rôle notable dans le processus d’homogénéisation biotique. Les variations de température locales amènent une perte des espèces spécialistes et fonctionnellement originales, probablement via le relâchement des filtres écologiques sur l’assemblage des communautés.J’explore les conséquences de ces résultats sur notre compréhension des processus qui sous-tendent l’impact du changement climatique sur la composition fonctionnelle des communautés, ainsi que sur l’adaptation de nos stratégies d’aménagement du territoire. Je propose en conclusion de dépasser les clivages de l’écologie pour prendre plus explicitement et plus systématiquement en compte les interactions entre échelles. Je défends l’idée selon laquelle cette évolution de paradigme est nécessaire au développement d’une (macro) écologie plus mature et prédictive à même de répondre au défi imposé par la crise de la biodiversité. / Global changes affect biodiversity at all spatial, temporal and biological scales. In order to mitigate the human impact on nature, we must balance our activitis with biodiversity dynamics. To this end, scientific ecology must provide the scientific knowledge necessary for the understanding and prediction of biodiversity responses facing environmental changes. However, understanding the processes by which human activities affect the ecological diversity is still limited by the separation of ecology in different geographical, temporal, and biological levels.My work investigated birds’ communities responses to climate change by adopting an integrative view of global changes ecology. I precisely sought to show how considering interactions between different scales can unveil the processes involved in over large scales community responses previously described. By analyzing data from long-term monitoring of common breeding birds in Europe (France, Sweden) and North-America, I proposed proposed a multi-scale consideratin of space, time and levels of organizations. By confronting different scales, my work has shown that:(i) thermal recomposition of communities is a non-linear response to temperature variations locally determined, probably via demographic processes influenced by temperature anomalies.(ii) the amount of protected areas, habitat diversity and landscape topography promotes the response of common birds to local temperature variations.(iii) community level responses are shaped by the interaction between the species dynamics and their their thermal niche: both abundant species and rare species with cold thermal niches are responsible for the observed community dynamics.(iv) climate change drives a part of the biotic homogenization process. Local temperature changes lead to a relative loss of habitat-specialist and functionally original species, probably via the relaxation of environmental filters on the assembly of communities.I discussed the implications of these results on our understanding of the processes underlying the impact of climate change on the functional composition of communities, as well as adaptation of our land-management strategies. In conclusion, I suggest to move towards a more unified ecology by taking more explicitly and systematically into account the interactions between scales. I argue that such a change is necessary for the development of a more mature and predictive ecology able to took on the challenge imposed by the ongoing biodiversity crisis.

Os elevados custos de plantio e de manutenção de espécies nativas limitam a restauração florestal no Brasil. Buscando reduzir custos e acelerar a recuperação de vegetação ripária em região de cerrado, testou-se a utilização de espécie exótica de rápido crescimento (Pinus elliottii var. elliottii) como facilitadora da regeneração natural de espécies nativas lenhosas, no município de Assis, Estado de São Paulo, Brasil. A exploração de madeira e resina de Pinus poderia gerar receitas aos proprietários rurais e estimular ações de restauração com a compensação dos custos de plantio. Três tratamentos com plantio de Pinus nos espaçamentos 3 x 3 m, 3 x 2 m e 2 x 2 m, mais um quarto tratamento com áreas sem plantio (controle), foram instalados. Cada tratamento teve quatro repetições, em blocos ao acaso. Foram alocadas 16 parcelas (18 x 12 m cada) paralelamente ao rio, distando 20 a 40 m da margem. A área experimental fora utilizada como pastagem por duas décadas. Na ocasião do plantio (1995), predominavam gramíneas africanas. Plantas lenhosas e estruturas subterrâneas existentes foram preservadas. Avaliou-se área basal, cobertura de copas e sobrevivência das árvores plantadas, assim como composição florística, estrutura e cobertura de copas das plantas lenhosas em regeneração (altura mínima de 50 cm) em 1996, 1998, 1999, 2001 e 2006. Desejava-se verificar se: 1) Pinus facilitaria a regeneração da comunidade nativa; 2) Pinus dificultaria a regeneração da comunidade nativa ou 3) Pinus não alteraria a regeneração da comunidade nativa. Até 2006, a densidade média de plantas lenhosas regenerantes foi de 4923 ind/ha sob Pinus (maior quanto maior a densidade de Pinus) e de 3472 ind/ha no controle. Foram registradas 68 espécies lenhosas nativas em regeneração na área experimental, pertencentes a 31 famílias. Houve correlação positiva entre densidade das plantas regenerantes e densidade e área basal de Pinus, e correlação negativa entre parâmetros estruturais de Pinus e cobertura do terreno por gramíneas. Conclui-se que Pinus eliminou as gramíneas pelo sombreamento, favorecendo indiretamente as plantas nativas. Até 2006, não se constatou competição entre plantas nativas e Pinus pelos recursos do ambiente. Houve maior proporção de plantas zoocóricas regenerantes no controle, e correlação negativa entre proporção de regenerantes zoocóricos e parâmetros estruturais de Pinus. Foram favorecidas por Pinus 40% das espécies regenerantes e, 25%, prejudicadas. A sucessão deverá conduzir as duas situações a comunidades distintas, especialmente em função da tolerância das espécies à sombra, predominantes sob Pinus. A análise econômica do uso de Pinus elliottii como facilitadora da regeneração natural demonstrou menores custos de plantio (cerca de um terço dos custos de plantios mistos com espécies nativas), compensados por um ano de exploração de resina. Porém, as técnicas usuais de exploração podem danificar as plantas regenerantes do sub-bosque. Assim, a restauração da comunidade nativa exige meios menos impactantes de exploração dos plantios de espécies exóticas. / Among the obstacles to the native forests restoration in Brazil we find the high costs of planting high diversity of native trees. Searching for reduction of costs and vegetation recovery acceleration, the use of a fast growing exotic species (Pinus elliottii var. elliottii) as pioneer was tested in a riparian area in the cerrado domain, at Assis municipality, São Paulo State, Brazil. As observed in forest plantations with exotic species in the same region, we expected the natural regeneration of native species to occur under the planted exotic trees. In addition, the later exploitation of the exotic species could bring some profit to the land owner, surpassing the restoration costs, and thus stimulating forest restoration initiatives. Pinus was planted in three different spacings (treatments): 3 x 3 m, 3 x 2 m and 2 x 2 m, and a fourth treatment consisted of not planted plots (control). Every treatment had four replications in randomized blocks, the 16 plots (18 x 12 m each) settled along the stream, from 20 to 40 m far from the margin. The experimental area had been used as pasture for at least two decades, mostly covered by african grasses. Some native species then existing were preserved when the Pinus trees were planted, in 1995, without revolving the soil. Basal area, crown cover and survival of planted trees, as well as floristic composition, density and crown cover of native species regenerating in every plot (minimum height 50 cm) were assessed in 1996, 1998, 1999, 2001 and 2006. The aim was to verify if: 1) Pinus trees facilitating the regeneration of the native species, 2) Pinus trees obstructing the evolution of the native community or 3) the exotic species not affecting the native community. In 2006, density of the native woody species regenerating was 4923 ind/ha under Pinus and 3472 ind/ha in the control, from a total of 68 woody species (31 families) in the experimental area. Density of the regenerating community was positively correlated to density and basal area of Pinus. Thus, we concluded that Pinus eliminating grasses by shading (ground cover by grasses was inversely correlated to Pinus structure), indirectly favored the native woody species and are still not competing with them. The proportion of zoochorous species was negatively correlated to the Pinus density, showing that the exotic species does not attract animal seed dispersers. In the open areas (control), the zoochory was relatively more frequent. Density of some species (40%) increasing under Pinus and others (25%) decreasing or disappearing, which means secondary succession should go toward different directions if under Pinus plantation or in open areas. Analyzing the economical aspects of using Pinus as pioneer, we found that planting costs corresponded to a third part of those of planting mixed stands with native species. In addition, planting costs can be compensated by a single year of resin exploitation. However, current techniques of resin extraction or timber exploitation could cause considerable damages to the understory. Alternative exploitation techniques of the exotic species must be encouraged if restoration of the native community in the understory is expected.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-05-18T12:18:30Z No. of bitstreams: 1 taisanascimentodesouza.pdf: 1060861 bytes, checksum: 18f51d80da3fa7e5ec8e564e3b85452a (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-09-03T16:03:47Z (GMT) No. of bitstreams: 1 taisanascimentodesouza.pdf: 1060861 bytes, checksum: 18f51d80da3fa7e5ec8e564e3b85452a (MD5) / Made available in DSpace on 2018-09-03T16:03:47Z (GMT). No. of bitstreams: 1 taisanascimentodesouza.pdf: 1060861 bytes, checksum: 18f51d80da3fa7e5ec8e564e3b85452a (MD5) Previous issue date: 2018-02-19 / A dominância de espécies exóticas é uma das principais características de florestas secundárias e dos chamados Novel Ecosystems. Apesar de estudos avaliarem os padrões destas comunidades em florestas tropicais úmidas, pouco ainda é conhecido sobre esses padrões em florestas tropicais. A espécie Pinus elliotti possui alto potencial invasor em florestas neotropicais, sendo encontrada em florestas secundárias da Zona da Mata Mineira. O objetivo deste estudo foi analisar a dinâmica (5 anos) da comunidade arbórea de uma floresta secundária urbana dominada por P. elliotti. As mudanças florísticas e estruturais foram analisadas a partir de comparações entre dois inventários realizados em parcelas permanentes (15 parcelas de 20 x 20 m alocadas aleatoriamente na floresta) nos anos de 2011 e 2016. Todos os indivíduos arbóreos com DAP ≥ 5 cm foram amostrados, mensurados, e calculados os parâmetros estruturais, fitossociológicos e diversidade de espécies. Foram calculadas as taxas de dinâmica (recrutamento, mortalidade, ganho e perda de área basal), sendo amostrados 943 indivíduos, 168 recrutas e 151 mortos. A comunidade apresentou forte dominância específica, com grande concentração dos valores de importância (VI) distribuídos nas sete primeiras espécies (Pinus elliottii; Miconia artemisiana; Mimosa artemisiana; Myrcia splendens, Pleroma mutabilis, Piptadenia gonoacantha e Miconia urophyla), que, juntas, somaram 52,2% do VI total. Entre as duas medições, a taxa de mortalidade, de 3,50%.ano-1, foi pouco inferior a de recrutamento, de 3,85%.ano-1. A taxa de ganho em área basal de 5,98%.ano-1, superou a de perda, de 2,90%.ano-1. Apesar da presença das espécies invasoras e da dinâmica acelerada, não foram observadas grandes alterações estruturais no fragmento, com tendência da comunidade de se manter floristicamente estável, a curto e médio prazo, em função da resistência das principais populações. / The dominance of exotic species is a major feature of secondary forests and socalled Novel Ecosystems. Although studies assess the patterns of these communities in tropical rainforests, little is known about these patterns in tropical forests. The species Pinus elliotti have high invasive potential in neotropical forests, and are found in secondary forests of the Zona da Mata at Minas Gerais State. The aim of this study was to analyze the dynamics (5 years) of the tree community of an urban secondary forest dominated by P. elliotti. Floristic and structural changes were analyzed from comparisons between two inventories in permanent plots (15 plots of 20 x 20 m randomly allocated in the forest) in the years 2011 and 2016. All tree individuals with DBH ≥ 5 cm were sampled, measured, and calculated the structural, phytosociological and species diversity parameters. Dynamic rates (recruitment, mortality, gain and loss of basal area) were calculated, being sampled 943 individuals, 168 recruits and 151 deaths. The community showed a strong specific dominance, with a high concentration of importance values (VI) distributed in the first seven species (Pinus elliottii; Miconia artemisiana; Mimosa artemisiana; Myrcia splendens; Pleroma mutabilis; Piptadenia gonoacantha; Miconia urophyla), which accounted for 52.2% of the total VI. Between the two measurements, the mortality rate of 3.50% .year-1 was slightly lower than that of recruitment of 3.85% .year-1. The rate of gain in basal area of 5.98% .year-1 exceeded that of loss of 2.90% .year-1. Despite the presence of invasive species and accelerated dynamics, there were no major structural changes in the fragment, believing that the community is able to remain floristically stable in the short and medium term, due to the resistance of the main populations.

From August 1996 through September 1997 eleven fixed stations were sampled monthly in January, March , April , July, August, September, and November and fortnightly in May and June for the purposes of establishing baseline conditions present in Lake Texoma as related to U.S. Army Corps of Engineers chloride control activities in the upper Wichita River, Texas. Five reservoir zones were identified a priori using historical chloride concentration data and include the Red River Zone (RRZ), Red River Transition Zone (RRTZ), Main Lake Body (MLB), Washita River Transition Zone (WRTZ), and Washita River Zone (WRZ) in order of decreasing chloride concentration. The existence of the WRTZ is not supported here, however the Big Mineral Arm in the RRTZ was observed to be highly independent of the mixing patterns observed in the RRTZ and was treated post priori separately from the RRTZ. Spatial and temporal comparisons between reservoir zones were performed on seventeen (17) physicochemical parameters from each of the eleven sampling stations and phytoplankton count data from one sampling station within each reservoir zone and physicochemical parameters were observed to exhibit a fixed spatial gradient. Strong density gradients throughout the reservoir were observed to occur in conjunction with vertical stratification of the water column. Stratification stability at individual stations was attributable to both thermal and salinity density gradients throughout the period of stratification with the degree to which stratification is thermally or chemically induced influenced by inter-annual variability in hydraulic residence time. Hypolimnetic oxygen depletion rates were also observed to be affected by changes in hydraulic residence time with a long-term trend of decreasing relative areal hypolimnetic oxygen rates detected between the 1970s and 1990s. The algal assemblage present in Lake Texoma is dominated by the Cyanophyta, which comprises 82.1 % of the assemblage total standing crop with one species, Microcystis incerta, comprising 57.0 % of the assemblage total standing crop and is typical of a temperate eutrophic lake. The algal assemblage was affected more by temporal dynamics rather than spatial dynamics with variance observed in the algal assemblage attributable to physicochemical factors which vary through time.

No description available.

No description available.

Les communautés végétales constituent des systèmes complexes au sein desquels de nombreuses espèces, pouvant présenter une large variété de traits fonctionnels, interagissent entre elles et avec leur environnement. En raison de la quantité et de la diversité de ces interactions les mécanismes qui gouvernent les dynamiques des ces communautés sont encore mal connus. Les approches basées sur la modélisation permettent de relier de manière mécaniste les processus gouvernant les dynamiques des individus ou des populations aux dynamiques des communautés qu'ils forment. L'objectif de cette thèse était de développer de telles approches et de les mettre en oeuvre pour étudier les mécanismes sous-jacents aux dynamiques des communautés. Nous avons ainsi développés deux approches de modélisation. La première s'appuie sur un cadre de modélisation stochastique permettant de relier les dynamiques de populations aux dynamiques des communautés en tenant compte des interactions intra- et interspécifiques et de l'impact des variations environnementale et démographique. Cette approche peut-être aisément appliquée à des systèmes réels et permet de caractériser les populations végétales à l'aide d'un petit nombre de paramètres démographiques. Cependant nos travaux suggèrent qu'il n'existe pas de relation simple entre ces paramètres et les traits fonctionnels des espèces, qui gouvernent pourtant leur réponse aux facteurs externes. La seconde approche a été développée pour dépasser cette limite et s'appuie sur le modèle individu-centré Nemossos qui représente de manière explicite le lien entre le fonctionnement des individus et les dynamiques de la communauté qu'ils forment. Afin d'assurer un grand potentiel d'application à Nemossos, nous avons apportés une grande attention au compromis entre réalisme et coût de paramétrisation. Nemossos a ainsi pu être entièrement paramétré à partir de valeur de traits issues de la littérature , son réalisme a été démontré, et il a été utilisé pour mener des expériences de simulations numériques sur l'importance de la variabilité temporelle des conditions environnementales pour la coexistence d'espèces fonctionnellement différentes. La complémentarité des deux approches nous a permis de proposer des éléments de réponse à divers questions fondamentales de l'écologie des communautés incluant le rôle de la compétition dans les dynamiques des communautés, l'effet du filtrage environnementale sur leur composition fonctionnel ou encore les mécanismes favorisant la coexistence des espèces végétales. Ici ces approches ont été utilisées séparément mais leur couplage peut offrir des perspectives intéressantes telles que l'étude du lien entre le fonctionnement des plantes et les dynamiques des populations. Par ailleurs chacune des approches peut être utilisée dans une grande variété d'expériences de simulation susceptible d'améliorer notre compréhension des mécanismes gouvernant les communautés végétales. / Plant communities are complex systems in which multiple species differing by their functional attributes interact with their environment and with each other. Because of the number and the diversity of these interactions the mechanisms that drive the dynamics of theses communities are still poorly understood. Modelling approaches enable to link in a mechanistic fashion the process driving individual plant or population dynamics to the resulting community dynamics. This PhD thesis aims at developing such approaches and to use them to investigate the mechanisms underlying community dynamics. We therefore developed two modelling approaches. The first one is based on a stochastic modelling framework allowing to link the population dynamics to the community dynamics whilst taking account of intra- and interspecific interactions as well as environmental and demographic variations. This approach is easily applicable to real systems and enables to describe the properties of plant population through a small number of demographic parameters. However our work suggests that there is no simple relationship between these parameters and plant functional traits, while they are known to drive their response to extrinsic factors. The second approach has been developed to overcome this limitation and rely on the individual-based model Nemossos that explicitly describes the link between plant functioning and community dynamics. In order to ensure that Nemossos has a large application potential, a strong emphasis has been placed on the tradeoff between realism and parametrization cost. Nemossos has then been successfully parameterized from trait values found in the literature, its realism has been demonstrated and it has been used to investigate the importance of temporal environmental variability for the coexistence of functionally differing species. The complementarity of the two approaches allows us to explore various fundamental questions of community ecology including the impact of competitive interactions on community dynamics, the effect of environmental filtering on their functional composition, or the mechanisms favoring the coexistence of plant species. In this work, the two approaches have been used separately but their coupling might offer interesting perspectives such as the investigation of the relationships between plant functioning and population dynamics. Moreover each of the approaches might be used to run various simulation experiments likely to improve our understanding of mechanisms underlying community dynamics.