Entre permis forestier et permis minier, la diff icile émergence des forêts communautaires au Gabon

A l’heure de l’attribution des premières forêts communautaires au Gabon, de multiples questions surgissent et attendent de manière urgente une réponse de la part de l’Etat. Le présent article se penche sur l’une d’entre elles, à savoir la superposition des permis d’exploitation (minier, forestier) avec l’espace utilisé traditionnellement par les communautés locales et candidates à l’obtention d’une forêt communautaire. Quelques situations rencontrées sur le terrain sont présentées et discutées. Il est urgent qu’un réel aménagement du territoire voie le jour au Gabon, qui détermine la place de chaque activité, hiérarchise l’affectation de l’espace et détermine le cas échéant les conditions de « cohabitation » de plusieurs permis.Projet Développement d'alternatives Communautaires à la Foresterie Illégale (DACEFI

Effects of low-frequency noise and temperature on copepod and amphipod performance

Offshore wind farms (OWF) are bound to increase as a mitigation strategy to reduce the emission of greenhouse gases, it is crucial to address all of their potential impacts on key ecosystem components in detail. Especially, the chronic effect of noise created during OWF turbine operations (duration 20-25 years) must be understood. As sensitive receptors cover the whole body of crustaceans to detect their surroundings, those low frequency noises may disrupt basic ecological (prey detection and predator avoidance) and physiological (metabolism) functions. Here we present an investigation designed to understand the joint effect of noise and increased temperature on copepod. The pelagic copepod Acartia tonsa is commonly used as a proxy for a range of fundamental processes that relate to marine planktonic crustaceans. Given that higher temperatures increase metabolic demands, the experiment was conducted at three different temperature levels (18, 21, 24°C) combined with silent and noise treatments. We assessed the combined effects on energetic balance, and oxidative stress indicators. The outputs of the project will provide important information on the potential impact of low-frequency noise on marine invertebrate key organisms with implications for secondary production and ecosystem functioning

Comparaison d'analyses phonétiques de parole dysarthrique basées sur un alignement manuel et un alignement automatique

International audienceThe reliability of an automatic speech alignment procedure for the phonetic description of dysarthric speech is assessed through the comparison of durational and spectral measurements obtained from an automatic and a manual alignment of the production of 4 dysarthric speakers varying in severity. Results show that formant values computed in the middle of the vowel intervals and center of gravity of fricative noise computed over the consonant intervals, are reliable when based on automatic alignments. However, the analysis of pause occurrences and absolute segmental duration require manual corrections of the automatic outputs.Les performances d'une procédure d'alignement automatique permettant la description de la parole dysarthrique est évaluée dans cette étude. Les durées et valeurs spectrales extraites des enregistrements de 4 patients dysarthriques (différents niveaux de sévérité) obtenues à partir de l'alignement automatique sont comparées à celles obtenues partir d'un alignement manuel. Les résultats sur l'analyse spectrale des voyelles et des fricatives montrent que l'alignement automatique est performant. Toutefois, l'analyse des pauses et les mesures de durées manquent de précision et suggèrent qu'une correction manuelle de l'alignement automatique est nécessaire

Environmentally induced functional shifts in phytoplankton and their potential consequences for ecosystem functioning

Phytoplanktonic organisms are particularly sensitive to environmental change, and, as they represent a direct link between abiotic and biotic compartments within the marine food web, changes in the functional structure of phytoplankton communities can result in profound impacts on ecosystem functioning. Using a trait-based approach, we examined changes in the functional structure of the southern North Sea phytoplankton over the past five decades in relation to environmental conditions. We identified a shift in functional structure between 1998 and 2004 which coincides with a pronounced increase in diatom and decrease in dinoflagellate abundances, and we provide a mechanistic explanation for this taxonomic change. Early in the 2000s, the phytoplankton functional structure shifted from slow growing, autumn blooming, mixotrophic organisms, towards earlier blooming and faster-growing microalgae. Warming and decreasing dissolved phosphorus concentrations were linked to this rapid reorganization of the functional structure. We identified a potential link between this shift and dissolved nutrient concentrations, and we hypothesise that organisms blooming early and displaying high growth rates efficiently take up nutrients which then are no longer available to late bloomers. Moreover, we identified that the above-mentioned functional change may have bottom-up consequences, through a food quality-driven negative influence on copepod abundances. Overall, our study highlights that, by altering the phytoplankton functional composition, global and regional changes may have profound long-term impacts on coastal ecosystems, impacting both food-web structure and biogeochemical cycles

A systematic study of zooplankton-based indices of marine ecological change and water quality: Application to the European marine strategy framework Directive (MSFD)

Marine zooplankton are central components of holistic ecosystem assessments due to their intermediary role in the food chain, linking the base of the food chain with higher trophic levels. As a result, these organisms incorporate the inherent properties and changes occurring atall levels of the marine ecosystem, temporally integrating signatures of physical and chemical conditions. For this reason, zooplankton-based biometrics are widely accepted as useful tools for assessing and monitoring the ecological health and integrity of aquatic systems. The European Marine Strategy Framework Directive (EU-MSFD) requires the use of different types of bio-monitors, including zooplankton, to monitor progress towards achieving specific environmental and water quality targets in EU. However, there is currently no comprehensive synthesis of zooplankton indices development, use, and associated challenges. We addressed this issue with a two-step approach. First, we formulated the indicator-metrics-indices cycle (IMIC) to redefine the closely related but often ambiguously utilized terms - indicator, metric and index, highlighting the convergence between them and the iterative nature of their interaction. Secondly, we formulated frameworks for synthesizing, presenting and systematically applying zooplankton indices based on the IMIC framework. The main benefits of the IMIC are twofold: 1). to disambiguate the key elements: indicators, metrics, and indices, revealing their links to an operational ecological indicator system, and 2) to serve as an organizing tool for the coherent classification of indices according to the MSFD descriptors. Using the IMIC framework, we identified and described two broad categories of indices namely the core biodiversity indices already in use in the Baltic Sea and North Atlantic regions, including the ‘Zooplankton Mean Size and Total Stock (zooplankton MSTS)’ and 'Plankton Lifeforms index (PLI)', and stressor-response indices retrieved from the existing literature, elucidating their applicability to different MSFD descriptors. Finally, major challenges of developing new indices and applying existing ones in the context of the MSFD were critically addressed and some solutions were proposed

Projet DACEFI 2. Atlas cartographique. Présentation des outils d'analyse spatiale et d'aide à la décision.

Faisant suite à une première phase (2006-2008), le projet pilote Développement d’Alternatives Communautaires à l’Exploitation Forestière Illégale (DACEFI-2, de 2010 à 2014) s’est employé à tester au Gabon la mise en oeuvre des forêts communautaires, promues par le code forestier gabonais en 2001 (loi n°016/01). Pour cela, le projet a appuyé les communautés rurales désireuses de gérer elles-mêmes une portion de forêt et les a accompagnées tout au long du processus de création d’une forêt communautaire. Ce processus, adapté dans la mesure du possible aux communautés rurales, est jalonné de multiples étapes et peut paraitre parfois long et fastidieux. Présentant des méthodologies d’action et des cartes, cet atlas a été développé à la fin des 5 années d’exécution dans l’idée de capitaliser la démarche adoptée par le projet pour aboutir à la délimitation d’une forêt communautaire. Il vient également synthétiser pour le lecteur les travaux cartographiques réalisés dans les villages et regroupements de villages, que le projet a appuyés tout au long de sa mise en oeuvre. Par ailleurs, la loi indique qu’une « forêt communautaire est une portion du Domaine Forestier Rural (DFR) affectée à une communauté villageoise ». Dans le contexte local, lors du projet DACEFI-2, l’absence de définition précise du DFR a poussé l’équipe à mener une étude complémentaire pour déterminer l’espace nécessaire et l’espace disponible pour la mise en place de forêts communautaires. Cet atlas est donc également l’occasion de présenter cette synthèse.Développement d'Alternatives Communautaires à l'Exploitation Forestière Illégale (DACEFI, phase 2)Diverse

Newsletter N°2-DACEFI

Développement d'Alternatives Communautaires à la Foresterie IllégaleVersion allégé

To Regulate or Not to Regulate: Assimilation of Dietary Fatty Acids in the Temperate Copepod Temora longicornis

Consumer regulation of lipid composition during assimilation of dietary items is related to their ecology, habitat, and life cycle, and may lead to extra energetic costs associated with the conversion of dietary material into the fatty acids (FAs) necessary to meet metabolic requirements. For example, lipid-rich copepods from temperate and polar latitudes must convert assimilated dietary FAs into wax esters, an efficient type of energy storage which enables them to cope with seasonal food shortages and buoyancy requirements. Lipid-poor copepods, however, tend to not be as constrained by food availability as their lipid-rich counterparts and, thus, should have no need for modifying dietary FAs. Our objective was to test the assumption that Temora longicornis, a proxy species for lipid-poor copepods, does not regulate its lipid composition. Isotopically-enriched (13C) diatoms were fed to copepods during a 5-day laboratory experiment. Compound-specific stable isotope analysis of algae and copepod samples was performed in order to calculate dietary FA assimilation, turnover, and assimilation efficiency into copepod FAs. Approximately 65% of the total dietary lipid carbon (C) assimilated (913 ± 68 ng C ind-1 at the end of the experiment) was recorded as polyunsaturated FAs, with 20 and 15% recorded as saturated and monounsaturated FAs, respectively. As expected, T. longicornis assimilated dietary FAs in an unregulated, non-homeostatic manner, as evidenced by the changes in its FA profile, which became more similar to that of their diet. Copepods assimilated 11% of the total dietary C (or 40% of the dietary lipid C) ingested in the first two days of the experiment. In addition, 34% of their somatic growth (in C) after two days was due to the assimilation of dietary C in FAs. Global warming may lead to increased proportions of smaller copepods in the oceans, and to a lower availability of algae-produced essential FAs. In order for changes in the energy transfer in marine food webs to be better understood, it is important that future investigations assess a broader range of diets as well as lipid-poor zooplankton from oceanographic areas throughout the world’s oceans.</jats:p

An integrated multiple driver mesocosm experiment reveals the effect of global change on planktonic food web structure

AbstractGlobal change puts coastal marine systems under pressure, affecting community structure and functioning. Here, we conducted a mesocosm experiment with an integrated multiple driver design to assess the impact of future global change scenarios on plankton, a key component of marine food webs. The experimental treatments were based on the RCP 6.0 and 8.5 scenarios developed by the IPCC, which were Extended (ERCP) to integrate the future predicted changing nutrient inputs into coastal waters. We show that simultaneous influence of warming, acidification, and increased N:P ratios alter plankton dynamics, favours smaller phytoplankton species, benefits microzooplankton, and impairs mesozooplankton. We observed that future environmental conditions may lead to the rise of Emiliania huxleyi and demise of Noctiluca scintillans, key species for coastal planktonic food webs. In this study, we identified a tipping point between ERCP 6.0 and ERCP 8.5 scenarios, beyond which alterations of food web structure and dynamics are substantial.</jats:p

A common temperature dependence of nutritional demands in ectotherms

In light of ongoing climate change, it is increasingly important to know how nutritional requirements of ectotherms are affected by changing temperatures. Here, we analyse the wide thermal response of phosphorus (P) requirements via elemental gross growth efficiencies of Carbon (C) and P, and the Threshold Elemental Ratios in different aquatic invertebrate ectotherms: the freshwater model species Daphnia magna, the marine copepod Acartia tonsa, the marine heterotrophic dinoflagellate Oxyrrhis marina, and larvae of two populations of the marine crab Carcinus maenas. We show that they all share a non-linear cubic thermal response of nutrient requirements. Phosphorus requirements decrease from low to intermediate temperatures, increase at higher temperatures and decrease again when temperature is excessive. This common thermal response of nutrient requirements is of great importance if we aim to understand or even predict how ectotherm communities will react to global warming and nutrient-driven eutrophication