Dynamique Spatio-Temporelle et Intérêt pour la Conservation de la Forêt Classée de Goin-Débé, une Aire Protégée Menacée de Disparition à l’Ouest de la Côte d’Ivoire

La forêt classée de Goin-Débé considérée comme zone d’importance pour la biodiversité, est depuis la crise post-électorale, l’objet d’exploitations agricoles et d’infiltrations par des paysans mettant ainsi en péril son statut de refuge de la biodiversité. Ainsi, cette étude vise évaluer l’état de conservation de la végétation et de la flore de cette forêt. L’exploitation des images satellitaires couplée aux analyses des données d’inventaire floristique révèlent des dynamiques diamétralement opposées entre les périodes 1988 à 1998 et 1998 à 2020 dans la végétation. La première période a été marquée par un gain considérable en termes de superficie des jachères du sud-ouest au nord-ouest de la forêt classée. Alors que la seconde a vu une régression significative des surfaces des formations végétales au profit des exploitations cacaoyères. Les relevés floristiques ont permis d’inventorier 220 espèces appartenant à 176 genres répartis en 63 familles. Cette flore comporte 15 espèces à statut particulier selon la liste rouge de l’UICN (2020, 2021 & 2022) et 22 espèces endémiques du bloc forestier de la Haute Guinée (GCW), entre autres éléments qui confèrent à cette forêt un intérêt particulier pour la conservation. Since the post-electoral crisis, the Goin-Débé classified forest, considered as an area of importance for biodiversity, has been subject to agricultural exploitation and infiltration by peasants, thus jeopardizing its status as a biodiversity refuge. The aim of this study is to assess the state of conservation of the forest's vegetation and flora. Satellite images and floristic inventory data reveal diametrically opposed vegetation dynamics between the periods 1988 to 1998 and 1998 to 2020. The first period was marked by a considerable gain in fallow area from the south-west to the north-west of the classified forest. The second period, on the other hand, saw a significant decline in the area of plant formations in favor of cocoa farms. Floristic surveys have identified 220 species belonging to 176 genera divided into 63 families. This flora includes 15 species with special status according to the IUCN Red List (2020, 2021 & 2022) and 22 species endemic to the Upper Guinea Forest Block (GCW), among other elements that give this forest a particular interest for conservation

Dynamique Spatio-Temporelle et Intérêt pour la Conservation de la Forêt Classée de Goin-Débé, une Aire Protégée Menacée de Disparition à l’Ouest de la Côte d’Ivoire

La forêt classée de Goin-Débé considérée comme zone d’importance pour la biodiversité, est depuis la crise post-électorale, l’objet d’exploitations agricoles et d’infiltrations par des paysans mettant ainsi en péril son statut de refuge de la biodiversité. Ainsi, cette étude vise évaluer l’état de conservation de la végétation et de la flore de cette forêt. L’exploitation des images satellitaires couplée aux analyses des données d’inventaire floristique révèlent des dynamiques diamétralement opposées entre les périodes 1988 à 1998 et 1998 à 2020 dans la végétation. La première période a été marquée par un gain considérable en termes de superficie des jachères du sud-ouest au nord-ouest de la forêt classée. Alors que la seconde a vu une régression significative des surfaces des formations végétales au profit des exploitations cacaoyères. Les relevés floristiques ont permis d’inventorier 220 espèces appartenant à 176 genres répartis en 63 familles. Cette flore comporte 15 espèces à statut particulier selon la liste rouge de l’UICN (2020, 2021 & 2022) et 22 espèces endémiques du bloc forestier de la Haute Guinée (GCW), entre autres éléments qui confèrent à cette forêt un intérêt particulier pour la conservation. Since the post-electoral crisis, the Goin-Débé classified forest, considered as an area of importance for biodiversity, has been subject to agricultural exploitation and infiltration by peasants, thus jeopardizing its status as a biodiversity refuge. The aim of this study is to assess the state of conservation of the forest's vegetation and flora. Satellite images and floristic inventory data reveal diametrically opposed vegetation dynamics between the periods 1988 to 1998 and 1998 to 2020. The first period was marked by a considerable gain in fallow area from the south-west to the north-west of the classified forest. The second period, on the other hand, saw a significant decline in the area of plant formations in favor of cocoa farms. Floristic surveys have identified 220 species belonging to 176 genera divided into 63 families. This flora includes 15 species with special status according to the IUCN Red List (2020, 2021 & 2022) and 22 species endemic to the Upper Guinea Forest Block (GCW), among other elements that give this forest a particular interest for conservation

Dynamique Spatio-Temporelle et Intérêt Pour la Conservation de la Forêt Classée de Goin-Débé, Une Aire Protégée Menacée de Disparition à l’Ouest de la Côte d’Ivoire

La forêt classée de Goin-Débé considérée comme zone d’importance pour la biodiversité, est depuis la crise post-électorale, l’objet d’exploitations agricoles et d’infiltrations par des paysans, mettant ainsi en péril son statut de refuge de la biodiversité. Ainsi, cette étude vise à évaluer l’état de conservation de la végétation et de la flore de cette forêt. Pour ce faire, une étude diachronique a d’abord été effectuée à partir des images satellitaires Landsat TM des années 1988 et 1998 et des images Landsat OLI/TIRS de l‘année 2020. Ensuite, un inventaire floristique a été effectué dans les différentes formations végétales de la forêt classée. L’exploitation des images satellitaires couplée aux analyses des données d’inventaire floristique révèle des dynamiques diamétralement opposées entre les périodes 1988 à 1998 et 1998 à 2020 dans la végétation. La première période a été marquée par un gain considérable en termes de superficie des jachères du sud-ouest au nord-ouest de la forêt classée. Alors que la seconde a vu une régression significative des surfaces des formations végétales au profit des exploitations cacaoyères. Les relevés floristiques ont permis d’inventorier 220 espèces appartenant à 176 genres répartis en 63 familles. Cette flore comporte 15 espèces menacées (1 EN, 13 VU, 1 NT) et 22 espèces endémiques du bloc forestier de la Haute Guinée (GCW). Ces espèces, entre autres éléments, confèrent à cette forêt un intérêt particulier qui devrait susciter plus d’actions pour sa conservation.   Since the post-electoral crisis, the Goin-Débé classified forest, considered as an area of importance for biodiversity, has been subject to agricultural exploitation and infiltration by peasants, thus jeopardizing its status as a biodiversity refuge. The aim of this study is to assess the state of conservation of the forest's vegetation and flora. To do this, a diachronic study was first carried out using Landsat TM satellite images from 1988 and 1998 and OLI/TIRS images from. Next, a floristic inventory was carried out in the different plant formations of the classified forest. Satellite images and floristic inventory data reveal diametrically opposed vegetation dynamics between the periods 1988 to 1998 and 1998 to 2020. The first period was marked by a considerable gain in fallow area from the south-west to the north-west of the classified forest. The second period, on the other hand, saw a significant decline in the area of plant formations in favor of cocoa farms. Floristic surveys have identified 220 species belonging to 176 genera divided into 63 families. This flora includes 15 threatened species (1 EN, 13 VU, 1 NT) and 22 species endemic to the Upper Guinea Forest Block (GCW), among other elements that give this forest a particular interest for conservation

Usages Traditionnels Et Disponibilité Des Plantes Exploitées Dans L’artisanat Chez Les Populations Koulango Et Lobi De La Périphérie Est Du Parc National De La Comoé, Côte d’Ivoire

Cette étude vise à faire l’inventaire et à évaluer la disponibilité des plantes utilisées dans la construction et la confection des outils par les populations Koulango et Lobi. Les enquêtes ethnobotaniques à travers les approches du « porte à porte » et des randonnées ont permis d’obtenir les informations sur les usages des plantes. La disponibilité des ressources a été évaluée à travers l'indice de raréfaction à partir des relevés de surface. Le niveau de connaissance des usages des plantes a été évalué à l’aide de la fréquence de citation. L’intensité d’utilisation des plantes a été calculée grâce à la valeur d’usage ethnobotanique. Les similitudes entre les usages des plantes ont été révélées grâce à la classification hiérarchique ascendante. Le statut des espèces a été déterminé par l’indice de raréfaction. De ces travaux, il ressort que 39 plantes appartenant à 38 genres et 22 familles sont utilisées dans la construction et 55 espèces végétales, reparties en 48 genres et 22 familles, sont utilisées dans la fabrication des objets domestiques. Les usages de six plantes sont très connus. Il s'agit de Raphia sudanica (92,15%), Vitellaria paradoxa (89,6%), Khaya senegalensis (83,05%), Pterocarpus erinaceus (70,15%), Phoenix reclinata (52,75%) et Pseudocedrela kotschyi (51,7%). Pour les deux ethnies confondues, cinq plantes sont les plus utilisées. Ce sont Raphia sudanica (1,84), Vitellaria paradoxa (1,76), Phoenix reclinata (1,74), Khaya senegalensis (1,66) et Pterocarpus erinaceus (1,38). Plusieurs plantes dont Bombax costatum, Ceiba pentandra, Adansonia digitata ont des individus juvéniles et adultes très rares dans le PNC comme dans le domaine rural. This paper focuses on keeping inventory and assessing the availability of plants used in the construction and making of tools by the Koulango and Lobi populations. Ethnobotanical surveys through door-to-door and trekking approaches have provided information on the uses of plants. The availability of resources was assessed using the scarcity index from surface surveys. The level of knowledge of plant uses was assessed using the frequency of citation. The intensity of use of the plants was calculated using the ethnobotanical use value. The similarities between the uses of plants were revealed, thanks to the ascending hierarchical classification. The status of the species was determined by the depletion index. From this work, it emerges that 39 plants belonging to 38 genera and 22 families are used in construction. 55 plant species, divided into 48 genera and 22 families, are used in the manufacture of household objects. The uses of six plants are well known. These are Raphia sudanica (92.15%), Vitellaria paradoxa (89.6%), Khaya senegalensis (83.05%), Pterocarpus erinaceus (70.15%), Phoenix reclinata (52.75%), and Pseudocedrela kotschyi (51.7%). For the two ethnic groups combined, five plants are the most used. These are Raphia sudanica (1.84), Vitellaria paradoxa (1.76), Phoenix reclinata (1.74), Khaya senegalensis (1.66), and Pterocarpus erinaceus (1.38). Several plants, including Bombax costatum, Ceiba pentandra, Adansonia digitata, have juvenile and adult individuals which are very rare in the PNC as in the rural area

Low-cost activated carbon for adsorption and heterogeneous ozonation of phenolic wastewater

This work is aimed at elaborating an innovative material from palm tree waste that can be used in industrial applications for adsorption and catalytic oxidation. This low-cost activated carbon, elaborated from Borassus palm tree waste (bpAC) showed textural and chemical properties comparable with common activated carbon. Moreover, it demonstrated interesting behaviour when it was coupled with ozone to remove a phenolic compound, 2,4-dimethylphenol (2,4-DMP). This refractory model molecule was removed two times faster in the presence of bpAC and was achieved in only 7 min. The total organic carbon (TOC) removal by only adsorption on bpAC was satisfactory with a value of 93.8% after 8 h. Nevertheless, the most interesting result concerned the TOC removal during catalytic ozonation which increased from 26% (single ozonation, i.e., without bpAC) to 91% in the presence of bpAC. The addition of a radical scavenger (tert-butanol) showed that hydroxyl radicals were involved during ozonation with bpAC. Moreover, a kinetics study highlighted that both radical and molecular mechanisms were acting in heterogeneous reaction. All the results were finally validated by treating real wastewater spiked with 2,4-DMP, confirming the ability of this bpAC to enhance the treatment of phenolic wastewaters

Tsetse fly ecology and risk of transmission of African trypanosomes related to a protected forest area at a military base in the city of Abidjan, Côte d’Ivoire

African trypanosomoses, whose pathogens are transmitted by tsetse flies, are a threat to animal and human health. Tsetse flies observed at the military base of the French Forces in Côte d’Ivoire (FFCI base) were probably involved in the infection and death of military working dogs. Entomological and parasitological surveys were carried out during the rainy and dry seasons using “Vavoua” traps to identify tsetse fly species, their distribution, favorable biotopes and food sources, as well as the trypanosomes they harbor. A total of 1185 Glossina palpalis palpalis tsetse flies were caught, corresponding to a high average apparent density of 2.26 tsetse/trap/day. The results showed a heterogeneous distribution of tsetse at the FFCI base, linked to more or less favorable biotopes. No significant variation in tsetse densities was observed according to the season. The overall trypanosomes infection rate according to microscopic observation was 13.5%. Polymerase chain reaction (PCR) analyses confirmed the presence of Trypanosoma vivax and T. congolense forest type, responsible for African animal trypanosomosis. Our findings suggest that there is a risk of introduction and transmission of T. brucei gambiense, responsible for human African trypanosomiasis, on the study site. This risk of transmission of African trypanosomes concerns not only the FFCI base, but also inhabited peripheral areas. Our study confirmed the need for vector control adapted to the eco-epidemiological context of the FFCI base

The Forest Observation System, building a global reference dataset for remote sensing of forest biomass

International audienceForest biomass is an essential indicator for monitoring the Earth's ecosystems and climate. It is a critical input to greenhouse gas accounting, estimation of carbon losses and forest degradation, assessment of renewable energy potential, and for developing climate change mitigation policies such as REDD+, among others. Wall-to-wall mapping of aboveground biomass (aGB) is now possible with satellite remote sensing (RS). However, RS methods require extant, up-to-date, reliable, representative and comparable in situ data for calibration and validation. Here, we present the Forest Observation System (FOS) initiative, an international cooperation to establish and maintain a global in situ forest biomass database. aGB and canopy height estimates with their associated uncertainties are derived at a 0.25 ha scale from field measurements made in permanent research plots across the world's forests. all plot estimates are geolocated and have a size that allows for direct comparison with many RS measurements. The FOS offers the potential to improve the accuracy of RS-based biomass products while developing new synergies between the RS and ground-based ecosystem research communities

Accuracy Assessment of the ESA CCI 20M Land Cover Map: Kenya, Gabon, Ivory Coast and South Africa

This working paper presents the overall and spatial accuracy assessment of the European Space Agency (ESA) 20 m prototype land cover map for Africa for four countries: Kenya, Gabon, Ivory Coast and South Africa. This accuracy assessment was undertaken as part of the ESA-funded CrowdVal project. The results varied from 44% (for South Africa) to 91% (for Gabon). In the case of Kenya (56% overall accuracy) and South Africa, these values are largely caused by the confusion between grassland and shrubland. However, if a weighted confusion matrix is used, which diminishes the importance of the confusion between grassland and shrubs, the overall accuracy for Kenya increases to 79% and for South Africa, 75%. The overall accuracy for Ivory Coast (47%) is a result of a highly fragmented land cover, which makes it a difficult country to map with remote sensing. The exception was Gabon with a high overall accuracy of 91%, but this can be explained by the high amount of tree cover across the country, which is a relatively easy class to map

Comparison of surface properties between kaolin and metakaolin in concentrated lime solutions

International audienceThe surface adsorption of calcium hydroxide onto kaolin and metakaolin was investigated by monitoring with atomic emission spectroscopy and pH measurements the amounts of ions left in solution after exposing clays to calcium hydroxide solutions of various concentrations. Both clays adsorb calcium and hydroxyl ions but differently. Kaolin adsorbs calcium hydroxide not only at the edges of the clay particles but also onto the basal faces. The adsorbed hydrated calcium ions form a layer on the clay particle surfaces, preventing further dissolution of the clay mineral platelet. Metakaolin shows high pozzolanic activity, which provides the quick formation of hydrated phases at the interfaces between metakaolin and lime solutions. The nature of the hydration products has been investigated using X-ray diffraction (XRD) and differential thermal analysis (DTA). The most important hydrated phases like CSH (hydrated calcium silicate) and C2ASH8 (gehlenite) have been identified