Analyse De La Diversité Floristique De La Forêt Classée D’agbo I (Côte d’Ivoire)

This study was carried out in the Agbo I classified forest (6 ° 24 '- 6 ° 41' N, 4 ° 50 '- 4 ° 09' W), which covers 15,575 ha. It contributes to a better knowledge of the dense semi-deciduous moist forest of Nesogordonia papaverifera (A. Chev.) Cap. (Malvaceae) and Khayaivorensis A. Chev. (Meliaceae). The surface surveys coupled with the itinerant inventories made it possible to have an inventory of 686 species, which are divided into 428 genera and 101 families. The most abundant families are Fabaceae, Rubiaceae, Malvaceae, Apocynaceae, and Euphorbiaceae. Out of these species, 84.11% are phanerophytes and 3.50% are hemicryptophytes. In conclusion, this study improves the knowledge which is based on the composition, structure, and diversity of the woody vegetation of the Agbo I forest. The results show that the species richness of the Agbo I classified forest is important. However, this floristic richness of the Agbo I listed forest is sufficient to justify its protection and sustainable management for the conservation of biodiversity in Côte d'Ivoire

Diversité végétale et usages des plantes dans une zone de savane soudanienne : Cas de la localité de Ferkessédougou (Nord, Côte d'Ivoire)

En Côte d’Ivoire, principalement dans le nord, on observe la présence de plusieurs formations végétales très variées allant des forêts claires et aux différents faciès de savanes. Dans la localité de Ferkessédougou, une étude a été menée dans le but de connaître la flore, la végétation et de l’usage des plantes. Cette étude a permis de recenser 192 espèces de végétales. Elles se répartissent en 148 genres et 64 familles. Parmi ces espèces, certaines ont été identifiées comme alimentaires, médicinales ou à divers autres usages. Aussi, vingt sont considérées comme des espèces ayant un statut particulier et qui nécessite une attention particulière en vue de leur protection ainsi que les habitats où elles se rencontrent. La présence de ces espèces peut constituer des indicateurs clés pour le suivi environnemental de la zone d’étude.Mots clés : Diversité végétale, Services écosystémiques, savane soudanienne, Ferkessédougou, Côte d’Ivoire.   English Title: Plant diversity and plant uses in a Sudanese savannah area: Case of the locality of Ferkessédougou (North, Côte d'Ivoire)In Ivory Coast, mainly in the north, we observe the presence of several very varied plant vegetations anging from open forests to different facies of savannah. In the locality of Ferkessédougou, a study was carried out to learn about the flora, vegetation and the use of plants. This study identified 192 species of plants. They are divided into 148 genera and 64 families. Among these species, some have been identified as food, medicinal or various other uses. Also, twenty are considered to be species with a special status and which requires very special attention for their protection as well as the habitats where they occur. The presence of these species can constitute key indicators for the environmental monitoring of the study area. Keywords: Plant diversity, Ecosystem services, Sudanese savannah, Ferkessédougou, Ivory Coast

Co-limitation towards lower latitudes shapes global forest diversity gradients

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 ~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

Dynamique de reconstitution de la biodiversité végétale de la forêt classée de Foumbou (Nord de la Côte d’Ivoire)

La forêt est un milieu essentiellement dynamique dont les multiples composants sont en perpétuelle évolution. La forêt classée de Foumbou, situé dans le département de Korhogo au Nord de la Côte d’Ivoire, est confrontée à l’orpaillage clandestin couplé aux infiltrations paysannes. Ces exploitations demeurent une préoccupation écologique majeure car elles menacent les services écosystémiques. Ces travaux avaient pour objectif d'évaluer la diversité floristique de la forêt classée de Foumbou dans une perspective de gestion durable forestière de la biodiversité. Les méthodes de relevé de surfaces associées à des inventaires itinérants ont été adoptées lors de ces travaux dans vingt parcelles de 2000 m2 chacune. Les analyses multivariées ont permis d’identifier cinq stades de succession secondaire postculturale le long d’une chronoséquence de 35 ans. Les paramètres de composition augmentent avec l’âge de la jachère (biotopes). La forêt renferme, au total, 259 espèces, réparties en 191 genres et 56 familles. Du point de vue de la composition floristique, cette forêt est riche en Fabaceae, en Rubiacea, en Combretaceae, en Malvaceae, en Moraceae, en Poaceae et en Lamiaceae. Dans cette étude, les biotopes les plus diversifiés sont les jachères de plus de 20 ans et les Forêts anciennes. Le site renferme également des espèces endémiques et des espèces à statuts particuliers. La flore de cette forêt est diversifiée avec une répartition équitable des espèces au sein des biotopes. De ce fait, des actions de gestion intégré et participative de cette forêt s’imposent pour minimiser sa dégradation. English title: Dynamics of reconstitution of the vegetal biodiversity of the Foumbou class forest (north of the Ivory Coast) The forest is an essentially dynamic environment whose multiple components are in perpetual evolution. The classified forest of Foumbou is confronted with clandestine gold panning coupled with peasant infiltration. These operations remain a major ecological concern because they threaten ecosystem services. The objective of this work was to assess the floristic diversity of the floristic diversity of the classified forest of Foumbou in order to promote its sustainable management. Surface survey methods and itinerant inventories were adopted during this work in twenty plots, sixteen of which were in post-cultivation fallows. Multivariate analyses identified five stages of postcultural secondary succession along a 35-year chronosequence. The compositional parameters increase with the age of fallow land. The forest contains a total of 259 species, divided into 191 genera and 56 families. From the point of view of floristic composition, this forest is rich in Fabaceae, Rubiacea, Combretaceae, Malvaceae, Moraceae, Poaceae and Lamiaceae. Of this study, the most diversified are the fallow land of more than 20 years and the Old Forest. The flora of the estate is diversified with an equitable distribution of species within the biotopes. Integrated and participative management of the forest is necessary to minimise the degradation of the site

Causes and consequences of Cedrela odorata invasion in West African semi-deciduous tropical forests

International audienc

Lessons from a regional analysis of forest recovery trajectories in West Africa

In West Africa, very poorly documented are the recovery trajectories of secondary forests, and even less is known about the origin of the observed variability in recovery rates. To understand the relative importance of local and regional environmental conditions on these trajectories, we inventoried all trees larger than 2.5 cm DBH on 236 plots (0.2 ha), aged from 0 to 45 years plus controls, on eight chronosequences representing the typical regional North-South climatic gradient of West Africa. In a hierarchical Bayesian framework, we modelled recovery trajectories of biodiversity, aboveground biomass and floristic composition and tested the influence of variability in local (plot history, landscape context, remnant trees) and regional (climate and soil) conditions on recovery rates. Our results show that (a) diversity recovers faster than composition and biomass, (b) among the local variables, the number of remnant trees has a positive impact on recovery rates while the duration of agricultural cultivation has a negative impact, and (c) among the regional variables, the high seasonality of precipitation and climate, typical of the dry forests of the northern West African forest zone, leads to faster secondary successions. Our simulation approaches have indicated that poor regional conditions can be counterbalanced by adequate local conditions and vice versa, which argues strongly in favour of a diagnosis that integrates these two aspects in the choice of more or less active technical itineraries for forest restoration

Multidimensional tropical forest recovery

International audienceTropical forests disappear rapidly because of deforestation, yet they have the potential to regrow naturally on abandoned lands. We analyze how 12 forest attributes recover during secondary succession and how their recovery is interrelated using 77 sites across the tropics. Tropical forests are highly resilient to low-intensity land use; after 20 years, forest attributes attain 78% (33 to 100%) of their old-growth values. Recovery to 90% of old-growth values is fastest for soil (12 decades). Network analysis shows three independent clusters of attribute recovery, related to structure, species diversity, and species composition. Secondary forests should be embraced as a low-cost, natural solution for ecosystem restoration, climate change mitigation, and biodiversity conservation

Co-limitation towards lower latitudes shapes global forest diversity gradients

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 ~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