Spatial Distribution of Cedrela Odorata Smaller Trees Affects Forest Regeneration in Exotic Tree Plantations in Central Côte d’Ivoire

Cedrela odorata L. was introduced as a possible forest restauration species in classified forests at Côte d’Ivoire. Because of its demonstrated invasive behavior in other tropical forests, this study aimed to assess the impact of Cedrela odorata on the regeneration of spontaneous plant species in tree plantations. On the base of Cedrela odorata larger tree densities, two types of forest plantation were considered: Type I (240 stems/ha) and Type II (176 stems/ha). In these plantations, plots with 0.25 ha were chosen to locate each tree with dbh ≥ 2.5 cm, in an orthonormal reference. The tree density, the basal area, the species richness, the Shannon diversity index and the rank-abundance curves were determined considering smaller and larger trees. The horizontal spatial arrangement and Ripley’s K function were performed to understand the spatial relationship between Cedrela odorata smaller trees and those of spontaneous species. The results shown lower spontaneous plant species richness (15-20 species) and diversity (1.15 - 1.43); the dominance of Cedrela odorata smaller trees (43.02 – 62.95 % of all stems). The Cedrela odorata smaller trees and those of other species have dependent spatial distributions; expressed by a spatial repulsion between the two groups up to a distance of 18 m in the most densified forest plantation. This repulsion was related to an aggregated distribution of Cedrela odorata smaller trees in plantation with higher tree density. The study suggests a 170-stems/ha (or lower) of Cedrela odorata planting density for biodiversity establishment improvement outcomes in forest plantations.

Déterminismes De La Dynamique De La Forêt Des Marais Tanoé-Ehy (Sud-Est, Côte d'Ivoire)v

Objective: The Tanoé-Ehy Forest (FMTE) has been identified as a top priority site for primate conservation in West Africa. Pending the completion of the measures of its final classification in protected area, anthropic pressures are constantly nibbling the types of habitat that the FMTE contains. The objective of the present study was to analyze the spatial and temporal evolution of this forest from 1986 to 2016. The study consisted in mapping and following through Landsat satellite images from 1986, 2000, and 2016 the dynamics of the land use that constitute the FMTE. To better understand the underpinnings of this evolution, based on anthropogenic threats, surveys were carried out in the five villages closest to the forest. Treatments show a 10% degradation of swamp forest area to degraded forests in 30 years. The habitats temporarily flooded forests remained intact during this 30 years period, reflecting efforts to maintain the integrity of the FMTE. Surveys have shown that the types of pressure and their intensity vary from peripheral villages. Overall, this involves wood harvesting and hunting. In view of the importance of the FMTE in terms of a particular ecosystem and the conservation of biodiversity, it is desirable and urgent that, in addition to awareness-raising campaigns for local populations, the process of its final ranking be accelerated to end its degradation

Evaluation De La Diversité Et Estimation De La Biomasse Aérienne Des Arbres Du Jardin Botanique De Bingerville (District d’Abidjan, Côte d’Ivoire)

The Bingerville Botanical Garden is an urban green space which can contribute to the quality of the living environment and to attractivity of tourists in Abidjan city. Its floristic diversity and socio-economic and ecological benefits remain still unknown. The present study was conducted to assess botanical species diversity and the reduction of CO2 emissions in this space. Trees species with dbh ≥ 10 cm were recorded in 41 plots of 500 m² surveyed in four types of biotopes: two arboretums with 20 and 100 years old, one secondary forest with more than 100 years and a fallow of 20 years old. Floristic indices and aboveground biomass (AGB) were determined for each biotope. A total of 742 trees with dbh ≥ 10 were counted: 127 species. Preponderance species are Cassia siamea, Terminalia mantaly, Milicia excelsa and Ceiba pentandra in arboretums, Pentadesma butyracea and Acacia mangium in the secondary forest, Ficus exasperata and Borassus aethiopum in the fallow. Arboretums are richest (96 species), and they have more AGB (566.7 t/ha). The secondary forest has 71 species with an aboveground equal to 381.4 t/ha. The fallow is less rich (13 species) with an AGB of 21 t/ha. This study has shown the importance of Bingerville Botanical Garden in plant and fighting against climate change

Diversité Des Espèces Herbacées Et Lianescentes De La Forêt Classée Du Haut-Sassandra (Centre-Ouest, Côte d’Ivoire) Après Plusieurs Années D’exploitation Forestière

Natural and anthropogenic disturbances affect forest integrity and floristic composition. The resulting secondary habitats is characterised by liana and herb species which modified the forest physiognomy. To elucidate the floristic characteristics of these secondary forests, the present study was carried out after logging operations in the the Haut-Sassandra protected Forest. The inventory has been realised in 18 individual one ha in three level of logging operation. A total of 445 species have been identified. Floristics parameters vary according to the time after logging operation: from 255 in the south sector, 296 species in the center sector, 271 species in the north sector, 15 years after logging. The family diversity is between 56 and 62 with a predominance of Rubiaceae. Phytogeographic-types are characterized by Guinean-Congolese species (71,2 %), and species endemic to SavannahForest transition zone (14,6 %). The presence of herb and liana species which are pioneer and heliophile, could generate a micro climate favorable to the recovery of other forest plant species

Système agroforestier à cacaoyers en Côte d’Ivoire: Connaissances existantes et besoins de recherche pour une production durable

This study has assessed the ecological sustainability of cocoa production systems in Côte d'Ivoire. The litterature has shown that cocoa crop has been introduced in 1988 and this crop has been suitable with various pedoclimatic and vegetation factors in Côte d’Ivoire. This suitability has involved a move of the cocoa boom area and some changing practices from the South-east to the South-west of the country. The study has shown the existence of some divergences between farmers and scientists about the choice of associated tree species in cocoa agrosystems. Also, none adequate scientific research have been achieved in order to suggest to the farmers the most sustainable cocoa agroforest system. Future research should be focused on finding a trade-off about the choice of associated tree species which can be profitable to the farmers and ecological sustainable. These research will approve or deny some empirical perceptions from traditional practices. These research will also demonstrated to the farmers, the political decision-maker and management structures the need of a synergy between cocoa production and the economic value from of the ecosystem services produced in the farms. Key words: Shade trees, Agroforest, cocoa pioneer front, Traditional agricultural practices, Ecosystem servicesLa présente étude a fait un diagnostic écologique de la durabilité des systèmes de production de cacao en Côte d’Ivoire. L’analyse de la bibliographie a montré que cette culture introduite en 1988, a été compatible à divers facteurs pédoclimatiques et de végétation de la Côte d’Ivoire. Cette comptabilité se traduit par l’évolution de la boucle de cacao et des pratiques culturales du Sud-est au Sud-ouest du pays. L’étude a fait le constat de l’existence de divergences entre les paysans et les scientifiques au sujet des espèces d’arbres à associer aux cacaoyers. Elle soulève également le manque de preuves suffisantes et scientifiques pouvant guider le choix d’un système agroforestier à cacao, à la fois profitable aux producteurs et écologiquement soutenable. Des recherches futures devront être orientées vers la recherche de compromis sur le choix des espèces à associer aux cacaoyers ; ce qui nécessitera la confirmation ou l’infirmation scientifique des perceptions empiriques issues de pratiques traditionnelles. Il faudra également éclairer le producteur, le décideur politique et les structures d’encadrement de paysans, sur la nécessité d’une complémentarité entre la production de cacao et la valeur économique des services écosystémiques produits dans les cacaoyères. Mots-clés: Arbres d’ombrage, Agroforêt, Front pionnier du cacao, Pratiques agricoles traditionnelles, Services écosystémique

DYNAMIQUE DE LA VEGETATION ET FREQUENCE DES FEUX DE BROUSSE DANS LA RESERVE DE FAUNE D’ABOKOUAMEKRO (CENTRE, COTE D’IVOIRE)

In Côte d'Ivoire, the use of repeated and anarchistic bushfires creates damages on the ecosystem, and constitutes an alarming issue for protected areas managers. This study aims to enhance knowledges on the vegetation, by evaluating their floristic potential and their relationship with some environmental factors, in the wildlife Reserve of Abokouamékro. To reach those objectives, floristic and structural characteristics of gallery forests, island forests, woodland savannas and shrubs, burned by different frequency of bushfires were compared, after a floristic inventory. The results showed that 321 species belonging to 220 genera and 77 families had been recorded in the wildlife Reserve of Abokouamékro. Also, despite the type of vegetation, when the fires frequency is higher, the various types of végétation of the reserve are converted into savannas by decreasing the number, the diversity and the basal area of the species. In order to do a better conservation and a sustainable management of this reserve, a particular attention must be observed for its protection from bushfires

Diversité Et Variabilité Du Régime Alimentaire Des Éléphants Du Parc National d’Azagny (Sud - Côte d’Ivoire)

In Côte d'Ivoire, Azagny National Park has a small forest elephants population, described as isolated, self-contained and whose survival depends on the diversity of local biological resources. A study was undertaken to assess the diversity of the plant species consumed and the feeding preference of this large mammal. Pedestrian surveys were carried out in the different biotopes traveled by the elephants during one year, in search of fresh and old traces of nutrition and droppings. As a result of these inventories, six organs of 282 plant species have been identified has consumed by elephant. In this plant species list, three families are the most represented: the Apocynaceae, the Euphorbiaceae and the Rubiaceae. Among the elephant diet, five species appear to be the most consumed: Aframomum melegueta (1.45%), Aframomum sceptrum (1.45%), Sacoglottis gabonensis (1.27%), Echinochloa pyramidalis (1.2%) and Albizia adianthifolia (1.2%). Considering the number and type of organs harvested from plants, the study reveals that they varied from one species to another well. In general, leaves (256 species 90.8%) and fruits (95 species or 33.7%) have emerged as the most consumed organs of elephants. In view of this diet importance in elephant survival in the park, it would be important to identify the type of species consumed seasonally and to assess their availability in each of the biotopes traveled

Relations entre la diversité et la biomasse aérienne des espèces arborescentes dans les agroforêts traditionnelles à base de cacaoyers: Cas de la localité de Lakota (Côte d’Ivoire)

En matière de gestion durable des systèmes agroforestiers à base de cacao, il serait important de trouver un compromis pour à la fois conserver la biodiversité et les stocks de carbone ; ce qui constituerait une alternative écologiquement soutenable à l’agriculture conventionnelle. En Afrique sub-saharienne, peu d’études ont mis la lumière sur les relations éventuelles entre la biomasse végétale et la diversité biologique dans ces systèmes. La présente étude a permis de tester ces relations dans des agroforêts à cacao de Lakota en Côte d’Ivoire. Des cacaoyères et des forêts ont été inventoriées selon la méthode des transects à aire variable. Plusieurs indices floristiques, ont été calculés et la biomasse aérienne a été estimée, pour les espèces arborescentes de dbh > 2,5 cm. Au total, 215 espèces ont été dénombrées dans l’ensemble des biotopes dont 57,2 % en forêts anciennes, 50,2 % en forêts secondaires et 26 à 45 % dans les plantations. La biomasse aérienne des arbres sur pied dans les forêts anciennes est plus élevée (203,7 t ha-1) que dans les plantations où la biomasse baisse jusqu’à 90,2 t ha-1. Il n’existe pas de relations significatives entre la biomasse aérienne et la diversité des espèces dans les forêts. Dans les plantations âgées de plus de 15 ans, une forte diversité spécifique peut être bénéfique à 20 % dans l’augmentation de la biomasse sur pied. Les pratiques paysannes traditionnelle sen cacao culture peuvent donc garantircon comitamment, la diversité floristique et la biomasse qui est le facteur déterminant dans la séquestration du carbone.Mots Clés: Réchauffements climatiques, système agroforestier, Côte d’Ivoire, activité anthropiqueEnglish AbstractFor sustainable management of cocoa based agroforestry systems, it is important to find a tradeoff to conserve both biodiversity and carbon stock; which would be an ecologically sustainable alternative to conventional agriculture. In Sub-Saharan Africa, few studies have tested relationships between plant biomass and biodiversity in these systems. This study analysed these relationships in Cocoa based agroforest in Lakota area in Côte d’Ivoire. Cocoa farms and forest patches were inventoried using the variable-area transect method. We considered all trees species with dbh> 2.5 cm. Pearson correlation was used to test probable links between aboveground biomass and diversity indexes. We recorded a total of 215 tree species in all habitats, of which 57.2% were in old growth forests, 50.2% in secondary forests and 26-45% in cocoa farms. Biomass stock of old growth forests was greater (203.7 t ha-1) than in plantations, where it dropped to 90.2 t ha-1. There was no significant relationship between aboveground biomass and floristic indices in forests. In old plantations of over 15 years old, high species diversity could contribute up to 20% in the aboveground biomass. The conservation of floristic diversity in cacao based agroforestry systems may represent an important factor in mitigating global warming, through the storage of large amounts of carbon.Keywords: Climate change, cocoa based agroforestry system, Côte d’Ivoire, human activitie

Caracterisation Des Pratiques Agroforestieres A Base De Cacaoyers En Zone De Foret Dense Semi- Decidue : Cas De La Localite De Lakota (Centre- Ouest, Cote d’Ivoire)

In the area of Lakota (Midwest, Côte d'Ivoire), where the vegetation is a semi-deciduous forest, cacao growing is practiced by people from different origins. Cacao cropping techniques seem to be influenced by some social and cultural habits, according to the people and the agroecological areas. The present study aimed to understand(1) the cacao cropping systems and to identify(2) the reasons underlying the choice of vegetal species combined to cacao trees in these rural communities. To achieve this goal, interviews were realised with cacao farmers of four villages of the area. These interviews concern farmers’ profiles, the former agriculture practices, the variety of the cultivated cacao and the plants combined to cacao trees. The results show that among the 223 interviewed farmers, 72 (32.3% of the farmers) are natives, 42 (18.8% of the farmers) are immigrants and 109 (48.9% of the farmers) are non-native Ivorians. In total, 77 species regularly combined to cacao trees were named by the farmers and they can be divided into local species and exotic species. Plots ordination shows three agroforestry systems according to ethnic group of the locality. Cacao farms with the large proportion of local species are owned by Lakota native people "Dida". The exotic species are dominant in cacao farms that belong to immigrants (Malian, Burkina Faso and Guinean people) and "Malinké" people (a non-native ivorian ethnic group). The Akan people (a non-native ivorian ethnic group) combine in a same proportions exotic and local species in their cacao farms

Valeur écologique et produits de cueillette des plantations forestières de la Forêt classée de la Téné

En Côte d’Ivoire, la Forêt classée de la Téné a été reboisée sur plus de 21 000 ha, en espèces exotiques pour la production de bois depuis 1986. Des inventaires botaniques dans des plantations forestières et une relique de forêt, ainsi que des enquêtes ethnobotaniques, ont permis d’estimer la valeur écologique et de conservation, les relations entre les communautés riveraines et ce système de production. La relique de forêt (109 espèces) et les plantations forestières multi-spécifiques (104 espèces) sont plus diversifiées, plus stables et ont une biomasse végétale plus importante que les jeunes et vieilles plantations mono-spécifiques de Teck. Outre les pratiques d’entretien des plantations, responsables de la perte d’une bonne partie de la diversité des espèces dans les plantations forestières, le fort potentiel de régénération de Cedrela odorata, une des espèces exotiques de reboisement dans les habitats de la Forêt classée de la Téné, mérite un suivi quant à son impact négatif sur l’installation des espèces arborescentes indigènes. Près de la moitié (49%) des produits de cueillette est issue de la Forêt classée de la Téné, signe d’une bonne collaboration entre les services des gardes forestiers et les populations riveraines.In Côte d’Ivoire, since 1986, the Téné Gazetted Forest has been reforested based of exotic species on more than 21,000 ha for timber production. Botanical inventories in these forest plantations and a remaining natural forest and ethnobotanical surveys have permitted us to assess the ecological and conservation value and the relationships between the neighbouring communities and this timber production system. The remaining forests (109 species) and multi-specific forest plantations (104 species) have higher plant diversity than mono-specific teak plantations. These two habitats are also more stable and have high plant biomass than mono-specific young and old teak plantations. The high abundance of Cedrela odorata, one of the exotic reforestation species in the remaining forest, may require future study about its potential negative impacts on establishing native tree species in the reforested area at Téné Gazetted Forest. More than half (49%) of the harvested products are from the Téné Gazetted Forest; that attests to good collaboration between the forest police officers and the neighbouring communities