Madjidou Oumorou

An assessment of climate variation risks on agricultural production

– The purpose of this paper is to assess the local communities perception of climate variation effects on crop production and the adopted strategies by farmers in order to cope with the negative effects of climate on the agriculture in the coastal zone of Benin., – A total of 290 agricultural households were sampled and surveyed through structured interviews. The principal component analysis (PCA) was performed on the relative frequencies citation of perceived climate variation indication in order to describe the relationship between risk perceptions according to socio‐demographic characteristics. The relative frequency of citation was calculated according to age, gender, ethnic group and agro‐ecological region., – Results showed that almost 83 per cent of the respondents already perceived the climate change risks through several indications. Climate variation perception varied with respect to age. Respondents opinion regarding climate variation causes depended generally on their age, religion and level of education. As far as climate variation risks impact on crop production is concerned, the respondents opinions diverged., – The assessment of local communities perception is important to design participatory and sustainable measures to cope with harmful effects of climate variation on crop production.

Étude de la diversité spécifique du groupement à Cochlospermum tinctorium A. Rich, des savanes arbustives du nord-Bénin

Abstract Species diversity of Cochlospermum tinctorium community that occurs in dry savannas was studied in northern Benin. The objective of this study is to describe the community using the phytosociological method and to determine the variability of floristic composition of constitutive relevés. The analysis of life form spectras had revealed the abundance and the dominance of annual species. The phytogeographical spectras allowed to establish the abundance and the dominance of the sudanian base-element. Species classification among higher phytosociological taxa showed that species that were most dominant were those of the Hyparrhenietea class of savannas and Soncho-Bidentetea pilosae class of fallows. The species diversity was higher at the community level than the constitutive relevés. The herbaceous biomass of the Cochlospermum tinctorium community was 4.94 ± 2.41 t DW/ha from wich the grass species bio- mass recorded was 3.84 ± 1.44 t DW/ha. Statistical tests showed that the floristic homogeneity at the community level can include differences between some constitutive relevés and then the phytosociological table can be seen as a synthesis of dissimilar and similar relevés.

Mangroves in Benin, West Africa: threats, uses and conservation opportunities

Mangrove ecosystems constitute valuable resource all over the world. They provide habitats for flora and fauna species, protect the coast against erosion and supply various products for local communities. Currently, mangroves are overused and degraded. Up to now, perceptions of local communities on the dynamic of mangrove forest and their acceptable participation forms for mangroves restoration have not been entirely understood. This study was undertaken in order to assess human pressure on mangroves from user perspective and to provide baseline information for its sustainable management in three districts (Grand-Popo, Ouidah and Sèmè-Kpodji) located in the coastal area of Benin. Structured and semi-structured questionnaire surveys regarding perceptions of mangrove forest dynamic, causes of mangrove forest degradation, indigenous restoration strategies and forms of participation were conducted among randomly selected informants. It has been reported that Beninese mangrove ecosystems supply timber and non-timber forest products, rich fishing grounds and salt for local communities. Local communities are aware of the need of restoring and ensuring sustainable conservation of mangrove ecosystems. Dominant measures for restoration and conservation indicated by informants for mangrove users include the reintroduction of traditional rules, avoidance of uncontrolled settlements, planting of mangrove trees, planting alternative fuelwood, use of solar energy for salt production and creation of alternative income generating activities. Planting mangrove trees and alternative cooking energy sources supplying to local communities to avoid mangrove destruction are urgent needs for the coastal area of Benin.

Topographic and edaphic factors determining Chromolaena odorata and Hyptis suaveolens invasion of grassland in the Guineo-Congolian / Sudanian transition zone (Benin)

Objectives: Soil properties-invasive vegetation relationships remains uninvestigated. This study aimed at analyzing the main ecological factors, which explain the spatial distribution of two invasive species: Chromolaena odorata (Siam weed) and Hyptis suaveolens (Tea-bush). Methodology and Results: The Data were collected in 33 plots installed randomly according to the phytosociological method. These data were submitted to the Canonical Analysis of Correspondence. The, wet grasslands contamined were distinguished from grasslands of dry plateaus. A difference was also made between establishment and invasion from the step of contamination of both plants. The relevant edaphic main factors related to grasslands on dry plateau were sandy rate, pH, potassium and carbon rate. Wet grasslands of floodplains were located on soils with a high concentration of clay and silt, phosphorus, calcium and magnesium, as well as a high cation exchange capacity. Conclusions and application of findings: It could be concluded that the texture-moisture of the soil is the main factor, which explained the invasion intensity and the floristic composition of the investigated savannah. Dry plateau soil and oligotrophe induced the development of these alien plants. Therefore, it was suggested planning activities to prevent the expansion of these species on dry plateau grasslands. Keywords: alien plants, Canonical analysis of correspondence, dry plateau, floodplain, plant community, soil properties

Fruit and pulp production of the African grape Lannea microcarpa Engl. & K. Krause from dry and humid Sudanian zone in Northern Bénin, West Africa

Lannea microcarpa , an Anacardiaceae species associated to croplands in West Africa is a multipurpose tree used in traditional medicine, human and animal feeding in Sudanian zone of Benin. This study aimed at evaluating its fruits and pulp yield. Fruit and pulp production and dendrometric variables were collected on 21 and 27 trees respectively in dry and humid Sudanian zone. Data were analysed using two independents samples t-test and Pearson correlation to find out variation in production and relation between variables. Trees in dry Sudanian zone showed the largest crown. The number of fruit, fruit mass and pulp mass were highest in dry Sudanian zone. Also, trees with high diameter at 1.30 m above the ground had produced low number of grapes and fruit per grape. Pruning and debarking did not affect the fruit and pulp mass. In humid Sudanian zone, tree crown could be used as indicator of number of fruit per grape in the one hand and in other hand the number of tertiary branches could be used for fruit and pulp yield. This study highlighted that in northern Benin, dry Sudanian zone could be preferable for L. microcarpa fruit and pulp production. The variations observed between zones deserve to be investigated. Keywords : Lannea microcarpa production, Humid and dry Sudanian zone, Benin, West Africa.

Caractéristiques écologiques et phytosociologiques des galeries forestières de la Réserve de biosphère de la Pendjari (nord-ouest du Bénin)

Abstract The flora and plant communities of gallery forests were studied of the Biosphere Reserve of Pendjari using the phytosociological approach. A total of 350 plant species were identified, of which 98 are typically gallery forest species of the Sudanian region of northern Benin. We define five plant communities: (1) the Broenadia salicina—Garcinia ovalifolia comm., (2) the Cassia sieberiana—Terminalia glaucescens comm., (3) the Cola laurifolia—Parinari congensis comm., (4) the Garcinia livingstonei—Combretum acutum comm. and (5) the Ficus congensis—Alchornea cordifolia comm., Since the climate does not substantially vary throughout the reserve, relief and topography turn out to be the two major ecological factors that best discrimate gallery forest types in the study area.