Paolo Lesse (2016). Managment and modeling of the transhumance pasture dynamic in a climatic variabilies context in North-East of Benin. University of Abomey-Calavi, Laboratoire d’Ecologie Appliquée. 299p
Promotor: Prof. Marcel R. B. HOUINATO.
ABSTRACT: Transhumance is a herding system which occupies an important place in the West Africa region and in Benin particularly. This study has been carried out in the North-East Region of Benin which is herders’ predilection area. The general objective of this work is to contribute to a sustainable management of transhumance corridors in the North-East of Benin. The natural corridors have been characterized using linear plots measurements, the method of short cut for the biomass quantification and the phytosociological plots. The herding system has been studied using the system approach. The sensitivity matrix has been used to better assess the vulnerability level of the herders to hydroclimatic variabilities. The future evolution of rainy and thermometric extremes in the basin has been analyzed thanks to the data of the regional climatic model REMO. The Land Change Modeler (LCM) of IDRISI Selva has been used to predict the land occupation state in 2050. The current study allowed bringing out the system constraints. They were feeding, climatic variabilities, legislation, conflict and availability of pastoral infrastructures problems. In total, 162 infrastructures capable of serving as water sources in the study area have been identified but not functional or in a bad state characterized by the inexistence of access trails toward the water points, the presence of abundant vegetables floating on the surface of the waters and the functioning problems of the management mechanisms put in place. Four (04) types of pastures having productivity varying between 3.46 and 5.7 tons of Dry Matter/ha have been identified. The Prosopis africana and Eragrostis atrovirens pasture and the Piliostigma honningii and Stylosanthes fruticosa pasture presented respectively the highest nutritive value for the grass and the legume plants. Twelve (12) transhumance corridors oriented toward the water points and the protected areas have been repertoried and mapped in the study area. About the demographic parameters, the mean annual rate growth is of 1.068 ± 0.05 while the mean production rate is low (0.155 ± 0.02). By the 2050 horizon a contrasted evolution of the rains regimes have been predicted with a mean heating of 1°C. Under the transition probabilities basis, the predictive modeling realized on the land occupation by the horizon 2050 predicted that the tree and shrub savannas will occupy 49.89 % of the total area of the natural North East grassland of Benin Republic. The variability observed is explained by the delay in the beginning of the rains, the bad repartition of the early arrest of the rains, the violent winds. The vulnerability analysis allowed noticing that herding is the most vulnerable and that herders fear more droughts and floods than the rains decreases.