Concept de Modèle Ecologique pour la Zone Humide Alaotra

Abstract

"The wet zone Alaotra consists of the largest lake of Madagascar with about 20,000 ha of open - water and up to 23,000 ha of marshes. This wet zone is unique by the presence of an endemic fauna, and its marshes consist of a monospecific vegetation. The local communities directly depend on this wet zone with fishing and agriculture being an integral part of the region’s economy. Consequently, various anthropological pressures such as burning of the vegetation, over - fishing, pollution of the lake by the use of weed-killers, and sedimentation of the watersheds due to heavy erosions of the surrounding hills, negatively impact on this ecosystem. The wet zone Alaotra has been classified as an official Ramsar wetland site since 2003 and also as a SAPM protected area in January 2007 because of its ecological importance and its various threats to this ecosystem. The objective of this article is to present and describe the ecological model, which consists of the identification of the various ecological entities as well as their interdependence, in order to justify the wetlands classification as both a Ramsar and a New Protected Area site. The model has been adopted from Ogden (2005), and its ecological entities integrated in the conceptual model are derived from various research works conducted on the wet zone Alaotra. The model will be critically important in convincing the local authorities as well as the local communities to work together with the researchers, in order to implement the best conservation practices and ensure the sustainable management of the wet zone Alaotra."