This site is located 17 km from Betioky, on the Mahafaly plateau, and is divided into two parcels, covering 80 ha (Parcel 1) and 520 ha (Parcel 2) respectively. It lies in a large valley, with flat lowlands and gentle slopes. The soil is generally sandy. The Sakamena river, a seasonal tributary of the Onilahy, flows along the boundary of the reserve. The vegetation comprises riparian forest and xerophilous bushland. Riparian forest, found mainly in Parcel 1, is dominated by trees of Tamarindus, Acacia, Quivisianthe and Albizia in the upper layer, by small trees and shrubs of Crateva, Azima, Antidesma and Euphorbia in the mid-stratum, and by Tarenna, Byttneria and Greslania in the ground layer. Xerophilous bushland, found mainly in Parcel 2, is dominated by Alluaudia, Cedrelopsis and Grewia in the upper layer, and by Commiphora, Euphorbia, Gyrocarpus, Pachypodium and Aloe in the lower layer.
See Box and Tables 2 and 3 for key species. Sixty-one species are known from this site, of which 27 are endemic to Madagascar. Species of global conservation concern include Accipiter madagascariensis.