Preliminary survey of lemur density in the semimontane rainforest of Anka, Fort-Dauphin region

Here we present the first lemur survey conducted in the forest of Anka, a semimontane rainforest area located in the southern sea-side part of the Vohimena Mountains and included in the classified area Tsitongambarika I. The estimated densities of the lemur species encountered during the survey (Eulemur collaris, Avahi laniger , Cheirogaleus spp., Microcebus rufus) appear to be at the upper end of the values for the southeastern rainforest and, in some case, similar to the high densities recorded in the littoral forests close to Fort-Dauphin. Knowing the relative density of lemurs in different forest sites of the Fort-Dauphin region can help to understand the complex migration dynamics of predators (fossa) in the area. In fact, from a fossa's perspective, the forests of Andohahela, Anka and Mandena may be part of "meta-forest" since they are able to move from one site to another within their home-range: the fossa may follow a "density gradient" of the favourite preys when prey population falls under a sustainable threshold.