The El Montuoso Forest Reserve (EMFR) is a northwestern forested mountain chain of Azuero, origin
of La Villa River, an important water source. We studied the mammal biodiversity and the population status of the endemic and Critically Endangered Azuero howler monkeys A. c. trabeata, and its relationship with other species. We took A.c. trabeata as an indicator to evaluate its role as seed dispersers to keep forest connectivity along the tributaries of the La Villa river. We found the population density (0.004 ind/km2) was lower than past records. We found five species of mammals that have not been detected before at the EMFR. We noted absence of taxonomic groups such as cervids and large felines, and prevalence of phyllostomids, as important seed and fruit’s dispersers, turning the reserve as the main habitat donor to their tributaries. Conservation in this area depends on reforesting with native tree species and the enforcement of environmental and prosecution for illegal hunting and logging within the reserve. FCPP implemented training activities, reforestation, and distribution of educational materials for the area of RFEM, Chupá, and Macaracas.