Ranomafana National Park is located 45 km north-east of Fianarantsoa. The forested terrain comprises a succession of hills and summits, separated by narrow valleys and lowlands. The Namorona river flows across the park. Three types of forest are present: the low- and mid-altitude, dense, humid evergreen forest and the sclerophyllous montane forest. Marshes have formed on the sites of former rice-fields; the IBA includes c.100 ha of marsh outside the park.
See Box and Tables 2 and 3 for key species. One hundred and thirteen species are known from the area of the site, of which 64 are endemic to Madagascar. The majority of species of mid- and high altitudes are present. Some lowland species known from elsewhere are absent; it is unclear if others occur within or just outside the park. Xenopirostris polleni and Mesitornis unicolor, scarce and patchy elsewhere in Madagascar, seem to be reasonably common. Several marshland species, including Sarothrura watersi and Anas melleri, occur just outside the National Park, and this area is included within the IBA.