The site lies on the escarpment zone where an area of about 200,000 ha of impoverished semi-deciduous moist forest (an outlier of Guinea–Congo forest) has the richest array of local endemics bird species in Angola. The rainfall is markedly seasonal, with November–December and February–April the months in which most rain falls. Tree genera in the forest include Ficus, Newtonia, Albizia, Celtis, Ceiba and Pterocarpus. Oil palms Elaeis are common, and epiphytes are abundant on the trees. Although the undergrowth of the forest has been cleared and the forest floor extensively planted with coffee, current coffee production is low, and much of the forested area is relatively undisturbed by human activity. However, valley bottoms in the area are now being cleared by subsistence farmers (Hawkins 1993) and this is a matter for some concern.
See Box and Tables 2 and 3 for key species. The site is important for six species of global conservation concern—all have a restricted range, all but one are endemic to Angola, and most are uncommon at the site. Prionops gabela is found only at Gabela and along the road to Muxima, while Sheppardia gabela is virtually confined to the Gabela area. The Angolan endemic Platysteira albifrons has been collected at Quirimbo, just north of Gabela, and is likely to occur in thickets and woodland at lower elevations in the general area. The globally threatened Macrosphenus pulitzeri is highly likely to occur in secondary forest in the south of the region. The site is also important for species of the Guinea–Congo Forests biome and Afrotropical Highlands biome. The forests at Gabela are the only known locality in Angola for Alethe poliocephala, Dyaphorophyia blisseti, Parus funereus, Ploceus insignis and Cryptospiza reichenovii, and are one of the few sites in Angola where Stephanoaetus coronatus is known to occur. Other poorly known species that occur in the forest include Cercotrichas leucosticta and Hylia prasina. Numerous species reach the southern limit of their Angolan distributions at Gabela, including Campethera nivosa, C. caroli, Phyllastrephus albigularis, Neocossyphus fraseri, Muscicapa cassini, Trochocercus nitens, Batis minulla, Illadopsis fulvescens, Oriolus nigripennis and Spermophaga ruficapilla.
Non-bird biodiversity: Bats that have been collected include the rare Epomops franqueti (Cabral 1989).
BirdLife International (2019) Important Bird Areas factsheet: Gabela. Downloaded from http://www.birdlife.org on 20/04/2019.