This is the largest National Park in Angola and is situated in the south-western corner of Namibe, between the Curoca and Cunene rivers. The altitude ranges from sea-level to about 800 m at Posto do Iona and higher in the Tchamalinde Mountains, and there is a gradient in rainfall, from about 100 mm at the coast to 300 mm or more on the eastern boundary of the park. The protected area includes the mouth of the Cunene river, the extensive sand-spit and bay of the Baia dos Tigres and about 200 km of Atlantic coastline. Of particular importance is that the park is contiguous with the Skeleton Coast Park in Namibia, which is itself contiguous with the Namib-Naukluft National Park so that all three protected areas form a continuous block covering some 1,200 km of Namib Desert coastline and adjacent dunes. There are a variety of desert and semi-desert ecosystems in Iona National Park, including mobile dunes along the coast, calcrete plains,desert grasslands of perennial Aristida and Stipagrostis, arid montane shrubland and open woodland and arid savanna. Welwitschia mirabilis is common on gravelly substrates (Huntley 1974b). As a result of the rainfall gradient, the perennial grasslands in the park lead into Acacia–Commiphora semi-arid savanna and, further east, to mopane (Colophospermum mopane) woodland.
See Box and Tables 2 and 3 for key species. Only 114 species have been recorded for the area, but the avifauna is likely to be far richer than this, with all the typical Namib Desert avifauna present. The site is important for species restricted to the Namib–Karoo and Kalahari–Highveld biomes. Among species of global conservation concern, Namibornis herero and Estrilda thomensis are frequently encountered residents, while Spheniscus demersus, Morus capensis and Sterna balaenarum are frequent to common non-breeding visitors along the coast. Observations of an adult S. balaenarum feeding young, and adults carrying fish at the mouth of the Cunene river in December (Simmons and Braine 1994), as well as specimens of S. balaenarum in breeding plumage (but with small gonads) at the same locality in November (Pinto 1973b), all support the suggestion by Brooke (1981) that this tern may breed in dunes along the coast of extreme south-west Namibe (i.e. at this site). The coastal parts of the park are an important part of the non-breeding range of Sterna maxima albididorsalis.
Non-bird biodiversity: Large herbivores in the park include Diceros bicornis (CR), Equus zebra hartmannae (EN) and Aepyceros melampus petersi (Huntley 1974a). Carnivores include Lycaon pictus (EN), Hyaena brunnea (LR/nt), Acinonyx jubatus (VU) and Panthera leo (VU) (Cabral 1987; Cabral and Simões 1988).
BirdLife International (2020) Important Bird Areas factsheet: Iona National Park. Downloaded from http://www.birdlife.org on 26/02/2020.