Arusha National Park covers the eastern portion of Mount Meru and extends 16 km to the east of the mountain. The site lies to the east of the Rift Valley and to the west of Mount Kilimanjaro (TZ003). The park encompasses a wide variety of habitats including montane forest similar to that on Mount Kilimanjaro, characterized by Diospyros abyssinica, Olea welwitschii, O. hochstetteri and O. africana, and several freshwater and alkaline lakes, ponds and swamps. The IBA also includes lower and mid-altitude forest lying outside the park in Forest Reserves.
See Box and Tables 2 and 3 for key species. The site is known to support at least 411 species, including Ardeola idae, as a non-breeding visitor in small numbers, and one species of the Serengeti plains EBA, as well as 11 species of the Somali–Masai biome (see Tables 2 and 3). The National Park is the only protected area utilized by the dwindling East African population of Oxyura maccoa which winters on the large alkaline lakes and breeds in the small, secluded freshwater ponds and swamps. The mountain streams hold Anas sparsa and the towering cliffs support a large population of Apus niansae and two pairs of Gypaetus barbatus. Apus horus and Merops bullockoides share nest-sites along the riverbanks, while the swamp on the floor of Ngurdoto Crater provides a safe nest-site for Ephippiorhynchus senegalensis. There are important populations of montane forest birds in the natural forest including Poicephalus gulielmi, Apaloderma vittatum and Linurgus olivaceus.
Non-bird biodiversity: A population of Loxodonta africana (EN) occurs in the park, while Lycaon pictus (EN) is an occasional visitor. The commonest duiker in the forest is Cephalophus harveyi (LR/cd).
Pressure/threats to key biodiversity
Whilst natural forest inside the National Park is protected, forest areas in adjacent Forest Reserves are vulnerable to degradation and should be included within the boundaries of the National Park. The Momela lakes, on the edge of the National Park, are threatened by chemical run-off from nearby farms. This threat is likely to intensify as higher agricultural yields are required to meet the needs of a growing population.The National Park has a relatively small area and is becoming increasingly isolated as surrounding land is developed for agriculture. The long-term viability of this park, particularly for the majority of large mammals, would be enhanced by creating a corridor to the north–north-east linking it with the extensive areas of Acacia-dominated woodland which continue north to the Kenyan border and to the foothills of Mount Kilimanjaro.