The National Park lies on the western bank of the Great Ruaha river in the rain-shadow of the Udzungwa mountains (TZ066), which lie some 80 km to the south-east. The western boundary is formed by the Rungwa Game Reserve. The site is largely a dry habitat southern extension of the Masai steppe. Average annual rainfall is only about 520 mm, making it one of the driest protected areas in Tanzania. The Great Ruaha river runs for 130 km along the south-eastern boundary and is perennial, drying out only in the driest of years. The southern and western areas of the park are mainly miombo woodland dominated by Brachystegia. This grades into Commiphora–Combretum woodland in the north-east with extensive areas of Terminalia- and Adansonia-dominated plains in the central areas.
See Box and Table 3 for key species. Some 410 species have been recorded for the park, but this figure is almost certainly incomplete as only the main tourist areas are well known. This total includes seven species of the Zambezian biome (see Table 3). Ruaha holds important populations of two Tanzanian endemics of the dry central plateau—both Cosmopsarus unicolor and Agapornis personatus are reasonably common. Large flocks of Ciconia ciconia and Ciconia abdimii frequent the park when conditions are suitable and especially on passage. In the past, significant numbers of Falco eleonorae occurred, but there are few recent records.
Non-bird biodiversity: A large population of elephant Loxodonta africana (EN) occurs, but the population of rhino Diceros bicornis (CR) was wiped out by poachers during the early 1980s. An important population of Lycaon pictus (EN) is present and there are large populations of Tragelaphusstrepiceros (LR/cd) and T. imberbis (LR/cd). A small remnant herd of Hippotragus equinus (LR/cd) occurs and H. niger (LR/cd) is not uncommon in the miombo woodland. The park represents the southern limit of the tortoise Malacochersus tornieri (VU), an East African endemic.
Pressure/threats to key biodiversity
The National Park was established in 1964 by detachment from Rungwa Game Reserve to protect an important population of elephant and rhino. There are considerable concerns about rainfall in the Kipengire mountains catchment area of the Great Ruaha river. There have been recent attempts to upgrade the Game Controlled Area upstream of the National Park to Game Reserve Status. This is intended to help protect parts of the Usangu flats (TZ038) and would also enhance the biodiversity values of Ruaha National Park. There is a wedge of land downstream of the park and north of the Ruaha river that extends to the shore of Mtera reservoir (TZ029). This land should be considered for incorporation into the National Park. It would provide a safe corridor for the movement of large mammals to permanent water in years of drought and protect part of the shoreline of Mtera from erosion, as well as increasing the value of the park and creating further opportunities for tourism.