These small, adjoining savanna National Reserves lie either side of the Northern Ewaso Ngiro river, some 340 km north north-east of Nairobi. They were established in 1948 as the Samburu-Isiolo Game Reserve, part of the once extensive Marsabit National Reserve. Now their respective County Councils, Samburu and Isiolo manage them. Buffalo Springs consists of gently rolling plains of volcanic origin, while Samburu is more rugged, with outcrops of ancient basement rocks forming isolated inselbergs. The soils are mainly sandy or gravelly; rainfall is c.350 mm/year. Despite their relatively small size, the reserves contain contrasting habitats: rocky cliffs and scarps; pools, swamps and riverine sandbanks; arid open bush and grassland; tracts of Acaciatortilis woodland; and, along the banks of the Ewaso Ngiro and its tributaries (the Isiolo and Ngare Mara), a narrow band of riverine forest with magnificent Acacia elatior, Tana River poplar Populus ilicifolia and doum palm Hyphaene compressa. The Buffalo Springs themselves, with their pools and streams of clear, fresh water, are a magnet for thirsty wildlife in the dry season.
See Box and Table 3 for key species. Over 380 species have been recorded from the reserves, and the birdlife is generally abundant and colourful. Birds of the arid northern bush country are augmented by a number of riverine forest species. Numerous raptors nest on the cliffs of Samburu’s inselbergs. Several arid-country birds reach their southern limit here, including Plocepasser donaldsoni, Nectarinia habessinica and Onychognathus salvadori. Two globally threatened species are recorded, Falco naumanni (a passage migrant) and Falco fasciinucha (status unclear, probably resident). Regionally threatened species include Anhinga rufa (sporadic visitor); Casmerodius albus (sporadic visitor); Trigonoceps occipitalis (resident in small numbers); Polemaetus bellicosus (resident in small numbers); and Buphagus africanus (fairly common resident).
Non-bird biodiversity: The reserves hold populations of several threatened mammal species, including Equus grevyi (EN), Loxodonta africana (EN) and Acinonyx jubatus (VU). The increasingly uncommon Giraffa camelopardalis reticulata occurs in good numbers. The tree Populus ilicifolia, which grows along the Northern Ewaso Ngiro river,is restricted to just three Kenyan river systems.
Pressure/threats to key biodiversity
The Samburu and Buffalo Springs National Reserves (16,500 ha and 13,100 ha respectively) are a popular tourist destination, the main attractions being their scenic beauty, remoteness and concentrations of photogenic wildlife. The surrounding areas are under increasing pressure from an expanding human population. Overstocking and unsustainable cutting of trees and shrubs for fuelwood and building are causing substantial environmental changes. The reserves themselves remain well protected, and there are few immediate threats to the birds that they contain.