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Site description (2001 baseline):
Site location and context
The Chyulu Hills are situated 190 km south-east of Nairobi and 30 km south-west of Kibwezi. They are of relatively recent volcanic origin, and the range is composed of ash cones and craters. The hills hold no permanent surface water, but rainfall percolating through the porous rock feeds many permanent fresh water sources in the surrounding plains, notably Mzima Springs and the Tsavo and Galana rivers. The hills are relatively undisturbed and still shelter indigenous vegetation and wildlife. Rough grassland and thicket give way to patches of montane forest along the spine of the hills, mainly above the 1,800 m contour; the largest tract of forest is around the highest peaks in the central-southern portion. Characteristic trees include
Ficus spp,
Neoboutonia macrocalyx,
Tabernaemontana stapfiana,
Prunus africana,
Strombosia scheffleri,
Cassipourea malosana,
Olea capensis and
Ilex mitis, with islands guarded by
Erythrina abyssinica. Lower down, there are areas of
Juniperus procera forest and, particularly on lava flows, forest dominated by the blue-stemmed
Commiphora baluensis. The eastern flank of the hills, including about half the forested area, is in the 47,100 ha Chyulu East National Park, administered by Kenya Wildlife Service. The park boundary runs down the centre of the hills along the line of the peaks. The western half is part of the ungazetted West Chyulu Game Conservation Area, owned by several Maasai group ranches. At present, this area has no formal conservation status. The notional boundary of the IBA follows the 1,500 m contour, including an area of some 18,000 ha of which around half is included in the park and slightly under half (c.7,900 ha) is forested.
See Box and Table 2 for key species. The Chyulu Hills may be an important stopping-point (when forest trees are in fruit) for
Cinnyricinclus femoralis as they move between forests on Mount Kilimanjaro and the central Kenyan highlands. The hills hold endemic races of
Francolinus shelleyi (
macarthuri),
Pogonocichla stellata (
macarthuri) and
Zoothera gurneyi (
chyulu). The race
chyulu of the
Bradypterus cinnamomeus is now generally merged with the race
rufoflavidus of northern Tanzania, but Chyulu birds are darker. Van Someren (1939) named 22 further Chyulu Hills subspecies, and although most are no longer considered valid, definitive taxonomic work remains to be done. Regionally threatened species include
Hieraaetus ayresii (status unknown);
Stephanoaetus coronatus (status unknown) and
Polemaetus bellicosus.
Non-bird biodiversity: A variety of large mammals occurs on Chyulu, including, at times, Loxodonta africana (EN). The rich butterfly life includes the endemics Pentila tropicalis chyulu, Acraea anacreon chyulu, Papilio desmondi desmondi and the near-endemic Amauris echeria chyuluensis. Ongoing research on the vegetation gives some 550 plant taxa, excluding the numerous grasses. Amongst these are 37 species of orchid, mostly epiphytes supported by the heavy mists and the rare saprophyte Epipogium roseum. Notable trees are Chionanthus mildbraedii and the most northerly population of Podocarpus usambarensis.
Pressure/threats to key biodiversity
Agricultural settlers, who were displaced in 1988 to make way for the National Park, occupied the lower eastern slopes of the hills in the past. This has led to lingering resentment among those evicted, and difficulties in policing use of the park. There have been particular problems with forest burning and cutting to encourage sprouting of ‘miraa’,
Catha edulis, a valuable tree whose young shoots are used as a stimulant in parts of Kenya and Somalia. ‘Miraa’ harvesting could well be sustainable if properly managed, but National Park regulations do not allow for it to be extracted legally. The hills provide wet-season grazing for Maasai pastoralists from the nearby group ranches. Regular burning of the grassland is also caused by meat poachers either driving game into snare lines or using the resultant new grass as bait. It is debatable how destructive these annual grass fires are to the forests, quite possibly protecting them in the long run by ensuring that flammable brush and litter do not build up to dangerous levels. The hills have great potential for ecotourism, but difficulties of access and the lack of surface water have kept this to a limited scale so far. Chyulu Lodge, on the north-west slopes, caters for visitors interested in walking or horse-riding in the hills, or bird-shooting on the plains below. There has been little ornithological work in Chyulu since an East Africa Natural History Society expedition in the 1930s. A bird conservation survey of the forests is overdue. It should focus on the status and requirements of
Cinnyricinclus femoralis and the endemic subspecies of forest robin and thrush.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Chyulu Hills forests (Kenya). Downloaded from
https://datazone.birdlife.org/site/factsheet/chyulu-hills-forests-iba-kenya on 23/11/2024.
