Key Biodiversity Areas

South Nandi forest (6445)
Kenya, Africa

Site overview


KBA status: confirmed
Year of last assessment: 2011
National site name: South Nandi forest
Central coordinates: Latitude: 0.1050, Longitude: 34.9980
System: terrestrial
Elevation (m): 1700 to 2000
Area of KBA (km2): 169.95023
Protected area coverage (%): 98.28
KBA classification: Global/Regional TBD
Legacy site: Yes

Site details


Site description: This area is a mid-elevation forest lying just west of Kapsabet town and south of the main Kapsabet–Kaimosi road. South Nandi was once contiguous with Kakamega forest (IBA KE058) and the two forests are still no more than a few kilometres apart at their closest points. Rainfall is high, 1,600–1,900 mm/year depending on altitude. The forest is drained by the Kimondi and Sirua rivers, which merge to form the Yala river flowing into Lake Victoria. The landscape is gently undulating and underlain by granitic and basement complex rocks, which weather to give deep, well-drained, moderately fertile soils. The South Nandi area has high agricultural potential and human densities around it are also high, particularly to the west. Biogeographically, South Nandi is often considered an eastern extension of Kakamega. However, it is higher in altitude than Kakamega and floristically less diverse. In effect, South Nandi is transitional between the lowland forests of West and Central Africa (the easternmost outlier of which is Kakamega) and the montane forests of the central Kenya highlands. Common trees include Tabernaemontana stapfiana, Macaranga kilimandscharica, Croton megalocarpus, C. macrostachyus, Drypetes gerrardii, Celtis africana, Prunus africana, Neoboutonia macrocalyx and Albizia gummifera. South Nandi was gazetted in 1936 as a Trust Forest covering 20,200 ha, since when c.2,200 ha have been excised for settlement, c.340 ha planted with tea, and 1,400 ha planted with exotic tree species. Of the remaining area, at most c.13,000 ha is closed-canopy forest, the rest being scrub, grassland or cultivation.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance because it meets one or more previously established criteria and thresholds for identifying sites of biodiversity importance (including Important Bird and Biodiversity Areas, Alliance for Zero Extinction sites, and Key Biodiversity Areas) KBA identified in the process of compiling the CEPF Ecosystem Profile of the East Afromontane Hotspot. Species taxonomy and threat category was based on IUCN Red List 2010-4.
Additional biodiversity: See Box and Table 3 for key species. South Nandi forest is almost certainly the most important site in the world for the threatened Eremomela turneri. The area supports exceptionally high densities of this little-known species (around 0.27 groups/ha, equating to 1.1 birds/ha), and an estimated population of 13,000 birds. The avifauna (like that of North Nandi, IBA KE053) is mainly Afromontane, but with strong western affinities. There is so far no comprehensive bird list, but a survey in 1996 recorded 111 species of forest birds, including 47 forest specialists. Regionally threatened species include Stephanoaetus coronatus (uncommon resident), Glaucidium tephronotum (status unknown), Indicator conirostris (local and uncommon), Indicator exilis (local and uncommon), Kakamega poliothorax (scarce and very local), Sheppardia polioptera (local and uncommon), Dyaphorophyia concreta (scarce) and Hyliota australis (uncommon). Non-bird biodiversity: The ungulate Tragelaphus eurycerus (LR/nt) is reported to occur, but there are no confirmed records.
Delineation rationale: 2013-07-10 (BL Secretariat): following CEPF East Afromontane ecosystem profiling process, the reported IBA area of 18000 ha has been changed to 13000 ha (as measured in GIS from latest boundary polygon, rounded to nearest 10%).

Habitats


Land use: agriculture | forestry
IUCN HabitatCoverage %Habitat detail
Forest70
Grassland30

Threats


Summary of threats to biodiversity at KBA: South Nandi is one of the most threatened IBAs in Kenya. A dense and rapidly growing human population surrounds the forest, and pressure on land is very high. Several large excisions have taken place in the recent past, and there is no indication that this process will end soon; in February 2001 a further 35 ha were designated for degazettement. Substantial chunks of indigenous forest have also been clear-felled to create the Nyayo Tea Zone and for running a power line from Kobujoi town to a water tank in the forest. Illegal encroachment is a very serious problem. The policing of forest boundaries seems to have failed completely in the south-western sector, and hundreds of hectares have recently been encroached in the Morongiot and Kamaindi areas. Beyond the Nyayo Tea Zone, which was meant to act as a buffer, all the forest undergrowth has been cleared and maize planted as far as the eye can see. Only large trees are left standing, and these are rapidly being converted into charcoal. There is an evident failure to appreciate the biodiversity conservation and water catchment importance of South Nandi, either at the level of land-use planning or the day-to-day work of the Forestry Department. South Nandi has been heavily logged-over in the past, which has severely affected the vegetation structure—some parts have reverted to a thicket formation. For unknown reasons, this forest appears now to be exempted from the general Presidential ban on commercial exploitation of indigenous trees. An Eldoret-based company, Rai Ply, has been logging intensively in several parts of the forest since the early 1990s. The felling targets valuable timber as well as species with lighter wood. The logging operation is intensive and appears very poorly managed, with enormous structural damage to the forest as a result. As early as 1993, a survey report recommended that “the discontinuation of logging should be strongly enforced” because of extensive depletion of the growing stock. The present logging gives the impression of an exercise that is deliberately unsustainable, aiming to extract the maximum amount of timber before commercial exploitation is controlled once again. Many of the other problems faced by South Nandi are common to indigenous forests all over Kenya. Tree poaching and platform sawing are rampant in the Kaimosi area, and near other major settlements. Forest antelope are hunted heavily in the eastern sector, where the surrounding human population is lowest; the lack of hunting elsewhere may reflect a lack of wildlife to hunt! Birds are also trapped seasonally, particularly Coturnix delegorguei in the grasslands. Honey gathering, seemingly a sustainable activity, also constitutes a conservation threat. Honey collectors here frequently fell an entire tree in order to reach one bee’s nest. These trees are often large and old, with natural cavities that provide essential nesting sites for a large array of hole-nesting forest birds. Livestock grazing inside the forest occurs, but may be a less serious problem than at Kakamega. Areas cleared for the development of tea plantations but not planted with tea are heavily grazed, preventing forest regeneration. South Nandi is especially significant for its population of Eremomela turneri. A six-month study of this species shows that the birds are most abundant in the low-altitude parts of the forest (which have been substantially encroached by people) and show a strong preference for foraging in large Croton trees (which are one of the particular targets of the commercial loggers). Scientists, conservationists and the forest management authorities alike have unjustly neglected South Nandi. A laissez-faire approach prevails that seems to allow practically any abuse of the forest to continue unchecked. A proper management plan for the forest, produced with the whole-hearted involvement of both the Forest Department and Kenya Wildlife Service, and incorporating the needs of local people as opposed to industrial timber companies, is urgently needed. In the meantime, commercial logging should cease, encroachers should be repulsed, and a moratorium should be placed on any further degazettements.
Threat level 1Threat level 2Threat level 3Timing
Agriculture & aquacultureLivestock farming & ranchingSmall-holder grazing, ranching or farmingOngoing
Biological resource useLogging & wood harvestingIntentional use: subsistence/small scale (species being assessed is the target) [harvest]Ongoing
Invasive & other problematic species, genes & diseasesInvasive non-native/alien species/diseasesNamed speciesOngoing
Residential & commercial developmentHousing & urban areasOnly in the future
Transportation & service corridorsRoads & railroadsOngoing
Human intrusions & disturbanceRecreational activitiesOngoing
Human intrusions & disturbanceWork & other activitiesOngoing

Additional information


References: Blackett (1994h), Kigomo (1987), Kosgey (1998), Waiyaki (1998).