Managing the Mount Kenya environment for people and elephants

Abstract

Forests contain much global biodiversity, and over 90% of the worlds' poorest people depend on them. Few forests remain in East Africa, and these are vulnerable to further fragmentation from expanding settlement, and to over-exploitation by people and wildlife that become prone to over-crowding through isolation. Kenya contains 26 natural habitat fragments and only 3% of forest cover across five main forest blocks. These blocks form the main water towers in semi-arid Kenya on which people and wildlife, far beyond the protected boundaries, depend. Mount Kenya (MK) is the largest forest block, and the protection of its water catchment function is of national importance (Chapter 2). The five forest blocks in Kenya hold almost one third of the total of 28,806 elephants in Kenya, of which MK was estimated as having the largest highland elephant population with 2,911 (±640) individuals in 2001 (Chapter 3). Elephant estimates in forest are usually derived from dung count surveys, which are prone to bias and accordingly most often classed as C or D, in the range from A (best) to E (worst), in the African Elephant Database (AED). The MK elephant estimate described in this thesis was one of only two dung count estimates that were classed as quality B in the AED of 2002 (Chapter 3). Explanatory models based on the dung count data were integrated with a geographic information system (GIS) to develop the most advanced predictive seasonal distribution maps currently available for elephants in a forested environment (Chapter 4). Furthermore, least-cost elephant travel routes and foraging paths were digitally traced over cost surface images, developed from data on preferred elephant habitats in different seasons, physical barriers such as extreme slopes, and land use barriers such as farmland (Chapter 5). This enabled the location of elephant movements in relation to plantations inside the MK forest, and investigation of the relationship between measured tree damage in plantations and elephant movements (Chapter 5). Two areas where subsequently identified where elephant routes strayed from the forest into adjacent farmland, which was where most elephant crop damage was reported by farmers to Kenya Wildlife Service stations and outposts (Chapter 6). Elephants and people trespassing on each other's habitats is pronounced because MK is surrounded by a ring of small-scale farmers, totalling over 500,000 people living within 5,000m of the MK forest boundary on farms of 1.6ha on average (Chapter 6).Time-series analysis of satellite imagery of 1987,1995, and 2000 illustrated a gradual deterioration of MK land and resources, and results of an aerial survey conducted in 1999 showed high levels of illegal exploitation of land and resources (Chapter 7). However, management responsibility of the MK forest transferred from the Forestry Department to the Kenya Wildlife Service in July 2000, and time-series analysis of satellite images of 2000 and 2002 show regeneration of degraded MK land by 2002 (Chapter 8). Comparison of two aerial surveys conducted in 1999 and 2002, showed a significant reduction of illegal exploitation of forest resources on MK by 2002 (Chapter 8). Sound land use management plans are needed for MK to avoid deterioration of the forest by an over-crowded and confined elephant population, and by surrounding people. These plans need to address problems with longer term solutions, regardless of the short term disadvantages that they may entail (Chapter 9).