AbstractAnthropogenic disturbance is one of the leading causes of biodiversity change in tropical African forests, coupled with high rate of adoption of exotic plantations near natural forests. This is compounded by contemporary forest conservation approaches adopted, such as participatory forest management (PFM), that legally allows local community to use forest resources, leading to local disturbance within the forests. Increase in exotic plantation in Afrotropical forests is exacerbated by the need to increase forest cover and to meet high demands for commercial and non-commercial woods, particularly in montane forests. Mount Kenya’s montane forest represents an ecologically important protected Man and Biosphere Reserve and an important bird area. However, it is managed under PFM and planted with exotic plantations on cleared, unforested and degraded forest sites. But the changes in forests’ habitat structure and characteristics, and how it affects local biodiversity following these local disturbance and plantations remains significant knowledge gaps in Afromontane forests. The aims of this research are to determine the habitat characteristics in undisturbed, disturbed, and eucalyptus plantation forest types, and the impact of these on bird diversity and community compositions.
Birds and habitat characteristics data were collected for a year in a total of 190 systematically placed point counts distributed in forest types across three study sites in eastern, southeastern, and southern Mount Kenya forest. All forest types were characterised by different habitat characteristics. Undisturbed forest had most forest complexity characteristics, with increasing habitat homogeneity from disturbed to eucalyptus plantation. Eucalyptus plantation had exceptional open canopy, tall, and dispersed trees. Forest types significantly influenced combined bird species, Afrotropical highlands biome restricted species (ATHB), frugivores, granivores and nectarivore dietary guilds, and all forest dependency groups except generalists. Habitat characteristics related to complex forests positively predicted forest specialists’, frugivores’, insectivores’, and ATHB’s species richness and abundance. It negatively predicted richness and abundance of forest visitors (FV), non-forests birds (NF), granivores, omnivores and nectarivores. Characteristics in eucalyptus plantation predicted positively FV’s, NF’s, granivores’ and omnivores richness and abundance, and negatively ATHB’s, and frugivores’ richness and abundance, and influenced their compositions. Although community composition of birds among forest types revealed a general ecological complementarity, there was important contribution of natural forests irrespective of local disturbance. Eucalyptus plantation represented species more associated with surrounding landscape rather than forests. This research has demonstrated the importance of natural forests irrespective of local disturbance, yet exotic plantations contribute minimally to forest birds in Afrotropical montane forests.
|Date of Award||Feb 2023|
|Supervisor||Rachel White (Supervisor), Chris Joyce (Supervisor) & Dawn Scott (Supervisor)|