Phylogeography and systematics of montane forest birds in Cameroon

The highlands of Western Cameroon support the only remaining extensive tracts of Afromontane flora and fauna in West Africa. The region supports a unique avifauna with a high level of endemism. This thesis focuses on several co-distributed endemic avifauna of the region with the aim of understanding their evolutionary origins and current population structure, and in turn, seeks to stimulate new initiatives and partnerships for the conservation and restoration of montane forests within the region. The research focuses on several exemplary taxa, including the African Hill Babblers, Pseudoalcippe abyssinica, a group of allopatric montane or insular populations with a broad distribution in all Afrotropical montane forests; the Mountain Robin Chat, Cossypha isabellae, which is restricted to the Cameroon Endemic Birds Areas; the African Wattle-eyes, a group of 10 species that includes both montane and lowland forms; and the Musophagidae, an enigmatic family of 23 species notable for their brightly colored feathers and ubiquitous distribution throughout sub Saharan Africa. Analyses of both mitochondrial and nuclear DNA sequence data from multiple loci for Hill Babbler and Robin Chat populations show strong evidence for long term isolation and genetic divergence of populations on different mountains. Morphological and behavioral divergence of Hill Babbler populations along with divergence times ranging up to ∼3 million years suggest the recognition of at least six distinct species. Their distributions support Moreau's theory that East African species have larger ranges than West African species with the former harboring ancestral populations. Complete molecular phylogenies for the turacos and wattle-eyes were generated to study the evolutionary origins of two endangered species in Cameroon and allow inferences about the geography of speciation. These analyses suggest that historical climate change, through its effects on the vegetation of this region, resulted in vicariance of populations and promoted allopatric speciation on isolated montane islands. At present, lowland forests and savannah act as barriers to gene flow between montane populations. This research has helped to identify previously unrecognized avian biodiversity within the Cameroon mountains. Given the rapid depletion and destruction of these montane habitats, the conservation implications of recognizing these distinct species-level taxa are considerable.