The goal of my dissertation research is to understand how physical environmental conditions and human management practices modify vegetation patterns in Acacia-Commiphora bushland. This research applies a hierarchical approach to study the distribution and ecology of bushland in the Tsavo ecosystem, southeastern Kenya, including lands managed for wildlife protection, human settlement and farming, and cattle ranching.
The regional scale of the investigation explores why wooded bushland appears to dominate in only certain parts of the ecosystem. This is done by first comparing the distribution of wooded-bushland and grassland vegetation in Tsavo East National Park and privately owned Rukinga ranch, and then examining whether their distributions are related to environmental factors or management histories. The study concludes that most grassland vegetation should be classed as derived savanna.
The landscape scale of the research focuses on the Taita wildlife corridor where dense bushland vegetation is predominant. The study applies remote sensing to the examination of diversity patterns within this bushland vegetation type and considers how diversity is distributed environmentally across the landscape and influenced by local management. The study classifies seven bushland types and documents structural heterogeneity among these bushland. Land-cover proportions correlate with land management but relationships with environmental conditions are complicated by the history of land use and vegetation.
The local scale focuses on the composition and structure of bushland and relationships with physical-environmental and human-historical factors. The focus is on three bushland community types (Commiphora-dominated, Acacia-dominated, and mixed-species) identified at the landscape scale. The results indicate that community types within the bushland have distinct species compositions. Acacia-dominated sites are the most heterogeneous, which may relate to the regeneration attributes of Acacia species.
The study validates the application of remote sensing in analyzing vegetation patterns at multiple scales as it applies a hierarchical model, developed for savanna, to explore bushland diversity patterns. Bushland needs greater recognition as a heterogeneous system that should be prioritized for biodiversity conservation.