Doctoral Dissertation Improvement: The Effects of Disturbance and Fragmentation on Wild Primates in Tanzania - Individual and Evolutionary Implications

University Of California-Davis, Davis CA

Investigators

Abstract

Individuals and populations may fail to survive and reproduce in habitats disturbed or fragmented above some critical point, whereas those in less severely disturbed and fragmented habitats may persist. Although the critical point of disturbance and fragmentation for individuals and populations is often unknown, differential extinction and persistence of first individuals, then populations, and finally of species is vital to understanding evolutionary processes and successful conservation efforts. This study of black-and-white colobus monkeys (Colobus angolensis palliatus) in twelve forests with various levels of disturbance and fragmentation in West Usambara, Tanzania, contributes to the understanding of evolutionary process and conservation management. It's goal is to assess at what point of habitat alteration do some individuals and populations fail to survive. It also examines the underlying causes of either persistence or failure to survive. Data from randomly-placed plots in each forest provide evidence of the level of disturbance. Forest fragmentation scores are gleaned from published literature. Food availability is estimated from tree density and phenology in plots in each forest. Observations of feeding and foraging behavior inform on individuals' diet breadth, energy balance, protein intake, and mineral intake. Ratios of immature individuals-to-adult females provide evidence of survival and reproduction rates. Monitoring how disturbance and fragmentation affect food availability and how food availability affects individuals' feeding and foraging behaviors provide insight into how individuals' behavior affect survival and reproduction. The pattern that emerges from the twelve sites provides insights into the broader effects of disturbance and fragmentation on survival and reproduction. The results contribute to understanding of the behavioral biology of a primate's reactions to an altered environment and ultimately contribute to understanding of the process of evolution. Monitoring animal's reactions to extinction threats also contributes to the success of conservation efforts. Training local villagers as field biologists and establishment of a conservation education program for local students expands the contribution of this study to conservation efforts.