The balance between speciation and extinction determines the biological diversity existing on earth at any time. Thousands of animal and plant species around the world are now threatened with premature extinction by human activities, especially habitat destruction and fragmentation, overexploitation, and introduction of exotic species. Because of the complexity of the processes involved, mathematical models and computer simulations are necessary to assess the relative importance and interactions of different factors affecting extinction risks.
This proposal concerns models of several demographic and genetic factors affecting the risk of population extinction, with emphasis on random factors operating in small and spatially distributed populations, and in communities of interacting species. Formulas for probabilities and times of extinction will be derived and computer simulations performed to understand the importance of various risk factors and their interactions. The results of this investigation will help in the assessment of extinction risks and the development of management plans for threatened and endangered species. The synthesis of realistic models of demographic and genetic processes in small and spatially distributed populations is an area in which conservation biology can contribute to fundamental advances at the interface of ecology and evolution.
