"Biodiversity scenarios have the potential to exert a strong influence on public perception of the current biodiversity crisis, and on national and international policies to mitigate that crisis. Here, I propose to generate a novel conceptual and analytical model of biodiversity loss, and combine that with deforestation models to generate biodiversity scenarios for the world’s most species rich ecosystem, the rainforests of the humid tropics. Studies of the ecological consequences of habitat fragmentation almost entirely ignore the historical patterns of landscape change that have led to habitat patches being distributed in the way they are. I have developed a simple random sampling model that shows how explicit consideration of landscape ontogeny generates a remarkably diverse set of testable predictions about biodiversity patterns in fragmented landscapes. The model, termed terragenesis, combines the random sampling hypothesis with a landscape terrageny, the latter representing the historical relationships between patches much as a phylogeny represents evolutionary relationships among species. I propose to extend the simple model based on the random sampling hypothesis to incorporate real-world complexity such as variation in rates and timing of historical habitat loss, spatial variation in habitat quality within patches, species dispersal among patches and the way in which matrix habitat influences those dispersal patterns, and variation among species in their susceptibility to habitat loss and fragmentation. I will combine the analytical biodiversity predictions with modelled scenarios of deforestation and logging damage across the humid tropics that my research group is already developing to generate biodiversity scenarios for the world’s most biodiverse biome."