Theory of Biodiversity, Extinction and Habitat Change on Islands and Mainlands

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Biodiversity is declining worldwide at a frightening rate; never before have the issues of conservation been more prominent in society. Humans are changing the natural world, with only a basic understanding of the long-term consequences. I aim to develop and use new ways of understanding how clearing or modifying natural habitats will impact the processes that normally generate and maintain biodiversity. I will focus on two systems: remote groups of islands and tropical rainforests. The rainforest work will be carried out in partnership with project SAFE: 'Stability of Altered Forest Ecosystems'. SAFE has negotiated that, when a large region of rainforest is cleared for an oil palm plantation during 2011, carefully chosen patches of forest will be left untouched within the plantation. This makes SAFE one of the world's largest ecological experiments; it will collect extensive data both before and after 2011. 'Prediction is very difficult, especially about the future.' (Niels Bohr, Physicist.) To predict future biodiversity loss in partly cleared natural habitat, a simple mathematical formula is most commonly used which gives the number of species in the region as a function of area. However, we are also interested in how common or rare the remaining species are and how the spatial arrangement of the rainforest and oil palm plays a role. Furthermore, many rainforest species can live in oil palm so this is not the same as total habitat destruction. To account for these additional factors, I will develop a simulation approach capable of modelling a large area of forest by sampling individuals from the computer-generated forest in much the same way as they would be sampled from a real forest. I will make general predictions about how biodiversity will respond to the habitat modification over time and will compare these to data collected by SAFE. For modelling biodiversity on islands I will face other challenges: the accepted theory for islands close to the mainland is that a natural balance exists between the immigration of species from the mainland and the loss of species through local extinction. This classic theory does not cover more distant islands, where endemic species are expected to evolve. On more distant islands, a more complex balance exists between immigration, extinction and the evolution of new species. Islands are often in groups, so immigration must be considered between every possible pair of islands. I will begin by developing further models for islands and their biodiversity, a particularly interesting area of research that links to both ecology and evolution. These models will follow the progress of immigrants onto the archipelago as they change their abundance and possibly form different species on each island. Later, I will apply this to study the effects on islands of habitat modification and increased immigration from the mainland. Both rainforests and distant archipelagos contribute in important ways to biodiversity and are threatened by similar factors; especially habitat destruction. Islands support many endemic species that exist nowhere else, whilst rainforests are valuable for the shear number of species they support. Similar technical methods can be used for modelling both systems and comparisons can be made between them. I find this topic exciting because it addresses import issues for society. We must be able to make informed decisions about conservation based on theory that can predict the consequences of our actions. Furthermore my project contains significant, yet not insurmountable technical challenges, which will make the very best use of my existing skills and experience. I believe that computer simulations such as the ones I propose will have an increasingly important role in future research into ecology and conservation; I am thrilled at having the chance to play a role in that future.