Species diversity, stability and loss

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My research elucidates the basic laws that underpin the maintenance of biodiversity. In this proposal, I synthesize recent advances from the scientific literature and my own research to test three overarching questions about how biodiversity is maintained and when it is lost. Are there characteristic differences in the stability of species that can be predicted by their abundances or functional traits? Ecologists have long noted that most species in most communities are rare, with only a few species occurring at high abundances. Recent theory posits that this distribution of rarity maps onto how species fluctuate through time and how likely they are to recover from disturbance. I contrast this with an alternate hypothesis about the functional roles that species perform, using experimentally-induced disturbances that target species with different traits and of different abundances. Can instabilities of monocultures of dominant species explain temporal patterns of biodiversity and aggregate functions? A second phenomenon that arises from having only a few abundant species is that they play a dominant role in regulating other species. I propose a test of the processes that limit these dominant species, with a focus on how the nature of that limitation influences other species and the net functioning of ecological communities. How and when do trophic interactions and dispersal dampen or inflate random fluctuations in species abundances? Ecosystems are described as dynamic movements of energy - organisms feeding off the sun and each other to gain energy and then redistributing that energy as they are consumed or decompose. The dynamic transfer of energy has consequences for biodiversity, as a slight change in the population of one species has impacts on those it consumes and those who hunt it, causing fluctuations to ripple through the food web. We address this third question using naturally isolated food webs that occur in plants, and use an experimental approach to measure how random fluctuations in one trophic level (e.g., filter feeders) propagate to their prey and their predators. Together, these questions test three parts to the larger question of how species and the services they provide fluctuate through time, and whether those fluctuations can be understood through the properties of the species and their interactions. The basic science that they provide is necessary for protecting biodiversity and the many services it provides. The research will be carried out in Canada and Costa Rica, using scientific experiments, mathematical modeling, statistics and molecular tools. It will train five PhD students, two MSc students and partially support a postdoctoral fellow in cutting-edge methods that are needed in fields like resource management, conservation, data analytics, and academia.