Towards a spatial coexistence theory for species rich communities

Ecologists have tried for long to explain coexistence of many competing species in communities such as tropical forests, but this key question of ecological theory remains largely unresolved. We argue that this failure originates as a scaling problem. Although plants compete mostly with their closest neighbours, the phenomenological models of most approaches addressing this question do not consider spatial mechanisms of how the dynamics and patterns at the “macroscopic” community scale emerge from the collective behaviour and interactions of individuals at the “microscopic” neighbourhood scale. We therefore propose to change the way the problem is tackled by incorporating this essential information into macroscopic mathematical models.The overarching objective of the project is to develop a spatially-explicit theory for understanding the dynamics and stability of plant communities of intermediate to high species richness at local scales. We integrate state-of-the-art mathematical and simulation approaches with methods from physics and spatial analysis of the best available spatial data, such as ForestGEO inventory data of 20-50 ha forest plots, each comprising the species identity, size and location of >100,000 trees. The link to the microscopic scale of individual plants allows us to integrate ecological detail in unprecedented ways, while keeping the theory tractable. Such a comprehensive and highly integrated research endeavour can only be tackled within the frame-work of a large project and will be a ground breaking advance at this final frontier of ecological research. The project will provide theoretical expectations and mechanistic understanding of how multiple (spatial) pattern and processes shape species richness, and reveal if simple laws govern the assembly and dynamics of complex species-rich communities. This proposal will also open the door to new research lines of spatial ecology to better understand and conserve biodiversity.