The natural world is inherently variable. The physical environment varies on all scales and so do the organisms. Organisms are adapted to this variability, not merely hedging against uncertainty but taking advantage of opportunities that variability brings. Key research questions are how the adaptation of organisms to variability promotes species diversity and affects ecosystem functioning, how ecosystems respond to long-term climate change, and vary over landscapes. We develop fundamental theory using advanced mathematical methods, and also work with a variety of field and laboratory systems to test fundamental theory, and to understand adaptations to variable environments, and to specific environmental conditions. Key field systems include desert plant communities, tropical forests, freshwater invertebrates and vertebrates, and plants wherever they are found. In collaboration with other labs, we study plant adaptations to low light, high salinity, aridity, herbivory and to variable conditions. Key organisms are Selaginella, mangrove trees, and variegated plants.