Savannas, Invasions and Lessons from Some Mathematical Models
Louis Gross (Ecology and Evolutionary Biology & Math , University of Tennessee)
(March 4, 2013 3:00 PM - 3:50 PM)
One of the long-standing questions in plant community ecology concerns the maintenance of savannas and other communities which exclude plant species which would typically out-compete the species present in the system. Savannas are communities that exist in many locations around the world, consisting of a mixture of grass-dominated ground cover and an over-story of trees with a distinct canopy layer. Savannas are open to invasion by species such as hardwood trees which out-compete the species present. I will present a collection of models that elaborate one of the proposed mechanisms to maintain savanna communities: disturbance arising from processes such as fire and hurricanes. A focus in these models is the nature of the feedbacks and the potential for climate change to impact the disturbance regime and modify the global pattern of savanna systems. As a cautionary tale, I will end with a discussion of limits to prediction in complex ecological systems, and discuss the potential computational irreducibility of invasion and global change projections.