Simulating Competition and Coexistence between Plant Functional Types in a Dynamic Vegetation Model

The global distribution of vegetation is broadly determined by climate, and where bioclimatic parameters are favorable for several plant functional types (PFTs), by the competition between them. Most current dynamic global vegetation models (DGVMs) do not, however, explicitly simulate interPFT competition and instead determine the existence and fractional coverage of PFTs based on quasi-equilibrium climate–vegetation relationships. When competition is explicitly simulated, versions of Lotka–Volterra (LV) equations developed in the context of interaction between animal species are almost always used. These equations may, however, exhibit unrealistic behavior in some cases and do not, for example, allow the coexistence of different PFTs in equilibrium situations. Coexistence may, however, be obtained by introducing features and mechanisms such as temporal environmental variation and disturbance, among others. A generalized version of the competition equations is proposed that includes the LV equations as a special case, which successfully models competition for * Corresponding author address: Vivek K. Arora, Canadian Centre for Climate Modelling and Analysis, Meteorological Service of Canada, University of Victoria, Victoria BC V8W 2Y2, Canada. E-mail address: [email protected] Earth Interactions • Volume 10 (2006) • Paper No. 10 • Page 1