Unstructured Cellular Automata and the Application to Model River Riparian Vegetation Dynamics

Abstract

Cellular automata (CA) have proved to be a robust approach to spatially-explicit modeling of ecosystems. Conventionally the CA models applied a structured square grid. However, due to the anisotropic properties of environmental conditions, the capability of CA method was not fully explored when using the regular squared lattice. This research investigated the unstructured cellular automata (UCA) by implementing a irregular triangular grid and used it to develop a vegetation dynamics model. The model was then coupled with a two-dimensional hydrodynamic model to simulate the riparian vegetation dynamics due to flow modifications by the reservoirs operations. The integrated model was applied to a compound channel of the Lijiang River in the Southwest China, which has been affected by the flow regulations for navigation purpose. Through the simulations, the previous evolutions of the riparian vegetations were recaptured and their future developments under the new flow regulation scheme were predicted. In particular, the potentials of UCA in ecosystem modeling were illustrated in the research.