Scheurer, D. L.. University of Maryland Center for Environmental Science, Appalachian Laboratory, scheurer@al.umces.edu
Gardner, R. L.. University of Maryland Center for Environmental Science, Appalachian Laboratory, gardner@al.umces.edu

 
SPATIAL HETEROGENEITY AND TROPHIC DYNAMICS OF A PELAGIC MODEL
 
The extrapolation of theoretical and experimental information across spatial and temporal scales confounds attempts to predict levels of species abundances and changes in ecosystem dynamics. We developed a simple, spatially explicit model to identify scale-dependent spatial and temporal behavior of a pelagic ecosystem. The model predicts temporal changes in nutrients, producers (phytoplankton) and consumers (zooplankton) within a gridded framework. Fluxes within and among grid cells are determined by difference equations. Experiments were performed by varying the spatial heterogeneity of initial conditions with simulations run until steady-state was reached. Results showed that the spatial variability in the distribution of resources produces pronounced transients that are not evident in equivalent non-spatial simulations with significantly increased time to equilibrium of the highest trophic level. The degree of top-down or bottom-up control alters both spatial patterns and the variance of population biomass levels. Knowledge of spatial heterogeneity is required for understanding and predicting ecosystem dynamics, even when the complexity of the system is minimal.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: CS67TU1008S