Speaker
Description
Ecosystems are commonly represented as directed graphs describing flows of energy or biomass among species. While these models highlight compartments and flows, neither provides a fundamental dynamical unit. We introduce fluxes as elementary processes that serve as building blocks of ecosystem networks. Inspired by flux balance analysis and metabolic control analysis, a flux represents the smallest process that can theoretically sustain itself, such as a material cycle or a simple food chain embedded within a larger food web. Mathematically, fluxes define a unique network decomposition: any ecological network can be represented as a linear combination of its fluxes. Because this decomposition preserves all network connections, it maintains system-wide properties of the original ecosystem. For example, the total amount of material cycling in the ecosystem equals the sum of cycling occurring within individual fluxes, independent of network size or complexity. More generally, several global ecosystem properties are conserved under this decomposition. We demonstrate the mathematical structure and ecological interpretation of this approach using EcoNet (http://eco.engr.uga.edu), a freely available online platform for ecosystem network analysis.
