6. Generate trophodynamic models of the ecosystem1
The integrating objective of the results obtained by the ECOMARG project is the general description of the ecosystem by means of a trophodynamic model. The use of mass balance metamodels, such as ECOPATH, has produced a considerable advance in understanding the cascading dynamic processes through the different trophic levels in many ecosystems. It has also permitted the generation of indices and descriptive parameters that characterize these ecosystems, allowing comparisons among them. At the same time these models provide estimations of the complexity of internal fluxes and niche overlap that may be correlated with stability and maturity of the ecosystem. These models allow integration of the information from fisheries which in turn permits quantification of their direct and indirect impact on each of the components of the ecosystem (Sánchez & Olaso, 2004). These impacts may be modeled in space (ECOSPACE) and time (ECOSIM) to estimate the consequences of particular management measures or environmental changes. Due to all these features, models are used in environmental impact evaluation both from fisheries and contaminating spills, using the strategy of comparing between previous and after disturbance trophodynamic structures and analysing the evolution of the relative importance of the biomass of the various trophic compartments after the disturbance.
Symplified scheme of the trophodynamic model of the Cantabrian Sea´s shelf ecosystem
(from Sánchez & Olaso, 2004).