Signal Flow Graph Theory Is Effective in Modeling Inter-Functional Relationships in Aquatic Ecosystems

Overview

Human activities have led to an unprecedented loss of freshwater species, thereby impairing ecosystem function. Novel analyses are necessary to create conservation strategies. For example, Graph Theory effectively visualized linkages between functional traits and taxonomic diversity in agricultural streams exhibiting a strong habitat gradient. Degrees, or number of edges linking taxa vertices to a specific functional group vertex, represent the compression or expansion of taxa fulfilling a function. Degrees were calculated for 79 taxa across 32 sites for use in quantitative models. A multiple regression analysis showed that the predator degree decreased with decreased habitat condition indicating that taxonomic compression of predators responded to changes in habitat. Linear regression analyses showed that as predator decree decreased, the degree of three other functional groups increased, indicating that compression or expansion of taxa fulfilling functions were related to each other. Results of the linear regressions were used to construct a Signal Flow Graph model, effectively representing changes in a food web due to loss of habitat. These novel analyses based on Graph Theory captured complex interactions between taxonomic and functional trait diversity in agricultural streams.

Competition history

• AJAS 2018 Category not listed

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