From Pallid and Shovelnose Sturgeon to Chubs to Invertebrates: A Lower Missouri River Community Model for Assessing Predation, Competition, and Resource Effects on Population Dynamics

We present the modular structure of a community model for a critical subset of the Lower Missouri River benthic fish assemblage. The model incorporates population submodels for Pallid Sturgeon (Scaphirhynchus albus), Shovelnose Sturgeon (S. platorynchus) and three Macrhybopsis chub species, and interactions between them. The critically endangered Pallid Sturgeon is piscivorous as an adult and declining, native Macrhybopsis chubs may be important prey.  The threatened, sympatric Shovelnose Sturgeon is a likely competitor for the Pallid Sturgeon during young-of-year and juvenile life stages.  Each species submodel incorporates hierarchical partitioned variance.  Each sturgeon submodel also incorporates a bioenergetics component. Interactions between species are modeled as a combination of predator-prey and competition dynamics. Our objective is a model that predicts joint population growth rates. Outputs that incorporate model uncertainties through implementation of hierarchical partitioning of variance should provide an understanding of how management actions (for example, stocking, habitat restoration, flow management) may affect future populations. Specifically the model could help to determine potential impacts of different habitat mitigation strategies; develop recruitment models as related to environmental flows; determine management-unit-specific carrying capacities; and explore relationships and/or interactions between river reach carrying capacities and effective population sizes.