Research Ecologist USACE-Engineer Research and Development Center Vicksburg, Mississippi, United States
Background/Question/Methods
Species of freshwater mussels in North America are becoming endangered faster than any other group of species. They provide important ecosystem goods and services and contribute to freshwater diversity. Planning freshwater mussel habitat restoration projects is complicated because life history requirements are complex. Ecological models help to determine important ecosystem components relevant to restoration of a community of interest. They can also elucidate differences between proposed restoration alternatives and prioritize restoration sites. This presentation will describe the development and application of a general freshwater mussel habitat model. The objectives of the model are to be applicable throughout the range of the North American freshwater mussel species, be sensitive to differences in proposed restoration actions or sites and contain parameters that reflect system-level functions, structures and processes that provide suitable habitat for freshwater mussels.
The first step in model development was to review critical life history traits and environmental drivers of mussel species. Based off of the review we came to consensus on important model parameters that met model objectives using the group mediated model development approach. Next model development steps included comparing model to a previously developed mussel habitat model and applying model to a real-world restoration planning study.
Results/Conclusions
Important model parameters were determined to be connectivity of waterway for host fish species, diversity of host fish species, percent aquatic cover, quality of substrate, summer maximum water temperature for adults and juveniles and flow regime. Results of model output comparison indicted model agreement when applying models to the same river reach. Model was applied in the Schuylkill River Aquatic Ecosystem Restoration Feasibility Study (Schuylkill), project located in Philadelphia, Pennsylvania. Application of the model revealed that the trade-offs made during development between being general enough to be applied to all freshwater mussel species and being sensitive to proposed habitat restoration actions resulted in the model being too general, such that the original model was not sensitive enough to site specifics in the Schuylkill River. Model was then modified through the group mediated model development approach, which resulted in an appropriate level of sensitivity to proposed restoration actions for the project site. In conclusion, model generality can be beneficial for a wide variety of applications, but it can be a determent to answering project specific questions. However, there was time and effort saved by modifying an existing model vs. developing a new model.
