Waterbird and vegetation response to reservoir water management in central Iowa

Description

Background:Lake Red Rock reservoir is situated on the Des Moines River and part of the nationwide Sustainable Rivers Program (SRP). Through the SRP, scientific experts and stakeholders have developed water management strategies that provide greater ecosystem benefits for the Des Moines River. Adaptively managing the reservoir to meet environmental targets is now possible due to recent revisions to the Water Control Manual and adoption of a “conservation band”. The introduced flexibility permits water managers and biologists to implement unique strategies that target needs of aquatic dependent species within the reservoir and downstream of the dam, in the river. The Des Moines River corridor, which meanders through the Prairie Pothole Region (PPR) of Iowa, is a major migratory corridor for waterbirds. In particular, the region hosts millions of migratory waterfowl and shorebirds, two groups of birds that are the focus of many management and conservation efforts. Extensive development and drainage for agricultural production have limited the number of wetlands throughout the PPR with a resulting decline in habitat for these birds. Wetlands with diverse habitat conditions (differing water depths, healthy aquatic plant communities, etc.) are critical stopover sites for migratory waterbirds, which they use to refuel for the next stage of migration. Identifying these stopover sites, and understanding how individuals use a site, is critical for future conservation and management efforts. Anthropogenic changes have also led to the creation of large flood control reservoirs on the Des Moines River, which have become important stopover sites for waterbirds. Waterbirds are consistently attracted to these reservoirs during fall migration when falling water levels expose vast mudflats that are slowly colonized by annual plants. This heterogeneous habitat is especially attractive to shorebirds (July through September) and waterfowl (August through November). Bird use of stopover sites is most commonly addressed by (1) regular surveys of the site, and (2) detailed studies of stopover ecology of a focal species through the use of color bands or radio telemetry. Brief Description of Anticipated Work:This agreement represents an opportunity to enter into a cooperative agreement for understanding the effects of reservoir water level management on waterbird habitat use and wetland characteristics. Work consists of three phases. Phase One focuses on formalizing hypotheses that relate reservoir operations to waterbird utilization and wetland responses and developing associated monitoring protocols for the delta area of Lake Red Rock. The Phase One deliverable is an ERDC Technical Note (<10 pages) on the purpose, hypotheses, and methods that would be implemented to quantify waterbird use of mudflat habitat, track shorebird behavior, and characterize wetland plant community composition as an indicator of waterfowl food value. Phase Two includes 2 field seasons of waterbird monitoring and wetland classification. Phase Two deliverables include short annual reports for In-Progress Review reporting. Phase Three is for data analysis, reporting, and communication. Existing data pertaining to waterbird utilization and wetland responses at reservoirs will be analyzed. Results will be summarized in technical reports and other communication materials. Reports and materials should focus on providing insights that aid development of best reservoir management practices for positive environmental outcomes related to waterbird and wetland management. Phase Three deliverables are a final report in an ERDC Technical Report format; additional sharing of results via webinars, conference presentations, and journal publications are encouraged.

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