Evaluating Dynamics of Food Availability for Lesser Scaup at Pools 13 and 19 of the Mississippi River

Lauren D. Larson, M. J. Anteau, Heath M. Hagy, Joseph D. Lancaster, Aaron P. Yetter, Christopher N. Jacques

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The Lesser scaup (Aythya affinis; hereafter, scaup) is an omnivorous diving duck that is a focal species of concern in the Midwest. Since the 1970s, the continental scaup population has declined, with numbers well below the 6.3 million goal set forth by the North American Waterfowl Management Plan. Several factors have been implicated in the scaup decline, including a decrease in food availability at stopover sites of the upper Midwest. Navigational Pools 13 and 19 of the Upper Mississippi River System (UMRS) are crucial refueling sites for migratory waterfowl, especially diving ducks, prior to reaching these higher latitudes where food shortages have been documented. Pool 19 itself has experienced changes in hydrology, traffic, and sedimentation since the installation of the Keokuk lock and dam system in 1913. Unlike other navigational pools of the UMRS, few aquatic invertebrate and vegetation evaluations have been conducted on Pool 19 in relation to environmental factors. Our research seeks to create a spatial and temporal habitat assessment of Navigational Pools 13 and 19 using historical and current data. We will use aquatic surveys to characterize distribution and density of vegetation and macroinvertebrates. We will use aerial survey data to evaluate scaup abundance in relation to habitat factors. Lastly, we will conduct true metabolizable energy (TME) trials using wild-caught scaup to establish energy values for common diet items. Though results will be preliminary, we will present TME values from completed trials in addition to biomass and vegetation data. This information will be used to determine energetic carrying capacity of study areas in response to current and future environmental change. Findings may also contribute to the geographical prioritization of conservation efforts and the development of habitat enhancement strategies.
Original languageEnglish (US)
Title of host publicationMidwest Fish and Wildlife Conference 2020
StatePublished - 2020

Keywords

  • INHS

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