Part of the Southeast Aquatic Resources Conservation Science and Practice Webinar Series, sponsored by the U.S. Fish and Wildlife Service Southeast Region. To see other webinars in this series, visit http://www.fws.gov/southeast/webinars/.
Using full life cycle habitat requirements of sturgeon and mussels to develop and apply metrics for assessing flow changes in a regulated river
Wednesday, March 15, 10:00 am ET
Working rivers with multiple uses such as flood risk management, water supply storage, hydroelectric power, and navigation are also important habitat for federally listed and at risk species. The section 7 consultation process requires that the Service assess the effects of river management on federally listed species. Starting with insights about habitat requirements and possible changes in these habitats at each phase of the life cycle for three freshwater mussel species and Gulf sturgeon, we developed a set of metrics to help model changes due to a proposed river management strategy for a series of 5 lock and dams managed by the Army Corps of Engineers in the Apalachicola-Chattahoochee-Flint River Basin (ACF) in Alabama, Florida, and Georgia. Mussel metrics described parameters such as floodplain inundation use by host fishes for spawning, low flow durations, and ramping rates. Sturgeon metrics described parameters such as floodplain inundation for invertebrate food production, estuary salinity, and spawning site depth. We calculated metrics based on daily flow outputs from two hydrologic models of the river basin, ResSim and STELLA, for a 74-year period (1939-2012). We also analyzed 15-minute gage data to calculate effects of peak hydropower production. The proposed management of increasing upstream water storage decreased floodplain inundation that negatively affected both mussel host fish production for fat threeridge and Chipola slabshell as well as food production for Gulf sturgeon. Increasing upstream water storage also increased the time spent at low flows and negatively affected mussel populations. The proposed management also had negative effects by increased the conditions appropriate for hydropeaking during the Gulf sturgeon spawning season. However, the proposed management of releasing more water in the winter to sustain navigation benefited Gulf sturgeon by decreasing estuarine salinity and providing more access for foraging juveniles. Incorporating the habitat needs of all phases of a species life cycle was beneficial in assessing proposed management actions. Data requirements to adequately assess each phase of the life cycle presented a challenge during the consultation, but the full life cycle assessment helped to identify gaps and uncertainties to be addressed through monitoring and adaptive management.
Sean Blomquist*, Adam Kaeser, Mark Cantrell (USFWS – Panama City, FL), Steve Leitman (Water Without Borders and University of KwaZulu-Natal), Lydia Stefanova (Florida State University), and Catherine Phillips (USFWS – Panama City, FL)