This article is a US Government work and is in the public domain in the USA.
EFFECTS OF FLOW DYNAMICS ON THE AQUATIC-TERRESTRIAL TRANSITION ZONE (ATTZ) OF LOWER MISSOURI RIVER SANDBARS WITH IMPLICATIONS FOR SELECTED BIOTA†
Article first published online: 25 FEB 2011
Published in 2011 by John Wiley & Sons, Ltd.
River Research and Applications
Volume 28, Issue 7, pages 793–813, September 2012
How to Cite
Tracy-Smith, E., Galat, D. L. and Jacobson, R. B. (2012), EFFECTS OF FLOW DYNAMICS ON THE AQUATIC-TERRESTRIAL TRANSITION ZONE (ATTZ) OF LOWER MISSOURI RIVER SANDBARS WITH IMPLICATIONS FOR SELECTED BIOTA. River Res. Applic., 28: 793–813. doi: 10.1002/rra.1492
- Issue published online: 5 SEP 2012
- Article first published online: 25 FEB 2011
- Manuscript Accepted: 5 JAN 2011
- Manuscript Revised: 1 JAN 2011
- Manuscript Received: 1 JUN 2010
- adaptive management;
- channelized river;
- environmental flows;
- habitat modelling;
- riverine fishes;
- river turtles;
- wading birds
Sandbars are an important aquatic terrestrial transition zone (ATTZ) in the active channel of rivers that provide a variety of habitat conditions for riverine biota. Channelization and flow regulation in many large rivers have diminished sandbar habitats and their rehabilitation is a priority. We developed sandbar-specific models of discharge-area relationships to determine how changes in flow regime affect the area of different habitat types within the submerged sandbar ATTZ (depth) and exposed sandbar ATTZ (elevation) for a representative sample of Lower Missouri River sandbars. We defined six different structural habitat types within the sandbar ATTZ based on depth or exposed elevation ranges that are important to different biota during at least part of their annual cycle for either survival or reproduction. Scenarios included the modelled natural flow regime, current managed flow regime and two environmental flow options, all modelled within the contemporary river active channel. Thirteen point and wing-dike sandbars were evaluated under four different flow scenarios to explore the effects of flow regime on seasonal habitat availability for foraging of migratory shorebirds and wading birds, nesting of softshell turtles and nursery of riverine fishes. Managed flows provided more foraging habitat for shorebirds and wading birds and more nursery habitat for riverine fishes within the channelized reach sandbar ATTZ than the natural flow regime or modelled environmental flows. Reduced summer flows occurring under natural and environmental flow alternatives increased exposed sandbar nesting habitat for softshell turtle hatchling emergence. Results reveal how management of channelized and flow regulated large rivers could benefit from a modelling framework that couples hydrologic and geomorphic characteristics to predict habitat conditions for a variety of biota. Published in 2011 by John Wiley & Sons, Ltd.