Effects of flood seasonality and frequency on northern pintail and other breeding ducks in managed prairie wetlands

• Main Authors: Thompson, Jonathan E., Bork, Edward W., Asamoah, Stephen A.
• Format: Other/Unknown Material
• Language: English
• Published: 2011
• Subjects: Pothole Region; Waterfowl Populations; Marsh; Visual Obstruction; Reproduction; Habitat; Dakota; Canada; Anas acuta
• Online Access: https://era.library.ualberta.ca/items/93e4f18d-5f52-4abd-90f0-c36096378a3b; https://doi.org/10.7939/R3WD3QF4N

Anthropogenic flooding to create wetlands is a management option intended to compensate for historical loss of natural wetlands in the Dry Mixedgrass Prairie of western Canada. It may help moderate or reverse declines in density of breeding Northern Pintails (Anas acuta L.) and other waterfowl. Little information exists, however, on breeding waterfowl use of created wetlands flooded at different seasons and frequencies. This study assessed the effects of 2 flooding seasons (fall and spring) on abundance of breeding Northern Pintails and other ducks within newly created wetlands. Additionally, we compared breeding waterfowl use of sites with spring and fall flooding by using 2 treatments (1 year vs. 2 years of flood cessation) intended to alter vegetation composition and density (measured as visual obstruction) on older wetlands currently dominated by cattail (Typha latifolia L.). Vegetation density was assessed across the landscape in all treatments. While recently initiated fall and spring flooding each increased breeding duck densities compared to naturally flooded wetlands, spring flooding led to a greater density of Northern Pintails and other ducks in 1 of 3 years. Within established wetlands, 2 years of flood cessation led to a marked decline in duck abundance, while removal of flooding for one year led to the greatest duck abundance, even compared to wetlands with sustained fall flooding. Finally, vegetation density (i.e., visual obstruction) varied by flooding treatment and year of sampling, and was an important predictor of use of created wetlands by both Northern Pintails and other duck species. Collectively these results indicate that duck use of managed wetlands in the Dry Mixedgrass Prairie of western Canada can be maximized with carefully planned flooding treatments that include spring flooding in newly created wetlands and intermittent flooding in established wetlands.