Projected Influences of Changes in Weather Severity on Autumn-Winter Distributions of Dabbling Ducks in the Mississippi and Atlantic Flyways during the Twenty-First Century

Abstract

Projected changes in the relative abundance and timing of autumn-winter migration are assessed for seven dabbling duck species across the Mississippi and Atlantic Flyways for the mid- and late 21st century. Species-specific observed relationships are established between cumulative weather severity in autumn-winter and duck population rate of change. Dynamically downscaled projections of weather severity are developed using a high-resolution regional climate model, interactively coupled to a one-dimensional lake model to represent the Great Lakes and associated lake-effect snowfall. Based on the observed relationships and downscaled climate projections of rising air temperatures and reduced snow cover, delayed autumn-winter migration is expected for all species, with the least delays for the Northern Pintail and the greatest delays for the Mallard. Indeed, the Mallard, the most common and widespread duck in North America, may overwinter in the Great Lakes region by the late 21st century. This highlights the importance of protecting and restoring wetlands across the mid-latitudes of North America, including the Great Lakes Basin, because dabbling ducks are likely to spend more time there, which would impact existing wetlands through increased foraging pressure. Furthermore, inconsistency in the timing and intensity of the traditional autumn-winter migration of dabbling ducks in the Mississippi and Atlantic Flyways could have social and economic consequences to communities to the south, where hunting and birdwatching would be affected.

Increases in the Number of American Black Ducks Wintering in Nova Scotia, 1970–2015

“…Our data indicate that wintering numbers are increasing in Nova Scotia, and may reflect a general shift in black duck nonbreeding distributions to the north. As climate warming continues, waterfowl at middle latitudes are likely to continue to further delay migration and eventually may not even migrate at all (Notaro et al 2016), leading to further increases in northern areas. These results highlight that distribution and trends of black ducks vary across their range, and provide further support to efforts to understand and manage black ducks at smaller spatial scales (Roy et al 2015;Robinson et al 2016).…”

Evaluating the waterfowl breeding population and habitat survey for scaup

“…Improvements to surveys and population models also may be required as science‐based information on environmental factors influencing waterfowl migration chronology, and timing and locales of settling on breeding sites become available (Cowardin and Blohm , Austin et al , Mallory et al , Finger et al ). Evaluations of the WBPHS have become increasingly important because responses (e.g., migration chronology and timing of settling) to climate change are likely to vary among species (Gurney et al , Drever et al , Notaro et al , Osnas et al , Zhao et al ).…”

Conserving and managing the subnivium

“…Natural resource managers recognize the importance of winter for charismatic fauna that live above the snow, but the ecological importance of the subnivium is often overlooked. Winter weather conditions are a well-known regulator of population dynamics for deer (DelGiudice et al 2002) and migrating waterfowl (Schummer et al 2010;Notaro et al 2016) and, as a result, are considered when making decisions about supplemental feeding (Smith 2001) and managing winter habitat (e.g., deer yards) (Hoving & Notaro 2015). However, for species that depend on the stability of the subnivium, an altered snowpack could exceed physiological capacities and disrupt predator-prey relationships (Pauli et al 2013).…”

“…; Notaro et al. ) and, as a result, are considered when making decisions about supplemental feeding (Smith ) and managing winter habitat (e.g., deer yards) (Hoving & Notaro ). However, for species that depend on the stability of the subnivium, an altered snowpack could exceed physiological capacities and disrupt predator–prey relationships (Pauli et al.…”