The Effect of Sea Level Rise on Dabbling Duck Energetic Carrying Capacity

Abstract

Waterfowl migrating and overwintering in the Atlantic Flyway depend on adequate availability of wetland plant communities to survive winter and fuel reproduction in the subsequent breeding season. Energetics models are the primary tool employed by conservation planners to estimate energetic carrying capacity based on energy supply and demand in different wetlands to assist with effective habitat conservation. Coastal impoundments have been used to provide a consistent, annual source of energy for migrating and wintering waterfowl. But few studies have attempted to comprehensively assess the relative value of managed coastal impoundments compared with unmanaged tidal salt marshes to wintering waterfowl in the Mid-Atlantic region with further consideration to the effect of sea level rise changing availability. We estimated biomass and energy of preferred foods for 5 dabbling duck species in 7 impoundments and 3 tidal salt marshes over winter by collecting soil core (n = 1,364), nekton (n = 426), and salt marsh snail (Melampus spp.; n = 87) samples in October, January, and April 2011-2013. Food-energy density was greater in freshwater impoundments for nearly all dabbling ducks (range = 183,344-562,089 kcal/ha), and typically greater in brackish impoundments (range = 169,665-357,160 kcal/ha) than most tidal salt marsh communities (range = 55,693-361,429 kcal/ha), whereas mudflat (range = 96,223-137,473 kcal/ha) and subtidal (range = 55,693-136,326 kcal/ha) communities typically contained the least energy. Extrapolating to the state level, we estimated 7.60 × 10 9 -1.14 × 10 10 kcal available within a 16-km buffer from the Delaware Bayshore, depending on species. Combining estimates for daily energy expenditure and food energy, we estimated 2.86 × 10 7 -7.06 × 10 7 duck energy days currently available to dabbling ducks over winter. We estimated that in the next century, dabbling duck carrying capacities are likely to decrease under all but the most conservative sea level rise scenarios because of the gradual replacement of land-cover types that provide high energy density (i.e., low marsh, high marsh communities) with those that provide low energy density (i.e., subtidal, mudflat communities). Coastal impoundments in Delaware, USA, will provide increasingly important habitat for wintering dabbling ducks in the coming decades provided they are properly maintained and retain their current energetic density because they will contain a growing proportion of the available duck energy days on the landscape. Our research will assist managers in meeting target population goals for dabbling ducks in Delaware and the Mid-Atlantic region by highlighting key differences in the function and value of various wetlands.

Waterbird–habitat relationships in South Carolina: implications for protection, restoration, and management of coastal and inland wetlands

“…Multiguild waterbird selection of MTIs suggests their loss in the South Atlantic could result in winter redistributions, potential population declines, or both (Erwin et al 2006; Meehan et al 2021). Livolsi et al (2021) modeled reductions in American black duck foraging resources in mid‐Atlantic regions as managed coastal wetlands were lost to rising seas. We posit similar reductions in foraging habitat carrying capacity for waterbirds in coastal South Carolina as MTIs are lost or degraded (NOAA 2022; Bauer et al 2023).…”

“…Sea‐level rise will accelerate coastal erosion, flooding, and saltwater intrusion threatening these foraging habitats that are often near colonial waterbird nesting habitats (Daniels et al 1993; Erwin et al 2006; Murphy & Coker 2008). Increasingly frequent and intense tropical storms and flooding are already causing significant and costly infrastructural damage to MTIs and other wetlands annually (Livolsi et al 2021; IPCC 2021). Those MTIs breached by storm surges and remain unrepaired are legally reverted to “navigable waters” within 2 years and can no longer be managed (Folk 2018 c ).…”

Using learner‐generated poetry to help students understand technical scientific literature

“…During the last 2 weeks of the semester, we compared students’ perceived understanding of peer‐reviewed scientific literature by using a pre‐ and post‐survey design. We created pool of recently published articles (2016–2021) in Journal of Wildlife Management that broadly covered topics relevant to the course, including wetlands and waterfowl management (Anderson et al., 2018; B. M. Ballard et al., 2021, D. C. Ballard, 2021; Croston et al., 2018; Dyson et al., 2018; Finger et al., 2016; Fino et al., 2017; Fowler et al., 2020; Kemink et al., 2019; Livolsi et al., 2021; Marty et al., 2020; Meehan et al., 2021; Messmer et al., 2021; Triezenberg & Knuth, 2018; Williams et al., 2021). Much of the science covered in these papers was already broadly addressed in lectures and laboratory exercises during the semester.…”