Synchronizing conservation to seasonal wetland hydrology and waterbird migration in semi‐arid landscapes

Abstract

2019.Synchronizing conservation to seasonal wetland hydrology and waterbird migration in semi-arid landscapes. EcosphereAbstract. In semi-arid ecosystems, timing and availability of water is a key uncertainty associated with conservation planning for wetland-dependent wildlife. Wetlands compose only 1-3% of these landscapes; however, large populations of migratory waterbirds rely on these wetlands to support energetically demanding life history events such as breeding and migration. Migration is considered a crucial period for birds associated with individual survival and reproductive success, yet our understanding of migration ecology remains limited. To better inform conservation planning supportive of these demands, we quantified synchrony of wetland flooding and waterbird migration by reconstructing bi-monthly surface water patterns from 1984 to 2015 across 11.4 million ha of the semi-arid Great Basin, USA. Results were then linked to seasonal migration chronologies for seven dabbling ducks species. Seasonal patterns were used in landscape planning simulations to assess efficiency in conservation strategies that aligned temporally sensitive wetland flooding and species migration. Wetland data were combined with land tenure to evaluate periodicity in waterfowl reliance on public and private lands. We found migration chronologies misaligned with wetland flooding. In spring, half (43-59%) to three-quarters (68-74%) of seasonal wetlands were flooded and available to early-and latemigrating species while seasonal drying restricted wetland flooding to 13-20% of sites during fall migration. Simulations showed wetland conservation inconsiderate of temporal availability was only 67-75% efficient in meeting waterfowl habitat goals on private lands that made up~70% of flooded wetland area in spring. Private-public wetland flooding was equivalent during fall migration. Accounting for spatiotemporal patterns of wetland flooding is imperative to improving efficiencies linked to migratory bird conservation. Timing of public-private wetland flooding, demonstrated by our models, provides landscape context that emphasized a joint role in supporting migratory waterbird habitat. Integrated management scenarios may capitalize on public lands' flexibility to expand fall flooding to offset seasonal drying on private lands while targeted incentive-based conservation assures private wetland flooding in spring. Such scenarios illustrate benefits of holistic public-private wetlands management representing a forward-looking alternative that aligns conservation with forecasts of increasing water scarcity.

Climate and human water use diminish wetland networks supporting continental waterbird migration

“…A gap in satellite coverage prevented surface water monitoring in 2012. Following an approach outlined by Donnelly et al (2019), surface water area was measured using constrained spectral mixture analysis (SMA; Adams & Gillespie, 2006) that allowed proportional estimations of water contained within a continuous 30 × 30 m pixel grid (Halabisky, Moskal, Gillespie, & Hannam, 2016;Jin, Lang, Yeo, Stehman, & Stephen, 2017). This approach provides an accurate account of surface water area/extent when detectability is reduced due to interspersion of emergent vegetation, shallow, or turbid water (DeVries et al, 2017), characteristics common to lakes and wetlands in arid and semi-arid regions (Jolly, McEwan, & Holland, 2008 (McFeeters, 1996).…”

Evaluating Irrigation Efficiency: Toward a Sustainable Water Future for Montana

“…However, conversion to sprinkler or lining canals may also increase consumption and reduce aquifer recharge and irrigation return flows, which in turn could cause downstream reductions in late summer and early fall streamflow and reduce the stream cooling provided by groundwater return flow. Conversion may also affect the existence and distribution of wetlands, 23 which provide critical habitat for migratory waterfowl, 24 support high diversity and abundance of other plants and animals, and also provide important services to human communities such as erosion control, enhanced water quality, and flood control.…”

The history and importance of private lands for North American waterfowl conservation

“…During spring migration, SONEC may support approximately half of all ducks that winter in the Central Valley of California and up to one‐third of northern pintail ( Anas acuta ) in North America (Fleskes and Yee , Petrie et al ). Greater than 60% of seasonal emergent wetlands that occur within the region during spring are privately owned and consist primarily of shallowly flooded meadows and pastures used for livestock forage production (i.e., haying and grazing; Donnelly et al ). These working wetlands receive surface water from spring snowmelt, overbank flooding, or active irrigation that creates ideal foraging conditions for migrating ducks and other wetland birds (Petrie et al , Donnelly et al ).…”

“…The Agricultural Conservation Easement Program–Agricultural Land Easements (ACEP–ALE) program administered by NRCS provides an important opportunity to protect producer and wildlife interests on working lands against the threats of ranch subdivision and rural fragmentation; therefore, preserving valuable land‐use practices that provide migratory waterfowl habitat. Partners are working to address ACEP–ALE delivery challenges in the SONEC region through development of regional land‐trust capacity, securement of easement acquisition match funding, stakeholder outreach, and investments in social (Sketch et al ) and ecological science (Donnelly et al ) to inform ACEP–ALE decision support tools.…”

“…Additional wetland conservation funding sources such as NAWCA and state migratory‐bird stamp programs have been used over the past decade to restore, enhance, and protect up to 23,500 ha of wetlands and associated uplands on private and public lands that support waterfowl throughout the annual cycle in the region. Ultimately, a diverse mix of conservation programs, funding, and partners is necessary for delivering conservation actions to address the complex natural resource concerns and agricultural objectives across private and public lands (Donnelly et al ) within this economically and environmentally valuable region.…”