Impact of extreme drought and incentive programs on flooded agriculture and wetlands in California’s Central Valley

Reiter, Matthew E.; Elliott, Nathan; Jongsomjit, Dennis; Golet, Gregory H.; Reynolds, Mark

doi:10.7717/peerj.5147

Cited by 25 publications

(52 citation statements)

References 30 publications

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“…Movement data in our study were representative of movements by wintering shorebirds during an ongoing drought in the Central Valley that resulted in reduced freshwater available for flooding wetlands and agricultural lands during years two and three of the study Reiter et al 2018). Yet movements were highly correlated to changes in the 10-year average water distribution (Dwater) and structural connectivity of reliable water (Dpatch and Daggregation).…”

Section: Discussionmentioning

confidence: 99%

Dynamic surface water distributions influence wetland connectivity within a highly modified interior landscape

et al. 2018

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Context Animal movements are inherently linked to landscape structure. Understanding this relationship for highly-mobile species requires documenting their responses to spatiotemporal variability of resources. To that end, characterizing movement behaviors and resource distributions using the principles of habitat connectivity facilitates coordinated landscape planning efforts within highly modified landscapes. Objectives and methods We tracked locations and movements for 156 dunlin (Calidris alpina) and 109 long-billed dowitchers (Limnodromus scolopaceus) overwintering in two regions with distinct water distributions in California's Central Valley. We then compared residency rates, functional connectivity to other regions, and associations between movement distances and average habitat availability and structural connectivity of habitat at multiple temporal and spatial scales. Results A widespread yet highly variable regional water distribution was associated with lower residency rates and substantially higher functional connectivity to nearby regions when compared to a stable regional water distribution characterized by a large, contiguous wetland complex. Longer movements were associated with decreasing average availability and spatial aggregation of surface water. Movement models suggested shorebirds primarily responded to habitat availability at smaller scales (\ 10 km) and structural connectivity at larger scales (C 10 km). Conclusions Differences in movement behaviors suggested that wintering shorebirds will avoid long distance movements and remain resident within a wetland region when possible. Conservation and management efforts should reliably flood individual wetlands and agricultural lands from November to April and prioritize locations that maximize structural wetland connectivity and limit spatiotemporal variability of surface water throughout the Central Valley.

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Section: Discussionmentioning

confidence: 99%

Dynamic surface water distributions influence wetland connectivity within a highly modified interior landscape

et al. 2018

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“…Models tested for differences in a binary factor that characterized each survey as occurring during a drought (1) or a non-drought year (0). We identified 2013 to 2015 as drought years based on the water year type as defined by the California Department of Water Resources for the Sacramento and San Joaquin River Valleys based on the projected runoff (million acre feet) on 1 May (see http://cdec.water.ca.gov/cgi-progs/iodir/WSIHIST for details on the level for each classification and data access) [24]. Over the six years of the study, the Sacramento Valley was classified as drought or critical from 2013 to 2015, below normal (2012, 2016) and wet (2011).…”

Section: Data Summary and Analysismentioning

confidence: 99%

“…Climatic conditions in southwestern North America from 2000 to 2018 have been classified as a megadrought [21] that included the driest four-year period in more than 1200 years in California from 2013 to 2016 [22] and resulted in shortages of fresh water for both humans and wildlife [23,24]. In California's Central Valley, where < 10% of historic wetlands remain [25], scarcity of fresh water during the drought likely caused food and energy shortfalls for waterfowl [26].…”

Section: Introductionmentioning

confidence: 99%

Effects of drought on the abundance and distribution of non-breeding shorebirds in central California, USA

et al. 2020

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Conservation of migratory species requires anticipating the potential impacts of extreme climatic events, such as extreme drought. During drought, reduced habitat availability for shorebirds creates the potential for changes in their abundance and distribution, in part because many species are highly mobile and rely on networks of interior and coastal habitats. Understanding how shorebirds responded to a recent drought cycle that peaked from 2013 to 2015 in central California, USA, will help optimize management of wetlands and fresh water for wildlife. In the Central Valley, a vast interior region that is characterized by a mosaic of wetlands and agricultural lands, we found 22% and 29% decreases in the annual abundance of shorebirds during periods of 3-year drought (2013-2015) and 2-year extreme drought (2014-2015), respectively, when compared to non-drought years. Lower abundance of shorebirds coincided with significant decreases in the mean proportion flooded of survey units (7% and 9%, respectively) that were reliant on fresh water. Drought was associated with lower abundance within both the interior Central Valley and coastal San Francisco Bay for greater and lesser yellowlegs (Tringa melanoleuca and T. flavipes) and long-and short-billed dowitchers (Limnodromus scolopaceus and L. griseus). Only dunlins (Calidris alpina) had patterns of abundance that suggested substantial shifts in distribution between the Central Valley and coastal regions of San Francisco Bay and Point Reyes. Our results indicate that drought has the potential to reduce, at least temporally, shorebird populations and flooded habitat in the Central Valley, and the ability to respond to drought by taking advantage of nearby coastal habitats may limit the long-term effects of drought on some species. Successful conservation strategies must balance the impacts of reduced habitat availability at interior sites with the ability of some migratory shorebirds to adapt rapidly to shifting distributions of resources.

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“…The drawdown of rice leaves managed wetlands to support the majority of the waterbirds in the Sacramento Valley in March and April. Precipitation may extend flooding of rice into March [ 14 , 15 ], however rainfall is highly variable from year to year (30-year precipitation [cm]: February minimum = 0.2, maximum = 30.7, mean = 8.2; March minimum = 0, maximum = 20.1, mean = 6.0). This creates a challenge for waterbirds since large numbers are still using the Sacramento Valley; waterfowl generally begin their northbound migration out of the Sacramento Valley in early March [ 9 ] and many shorebird species are still wintering in March as peak migration out of and through the region is in April [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Waterbird response to variable-timing of drawdown in rice fields after winter-flooding

et al. 2018

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Wetland loss and degradation have been extensive across the world, especially in California’s Central Valley where over 90% of the natural wetlands have been converted to agricultural and urban uses. In the Central Valley today, a much smaller network of managed wetlands and flooded agricultural fields supports almost five million waterfowl and half a million shorebirds. Over 50% of waterbird habitat in the Central Valley is provided by flooded agricultural land, primarily rice (Oryza sativa). Each year non-breeding waterbird habitat decreases in the late winter as flooded agricultural fields are drained after waterfowl hunting season in late-January to prepare for the next crop. This study evaluated a practice called ‘variable drawdown’ that involves delaying the removal of water from rice fields by 1, 2, and 3 weeks to extend the availability of flooded habitat later into February and March. We studied waterbird response to variable drawdown in 2012 and 2013 at twenty rice farms throughout the northern half of the Central Valley. The staggered drawdown created a mosaic of water depths throughout the six-week study period. The 3-week delay in drawdown supported more dabbling ducks than earlier drawdowns in the first half of the study and more shorebirds and long-legged wading birds during the second half of the study. The timing of highest use of each drawdown treatment differed for each waterbird guild; dabbling ducks, geese and swans benefited at the beginning, then long-legged wading birds, followed by shorebirds. Despite the presence of appropriate water depths for shorebirds across the treatments during the entire study period, shorebird densities were highest near the end of the study when the 3-week-delayed drawdown was providing the majority of the habitat on the landscape. This suggests that shorebirds may have concentrated in our study fields due to decreasing availability of shallow water habitat elsewhere. The practice of variable drawdown successfully extended the availability of waterbird habitat provided by post-harvest flooded rice fields later into winter.

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Impact of extreme drought and incentive programs on flooded agriculture and wetlands in California’s Central Valley

Cited by 25 publications

References 30 publications

Dynamic surface water distributions influence wetland connectivity within a highly modified interior landscape

Dynamic surface water distributions influence wetland connectivity within a highly modified interior landscape

Effects of drought on the abundance and distribution of non-breeding shorebirds in central California, USA

Waterbird response to variable-timing of drawdown in rice fields after winter-flooding

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