Three decades of Landsat-derived spring surface water dynamics in an agricultural wetland mosaic; Implications for migratory shorebirds

Schaffer‐Smith, Danica; Swenson, Jennifer J.; Barbaree, Blake A.; Reiter, Matthew E.

doi:10.1016/j.rse.2017.02.016

Cited by 40 publications

(50 citation statements)

References 62 publications

(105 reference statements)

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“…Secondarily, we tracked optimal habitat availability during the peak of spring migration from a satellite‐derived historical record of surface water extent (Schaffer‐Smith et al. ). We used ArcGIS for processing of topography data (ESRI ) and R for all data analysis (R Core Team ).…”

Section: Methodsmentioning

confidence: 99%

“…The extent of emergent wetland water at the peak of spring migration in the Sacramento Valley can fluctuate dramatically, with a 70–80% reduction in water extent within emergent wetlands detected during extremely dry years as compared to extremely wet years (Schaffer‐Smith et al. ). Ultimately water allocations in the Central Valley are highly managed and more closely tied with annual snowpack and runoff than with local precipitation.…”

Section: Methodsmentioning

confidence: 99%

“…Although we had previously mapped water, non‐water, and cloudy (no data) regions across the Sacramento Valley during spring using all available Landsat surface reflectance imagery (Schaffer‐Smith et al. ), we could only verify that wetland boundaries and topography had been consistent since 1996. We retained Landsat water distribution maps that represented a cloud‐free view of at least 90% of the area of each wetland based on the LEDAPS or LaSRC cloud identification algorithms (Zhu and Woodcock , Vermote et al.…”

Section: Methodsmentioning

confidence: 99%

“…, Schaffer‐Smith et al. ), optical remote sensing data does not provide water depth information (Alsdorf et al. , Turpie et al.…”

Section: Introductionmentioning

confidence: 99%

“…Managed wetlands at Sacramento NWR Complex provide the most reliable wetland habitat within the Sacramento Valley (Schaffer‐Smith et al. ), a globally important stopover site for migratory shorebirds during the spring migration season.…”

Section: Introductionmentioning

confidence: 99%

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Quantifying shorebird habitat in managed wetlands by modeling shallow water depth dynamics

Schaffer‐Smith

Swenson

Reiter

et al. 2018

Ecological Applications

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Over 50% of Western Hemisphere shorebird species are in decline due to ongoing habitat loss and degradation. In some regions of high wetland loss, shorebirds are heavily reliant on a core network of remaining human-managed wetlands during migration journeys in the spring and fall. While most refuges have been designed and managed to match the habitat needs of waterfowl, shorebirds typically require much shallower water (<10 cm deep). Traditional static habitat modeling approaches at relatively coarse spatial and temporal resolution are insufficient to capture dynamic changes within this narrow water depth range. Our objectives were to (1) develop a method to quantify shallow water habitat distributions in inland non-tidal wetlands, and (2) to assess how water management practices affect the amount of shorebird habitat in Sacramento National Wildlife Refuge Complex. We produced water depth distributions and modeled optimal habitat (<10 cm deep) within 23 managed wetlands using high-resolution topography and fixed-point water depth records. We also demonstrated that habitat availability, specifically suitable water depth ranges, can be tracked from satellite imagery and high-resolution topography. We found that wetlands with lower topographic roughness may have a higher potential to provide shorebird habitat and that strategically reducing water levels could increase habitat extent. Over 50% of the wetlands measured provided optimal habitat across <10% of their area at the peak of migration in early April, and most provided a brief duration of shallow water habitat. Reducing water volumes could increase the proportion of optimal habitat by 1-1,678% (mean = 294%) compared to actual volumes measured at peak spring migration in 2016. For wetlands with a high habitat potential, beginning wetland drawdown earlier and extending drawdown time could dramatically improve habitat conditions at the peak of shorebird migration. Our approach can be adapted to track dynamic hydrologic changes at broader spatial scales as additional high-resolution topographic (e.g., lidar, drone imagery photogrammetry) and optical remote sensing data (e.g., planet imagery, drone photography) become available.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…, Schaffer‐Smith et al. ), optical remote sensing data does not provide water depth information (Alsdorf et al. , Turpie et al.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Quantifying shorebird habitat in managed wetlands by modeling shallow water depth dynamics

Schaffer‐Smith

Swenson

Reiter

et al. 2018

Ecological Applications

Self Cite

View full text Add to dashboard Cite

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Using ricelands to provide temporary shorebird habitat during migration

Golet

Low

Avery

et al. 2018

Ecological Applications

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To help mitigate large wetland losses in California, The Nature Conservancy launched a dynamic conservation incentive program to create temporary wetland habitats in harvested and fallow rice fields for shorebirds migrating along the Pacific Flyway. Farmers were invited to participate in a reverse auction bidding process and winning bids were selected based on their cost and potential to provide high quality shorebird habitat. This was done in 2014 and 2015, for separate enrollment periods that overlapped with spring and fall migration, both before and after the traditional post-harvest flooding period. To assess the success of the program, we monitored shorebird use of fields that were enrolled (treatments), and others that were subject to typical rice farm management (controls). To put these observations in context, we used satellites to simultaneously monitor the extent of shallow-water habitat across the ~215,000 ha of ricelands in the area. Results showed that providing habitat during migration, when it is typically unavailable in rice fields, yielded the largest average shorebird densities ever reported for agriculture in the region. Treatment fields had significantly greater shorebird density, richness and diversity than control fields in both spring and fall (especially September-early October, and late March-early April), but in fall the difference was greater. Shorebird responses to habitat provisioning, and regional habitat conditions, were variable from year to year, and highly dynamic within a given season. Overall, shorebirds densities were found to be negatively related to the total amount of flooded habitat in the rice landscape. Factors that affected habitat availability included allocation schedules of water deliveries from reservoirs, and rainfall patterns, both of which were influenced by drought. Collectively, these results suggest that appropriately managed agricultural lands have great potential to provide high value habitat for shorebirds during times of habitat deficit, including migration, and that fall may be a particularly impactful time to create additional habitat. Migratory species face great challenges due to the climate change, conversion of historical stopover sites, and other factors, but dynamic conservation programs offer promise that, at least in certain instances, their needs can still be met.

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Shorebird food energy shortfalls and the effectiveness of habitat incentive programs in record wet, dry, and warm years

Golet

Dybala

Reiter

et al. 2022

Ecological Monographs

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Programs that incentivize private landowners to create habitats that offset losses due to conversion and climate change are increasingly being used to bolster sensitive wildlife populations. In the Central Valley of California, shorebird habitat incentive programs pay landowners to create additional habitat during the non-breeding season by flooding their fields. However, it remains unclear how successful these programs have been in supporting baseline shorebird population needs or meeting established population goals, particularly in the face of changing environmental conditions. To address these questions, we used bioenergetics modeling to estimate shorebird food energy needs over four consecutive years that had the highest annual mean air temperatures ever recorded in California, and included years of extreme drought, as well as the second wettest winter on record. Our objectives were to (1) characterize annual variability in the timing and magnitude of shorebird food energy shortfalls, (2) estimate the contributions that incentive programs made to meeting these needs, and (3) develop recommendations for implementation of future habitat programs to advance shorebird conservation in the region. Overall, we found a high level of consistency in the timing and magnitude of habitat shortfalls, especially in fall, despite large differences in annual rainfall, a result that was unexpected, but that emphasizes how highly managed the hydrological system is in the Central Valley. We also found that the magnitude of both fall and spring energy shortfalls increased, relative to recent (2007-2014) estimates, perhaps due to aberrantly warm conditions. Incentive programs implemented to provide supplemental habitat were somewhat effective in reducing shortfalls for the assumed baseline population, but there were consistent unmet habitat needs when there were not enough shallow open water foraging areas available. Strategies to offset these remaining food energy deficits include scaling up habitat investments, adjusting the timing of habitat programs to better match the migration patterns of the birds, and adapting

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Three decades of Landsat-derived spring surface water dynamics in an agricultural wetland mosaic; Implications for migratory shorebirds

Cited by 40 publications

References 62 publications

Quantifying shorebird habitat in managed wetlands by modeling shallow water depth dynamics

Quantifying shorebird habitat in managed wetlands by modeling shallow water depth dynamics

Using ricelands to provide temporary shorebird habitat during migration

Shorebird food energy shortfalls and the effectiveness of habitat incentive programs in record wet, dry, and warm years

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