Trophic structure and avian communities across a salinity gradient in evaporation ponds of the San Francisco Bay estuary

Takekawa, John Y.; Miles, A. Keith; Schoellhamer, David H.; Athearn, Nicole D.; Saiki, Michael K.; Duffy, W.D.; Kleinschmidt, S.; Shellenbarger, Gregory G.; Jannusch, Chris A.

doi:10.1007/978-1-4020-5556-0_23

Cited by 17 publications

(16 citation statements)

References 19 publications

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“…2). The pH of most ponds was alkaline, and water temperature ranged from 9 to 30°C, with greatest extremes in P1 and P4, ponds that also had the greatest changes in water levels (Takekawa et al, 2006). Decreased water levels combined with elevated temperatures resulted in low dissolved oxygen readings in P4 during the summer months.…”

Section: Salinitymentioning

confidence: 98%

“…P3 was more uniformly deep than the other ponds and supported diving birds almost exclusively. Waterbirds were most diverse and abundant on P1 (48 species and 23% of the total birds) and P4 (46 species and 46% of the total birds) (Takekawa et al, 2006). Water depths varied spatially in P1, very shallow at the southern end and deeper on the northern end, and temporally in P4, which was deep (0.5-2.0 m) in the winter and much shallower or dry in the summer.…”

Section: Avian Populationsmentioning

confidence: 99%

“…Macroinvertebrate prey on P1 were represented by 50-55 taxa, many of which were uncommon, and high densities of individuals from 3 to 4 taxa (Takekawa et al, 2006). Ponds P3 (25 taxa) and P4 (12 taxa) had lower numbers of taxa, but higher densities relative to P1.…”

Section: Salinitymentioning

confidence: 99%

“…Surveys were conducted during the day within 3 h of the highest high tide when the largest number of waterbirds was roosting in the salt ponds. Waterbirds were separated into seven guilds to examine differences among foraging groups rather than differences among species (Takekawa et al, 2006). In this study, we examined the diet of representative species from three of these foraging guilds: (1) sweepersobtained prey from the surface e.g., Recurvirostra americana (American avocet); (2) shallow probers-foraged in the top layer (\3 cm) of sediments e.g., Calidris mauri (western sandpiper); and (3) diving benthivores-fed in deeper water on benthic invertebrates e.g., Oxyura jamaicensis (ruddy duck).…”

Section: Bird Surveysmentioning

confidence: 99%

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Dietary flexibility in three representative waterbirds across salinity and depth gradients in salt ponds of San Francisco Bay

et al. 2009

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Salt evaporation ponds have existed in San Francisco Bay, California, for more than a century. In the past decade, most of the salt ponds have been retired from production and purchased for resource conservation with a focus on tidal marsh restoration. However, large numbers of waterbirds are found in salt ponds, especially during migration and wintering periods. The value of these hypersaline wetlands for waterbirds is not well understood, including how different avian foraging guilds use invertebrate prey resources at different salinities and depths. The aim of this study was to investigate the dietary flexibility of waterbirds by examining the population number and diet of three feeding guilds across a salinity and depth gradient in former salt ponds of the Napa-Sonoma Marshes. Although total invertebrate biomass and species richness were greater in low than high salinity salt ponds, waterbirds fed in ponds that ranged from low (20 g l -1 ) to very high salinities (250 g l -1 ). American avocets (surface sweeper) foraged in shallow areas at pond edges and consumed a wide range of prey types (8) including seeds at low salinity, but preferred brine flies at mid salinity (40-80 g l -1 ). Western sandpipers (prober) focused on exposed edges and shoal habitats and consumed only a few prey types (2-4) at both low and mid salinities. Suitable depths for foraging were greatest for ruddy ducks (diving benthivore) that consumed a wide variety of invertebrate taxa (5) at low salinity, but focused on fewer prey (3) at mid salinity. We found few brine shrimp, common in higher salinity waters, in the digestive tracts of any of these species. Dietary flexibility allows different guilds to use ponds across a range of salinities, but their foraging extent is limited by available water depths.

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Section: Salinitymentioning

confidence: 98%

Section: Avian Populationsmentioning

confidence: 99%

Section: Salinitymentioning

confidence: 99%

Section: Bird Surveysmentioning

confidence: 99%

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Dietary flexibility in three representative waterbirds across salinity and depth gradients in salt ponds of San Francisco Bay

et al. 2009

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“…For example, water depth strongly affects the use of wetlands by waterbirds, mainly because it influences the foraging ability of species which differ markedly in morphology and behavior (Vides Almonacid 1990; Ramesh and Ramachandran 2005;Bolduc and Afton 2008). Other factors, such as salinity and plant coverage and composition, can affect birds by influencing the use of foraging and nesting habitats (Takekawa et al 2006;Ma et al 2010).…”

Section: Introductionmentioning

confidence: 98%

Effect of habitat and landscape structure on waterbird abundance in wetlands of central Argentina

Brandolin

Blendinger

2015

Wetlands Ecol Manage

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Determining the response of birds to local habitat characteristics and landscape structure is essential to understanding habitat selection and its consequences for the distribution of species. This study identified the influence of environmental factors as determinants of the waterbird assemblage composition in 39 wetlands in the Pampas of central Argentina. Multivariate analysis allowed the identification of environmental factors affecting the use of habitat by waterbird species, whose variable numbers were explained by local and landscape environmental factors. Interspecific variation in responses to changes in environmental factors shows that habitat selection occurs at a species-specific level, although species with similar ecological requirements tend to respond similarly to environmental heterogeneity. Plovers and flamingos were mostly associated with high salinity and the presence of a muddy shoreline and temporary ponds; ducks, herons and ibises were associated with vegetation abundance and decrease in salinity; piscivores and carnivorous species were associated with water depth. The small degree of overlap of habitat requirements between some species suggests a high level of specialization within waterbird assemblages. This knowledge can be used for the design of appropriate conservation and management strategies in central Argentina, where the alarming loss of wetlands requires management strategies that ensure the permanence of the greatest diversity of waterbirds.

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Managing Wetland Habitats for Waterbirds: An International Perspective

et al. 2009

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The loss and degradation of wetlands worldwide has adversely affected waterbirds, which depend on wetland habitats. Many studies have indicated that effectively managed wetlands can provide alternative or complementary habitats for waterbirds and mitigate the adverse effects of wetland loss and degradation. We review the studies on the habitat variables affecting use of wetlands by waterbirds, and we suggest how wetlands can be managed to provide waterbird habitat. These habitat variables include water depth, water level fluctuation, vegetation, salinity, topography, food type, food accessibility, wetland size, and wetland connectivity. Overall, the practice of wetland management requires integrated knowledge related to the entire wetland ecosystem, and ecosystem-based approach is needed to improve the habitat quality of managed wetlands with considering multiple spatial scales, temporal variability, and trade-off among diverse habitat requirements of different waterbirds. Several priorities for future research and management are also suggested in this paper.

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Trophic structure and avian communities across a salinity gradient in evaporation ponds of the San Francisco Bay estuary

Cited by 17 publications

References 19 publications

Dietary flexibility in three representative waterbirds across salinity and depth gradients in salt ponds of San Francisco Bay

Dietary flexibility in three representative waterbirds across salinity and depth gradients in salt ponds of San Francisco Bay

Effect of habitat and landscape structure on waterbird abundance in wetlands of central Argentina

Managing Wetland Habitats for Waterbirds: An International Perspective

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