Tree swallow diet in relation to wetland acidity

Blancher, Peter J.; McNicol, Donald K.

doi:10.1139/z91-370

Cited by 78 publications

(54 citation statements)

References 43 publications

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“…Blancher and McNicol (1991) suggested that swallow chicks might not have obtained enough calcium in their diets because of a reduction in prey that is normally rich in calcium (Scheuhammer et al 1997;Keller et al 2001). Another potential mechanism for reduced breeding success on lakes with low pH could involve the decrease in eggshell thickness (Pollentier et al 2007).…”

Section: Ph Thresholds For Loon Breeding Successmentioning

confidence: 99%

Common Loon, <em>Gavia immer</em>, Breeding Success in Relation to Lake pH and Lake Size Over 25 Years

Alvo¹

2009

Can Field Nat

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Alvo, Robert. 2009. Common Loon, Gavia immer, breeding success in relation to lake pH and lake size over 25 years.Canadian Field-Naturalist 123(2): 146-156.I monitored Common Loon (Gavia immer) breeding success in relation to lake pH (range 4.0-8.5) between 1982 and 2007 on 38 single-pair lakes (5-88 ha) in the Sudbury, Ontario, area. No chicks fledged on lakes with pH < 4.4. Chicks fledged on lakes with slightly higher pH only if the lakes were relatively large. Acidic lakes became less acidic as sulphur dioxide emissions from the Sudbury smelters and sulphur deposition from other long-range sources decreased. Two lakes initially too acidic to support successful loon reproduction eventually had successful reproduction. One loon pair used two large acidic lakes (combined area 140 ha) connected by shallow rapids, and one of the adults made extremely long dives (χ -= 99 s) while foraging for the chicks. One chick died on that lake after apparently ingesting a very large food item; the lack of smaller items was attributed to the lake's acidity. My results suggest that a shortage of food for chicks is the main reason why low pH reduces breeding success. I suggest that, for lakes without high levels of dissolved organic carbon (DOC), the critical pH for loon breeding success is approximately 4.3, and the suboptimal pH is approximately 4.4-6.0.

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Section: Ph Thresholds For Loon Breeding Successmentioning

confidence: 99%

Common Loon, <em>Gavia immer</em>, Breeding Success in Relation to Lake pH and Lake Size Over 25 Years

Alvo¹

2009

Can Field Nat

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“…Louis and Barlow (1993) demonstrated reduced hatching success of tree swallows (Tachycineta bicolor) nesting near acidified lakes at the Experimental Lakes Area, northwestern Ontario. Acidified waters are often deficient in taxa rich in Ca such as Gastropoda, Pelecypoda, and Crustacea (Blancher and McNicol, 1991;Økland, 1992;Albers and Camardese, 1993b). Thus, any effects of Al on terrestrial animals are likely indirect, working in concert with H + to eliminate Ca-rich invertebrate food sources.…”

Section: F Bioaccumulation Of Al In Aquatic Invertebratesmentioning

confidence: 99%

The Bioavailability and Toxicity of Aluminum in Aquatic Environments

Gensemer

Playle

1999

Critical Reviews in Environmental Science and Technology

642

444

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ABSTRACT:In this article we review the biological effects of Al, primarily with respect to the chemical factors controlling Al bioavailability and toxicity, and how its biological effects are best predicted. Our intent is not to duplicate recent reviews on Al chemistry or toxicity, but rather to update the literature since these reviews were published, and to focus on Al speciation and other external chemical influences on Al bioavailability to freshwater biota. Briefly, we first review Al chemistry, with a specific focus on understanding, as well as measuring, Al chemical species of importance to aquatic biota. Next we more comprehensively review Al toxicity and bioavailability to freshwater algae, with a thorough analysis of the relationships between speciation and toxicity, the role of important chemical complexing agents such as P, Si, and organic carbon, as well as the potential for Al to impact algal community structure. A third section reviews the more sparse literature on aquatic higher plants; the fourth section reviews a somewhat more abundant literature of Al toxicity to freshwater invertebrates. We close with an updated review of Al toxicity to fish, again with a focus on mechanisms of toxicity, and the role of Al speciation in controlling bioavailability.

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“…Habitat is a critical factor in the determination of the diet of key receptors and the eventual determination of risk to those receptors. For example, Blancher and McNicol (1991) examined tree swallow diet in relation to wetland acidity. In wetlands with a high pH, tree swallows predominately preyed on mollusks and ephemeroptera, but in wetlands with low pH, they preyed on a greater percentage of diptera.…”

Section: Figurementioning

confidence: 99%

Exposure and Multiple Lines of Evidence Assessment of Risk for PCBs Found in the Diets of Passerine Birds at the Kalamazoo River Superfund Site, Michigan

Neigh

Zwiernik

Blankenship

et al. 2006

Human and Ecological Risk Assessment: An International Journal

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Dietary exposures of passerine birds at the Kalamazoo River, Michigan, were examined due to the presence of polychlorinated biphenyls (PCBs) in the terrestrial and aquatic food webs. Average potential daily doses in diets were 6-to 29-fold and 16-to 35-fold greater at a contaminated location than at a reference location for PCB exposures quantified as total PCBs and 2,3,7,8-tetrachlorodibenzo-p -dioxin equivalents (TEQs), respectively. Birds with diets comprised of primarily aquatic insects had greater dietary exposure than birds with diets of primarily terrestrial insects. Risk associated with dietary exposure varied with the selection of the threshold for effects including hazard quotients, which exceeded 1 in instances where the most conservative toxicity reference values were utilized. Risk based on concentrations of PCBs in the tissues indicated little risk to avian species, and co-located studies evaluating reproductive health did not suggest that observed incidences of diminished reproductive success were related to PCB exposure. Measures of risk based on comparison to toxicity reference values (TRVs) were consistent with direct measures of ecologically relevant endpoints of reproductive fitness, but uncertainty exists in the selection of threshold values for effects in these species especially based on TEQs. This is largely due to the absence of species-specific, dose-response relationships. Therefore, the best estimate of risk is through the application of multiple lines of evidence. INTRODUCTIONThe purpose of this study was to describe the exposure pathways for passerine birds exposed to polychlorinated biphenyls (PCBs) at the Kalamazoo River and to estimate risk associated with PCBs through those pathways. A secondary goal was to compare the two established methodologies for estimating exposure and subsequent risk. Finally, the results of the risk assessments based on the two methods of estimating exposure were compared to measures of reproductive fitness at the more PCB-contaminated site and the less contaminated, upstream reference location. The first method for estimating exposure, the "top-down" approach, measured concentrations of PCBs in the eggs, nestlings, and adults of each species. The other approach, which predicts exposure based on concentrations of PCBs in dietary items, is referred to as "bottom-up" (Fairbrother 2003). The two approaches, although inherently linked, have become disjointed in the risk evaluation process. The reason for this separation is often related to constraints on funding and time, but the assessor cannot be unequivocally assured that their selection of methodology does not overlook some important interaction in determining risk, or for that matter, does not over or underestimate risk based on uncertainties due to the adjustment of models from the given data.It has been suggested that several lines of evidence be used to evaluate risk instead of implementing only one type of methodology (Fairbrother 2003). However, it may not always be possible to apply mult...

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Tree swallow diet in relation to wetland acidity

Cited by 78 publications

References 43 publications

Common Loon, <em>Gavia immer</em>, Breeding Success in Relation to Lake pH and Lake Size Over 25 Years

Common Loon, <em>Gavia immer</em>, Breeding Success in Relation to Lake pH and Lake Size Over 25 Years

The Bioavailability and Toxicity of Aluminum in Aquatic Environments

Exposure and Multiple Lines of Evidence Assessment of Risk for PCBs Found in the Diets of Passerine Birds at the Kalamazoo River Superfund Site, Michigan

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