The role of density-dependence regulation in the misleading effect of the Aznalcollar mining spill on the booted eagle fecundity

Gil-Jiménez, Esperanza; Manzano, Javier; Casado, Eva; Ferrer, Miguel

doi:10.1016/j.scitotenv.2017.01.098

Cited by 12 publications

(2 citation statements)

References 53 publications

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“…The density of the population was measured as the number of pairs in the area, as the size of the study area remained constant over the studied period. The number of pairs in the population increased from 40 to 62 pairs over the study period (Gil‐Jiménez et al ). We also recorded the nearest neighbor distance (NND), as a measure of the population density.…”

Section: Methodsmentioning

confidence: 99%

Age of the breeders, but not territory quality, explains hatching sex ratio in booted eagles

Morandini

Baumbush

Balbontı́n

et al. 2020

Journal of Avian Biology

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Natal sex‐ratio variation is a central concept in population demography. When males and females are equally costly to rear, the population sex ratio should be 1:1, but if they differ in cost, more of the cheaper sex should be produced. According the age dependent sex ratio hypothesis, younger breeders should produce more chicks of the cheaper sex. On the other hand, the environmental sex determination hypothesis suggests that parents in poor conditions (scarce food and low‐quality territories) tend to produce more of the cheaper sex. To test hypotheses on adaptive sex ratio, we studied the booted eagle Aquila pennata, a raptor with marked sexual dimorphism, with females larger than males. We sexed 174 nestlings from 121 broods in 1996–2000 to study hatching and fledgling sex ratios. We did not find deviations of the 1:1 sex ratio at the population level during the length of the whole study period or on a yearly basis. Sex ratio was affected by age of the breeders, but not by territory quality (average productivity), quality of year, nearest nest distance or number of breeding pair in the population. Older breeders raised more females (i.e. the expensive sex), supporting the age dependent sex ratio hypothesis. In long‐lived species, older breeders tend to occupy better quality territories than younger ones, confounding some of the commonly used surrogates of territory quality, like frequency of occupation or year of first occupation; results obtained from observational studies should be interpreted with caution. We discuss alternative approaches and different scenarios that could provide new insight into the study of factors that influence sex ratio deviations in vertebrates.

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Section: Methodsmentioning

confidence: 99%

Age of the breeders, but not territory quality, explains hatching sex ratio in booted eagles

Morandini

Baumbush

Balbontı́n

et al. 2020

Journal of Avian Biology

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“…Roadside dust is another potential source of Pb and Sb in birds feeding near major roadways; however, Sb concentrations are not great enough to be a substantial source of Sb, especially when compared to the concentrations present Pb ammunition [78][79][80]. Mining/smelting sites are known to exhibit high soil Pb and Sb concentrations [81,82]; however, Sb concentrations in various tissues from birds exposed to contaminated mining sites were < 0.5 μg/g [83][84][85]. Further, Sb bioaccessibility was found to be < 3% from contaminated mining soils [86,87].…”

Section: Future Considerationsmentioning

confidence: 99%

Bioaccessibility of antimony and other trace elements from lead shot pellets in a simulated avian gizzard environment

et al. 2020

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Many studies have used grit (in the form of lead (Pb) pellets) presence in avian gizzards as an indicator of Pb shot exposure. However, due to nearly complete pellet absorption in gizzards or rapid passage of pellets, the absence of Pb shot presence in a gizzard does not confirm lack of Pb shot exposure. This study provides the basis for an additional technique to identify if elevated tissue Pb concentration is due to Pb shot exposure. Bioaccessibility of Pb and trace elements (Sb, As, and Sn) present in Pb shot were quantified to determine if any of these elements would be useful as a secondary marker of Pb shot exposure. An avian physiologically based extraction test (PBET) was used to determine pellet dissolution rate and bioaccessible concentrations of Pb, Sb, As, and Sn in a simulated gizzard environment. Of the three trace elements, only Sb concentrations (44-302 μg/mL) extracted into the gizzard solution were greater than environmental background levels (US soil average 0.48 μg/g); thus, no natural source likely provides this amount of Sb. Therefore, there is evidence that Sb can be extracted from Pb shot in bird gizzards at detectable concentrations (above natural background). While further studies are needed to delineate the mechanisms of absorption and distribution, this study lends credence to the hypothesis that Sb may be a useful marker of Pb shot exposure in biological tissues, particularly when Pb pellets are not present nor observed in avian tissues.

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Metalliferous Mining Pollution and Its Impact on Terrestrial and Semi-terrestrial Vertebrates: A Review

Gil-Jiménez¹,

Lucas

Ferrer

2021

Reviews of Environmental Contamination and Toxicology

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The role of density-dependence regulation in the misleading effect of the Aznalcollar mining spill on the booted eagle fecundity

Cited by 12 publications

References 53 publications

Age of the breeders, but not territory quality, explains hatching sex ratio in booted eagles

Age of the breeders, but not territory quality, explains hatching sex ratio in booted eagles

Bioaccessibility of antimony and other trace elements from lead shot pellets in a simulated avian gizzard environment

Metalliferous Mining Pollution and Its Impact on Terrestrial and Semi-terrestrial Vertebrates: A Review

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