A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Pollution-induced nutritional stress in birds: An experimental study of direct and indirect effects
Tekijät: Eeva T, Lehikoinen E, Nikinmaa M
Kustantaja: ECOLOGICAL SOC AMER
Julkaisuvuosi: 2003
Journal: Ecological Applications
Tietokannassa oleva lehden nimi: ECOLOGICAL APPLICATIONS
Lehden akronyymi: ECOL APPL
Vuosikerta: 13
Numero: 5
Aloitussivu: 1242
Lopetussivu: 1249
Sivujen määrä: 8
ISSN: 1051-0761
DOI: https://doi.org/10.1890/01-5375
Tiivistelmä
We tested the hypothesis that pollution-related reduction in the amount of invertebrate food would explain the lower breeding success of an insectivorous bird, the Great Tit (Parus major), around a point source of heavy metals (copper smelter), where invertebrate densities are known to be depressed. We provided additional food (mealworms and fat) to randomly selected territories near the smelter (<2 km, polluted area) and in the more distant sites (>4 km, control area). Additional food resulted in higher nestling growth and survival in both areas. Exposure of nestlings to heavy metals was estimated by measuring fecal concentrations of copper and lead. In the polluted area, extra food benefited most those broods that would have accumulated the highest lead concentrations. Nestlings in the polluted area exhibited higher asymmetry of primaries, suggesting that they experienced higher stress, but stress hormone (corticosterone) concentrations and metabolic rates (oxygen consumption) did not differ between the polluted and control areas. Contrary to our expectation, the positive effect of additional food on breeding success was greater in the unpolluted area. The results suggest that different amounts of invertebrate food (biomass) in the two areas cannot wholly explain differences in the breeding success of P. major.
We tested the hypothesis that pollution-related reduction in the amount of invertebrate food would explain the lower breeding success of an insectivorous bird, the Great Tit (Parus major), around a point source of heavy metals (copper smelter), where invertebrate densities are known to be depressed. We provided additional food (mealworms and fat) to randomly selected territories near the smelter (<2 km, polluted area) and in the more distant sites (>4 km, control area). Additional food resulted in higher nestling growth and survival in both areas. Exposure of nestlings to heavy metals was estimated by measuring fecal concentrations of copper and lead. In the polluted area, extra food benefited most those broods that would have accumulated the highest lead concentrations. Nestlings in the polluted area exhibited higher asymmetry of primaries, suggesting that they experienced higher stress, but stress hormone (corticosterone) concentrations and metabolic rates (oxygen consumption) did not differ between the polluted and control areas. Contrary to our expectation, the positive effect of additional food on breeding success was greater in the unpolluted area. The results suggest that different amounts of invertebrate food (biomass) in the two areas cannot wholly explain differences in the breeding success of P. major.
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