Relationships between carbon sources, trophic level and mercury exposure in generalist shorebirds revealed by stable isotope ratios in chicks

Tavares, P.C., McGill, R.A.R. , Newton, J. , Pereira, E., Duarte, A.C. and Furness, R.W. (2009) Relationships between carbon sources, trophic level and mercury exposure in generalist shorebirds revealed by stable isotope ratios in chicks. Waterbirds, 32(2), pp. 311-321. (doi:10.1675/063.032.0211)

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Publisher's URL: http://dx.doi.org/10.1675/063.032.0211

Abstract

Mercury exposure may he linked to several sources of variation related to habitat conditions and species ecology. In generalist birds, feeding habits may change quickly in response to environmental conditions, prey availability and individual requirements. Stable: nitrogen isotope ratios (δN15) were used as a marker of trophic level, and stable carbon isotope ratios (δC13) as a marker of carbon sources (terrestrial vs. marine) in food webs involving waterbirds, to infer the effect oil mercury exposure dice to differences in feeding ecology and the relative dependence em aquatic environments. Four generalist species occupying three different habitats were examined during the breeding season. Habitats: Brackish Water-saltwater (saltpans), brackish water-freshwater (ricefields anti some saltpans) and terrestrial environment (steppes). Species: Avocet (Recurvirostra avosetta), Black-winged Stilt (Himantopus himantopus), Kentish Plover (Charadrius alexandrinus) anti Cattle Egret (Bulbucus ibis). Chick feathers were collected at several locations between 2000 and 2003. Species used resources differently ill the environment, and distinct pathways were involved in the mobilization of mercury into food webs. The positive relationship between leather δN15 values and mercury levels indicated mercury bioaccumulation and biomagnification. Inter-specific variation in feather δC13 values revealed a different relative dependence among species on terrestrial vs. aquatic prey. Intra-specific variation in feather δC13 values also indicated differential use of marine inputs within each species, and within saltpans for Avocet chicks. Feather mercury levels and δC13 values suggested that the: relative use of marine-derived prey influences mercury levels in chicks

Item Type:Articles
Keywords:stable isotopes, trophic shift, carbon, nitrogen, mercury, birds, chicks
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Newton, Dr Jason and McGill, Dr Rona and Furness, Professor Bob
Authors: Tavares, P.C., McGill, R.A.R., Newton, J., Pereira, E., Duarte, A.C., and Furness, R.W.
Subjects:Q Science > QL Zoology
Q Science > QH Natural history > QH345 Biochemistry
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Waterbirds
ISSN:1524-4695
ISSN (Online):1938-5390

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