Cross-Seasonal Association Between Winter Trophic Status and Breeding Ground Selenium Levels in Boreal White-Winged Scoters

Abstract

The effect of cross-seasonal interactions on reproduction and fitness in migratory species is of increasing interest to ecologists, particularly because of the conservation implications of habitat change. Variation in contaminant levels that can affect reproduction in migratory species may reflect differing exposure across seasons. We examined the relationship between concentrations of liver selenium, a known teratogen, and winter trophic level in breeding White-winged Scoters (Melanitta fusca) using claw δ15N values as an index of winter trophic level. Claw δ15N was a significant predictor of variation in breeding ground selenium levels (r = 0.32), and liver selenium increased by approximately 12 ± 5 SE μg∙g-1 with one trophic level increase in δ15N (Î"3‰). This relationship demonstrates that contaminant exposure from wintering or staging areas can result in higher levels in birds on breeding grounds, where some contaminants are more likely to have impacts.

Keywords

• contaminants
• cross-seasonal effects
• scoters
• selenium
• stable-isotopes
• trophic levels.