Linking contaminant profiles to the diet and breeding location of American dippers using stable isotopes

نویسندگان

  • CHRISTY A. MORRISSEY
  • LEAH I. BENDELL-YOUNG
  • JOHN E. ELLIOTT
چکیده

1. Individual variation in contaminant levels is a common occurrence in many toxicology studies, but the exact cause is often unclear. We investigated the influence of diet and breeding location on individual bird contaminant profiles using a colour-marked population of American dippers Cinclus mexicanus . The population comprised two distinct groups within a single river system: resident dippers breeding on the main river and altitudinal migrants breeding on tributaries. 2. Residue analysis revealed that total organochlorines (OC), polychlorinated biphenyls (PCB) and mercury (Hg) were all significantly higher in eggs from river residents compared with tributary migrants. This trend was also apparent for the three most prevalent organochlorine compounds: p , p ′ -dichlorodiphenyl-dichloroethylene (DDE), hexachlorobenzene and trans -nonachlor. 3. We hypothesized that the observed differences in contaminant concentrations were partially related to the proportion of salmon fry Oncorhynchus spp. in the diet relative to aquatic invertebrates. Stable isotope analyses using δ 13 C and δ 15 N were conducted on blood and feathers of dippers in addition to aquatic invertebrates and salmon fry prey. Linear mixing models using the 15 N isotope in the dippers’ diet and blood revealed considerable variability in the proportion of fish consumed (0–71%). Resident dippers on the main river ate significantly higher proportions of fish (42%) than tributary migrants (22%) ( P = 0·01). 4. The difference in diet between migratory groups explained some of the observed variation in egg contaminant profiles, as total OC ( P = 0·002) in dipper eggs was positively correlated with blood δ 15 N values, indicating fish may be the primary source of contamination. 5. Synthesis and applications . We conclude that dipper eggs represent local conditions at the breeding site, making them useful tools for biomonitoring aquatic contaminants in watersheds. However, given the distinct difference in contaminant profiles between resident and migrant dippers and the link with diet, the results emphasize the importance of understanding individual species’ ecology for assessing toxicological effects at the population level.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Mercury trends in herring gull (Larus argentatus) eggs from Atlantic Canada, 1972-2008: Temporal change or dietary shift?

Mercury (Hg) is a pervasive contaminant that can adversely affect predatory wildlife. Bird eggs provide insights into breeding females' Hg burdens, and are easily collected and archived. We present data on Hg trends in herring gull (Larus argentatus) eggs from five sites in Atlantic Canada from 1972 to 2008. We found a significant decrease in Hg at Manawagonish Island, New Brunswick and Île du ...

متن کامل

Ancient Diet Reconstruction: A Case Study of Sidon, Lebanon

The present work is associated with dietary reconstruction using δ13C and δ15N analysis of humans from the site of Sidon, a Middle Bronze Age (2000BC-1550BC) settlement in Lebanon. The main objective of this research is to focus on collagen extraction of 23 individual bones, discovered in a cemetery, College site (season 2001-2002) in ancient Sidon. Collagen could only be extracted from the 8 a...

متن کامل

Assessing trace-metal exposure to american dippers in mountain streams of southwestern British Columbia, Canada.

To develop a suitable biomonitor of metal pollution in watersheds, we examined trends in exposure to nine trace elements in the diet (benthic invertebrates and fish), feathers (n = 104), and feces (n = 14) of an aquatic passerine, the American dipper (Cinclus mexicanus), from the Chilliwack watershed in British Columbia, Canada. We hypothesized that key differences may exist in exposure to meta...

متن کامل

Seasonal Trends in Population Density, Distribution, and Movement of American Dippers within a Watershed of Southwestern British Columbia, Canada

American Dippers concentrate on low-elevation streams during fall and winter in many parts of their range; however the breeding origin relative to the wintering location is poorly understood. Our objectives were to identify seasonal changes in the density and distribution of American Dippers, to classify the migratory behavior of the local population, and to determine the origin of winter migra...

متن کامل

Use of Chemical Tracers to Assess Diet and Persistent Organic Pollutants in Antarctic Type C Killer Whales

Measuring chemical tracers in tissues of marine predators provides insight into the prey consumed and the predator’s contaminant exposure. In this study, samples from Type C killer whales (Orcinus orca) biopsied in Antarctica were analyzed for chemical tracers (i.e., stable isotopes of carbon and nitrogen, fatty acids, and persistent organic pollutants [POPs]). Profiles of these individual trac...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2004