Pollutant accumulation patterns in nestlings of an avian top predator: biochemical and metabolic effects.
The exposure to persistent pollutants such as organochlorine compounds (OCs) or metals has been associated with declines in top predator populations, which can accumulate high amounts of these pollutants from their prey. However, understanding how variation in OC and metal accumulation in wild species affects their biochemical and physiological responses is a big challenge, especially for endangered predators like the Bonelli's eagle (Aquila fasciata). This bird of prey is an interesting study model because the differences in diet composition among populations and territories can account for important pollutant uptake variations. We compared OC and metal accumulation in blood of Bonelli's eagle nestlings from three populations across Spain as a function of origin, age class (nestlings vs. adults), sex and number of siblings per nest, and related accumulation patterns to responses indicative of body condition, biochemistry and antioxidant status. Nestlings from Catalonia, the most industrialized area, showed the highest concentrations of PCBs and arsenic, and the lowest concentrations of zinc. The two former substances, together with DDTs, exerted an overall influence on nestling's physiology. PCBs and arsenic were associated with reduced retinol levels, pointing to oxidative damage in exposed individuals, which was also consistent with the low zinc levels in individuals from the polluted region. Increased plasma DDT levels were related to reduced body condition and lower levels of triglycerides. Mercury accumulation in Castile and Leon was higher in nestlings that were alone in the nest than in nestlings that shared it with a sibling; this suggests an increased mercury uptake from secondary prey in territories where preferred prey (i.e. rabbits) are scarce, which are also the territories where productivity is reduced. Overall, the results reveal a spatial variation in pollutant accumulation patterns and associated physiological effects, and suggest the major role that territory quality may have in such patterns.
Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM) Ronda de Toledo s/n, 13071 Ciudad Real, Spain. Electronic address: mortizsantaliestra@gmail.com.
Manuel E
ME
Ortiz-Santaliestra
Equip de Biologia de la Conservació, Departament de Biologia Animal, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain.
Jaime
J
Resano-Mayor
Equip de Biologia de la Conservació, Departament de Biologia Animal, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain.
Antonio
A
Hernández-Matías
Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM) Ronda de Toledo s/n, 13071 Ciudad Real, Spain.
Jaime
J
Rodríguez-Estival
Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM) Ronda de Toledo s/n, 13071 Ciudad Real, Spain.
Pablo R
PR
Camarero
School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Wits 2050, Johannesburg, South Africa.
Marcos
M
Moleón
Equip de Biologia de la Conservació, Departament de Biologia Animal, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain.
Joan
J
Real
Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM) Ronda de Toledo s/n, 13071 Ciudad Real, Spain.
Rafael
R
Mateo
D000818:Animals; D004032:Diet; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000378:metabolism* / Q000633:toxicity; D046093:Falconiformes / Q000378:metabolism*; D020387:Food Chain; D013030:Spain
D004785:Environmental Pollutants
Biomonitoring; Bonelli's eagle; Dietary accumulation; Metals; Organochlorine compounds; Oxidative stress