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Influence of contamination by organochlorine pesticides and polychlorinated biphenyls on the breeding of the Spanish Imperial Eagle ( Aquila adalberti )
Author(s) -
Hernández Mauro,
González Luis M.,
Oria Javier,
Sánchez Roberto,
Arroyo Beatriz
Publication year - 2008
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/07-308r.1
Subject(s) - organochlorine pesticide , pesticide , polychlorinated biphenyl , hatching , zoology , biology , accipitridae , avian clutch size , toxicology , reproduction , ecology , predation
We evaluated temporal and regional trends of organochlorine (OC) pesticide (including polychlorinated biphenyl [PCB]) levels in eggs of the Spanish Imperial Eagle ( Aquila adalberti ) collected in Spain between 1972 and 2003. Levels of p,p ′‐dichlorodiphenyldichloroethylene (DDE) and PCBs varied significantly ( p = 0.022) among regions (central, western, and Doñana), being higher in Doñana than in the central and western populations (DDE: 1.64 ± 5.56, 0.816 ± 1.70, and 1.1 ± 2.66 μg/g, respectively; PCBs: 1.189 ± 5.0, 0.517 ± 1.55, and 0.578 ± 1.75 μg/g, respectively). Levels of DDE decreased with time, but a significant interaction was observed between region and time. In Doñana, egg volume and breadth as well as Ratcliffe Index were significantly lower after DDT use ( p = 0.0018) than during the pre‐DDT period ( p = 0.0018); eggs were significantly smaller overall than in the other two regions ( p = 0.04) and were smaller when DDE levels increased, even when controlling for regional differences ( p = 0.04). Productivity in Doñana was significantly lower than in the other regions ( p < 0.001). Clutch size in Doñana varied according to DDE concentrations ( p = 0.01), with the highest DDE concentrations found in clutches consisting of one egg. When considering eggs with DDE levels greater than 3.5 μg/g, a significant effect of DDE on fertility was found ( p = 0.03). Clutches with DDE levels greater than 4.0 μg/g had a higher probability of hatching failure ( p = 0.07) and produced fewer fledglings ( p = 0.03). If we consider 3.5 μg/g as the lowest‐observable‐adverse‐effect level, the proportion of sampled clutches that exceeded that level in Doñana (29%) was significantly higher than in other regions ( p < 0.001). These eggs showed a mean percentage of thinning of 16.72%. Contamination by OCs, mainly DDE, could explain, at least in part, the low productivity of the Spanish Imperial Eagles in Doñana.