Long-term breeding demography and density dependence in an increasing population of Golden Eagles Aquila chrysaetos - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Ibis Année : 2011

Long-term breeding demography and density dependence in an increasing population of Golden Eagles Aquila chrysaetos

Résumé

Few studies have quantified the dynamics of recovering populations of large raptors using long-term, spatially explicit studies. Using data collected over 37 years in the western Italian Alps, we assessed the trends in distribution, abundance, fecundity and breeding population structure of Golden Eagles Aquila chrysaetos. Using the spatial distribution of territory centroids in 2007, we found that the spatial distribution of eagle territories was over-dispersed up to 3 km. Although population size and total productivity increased from 1972 to 2008, the proportion of pairs that laid eggs showed a strong decline, falling to no more than 50% after 2003. On average, 15% of successful nests produced two fledglings, and productivity also declined over time. No significant relationship between population growth rate and total population size was detected, but the percentage of pairs that bred and breeding success showed evidence of density dependence, as they declined significantly with increasing density. Our results suggest that density dependence, operating across heterogeneous habitats, is currently regulating this population, while the carrying capacity may still be increasing. This may explain the apparent paradox of reduced breeding effort despite increasing total productivity.

Dates et versions

hal-00611709 , version 1 (27-07-2011)

Identifiants

Citer

Paolo Fasce, Laura Fasce, Alexandre Villers, Franco Bergese, Vincent Bretagnolle. Long-term breeding demography and density dependence in an increasing population of Golden Eagles Aquila chrysaetos. Ibis, 2011, 153, pp.581-591. ⟨10.1111/j.1474-919X.2011.01125.x⟩. ⟨hal-00611709⟩

Collections

CNRS INRA INRAE
49 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More