El Aguila Imperial Ibérica se recupera/Iberian Imperial Eagle is recovering

A pesar de ser una de las especies más vulnerables según la lista roja de la Unión Internacional para la Conservación de la Naturaleza (IUCN, por sus siglas en inglés), el águila imperial (Aquila adalberti) se está recuperando en España. La especie se ha multiplicado por seis, pasando de 38 parejas de águila en 1974 a 253 en 2008, un dato esperanzador para los científicos que han realizado el estudio demográfico en la Península Ibérica.
"El trabajo muestra que la especie se ha recuperado y que tiene una buena capacidad de respuesta a las actuaciones de conservación. Aunque ya se sabía desde hace tiempo, el estudio demuestra, una vez más, que es una especie muy sensible a los cambios en la supervivencia adulta”, explica a SINC Santi Mañosa, uno de los autores del estudio e investigador de la Universidad de Barcelona.
Según datos del Ministerio de Medio Ambiente, Medio Rural y Marino (MARM), en 2008 había 253 parejas de águila imperial. La especie ha aumentado en toda su área de reproducción a excepción del Parque Nacional de Doñana (Huelva) donde la población estuvo afectada gravemente por el uso ilegal de cebos envenenados en especial en los ‘90.
La colaboración entre los diferentes agentes sociales (investigadores, cazadores, agricultores, gestores forestales, industria energética, entre otros), es importante para que exista “un consenso estatal entre todas las Comunidades Autónomas y para regular todas las actividades que pueden afectar a la especie”.



Despite being one of the most threatened species on the International Union for Nature Conservation (IUCN)'s red list, the Spanish imperial eagle (Aquila adalberti) is recovering in Spain. The species has undergone a six-fold increase, from 38 pairs in 1974 to 253 in 2008, data viewed as hopeful by the scientists who carried out the demographic study on the Iberian Peninsula.
"This study shows that the species has recovered and has responded well to conservation initiatives. Although it has been known for a long time, the study shows once again that this species is highly affected by changes in adult survival rates", Santi Mañosa, one of the authors of the study and a researcher at the University of Barcelona, tells SINC.
Data from the Ministry of the Environment and Rural and Marine Affairs (MARM) show that there were 253 pairs of imperial eagles in 2008. The species has experienced an increase throughout its entire area of reproduction, except in the Doñana National Park in Huelva, where the population has been seriously affected by the illegal use of poisoned bait, especially during the 1990s.
Collaboration between various social agents (researchers, hunters, farmers, forest managers, the energy industry, etc.) is important to ensure the existence of "nationwide consensus between all the autonomous regions, and to regulate all those activities that could affect the species".

Tomado de/Taken from Plataforma SINC /Science Daily

Referencia bibliográfica/Journal reference
Ortega, Enric; Mañosa, Santi; Margalida, Antoni; Sánchez, Roberto; Oria, Javier; González, Luis Mariano. A demographic description of the recovery of the Vulnerable Spanish imperial eagle Aquila adalberti. Oryx, 2009; 43 (1): 113 DOI: 10.1017/S0030605307991048

Resumen/Summary
The population of the Vulnerable Spanish imperial eagle Aquila adalberti has experienced a gradual recovery from 38 pairs (1974) to 198 (2004). We analysed the spatial and temporal variation of the demographic parameters for 1981–2004. Annual productivity was 1.19–1.32 chicks per female and adult survival rate 0.918–0.986. Survival during the post-fledging period was 0.894 and the annual survival rate of the dispersing individuals was 0.561. Three phases of population evolution were distinguished: growth (1981–1993), stability or slight decrease (1994–1999) and growth (2000–2004). Variation in adult survival seems to explain this pattern for the first two periods. However, a large disparity between the observed growth rate and the modelled population growth in 2000–2004 is best explained if we assume that a decrease in the age of recruitment took place. This is supported by the recent increase in the frequency of non-adult birds in breeding pairs. The survival of unpaired eagles in dispersal areas is becoming more important for the maintenance of current population growth. Spatial variation of adult survival and breeding success is not congruent with the observed growth rate of the population, which suggests the existence of an important flow of individuals between populations. These results highlight the importance of addressing the conservation of the species from a global perspective and the need to focus on adult survival in breeding territories and on non-adult survival in dispersal areas.


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