Bonelliʼs eagle in Catalonia: from threat to conservation
Power line accidents and human persecution have caused more than 95% of Bonelliʼs eagle deaths occurred in Catalonia for the last decades. The monograph El águila perdicera en Cataluña: de la amenaza a la conservación. Aplicaciones a la mitigación de la electrocución points out that the application of some correction measures in power lines is a key strategy to reduce the number of electrocuted birds —the main cause of death for the species— in natural environments. The publication is signed by experts Joan Real, Antonio Hernández Matías, Àlex Rollan and Albert Tintó, members of the Conservation Biology Group, a research group affiliated with the Department of Animal Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona, together with the company Endesa.
Power line accidents and human persecution have caused more than 95% of Bonelliʼs eagle deaths occurred in Catalonia for the last decades. The monograph El águila perdicera en Cataluña: de la amenaza a la conservación. Aplicaciones a la mitigación de la electrocución points out that the application of some correction measures in power lines is a key strategy to reduce the number of electrocuted birds —the main cause of death for the species— in natural environments. The publication is signed by experts Joan Real, Antonio Hernández Matías, Àlex Rollan and Albert Tintó, members of the Conservation Biology Group, a research group affiliated with the Department of Animal Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona, together with the company Endesa.
About 80% of European populations of Bonelliʼs eagle (Aquila fasciata) are in the Iberian Peninsula. The species, described in 1822 by the French ornithologist Louis Jean Pierre Vieillot, was named after the ornithologist Franco Andrea Bonelli, who first documented it in 1819. The Bonelliʼs eagle, which usually lives in mountains, hills and river gorges in the Mediterranean area, is classified as an endangered species in Europe.
When humans transform natural landscape
Until mid-20th century, Catalonia hosted large populations of Bonelliʼs eagle. However, during the 1990s, the species abandoned progressively the territories it occupied for many years. Everything points out that the process of electrification of rural areas and the installation of line towers may have a direct relation with an increase of the number of cases of bird electrocution and, thus, the decrease of the species.
In order to find solutions to the problem, the Conservation Biology Group of the University of Barcelona —a research team that has been studying the ecology of the species since 1980 and it has provided solutions to improve species conservation— has signed several agreements with different organizations that have enabled to monitor Bonelliʼs eagle population in Catalonia for three decades and to analyse demographical parameters, population viability and the principal factors involved in species conservation.
The publication describes the results obtained from 1980 to 2014 thanks to the agreements signed by the Conservation Biology Group, the Barcelona Provincial Council, the company Endesa and the Miquel Torres Foundation, and the projects funded by the Spanish ministries of Education and Science and Innovation.
A protocol to avoid electrocution and improve the survival of the Bonelliʼs eagle in Europe
The publication includes information about species biology, population censuses for the last thirty years and a viability analysis.
It also includes one important novelty: a protocol to mitigate bird electrocution. The protocol is centred on detecting the areas where electrocution has a higher impact, in order to focus then on the most dangerous territories and get to the exact points where most electrocutions take place. To achieve this goal, the study uses progressive approximation and prediction models of areas and points with the highest risk of electrocution. This procedure allows optimising more than 70% of the resources devoted to correction (money and time), and it has very positive effects on eagles. The protocol was first applied in the Sant Llorenç del Munt and l''Obac Natural Park and its surroundings; it has enabled to reduce species mortality rate from 23% to 0%. These successful results were published in international prestigious journals like Journal of Wildlife Management (United States) and Biological Conservation (Great Britain).
In short, people responsible for species management and electrical companies have at their disposal a very effective protocol that can be applied to many other bird species affected by electrocution in the rest of the territory.
Joan Real, head of the Conservation Biology Group, says: “Among protocolʼs positive aspects, it is important to highlight the synergetic and reciprocal work done by agents involved in conservation (Barcelona Provincial Council), research (University of Barcelona) and power lines (Endesa)”.
“Besides improving processes and knowledge, this multidisciplinary approach has been proved to be effective in solving the problem of electrocution, which is one of the most serious threats to bird species conservation around the world”. Individuals of Bonelliʼs eagle and many other species continue dying electrocuted in Catalonia, so “this protocol should be applied as soon as possible because Catalan Bonelliʼs eagle population is not self-sustaining due to excessive mortality rates. If we achieve to avoid between 2 and 4 electrocutions of Bonelliʼs eagle individuals, the population will turn self-sustaining and it will recover”, highlights Real.
Raptor protection, biodiversity protection
Nowadays, Catalan population of Bonelliʼs eagle is stable and it is beginning to colonise new territories. According to authors, in the rest of the Iberian Peninsula, a dramatic decrease has taken place for the last three decades; populations at higher risk of disappearing are in northern sectors.
According to Joan Real, “birds are one of the most representative species of Mediterranean ecosystems, characterized by high biodiversity. Many species are threatened by new human activities that transform habitats and cause bird mortality”. “Therefore —he concludes—, the application of protocols that optimise the mitigation of human impact is crucial for bird population conservation. In the case of the Bonelliʼs eagle, an emblematic species in Mediterranean ecosystems, impact reduction has positive effects on biodiversity in general”.