A study led by Doñana Biological Station (EBD), research center of the Higher Council for Scientific Research (CSIC), warns of “devastating” effects wind farms on bats in Cadiz and possibly other areas of Spain.
This is the main conclusion reached by a group of researchers from EBD-CSIC, Lund University (Sweden) and University of Seville after analyzing data Mortality of bats collected between 2005 and 2016 in wind farms in the Andalusian province. The results of the study were published in the scientific journal Chiropterological law.
Cádiz’s environmental monitoring plans include the daily presence of security personnel in the parks during daylight hours throughout the year. The guards’ job is to locate animals killed or injured by the wind turbines and to instruct the turbines to stop in case of danger Collision with a birdor side, especially for endangered species.
This monitoring plan is the most intensive of all those carried out in Spain and is considered exemplary. The data from this plan put the number of bat corpses found during the study period at 2,371 and belonged to at least 15 different species of the 20 found in the province of Cádiz. The study focused on detailed analysis In 2011, 582 incidents were detectedYear for which the most comprehensive information was available.
High mortality rates
To estimate the actual mortality rate, scientists conducted an experiment in which they were placed more than a hundred bat corpses in nine wind farms to use them as bait and thus evaluate the search efficiency of the guards and the length of time the bodies remain in the field.
Surveillance personnel located only 17% of the bodies dumped there, even though the wind turbines were checked daily and were available for at least four days in a row. Furthermore, the search for bodies was limited to clean areas (platforms and runways), which on average represent less than 15% of the potential search area. Taking this detection bias into account, the researchers estimated an average mortality rate of 41 bats per turbine per year in the study area.
It is worth remembering that bats have a very low birth rate: one offspring (sometimes two) per female per year.
These results estimate that in Between 33,000 and 37,000 bats died in 2011 in the wind farms of Cadiz. Likewise, according to the study, some of the planned areas experienced the highest wind farm mortality rates documented to date in the world.
“It should be remembered that bats have a very low birth rate, one offspring (sometimes two) per female per year,” he points out. Sonia SanchezLead author of the study.
“Our data shows “devastating” impacts on bat populations, in this case affecting sedentary species, unlike in other parts of the world, such as: Northern Europe or North Americawhere the most affected bats are migratory birds,” he continues.
New monitoring methods
A first conclusion of this study is that these environmental monitoring programs are not efficient for searching for bats, and probably not for searching for small birds either, since they are designed to do so large gliding birds and mask very high mortality rates.
The authors therefore recommend the introduction of new surveillance methods more suitable for small animals, as well as studies to evaluate the real search efficiency of surveillance programs. Environmental monitoring.
Remedial measures such as temporarily stopping turbines during periods of high bat activity have proven crucial
A second conclusion the researchers come to is that we have to do it take urgent preventive measures and effective mitigation measures to protect this group of mammals with many threatened species from renewable energy development.
In this sense, Sánchez recognizes the Importance of wind energy as a source of renewable energy to combat climate change, but calls for the need to balance energy production with the protection of biodiversity.
“Mitigation measures, such as temporarily stopping turbines during periods of high bat activity, have proven crucial to reducing impacts on these species and achieving the ‘green energy’ that is so much talked about,” he concludes.
Reference:
Sánchez-Navarro, S. et al. “A high bat death rate is estimated in wind farms in southern Spain“. Chiropterological law.