Wind energy development is growing worldwide in an effort to limit greenhouse gas emissions and slow climate change. However, ideal locations for wind power harvesting often overlap with concentrations of wildlife, which can lead to collisions and habitat loss. Researchers found that data collected by weather radar networks could be used to reduce collisions and minimize habitat-related impacts of wind turbines on nocturnal migrating birds.
Billions of birds migrate seasonally across North America, most flying at night and stopping during the day to rest and refuel, often in places with high wind power potential. Migratory birds are particularly at risk when traveling to lower altitudes swept by wind turbine blades, known as the rotor-swept zone, as they descend and ascend from stopover habitat.
Efforts have been made to avoid and minimize bird strikes and habitat-related impacts at wind turbine installations, including siting installations to avoid high-risk areas, temporarily shutting down wind turbines when target species are observed nearby and visual and auditory deterrents of birds near facilities.
“All of these management approaches would benefit from more accurate knowledge of where and when large numbers of nocturnal migratory birds will cross the rotor-swept area and descend to stopover sites during migration,” said co-author Jeffrey Buler, associate professor of wildlife ecology at the University of Delaware.
By examining data collected continuously for four years by seven radars around the North American Great Lakes, an important bird migration corridor, researchers have found that weather radar can help identify areas where large numbers of birds migrants cross the area swept by the rotor and stop at high altitude. densities. They identified a distance of 20 km from shorelines where migratory birds are highly concentrated, a threshold that could be useful in guiding the placement of new wind power developments and in identifying peak take-off and landing times at which the turbine operation could be reduced.
For example, although nocturnal migratory birds often fly well above the altitudes traversed by wind turbines, researchers found that the proportion of birds in the area swept by the rotor peaked at almost 50% near sunrise. when birds migrating through the Great Lakes region ended their nocturnal migration by landing in terrestrial stopover habitats. However, the risk of exposure can be minimized by avoiding placement of turbines in areas with the highest stopover concentrations or by reducing turbine operation during twilight hours, particularly during the small fraction of nights during the migratory passage.
“By quantifying spatio-temporal patterns of aerial and terrestrial habitat use, it is possible to provide an exposure risk assessment that can help guide future wind energy growth and development in order to minimize negative impacts on nocturnal migratory birds due to wind turbine collision and habitat loss”, says Cohen.
Source: University of Maryland Environmental Science Center
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