Wind turbines have long been the poster-child for successful sustainable energy projects, but like the energy sources they seek to replace, they too exert an unwanted negative impact on the environment. In recent years, collisions with turbines in newly formed wind parks around the world have contributed to the large-scale thinning of native bird populations.
A recent study conducted by Michael Schaub at the Swiss Ornithological Institute-and published in Biological Conservation– analyzed the relationship between the spatial distribution of wind turbines and the relative population growth of the red kite, an eagle endemic to Europe that is a frequent victim of wind turbine accidents and whose population levels are on the decline across the continent.
The study found that population growth rate declines were more pronounced with an increasing number of turbines, but that a portion of the effect could be mitigated by grouping the turbines together into power plants. Additionally, the mortality rate declined the farther the turbines were placed from red kite concentration locations such as migration points, roosts and breeding colonies.
The advantages of wind energy are multi-fold: it is renewable, profoundly abundant, generates zero greenhouse gas emissions and is often (relatively) cheap to produce thanks to federal subsidies. As a result, many developed countries-especially those in Europe and North America-are beginning to invest large amounts of capital in the creation of wind farms. While the move toward sustainable energy is welcomed by many, the system remains far from perfect.
The creation of wind parks exert three profound effects on the biodiversity of the surrounding area, two of which are intimately linked. Habitat loss from the creation of the power plants in turn causes the displacement of local species, and both of these actions interfere with normal ecosystem interactions. The biggest threat, however, is extended to the airborne species that call the power plant areas home.
Turbines are often hundreds of feet tall, putting them directly in the flight path of most birds and bats. Coupled with the fact that they can be poorly illuminated at night, these structures represent a significant and deadly hazard to flying animals. Indeed, previous studies of the effects of turbine-induced mortality have documented declines in both breeding success and overall population growth of native avian species.
Schaub’s study was slightly unorthodox in that it made use of a simulation, rather than tracking live bird populations, in order to calculate the effects of varying the number and distribution of wind turbines. While this approach does not account for environmental or demographic variability between wind farm sites and does not predict effects on individual populations, its strength lies in its ability to highlight general patterns that can be used as guidelines for the future placement of power plants.
In essence, the ideal locations for turbines must meet two key criteria: they must be sites with strong and reliable wind patterns, and they should also be unoccupied by high-risk species such as birds and bats. This situation can often be achieved by clustering turbines in areas already disturbed by human activity, which also happen to be the less frequented by large birds such as the red kite. Doing so not only diminishes the threat to endemic avian species but also preserves a greater portion of the area’s biodiversity while simultaneously maximizing energy production. It’s a win-win for all parties involved.
The results of this study set an important precedent for the future state of renewable energy. If wind energy is going to continue to be an important part of our lives- as it well should- its planning and implementation must be regulated more tightly. As the plights of the red kite and many other species have proven, even “green” energy can harm the environment when mismanaged.
Biodiversity and ecological preservation have and always will be critical to the proper functioning of our planet and cannot be forsaken in the pursuit of alternative energy sources. Figuring out how to make these goals compatible with each other is one of the key challenges currently facing ecologists and engineers alike.
What does the future have in store for the red kite and its threatened brethren? It’s tough to say, but it is safe to assume that the issue, much like the wind, is not going away anytime soon.
Schaub, M. 2012. Spatial distribution of wind turbines is crucial for the survival of red kite populations. Biological Conservation. 155 (1): 111-118.
Image courtesy of http://i.telegraph.co.uk/multimedia/archive/01596/red-kite_1596489a.jpg
Link to article: http://www.sciencedirect.com/science/article/pii/S000632071200290X