Offshore Wind May Increase Biodiversity

As more utilities turn to wind power to reduce their reliance on fossil fuels, many green-minded individuals are understandably concerned about the environmental impacts of wind turbines.  After all, wind turbines are large, artificial structures, often built in what are otherwise semi-natural areas.  It makes sense to question what the impacts of wind turbines on wildlife and local ecosystems might be. 

Fortunately, a new study reveals that at least some wind farms seem to have very minimal impact on wildlife—and in fact may even increase local biodiversity.  The study looked at the effects on wildlife of the first large offshore wind farm in the Netherlands, over a period of two years.  The researchers examined effects of the giant wind turbines on sea birds, fish, marine mammals, and the plethora of invertebrate species that live on the ocean floor. 

The conclusion of the study is the overall effect of the Dutch wind farm was to increase biodiversity by providing habitat for invertebrates that attach themselves to hard underwater surfaces, and by serving as a haven for fish and other species that are protected from fishing within the confines of the wind farm. 

Though some kinds of birds are negatively impacted, even this effect seems to be minimal.  The study is welcome news for those who believe wind energy must have a place in the transition to a low-carbon energy grid. 

The most direct positive impact on marine species is that the submerged turbine pillars provide a hard surface on which mussels, anemones, and other invertebrates can anchor themselves.  In the ocean, almost all hard objects from large rocks to floating drift wood serve as habitat for largely stationary invertebrates that fix themselves to a surface and glean their food from the plankton and small fish swept past in the tides. 

These invertebrates in turn attract species like sea stars, crabs, and snails that rely on forests of stationary invertebrates for food, shelter, or both.  Healthy invertebrate populations also ensure a stable food source for many sea birds and marine mammals.

It’s unsurprising that submerged turbine pillars should turn out to serve as habitat for invertebrate communities.  However the Dutch study confirms what seems to make intuitive sense: offshore wind turbines attract a wide variety of invertebrates, actually increasing overall local biodiversity in the process. 

More indirect is the Dutch wind farm’s positive impact on large fish like cod, which have learned to seek refuge among the wind turbines.  Because fishing is not allowed in the wind farm, it serves as a de facto shelter for species that have suffered from decades or centuries of over-harvesting.  Similarly, the researchers recorded hearing more porpoise vocalizations inside the wind farm than outside.  The relative abundance of fish may have attracted these marine mammals to the area.

One group of animals on which offshore turbines clearly can have a negative impact is on sea birds—although even here, the Dutch study finds fewer negative effects than might be expected.  The researchers estimate the number of birds killed by rotating turbine blades to be very low.  However some bird species, like gannets, tend to avoid the area around the turbines.  Other species, like cormorants, actually seem to be drawn to the wind farm, perhaps because of the abundance of fish in the waters.

In short, the offshore wind farm examined in the study is not a disaster for wildlife, and even seems to provide benefits for some species.  Of course impacts on the local environment will vary from one farm to another, and may be more pronounced in other locations not looked at in this particular study. 

With that in mind, it’s important to remember what kind of energy development wind farms are displacing.  Failing to develop wind power will mean drilling and mining for more oil, coal, and gas—both in the oceans and on land.  This kind of energy has huge impacts on wildlife, from marine mammals affected by sonar equipment used to explore for oil and gas, to the multitude of species put at risk whenever an oil spill occurs

In the end, environmentalists may need to choose whether to embrace wind energy in offshore areas, or go along with the alternative choice of more oil, coal, and gas extraction.  Judging from the recently released Dutch study, wind farms should be the clear winner.  Not only does wind energy avoid the environmental devastation that comes with extracting fossil fuels, it can even provide benefits for at least some of the species that call offshore areas home.  

Photo credit: flickr.com/photos/pebondestad/3533177131/sizes/m/in/photostream/

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