Biodiversity on windmill farms

In the late spring of 2008 the first windmill farm was built off the Belgian coast. As well as a lot of green energy, the 6 windmills also provide new habitats. The North Sea bed is mostly sandy, and so the windmills attract species that would prefer to live on a hard substrate. New species attach themselves on and around the windmills, leading to higher biodiversity. The question is whether this biodiversity increase can be described as a positive development. Francis Kerckhof, a researcher with our North Sea department, is keeping an eye on the colonisation of the new windmills.

“The hard surfaces attract species that aren't normally found in the Belgian North Sea. On the one hand species are turning up that usually live in the Channel on rocky shelves which are being brought here by the currents, but on the other hand there are exotic species from other continents being brought on ships travelling on our busy shipping lanes. Due to global warming, these exotics are thriving here. We already have species that originally come from South America.”

So far the scientists have counted 49 species in total, of which a few are non-indigenous, such as the New Zealand barnacle and the midge T. Japonicus, which is normally found in Australasia and along the East coast of America. These new species could pose a threat to local biodiversity, for example by eating the present species, or by competing with them for food and space. The moment such a species becomes a threat, it is called an 'invasive species'.

“A good example of an invasive species is the Japanese oyster. Over time these can even form reefs in an area that is normally made up only of sandbars. Since hard substrates house a greater number of species, this could be seen as a good thing. But our sandbanks have a unique natural biodiversity of their own, which could be turned on its head.”

In order to catch any possible negative effects, Francis and his colleagues watch the new ecosystem extremely closely. “However we are not sure that we would then be able to take action,” warns Francis. “Once a negative effect has been detected, it is often already too late. You can try to control the invasive species, but destroying it is often impossible.”

In the future the Belgian North Sea will gain another 300 to 400 windmills. The research of the North Sea department is vital if we are to have good policies and effective management to protect our marine biodiversity.