The development of offshore wind energy is growing globally, with the potential to be an important source of clean renewable energy. However, offshore wind farms pose significant risks to seabirds and other marine animals.
A new study by UC Santa Cruz scientists outlines a framework for addressing the impacts of offshore wind farms on seabird populations and highlights conservation strategies that could more than offset these impacts.
“We all want wind energy, but we also want to make sure it can be produced sustainably,” said lead author Donald Croll, professor of ecology and evolutionary biology at UC Santa Cruz.
Co-author Aspen Ellis, a doctoral student at Croll’s Conservation Action Lab, explained that funding for offshore wind power development can be used to reduce other threats to seabird populations. This can be effective with seabirds, as studies have shown significant increases in their populations following interventions such as removing invasive species from nesting sites.
“This is a case where we have the data and the knowledge to make it work,” said Ellis. “Seabirds breed in colonies, so their populations are concentrated there during the breeding season and conservation strategies can have a big impact. We have a set of proven tools to increase the size of seabird populations, as well as established methods that can predict population levels and the impact of these different tools on individual seabird species.”
Seabirds are already the most endangered group of birds. Potential impacts of offshore wind farms include displacement of birds from feeding areas and direct mortality due to collisions with wind turbine blades. Displacement and mortality can have detrimental effects on the overall population of an affected species.
Croll and Ellis worked with an international team of seabird and wind energy experts to study these issues and how to solve them. They proposed a global framework, published on November 10 in biological conservationassess and mitigate the impacts of offshore wind farms on seabirds.
While the impacts of onshore wind turbines on eagles and other birds of prey have been well documented, assessing the impact of offshore installations on seabirds is more difficult.
“On land you can find carcasses under turbines, but in the ocean they just disappear,” Croll said.
In the absence of effective monitoring techniques, crash risk models can still provide useful estimates of crash frequencies.
“We’ve studied these species for years, so we have a good amount of information from surveys and tracking studies about what species exist and where they go,” Croll said. “We’ve also developed population models that can be used to assess impacts on seabird populations.”
The study outlined three steps to mitigate environmental impacts: avoid, minimize and compensate. While efforts can and should be made to avoid and minimize the impacts of wind energy development on seabirds, the researchers concluded that it is impossible to eliminate impacts with environmental approaches alone.
Offsetting impacts (also called “compensatory mitigation”) offers the potential for wind energy development to have a net positive effect on seabird populations.
“There is no need to choose between fighting climate change or protecting wildlife – it can be a win-win situation. That’s what we’re trying to do here,” said Ellis.
In addition to removing invasive species from islands where seabirds breed, researchers have also successfully transferred seabirds from existing colonies to other locations, either to establish new breeding colonies or to restore colonies that have disappeared in the past. Mitigation funding can also be used to implement strategies to reduce the bycatch of seabirds in fisheries.
“These interventions can be expensive, and there is a limit to the funding available from government agencies and non-profit organizations,” said Croll. “I hope that funding for offshore wind energy development will increase the resources available for these interventions.”
The study presents a general framework that can be applied globally to assess and mitigate the impacts of offshore wind energy development. Large offshore wind farms have been developed in Europe and the UK. In the United States, offshore wind energy is beginning to develop on the East Coast, but until recently it was not viable on the West Coast, where the continental shelf is rapidly plunging into deep water.
With the development of technologies for floating wind turbines, however, there is growing interest on the West Coast. The Bureau of Ocean Energy Management (BOEM) has identified two areas on the California coast for wind energy leases, one on the north coast near Humboldt County and another on the central coast near Morro Bay.
Ellis is currently applying the approach described in the study to evaluate potential wind power developments on the West Coast, with support from NOAA’s Office of National Marine Sanctuaries through a 2022 Nancy Foster Fellowship.
In addition to Croll and Ellis, co-authors on the paper include scientists from the US Geological Survey, British Trust for Ornithology, Center for Research and Technology (Kiel, Germany), Biodiversity Research Institute, National Fish and Wildlife Foundation, NOAA Fisheries, American Bird Conservancy , National Ocean Service, Audubon Seabird Institute, Conservation Metrics, Waardenburg Ecology (Netherlands), UK Center for Ecology & Hydrology, Ecological Dynamics Group (Netherlands), Blue Point Conservation Science, Pacific Rim Conservation and Nhydra Ecological (Canada).
This research was supported by BOEM through a grant to the National Center for Ecological Analysis and Synthesis (NCEAS) at UC Santa Barbara.