The Offshore Wind Strategic Monitoring and Research Forum (OWSMRF), led by seven offshore wind developers and delivered by the Joint Nature Conservation Committee (JNCC) – the conservation advisory body to UK governments – has published a report identifying key evidence gaps in the UK’s understanding of how offshore wind development is likely to affect Manx shearwater and storm-petrel seabirds.
The birds reproduce in significant numbers on several UK islands, according to the JNCC, and compared to other species of seabirds such as kittiwakes they are difficult to study due to their tendency to travel large distances for food.
As a result, very little is known about their use of the marine environment, how their populations are faring, and crucially, how they interact with offshore wind farms which are set for a boom in construction.
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Dr Helen Baker, JNCC marine species team leader, said: "The UK population of Manx shearwaters is internationally important at between 70–90% of the global population, and around 10% of the world’s European storm-petrels breed in the UK.
However, “there is little evidence about how shearwaters and petrels behave around wind farms, whether they avoid them or are likely to come into close contact”, she added.
The report outlines that total population numbers, colony size, and population trends for both species “are fundamental baselines against which impact is assessed”, and that uncertainty in these estimates will lead to “the continued use of precaution” when assessing impact and deciding on consenting conditions.
Population viability analysis (PVA) is commonly used in impact assessments. It uses the demographic rates of a given seabird population to generate projections of the future scenarios of population growth and decline, and predictions of impact – often from direct mortality from collision with wind turbines, but also from indirect from displacement – the report says.
“High-quality demographic rate data are important for reducing uncertainty in making predictions,” say the report authors, but add that the seabird demographic data needed to produce these models “are not always well defined either in accuracy or confidence”.
In order for robust impact assessments to be made for offshore wind developments, including Habitats Regulation Assessments for internationally protected marine sites, the authors write that “detection of change within a species population is vital, therefore continuing the census efforts is essential to ensure trends can be identified”.
The OWSMRF concludes with identifying 18 “research opportunities” intended to fill some of the evidence gaps reported on.
These include a strategic review of the current knowledge and research on population estimates and demographic rates for Manx shearwaters and european storm-petrels, the development of species distribution models, and the exploration of the use of trained scent-detection dogs to recognise seabird scents, differentiate between species, and identify new colonies.
Scent-detection dogs are widely used around the world for a variety of purposes but are “potentially underutilised in seabird conservation in the UK”, according to the report.
It continues: “Once potential locations for unknown colonies have been established, using scent-detection dogs may be the most cost- and time-effective method of undertaking surveys as current evidence suggests that in the same time period a dog can cover up to six times as many burrows than playback sampling.”