Abstract
Over the period October 2003 to August 2004 E.ON UK (formerly PowerGen) Renewables Offshore Wind Ltd. constructed an offshore wind farm (OWF) comprised of 30 high capacity turbines beginning approximately 2km offshore of North Denes in Great Yarmouth, Norfolk, on part of Scroby Sands, an extensive and dynamic sand bar system running broadly parallel to the coast for approximately 5km.
The development is located directly offshore from the Great Yarmouth North Denes Special Protection Area (SPA), designated as a result of the presence of the largest colony of Little Tern Sternula albifrons in the UK, protected and managed by the Royal Society for the Protection of Birds (RSPB) on behalf on Great Yarmouth Borough Council. Little Terns are an endangered species in long-term chronic decline in the UK, reducing by some 27% between 1985-87 and 2000. From 1983 to 2001, North Denes regularly held over 200 breeding pairs, ~11% of the UK total, around 3.5% of the North & Western European population and 0.6% of the entire European population (inclusive of the poorly defined but large populations in Russia and Turkey).
An Appropriate Assessment of the likely impact of the proposed wind farm concluded that although Little Terns used Scroby Sands when feeding, the impact of the wind farm on local bird populations was likely to be of moderate significance at most. But, such is the importance of the site and its species that Department for Environment, Food and Rural Affairs (DEFRA), after discussion with English Nature (now Natural England –NE) instructed that monitoring of Little Terns be undertaken to validate these conclusions. Suitable methodologies were developed after further consultation with the Royal Society for the Protection of Birds (RSPB).
The two years (2002 and 2003) prior to construction were to form a baseline against which future change relative to the presence of the wind farm could be evaluated. Monitoring following piling and during turbine construction was undertaken in 2004. Post-construction impacts may be evaluated in monitoring conducted in 2005 and 2006.
It must, however, be stressed that in relatively short-term studies of this type in which interactions are likely to be complex between the birds, their prey and predators, stochastic factors such as climate and disturbance it is extremely unlikely that cause and effect in relation to the impact of a development such as an OWF can be unambiguously determined. A carefully reasoned approach was therefore adopted to establish the most likely cause of observed patterns. Given the conservation importance of the species and the site the precautionary principle was applied throughout.