Abstract
The large year-to-year changes that can occur in the marine environment make it difficult to detect and measure changes to bird populations caused by offshore wind farms.
Consequently, a robust survey design is essential to both inform pre-construction Environmental Impact Assessment (EIA) and subsequent post-construction monitoring of effects for projects that are consented.
In 2009 Mainstream Renewable Power Ltd were awarded the exclusive rights to develop the proposed 450MW Neart na Gaoithe Wind Farm. The project is located in the outer Firth of Forth, 15.5 km off the Fife coast in eastern Scotland. The offshore Planning Application and Environmental Statement (ES) for Neart na Gaoithe Wind Farm was submitted to Marine Scotland in July 2012. Details of the Neart na Gaoithe project can be found at www.neartnagaoithe.com.
The use of Before-After-Control-Impact (BACI) study designs to monitor the impact of offshore wind farms has become standard practise (e.g. SNH 2009, Drewitt and Langston 2006, Fox et al. 2006). However, there are concerns that BACI studies have little power to detect change, particularly those relating to potential displacement of seabirds (Underwood et al. 1991, 1994). In addition, for far-ranging species like seabirds there are inevitable difficulties with identifying truly independent control sites in the vicinity of the development site. Our study overcomes the shortcomings of BACI and instead uses a Before-After-Gradient (BAG) design (Mainstream RP 2009).
The Before-After-Gradient (BAG) design assumes that:
• Impacts decline with increasing distance from the source (Ellis and Schneider 1997, Morrison et al. 2008);
• Any impacts due to displacement and habitat loss will be detected on the basis of changes in the distribution of seabirds in the area surveyed