TY - JOUR TI - Assessing Seabird Displacement at Offshore Wind Farms: Power Ranges of a Monitoring and Data Handling Protocol AU - Vanermen, N AU - Onkelinx, T AU - Verschelde, P AU - Courtens, W AU - Van de walle, M AU - Verstraete, H AU - Stienen, E T2 - Hydrobiologia AB - Prior to the construction of an offshore wind farm at the Belgian Thorntonbank, local seabird abundance was studied by means of ship-based surveys. ‘Seabirds at sea’ count data, however, exhibit extreme spatial and temporal variation, impeding the detection of human impacts on seabird abundance and distribution. This paper proposes a transparent impact assessment method, following a before–after control–impact design and accounting for the statistical challenges inherent to ‘seabirds at sea’ data. By simulating a broad range of targeted scenarios based on empirical model coefficients, we tested its efficacy in terms of power and investigated how the chance of statistically detecting a change in numbers is affected by data characteristics, monitoring period and survey intensity. Because of high over-dispersion and/or zero inflation, the power to detect a 50% decrease in numbers was generally low, but did reach 90% within less than 10 years of post-impact monitoring for northern gannet (Morus bassanus) and common guillemot (Uria aalge). DA - 2015/09// PY - 2015 VL - 756 IS - 1 SP - 155 EP - 167 UR - https://link.springer.com/article/10.1007%2Fs10750-014-2156-2 DO - 10.1007/s10750-014-2156-2 LA - English KW - Wind Energy KW - Fixed Offshore Wind KW - Displacement KW - Seabirds KW - Birds ER -