East Anglia ONE Offshore Windfarm Generation Assets Monitoring Plan


September, 2016


density surface to the survey data and permits the incorporation of explanatory covariates (e.g. distance to coast, bathymetry, etc.) to improve model fit (i.e. improve precision on estimates). This approach, referred to as model based analysis, also offers a major advantage over design based methods as it is possible to use the covariate relationships to predict abundance in areas not surveyed (e.g. between transects and beyond the surveyed area). Furthermore, following collection of post- construction survey data it will be possible to include ‘wind farm’ as an effect in the model to undertake statistical tests of displacement effects.


4.2.2 Wind farm avoidance 58.


Wind turbine avoidance by seabirds can occur across a wide range of distances, from macro-avoidance (at distances greater than the distance between turbines) to meso-avoidance (within wind farm avoidance of turbines) and micro-avoidance (last minute evasion of rotors). The latter cannot be analysed from aerial survey data, but macro-and meso- will be estimated for this study. A randomisation method will be used to estimate how probable the observed distributions of birds are given the wind farm and turbine locations. For species considered to exhibit macro-avoidance (e.g. gannet) this will be conducted using the density of birds within sequential 500m buffers around the wind farm (up to distances at which no further effect is detectable). For species which are expected to enter the wind farm but may avoid individual turbines this will be conducted on densities within sequential 100m buffers around turbines (up to half the turbine separation distance). Note that the Aerial Survey Power Analysis report (Appendix B) only provided examples of the macro-avoidance test for gannet, as this is the species of highest concern in this regard. However, the meso-avoidance study is also considered useful as this will help inform estimates of displacement for over-wintering auks. As the method is essentially the same, it can be scaled to suit the species of interest.


59.


For each species the survey data may be analysed for individual surveys separately, if sample sizes are of sufficient size (e.g. >50 observations), but will also be combined across surveys, on the assumption that bird responses would be expected to be consistent across a migration season or the winter period.


60.


The density of birds recorded within a buffer around the actual wind farm (or turbines) will be compared with the distribution of densities obtained by repeatedly re-locating the turbines with a random offset in both x and y coordinates. The null hypothesis being tested is that the density in each buffer around the real wind farm location lies in the middle of the distribution of densities generated by random offset. The pre-construction analysis will provide a baseline for this analysis, in order to check for the presence of pre-existing patterns of location. It will also be possible to test the reliability of the method by removing a known percentage of individuals within a given buffer distance (i.e. simulating displacement) and checking to see if the method correctly identifies the manipulation.


61.


Post-construction, consideration of the sequential buffers will enable identification of avoidance distances (i.e. at what buffer distance do the observed data become indistinguishable from the randomly re-sampled data).


62.


A permutation test can be used to provide a measure of the probability of obtaining the density estimated within the buffers from the actual wind farm location compared with those for the re-sampled wind farm locations.


4.3 Reporting 63.


Individual topic-specific reports, including the ornithology monitoring report, will be produced for all monitoring detailed in the Generation Monitoring Plan and in line with the reporting described in Section Error! Reference source not found. of this document (ornithology monitoring only). This will detail the analytical methods used, results obtained and provide discussion and interpretation of the findings.


64.


As a separate process and as per the requirements set out in the generation DML, the findings of all the environmental surveys detailed within the Monitoring Plan and the ornithological monitoring plan will be presented to the MMO in a consolidated standalone summary report. See Section 4 of the Monitoring Plan for further details on monitoring reporting requirements.


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