The local effect of the presence of offshore wind farms on the distribution of Red-throated Divers have been assessed in several studies. These results indicate that Red-throated Divers are less abundant within and around an offshore wind farm post-construction compared to pre-construction. Such displacement does not cause direct mortality, and the local effect is therefore not easily assessed in terms of the impact on the population level. Hence an agent-based model was developed in an attempt to assess the impact of these displacements on the general population. Model development was carried out using a Pattern-Oriented Modelling procedure which involved developing the model in an iterative cycle comparing model performance against real world data patterns via an inverse modelling procedure. The result is that the extent to which the model predicts impacts of windfarms correctly is directly related to the quality of real world test data available. Having established the model we compared the potential impact of 3 wind farm development scenarios encompassing the full range of possible wind farm developments in the region covering the entire Baltic and the eastern North Sea from the Netherlands in the south to mid Norway in the north.
The assessments were based on TWO BASIC assumptions. FIRSTLY, that windfarm development removed habitat pro-rata by area and did not have a wider reaching implication for diver resources. Based on this assumption, evaluation of the simulations led to predictions of minimal impacts of the proposed windfarm developments. Primarily this was due to the avoidance behaviour of the divers, whereby they would fly around or over windfarms, rather than perceiving windfarms as barriers to movement. THE SECOND ASSUMPTION IS THAT THE DATA USED TO DEVELOP THE MODEL WAS REPRESENTATIVE OF THE DIVER POPULATION BEHAVIOUR. HENCE, the results presented here must be INTERPRETED IN THE LIGHT OF THESE ASSUMPTIONS AND THE AVAILABLE DATA.