Effects of offshore wind farms on birds

Transcription

1 AARHUS VERSITY DEPARTMENT OF BIOSCIENCE 11. OCTOBER 2012 Effects of offshore wind farms on birds Ib Krag Petersen, Anthony D. Fox, Mark Desholm, Johnny Kahlert and Thomas K. Christensen Department of Bioscience Aarhus University Denmark

2 Save the Planet or protect nature Either / or Neither / nor Both / and

3 OVERVIEW OF PRESENTATION Legal framework Defining the problem a) Barrier effects b) Displacement effects c) Colission effects Assessing the impact a) with examples Quantify the impact Summing up

4 AARHUS VERSITY DEPARTMENT OF BIOSCIENCE 11. OCTOBER 2012 As of Jan 2012, 1371 turbines in 53 offshore wind farms in 10 European Union states, rated at 3.8 GW, produce 0.4% of total EU electicity consumption; there are current plans for up to turbines here.

5 AARHUS VERSITY DEPARTMENT OF BIOSCIENCE 11. OCTOBER 2012 The legislative framework European Union Directive (85/337/EEC) on Environmental Impact Assessments (known as the EIA Directive) applies to assessment of the environmental effects of major development projects. European Union Directive (2001/42/EC) on Strategic Environmental Assessments (known as the SEA Directive) applies to environment impacts of implementation of major plans and programmes, including assessments of alternative solutions.

6 AARHUS VERSITY DEPARTMENT OF BIOSCIENCE 11. OCTOBER 2012 Environmental Impact Assessment Considers the adverse consequences for the environment of placing windfarms at the site or local level Requires an assessment of the cumulative impacts arising from each development Such cumulative impacts also need to be considered in conjunction with other projects (i.e. other wind farms or other relevant projects) that impact upon the same populations of birds throughout their annual cycle

7 How do we assess how a development will affect the birds? 1. Which are the key species? 2. Which are the key hazards the development presents to these? 3. How can we assess the impact of these hazards pre-construction? Fox et al Ibis 148:

8 1. Which are the key species? A. Those which enjoy special protection measures B. Those for which the area is important at some stage in the life cycle C. Those which are vulnerable to windfarms in some way D. Those that exhibit high annual adult survival and low reproductive output

9 2. Quantifying the hazards A. The barrier effect B. Displacement from ideal feeding distribution C. Collision mortality Fox et al Ibis 148:

10 Defining the problem Hazard factor VISUAL STIMULUS AVOIDANCE RESPONSE PHYSICAL HABITAT LOSS/MODIFICATION COLLISION MORTALITY Physical effects Barriers to movement (migration, feeding flights, etc.) Displacement from ideal feeding distribution Destruction of feeding habitat under foundations/ anti-scour structures Creation of novel habitats on foundations anti-scour structures Birds collide with rotors or other structures, or mortally injured by air turbulence Ecological effects Increased flight distances Effective habitat loss Physical habitat loss Physical habitat gain Energetic costs Enhanced energy consumption Reduced energy intake rates and/or increased energy expenditure Enhanced energy intake rates and/or decreased energy expenditure Fitness consequences Changes to annual breeding output and survival Reduced survival Population impacts Changes to overall population size

11 3. Assessing the impacts A. Barrier effects 1. Birds avoid flying in the vicinity of windfarms and incur enhanced energy costs 2. Use radar (in combination with visual and other confirmatory observations) to compare preconstruction trajectories with those post-construction Desholm et al Ibis 148:

12 3. Assessing the impacts A. Barrier effects (migration) Nysted migrating waterbirds mainly Eiders Desholm & Kahlert 2005 Biology Letters 1:

13 3. Assessing the impacts A. Barrier effects (migration) Nysted migrating waterbirds mainly Eiders Additional average 500 m on a migration route of 1000 km energetically trivial Pre-construction Post-construction Difference Masden et al. (2009) ICES Journal of Marine Science 66:

14 3. What were the impacts? A. Barrier effects Responses highly species specific, but most species avoided wind farms Most showed gradual avoidance at long distance, others more dramatic deflections <1 km from outermost turbines c.75% of bird radar tracks heading for both wind farms at km avoided going through them, at night birds flew at great heights Mean additional flight distance was 500 m, so energetically trivial for 1000 km migrants More of a problem for commuting birds, although effects differed greatly between species (due to foraging ecology, energetics etc.) Bayesian models can use avoidance data to inform upon wind farm design configurations to minimise effects

15 3. What were the impacts? A. Barrier effects (migration) Lincolnshire, England Pink-footed Goose Horisontal and vertical avoidance Plonczkier & Simms (2012). Journal of Applied Ecology, 49,

16 3. What were the impacts? A. Barrier effects (daily movements) Egmond aan Zee: Some gulls attracted Common scoters, Gannet and Brents avoided Krijgsveld et al. Available at red: flying through wind farm green: not through wind farm

17 3. Assessing the impacts A. Barrier effects (daily movements) Masden et al. (2010) Marine Pollution Bulletin 60:

18 3. Assessing the impacts A. Barrier effects (geometry) Masden et al. (2012) J. Roy. Soc Interface online early.

19 3. Assessing the impacts B. Displacement

20 Petersen et al. (2006) available via 3. Assessing the impacts B. Displacement Red-throated Divers have very rarely been seen between the turbines since construction A. Pre-construction B. Post-construction

21 3. Assessing the impacts B. Displacement Kentish Flats, Thames Estuary, England: Diver displacement in the wind farm foot print and out to 500 m around it. Percival (2010). Available at PDF_1970_kB

22 Petersen & Fox (2007) available at 3. Assessing the impacts B. Displacement Common Scoter avoided the vicinity of the wind farms for the first five years post construction, but subsequently occur between turbines at the same densities as outside

23 3. Assessing the impacts B. Displacement Long-tailed duck has a restricted distribution in Danish waters Petersen et al. (2006) available at

24 3. Assessing the impacts B. Displacement but at the Nysted site, Long-tailed duck showed significant reductions in density post construction compared to preconstruction Petersen et al. (2011) available at

25 3. What were the impacts? B. Displacement Most species were too infrequent to detect effects or showed none, but responses highly species specific Red-throated Divers avoided windfarm areas almost completely Common Scoter showed initial avoidance, but no displacement 5 years after construction Long-tailed Ducks consistently exhibited lower densities in the windfarm than outside post construction No bird species increased in waters within the two Danish offshore wind farms This relative loss needs to be assessed in terms of the potential feeding habitat (and hence the proportion of birds) affected relative to areas outside of the wind farm

26 3. What were the impacts? B. Displacement For species considered here, that proportion was small and therefore likely of little biological consequence Additional effects of many more such wind farms may, however, constitute a more significant effect Measurement of such cumulative effects is a high priority when considering the effects of many such developments along an avian flyway in the future Our results are based on 5 years post construction monitoring given the responses of Common Scoter other species may modify their responses in the future

27 3. Assessing the impacts C. Collision 1. Pre-construction modelling 2. Post-construction monitoring (validation) Mark Desholm s PhD (2006) available at

28 3. Assessing the impacts C. Collision 1. Radar to describe migrating bird trajectories (pre- and postconstruction) 2. TADS to monitor collision rate post construction

29 3. Assessing the impacts C. Collision 1. Pre-construction modelling

30 3. Assessing the impacts C. Collision 2. Post-construction monitoring (validation) Mark Desholm s PhD (2006) available at

31 3. What were the impacts? C. Collision 1. Avoidance responses mean that fewer birds risk collision 2. Many bird species showed avoidance responses at distances of up to 5 km (and potentially more) from the turbines, and within a range of 1-2 km, 75% of birds heading for the wind farm avoided passing within it 3. Radar studies confirmed Eiders entering Nysted wind farm: (i) re-orientated to fly down between turbine rows, frequently equidistance between turbines, (ii) flew lower within the park always below rotor height, (iii) took the shortest route out and (iv) at night flew above rotor height, further minimising collision risk

32 3. What were the impacts? C. Collision 1. A stochastic predictive collision model for Common Eiders used parameters derived from radar and infra-red thermal imagery was run with 1,000 iterations to predict with 95% certainty that out of 235,000 passing birds, % would collide with the turbines in a single autumn (41-48 individuals). 2. This predicted TADS monitoring would fail to detect a single water bird collision during 2,400 hours of monitoring, which was the case 3. TADS showed no bird species came anywhere near the increase in annual mortality of 1% caused by wind turbine collisions at Nysted necessary to trigger mitigation mechanisms to reduce the effects of this impact. Mark Desholm s PhD (2006) available at See also Plonczkier & Simms (2012) J. Appl. Ecol. Online early

33 3. What were the impacts? C. Collision impact on breeding terns During the breeding seasons in 2004 and 2005, about 168 and 161 terns respectively collided with the wind turbines. A large majority (about 75%) of the tern fatalities were due to the 4 wind turbines that are situated alongside the breeding area. A significantly higher probability of the birds being hit by the turbines was calculated when the wind made the blades stand perpendicular to the flight route of the terns. In the considered breeding population, the additional mortality caused by the wind turbines differed for each species: 3.0%-4.4% for common tern, 1.8%-6.7% for the little tern and 0.6%-0.7% for the sandwich tern. No disturbance due to the turbines was observed in the breeding or flight behaviour of the terns. Everaert, J. & Steinen, W.M.(2007) Impact of wind turbines on birds in Zeebrugge (Belgiun) Biodivers Conserv (2007) 16: Available at:

34 3. Summing up Effective habitat loss was caused by behavioural displacement, but at Horns Rev/Nysted was highly species specific and not biologically significant Flying birds avoided both wind farms at a variety of levels; those entering between turbines showed clear behavioural changes minimised collision risk Collision risk modelling suggested very low levels of collisions amongst the Common Eiders at Nysted, confirmed by direct observations

35 3. Summing up More emphasis on Strategic Impact Assessment to zone developments to avoid early unnecessary conflicts and minimise impacts at individual project level We need to invest in new modelling approaches to guide wind farm design (with regard to the geometric placing of individual turbines) to avoid barrier effects

36 3. Summing up Whilst confident of the validity of our results and conclusions from these environmental impact studies, we would be extremely cautious of extending findings from two Danish sites to other species and other areas Although avian impacts from these two wind farms were minimal, taken together with other human impacts and the prospect of many more wind farms in the immediate future, we urge that assessments of the cumulative effects of all these developments be urgently undertaken All our reports, results and outputs can be accessed at: DK/UndergrundOgForsyning/VedvarendeEnergi/Vindkraft/Havvindmoe ller/miljoepaavirkninger/sider/forside.aspx

37 Thanks very much for listening!