Impact of wind farms on birds and bats

Transcription

1 Impact of wind farms on birds and bats Dr. Hermann Hötker Michael-Otto-Institut im NABU BirdLife Partner Germany

2 Methods Disturbance and Displacement Collision mortality Repowering download:

3 Methods Evaluation of 127 studies in ten countries Studies before construction, during operation, and in control site: 8 Studies before construction and during operation: 23 Studies during operation and in control site: 9 Studies just during operation: 87

4 Results: Local decreases in populations of non-breeding birds Number of studies showing Species increases decreases Stat. Sign. Geese Anser spec., Branta spec Wigeon Anas penelope Lapwing Vanellus vanellus Golden Plover Pluvialis apricaria Starling Sturnus vulgaris

5 Results: Displacement of birds from windfarm sites Curlew, non-breeding Number of Studies Distance (m) Geese, non-breeding Number of Studies Distance (m)

6 Results: Displacement of birds from windfarm sites Skylark, breeding season Number of studies Distance (m) Reed Bunting, breeding season Number of studies Distance (m)

7 Results: Repowering, Lapwing Minimum distance to tower (m) Tower height (m)

8 Habituation of birds to windmills Evaluation of 122 cases (species x studies) Minimal distances decrease: habituation Minimal distances increase: no habituation Breeding season (n=84): in 45 % of cases habituation Non breeding season (n=38): in 66 % of cases habituation

9 Wind turbines as barriers to bird movement 168 observations (studies x species) In 104 cases (81 species) wind turbines were barriers. Particularly sensitive: geese, kites, cranes, many small passerines Less sensitive: other raptors, ducks, gulls, terns, crows, Starlings

10 Collision mortality, birds Records of annual collision rates in 34 wind parks. Collision rates show high variance: 0 to more than 30 victims per year and turbine. Mean: 8.1 victims per turbine and year (median 1.7).

11 Collisions of birds Collisions in Germany, most important species (source: Dürr ): White Stork 8 Black-headed Gull 20 Black Stork 1 Herring Gull 15 Mute Swan 8 Common Gull 12 Barnacle Goose 6 Domestic Pigeon 10 Mallard 10 Wood Pigeon 5 White-tailed Eagle 14 Eagle Owl 6 Red Kite 53 Swift 9 Black Kite 6 Skylark 11 Common Buzzard 34 Corn Bunting 10 Kestrel 10 Yellowhammer 6 Golden Plover 10 Starling 11 Raven 9

12 Collisions of birds Worldwide: Raptors (mainly in the USA, vultures in Spain), Gulls Remarkably few victims among species sensitive to disturbance (geese, cranes, waders) Habitat is imortant: Particularly high collision rates at mountain ridges (USA, Spain) and next to wetlands

13 Collisions of bats Records of collision rates in 12 wind parks High variance: 0 up to > 50 victims per year and turbine Highest collision rates in late summer and early autumn Habitat is imortant: Collisions associated with wind farms in forests

14 Methods to minimize effects Choice of location of wind turbines Wind turbines should not be constructed 1. at places with important numbers of resting or migrating birds (in particular geese, swans, ducks and waders, migratory bottlenecks), 2. in SPAs and other reserves designed for potentially sensitive bird species, 3. next to wetlands and bodies of open water, 4. on mountain ridges, 5. next to or in forests. Caution has to be taken at sites with potentially sensitive breeding birds (e.g. storks, raptors, cranes, waders).

15 Research needed on 1. impacts of offshore wind turbines on migrating birds, on seabirds, marine mammals, and other biota, 2. effects of wind turbines on potentially sensitive protected bird species, 3. collision rates of birds and bats in relation to size of wind turbines and habitat, 4. Influence of lightening of wind turbines, 5. population level impacts of wind turbines, 6. influence of wind turbine noise on acoustic communication.