WREN SHORT SCIENCE SUMMARY WORKING TOGETHER TO RESOLVE ENVIRONMENTAL EFFECTS OF WIND ENERGY European and Wind Energy Development

EUROPEAN GROUSE disturbance, increased predation pressure overhunting and climate change. Grouse Grouse (Tetraoninae) inhabit a wide range can be sensitive to human disturbance, of habitats across the northern hemisphere. which leads to increasing conflicts between All grouse are ground nesting, with species conservation and human activities chicks mainly feeding on insects and adults in grouse habitats, particularly in remnant on a wide range of plants. Male grouse populations. In addition to influences by congregate at lekking sites and perform recreation, hunting and forest management, conspicuous displays to entice females wind turbines can affect grouse during the to mate. Six species occur in Europe: Photo by Dennis Schroeder, construction phase because of habitat loss ( tetrix), Capercaillie NREL 50696 or displacement (i.e., functional habitat (Tetrao urogallus), Caucasian grouse loss due to disturbance by vehicular (Lyrurus mlokosiewiczi), Willow ptarmigan traffic or construction noise), and during (Lagopus lagopus), Rock ptarmigan the operational phase through collision (Lagopus muta) and Hazel grouse (Tetrastes fatalities, disturbance due to noise, shadow bonasia). According to the International flickering and human activity. Union for Conservation of Nature (IUCN) Red List of Threatened Species, the populations of all European grouse species INTERACTIONS BETWEEN are declining, with the Caucasian grouse GROUSE AND WIND ENERGY designated as “near threatened”. The other species are listed as “least concern” Effects of wind farms on European grouse due to their large distributionrange and species range from collision mortality to population sizes. However, many species behavioral responses leading to spatial are included in national red lists of displacement, which may impact population threatened species. The main causes for size. Due to their wing loading (ratio of grouse population declines in Europe are body weight to wing area) and aspect related to habitat deterioration, human ratio (ratio of wingspan squared to wing Photo by Istock, by 465055817 Photo . Western area) grouse are considered “poor flyers” and are prone to RISK MANAGEMENT collisions with a wide range of structures such as power Mitigation measures, counterbalancing or preventing lines and fences. Although grouse generally fly below negative effects of wind turbines on grouse have rarely the rotor swept area, at least three European species have been implemented post-construction, and there is little been reported to collide with the towers of wind turbines: evidence of their effectiveness. The primary mitigation Black grouse, Capercaillie and Willow ptarmigan. In one measure is to avoid constructing wind farms in grouse study, Willow ptarmigan collision mortality was assumed habitats. One study indicates that constructing wind to have negative effects on the local population. Local farms more than 850 m away from known Capercaillie spatial avoidance of turbines has been observed in terms habitats may reduce detrimental effects. In an experimental of reduced numbers of lekking males and reduced year- study, painting the lower 10 m of the wind turbine towers round use of habitats surrounding wind farms compared black reduced collisions of Willow ptarmigan by 48%. to habitats farther away. Depending on landscape features, Whether improving local habitat suitability reduces the displacement of lekking grouse may occur within a radius negative effects of wind turbines on grouse habitat use of 500 to 850 m around wind turbines. Noise produced by and population densities remains unclear. To reduce wind turbines, has been suggested to mask the singing of detrimental disturbance effects, construction should be cocks, reducing the distance upon which displaying calls prohibited during the reproductive period. Furthermore, can be heard and inducing measures to reduce use of access roads during the males to adjust their operational phase may also help to reduce disturbance vocalizations. Although pressure on grouse. there are observations of males lekking within wind farms, reduced numbers of RESEARCH PRIORITIES lekking males have been documented within the The type and number of turbines widely vary between surroundings of wind farms studies, possibly explaining differences in results. after the construction in Moreover, the impact of wind energy infrastructure several cases. Black grouse. Photo by iStock, 92283386 is likely species- and site-specific, impeding general predictions of the impact of wind turbines on grouse in each area. To provide widely applicable results, RISK MONITORING future studies should include several study areas, using comparable data collection methods. Furthermore, it is Our understanding of the potential effects of wind important to collect data over multiple years to account energy infrastructure on grouse are based on several for any potential time lag in the response of grouse to studies, comprising different study designs and research wind energy infrastructure and associated disturbances. questions. The studies include six different countries Future studies should apply robust experimental designs, (Austria, Germany, Norway, Scotland, Spain, Sweden) such as before-after-control-impact designs to address: and four grouse species (Black grouse, Capercaillie, 1) the species- and habitat-specific factors enhancing risk Willow ptarmigan, Rock ptarmigan). Most studies were to grouse species, 2) the contributions of wind turbines performed in a single study area, however, data from up effects to population dynamics, 3) whether negative effects to 18 study areas have also been acquired. Differences in of wind turbines can be mitigated (e.g., by improving local study periods range from 1 to 15 years. Studies on collision habitat suitability) and 4) the mechanisms behind collision mortality consisted of both systematic surveys as well as impacts for all grouse species. anecdotal observations. Methods used to assess disturbance included counting of males at lekking sites, searches for Written by: Coppes, J., K. Bollmann, V. Braunisch, W. Fiedler, V. indirect signs of occurrence (i.e., feathers and droppings), Grünschachner-Berger, P. Mollet, U. Nopp-Mayr, K. E. Schroth, line transects with wildlife detection dogs, other census I. Storch, and R. Suchant techniques or telemetry. For more information, visit https://tethys.pnnl.gov/about-wren