Ingemar Ahlén1 & Hans J. Baagøe2 1Department of Ecology, SLU, Box 7002 (Natur icum), SE-750 07 Uppsala, Sweden, email@example.com 2Natura l History Museum of Denmark, Zoological Museum, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark Bats and wind power – investigations required for risk assessment in Denmark and Sweden We experienced an urgent need among authorities and consultancies to get clear guidelines for planning and field investigations at suggested wind parks. Certain minimum conditions must be fulfilled concerning evaluation of the project area, timing of investigations etc. to provide data necessary for a meaningful risk assessment. We prepared “Guidelines for bat investigations prior to wind projects” for distribution to authorities. Recommendations were based on our research on bat ecology and behaviour at wind power installations and our many years of experience of bat occurrence and behaviour in the landscape. To avoid misunderstandings our guidelines are detailed and carefully argumented, but only the headline contents can be given here: Current knowledge justifies an introductory classification of project areas into three categories: 1. high risk sites, 2. uncertain but possible, 3. low risk already documented. Only category 2 needs field investigations, while 1 should be stopped and 3 can go on. This will speed up the planning process and minimize expensive field investigations to the areas in most need of risk assessments. Field investigations require studies on activity and species composition in a project area also including suitable colony habitats and hunting sites within a radius of at least 2 km. Methods include automatic registration, detector listening etc. to ensure data on species presence, number of observations and facts on activity and status. Investigations are obligatory for the following periods: A) At least two separate nights in the breeding season (late June – early August), B) two nights in mid-August to mid-September when bats migrate or disperse. C) If certain “key habitats” are suspected with mass occurrence of insects in spring, two additional nights of investigation are required in late April – May. We warn that it is difficult to predict bat activity at wind turbines before they are built. At certain weather conditions turbines may attract huge masses of insects and bats are able to discover such new food resources even if they occur far out in “non-bat areas”. This also occurs in the breeding season. Investigations and risk assessments should be carried out by independent bat specialists with high competence. All data and conclusions must be presented with open access. Post-construction surveys and stop regulation are suggested for cases with remaining uncertainty about risks.
Book of Abstracts Conference on Wind Power and Environmental Impacts Stockholm 5-7 February: Report 6546 • F Ebruary 2013 Vindval Naturvårdsverket, 2013