Bat Fatalities at Wind Farms in North-Eastern Greece

Abstract

Several recent impact studies reveal that in some localities industrial wind farms are associated with high numbers of bat fatalities. In Europe, most published studies have been conducted in the northwest, while bat diversity generally is much higher in the south of the continent. Here we provide evidence from a post-construction monitoring study conducted in north-eastern Greece between August 2009 and July 2010. Overall, 88 turbines from nine wind farms were intensively searched, and 181 dead and two injured bats were found in their proximity. The most frequently killed species were Nyctalus leisleri (n - 56), Pipistrellus pipistrellus/ P. pygmaeus (53), P. nathusii (35), Hypsugo savii (23) and N. noctula (10). Fatality rates were high from June to September. Most killed bats were adult males. Observed differences in the temporal pattern of fatalities among species may be associated with differences in their behaviour and distribution. Sex segregation with males at higher elevation, where the wind farms were located, and/or absence of females from such areas during summer may be the reason behind the higher male mortality rates. Bat fatalities were unequally distributed among wind farms and turbines. Four turbines (5%) accounted for 27% and 13 turbines (15%) for 51% of the fatalities. The most frequently killed species exhibited different spatial patterns of fatality, presumably because some turbines were located closer to roosts and/or commuting corridors. Fatalities were positively correlated with tower height but not with rotor size. To reduce bat fatalities, we recommend an increase in the cut-in speed of turbines responsible for fatalities from sunset to sunrise.