1. Bats and wind energy Can bat activity patterns make them vulnerable to wind turbine impacts Tiffany Thwaits NMMU Prof. G. Kerley Dr. N. Mzilikazi Energy Postgraduate Conference 2013

2. WIND ENERGY Renewable Clean Environmentally friendly 88 applications for SA 4031 BUT HAS NEGATIVE IMPACTS ON WILDLIFE

3. Migratory & tree roosting species at greater risk Wind farm/facilityTotal fatalitiesReference Mountaineer Wind Energy Centre (West Virginia, USA) 2092 (over 2 yrs) Kerns & Kerlinger (2004) Casselman Wind Project (South- central Pennsylvania, USA) 784/yr Arnette et al. (2009) Coega test turbine (Eastern Cape, SA)17 (1 yr) Doty & Martin (2012) Wind turbine associated mortality greater than Natural mortality Slow to recover from adverse effects Long lived Slow reproductive rate Slow population growth SO WHAT?

5. HEIGHT TIMEWEATHER BAT ACTIVITY MONITORING BATS BAT PASS STUDY SITE MITIGATION & MANAGEMENT

6. Different bat groups are active at different seasons and occupy different aerial habitats

7. BIMODAL PEAK activity highest 1-2hrs after sunset 1-2hrs before sunrise SINGLE PEAK activity highest 1-2hrs after sunset reduced activity in winter months

8. WEATHER & BAT ACTIVITY Variables in global model ▪ Month ▪ Overnight average temperature ▪ Overnight average wind speed ▪ Temperature:Wind speed ▪ Month:Temperature ▪ Month:Wind ▪ Month:Temperature:Wind Predictor variable χ2χ2 d.f.P Month*121.524<0.001 Overnight average temperature* 51.551<0.001 Overnight average wind speed 5.9610.016 Final model = weak  High degree of variation in data Model may be dependent on other variables not quantified here

9. Lang et al. 2006 Milne et al. 2005 Another factors involved Temperature Wind Speed Barometric Pressure Humidity Precipitation Season Time of night Insect abundance Moon Phase Cloud cover MODEL

10. Mitigation & Management Bat activity & Monitoring Mitigation Management 2hrs after sunset High flying bats  at great risk (55m) Autumn = peak season Increase cut in speed of blades Curtailment Blades spin fast so that they are more “visible” to bats Switch off turbines during peak seasons or when wind conditions unfavourable Post construction monitoring (fatalities) Feasibility of mitigation methods Evaluations of next turbine locations