But Forest Service researchers may have a solution …
By Summit Voice
SUMMIT COUNTY —Bats are already under the gun from a variety of environmental pressures, including white-nose syndrome, and the profusion of new wind energy facilities isn’t making matters any better.
Bat fatalities at wind farms have become a frequent occurrence, but Forest Service biologists say they’ve developed an effective way to reduce those deaths by using a combination of wind and weather data and devices that can detect the bats’ echo-location calls.
Bats are critical parts of many ecosystems, pollination domestic and wild plants, and keeping insect populations in check.
“Properly deployed echolocation monitoring can be an effective way to predict bat activity and, presumably, fatalities at wind energy facilities,” said Forest Service ecologist Ted Weller. “These days, pre-construction echolocation monitoring is as common as meteorological monitoring at wind energy facilities, so the basic building blocks for these models are available at most proposed sites.”
The new research is helping scientists get a better handle on poorly understood bat migration patterns and the relationship between fatalities at wind energy facilities and migratory behavior.
Previous research showed that adjusting the operations of turbines can reduce the number of bats killed at wind energy facilities. However, this strategy has not yet been widely implemented.
Existing studies suggest that bat activity depends on time of year and a number of environmental conditions, such as wind direction and speed, air temperature, and moon phase.
This suggests that there may be ways to improve the effectiveness and efficiency of mitigation measures. PSW ecologist Ted Weller and statistician Jim Baldwin developed an interactive tool that allows users to visualize how changes in date and weather conditions affect the probability of bat presence. The tool can be found at: http://www.fs.fed.us/psw/topics/wildlife/bat/batprob.shtml.
“Increasing the wind speed at which turbines begin to spin and produce energy to the grid has proven to be an effective way to reduce bat fatalities. However, bat activity levels depend on more than just wind speed,” says Weller, who led the research. “Our work demonstrates the use of a decision-making tool that could protect bats when fatality risk is highest while maximizing energy production on nights with a low chance of fatalities.”
Using the ecolocation devices, Weller and his research team linked the presence of bats to the weather conditions measured on-site on a given night. Researchers found that echolocation detectors placed at 22 meters and 52 meters above ground were more effective at characterizing migratory bat activity then those located closer to the ground. Moreover, multiple echolocation detectors were required to accurately characterize bat activity at the facility. They then built models to predict the presence of bats based on date and weather variables.
Researchers conducted the study at a wind energy facility in the San Gorgonio Pass Wind Resource Area near Palm Springs, Calif. The study was a collaborative effort between government, industry, and a non-governmental organization to devise effective solutions to 21st century environmental issues. Cooperators included PSW, Iberdrola Renewables, and the Bats and Wind Energy Cooperative, with primary funding provided by the California Energy Commission Public Interest Energy Research program.
Findings from this study appear online in the Journal of Wildlife Management. Read the full article at: http://treesearch.fs.fed.us/pubs/39603.