Modelling the Impact of Wind Energy on Hoary Bat Populations
Erin Baerwald
AWWI
Erin Baerwald is a Postdoctoral Research Fellow at the American Wind Wildlife Institute. She received a BSc in conservation biology from the University of Alberta, Canada, a MSc in conservation biology from the University of Calgary, Canada, and a PhD in Ecology from the University of Calgary. Dr. Baerwald’s research interests are the conservation and ecology of migratory animals, particularly bats. Her research since 2005 has primarily been focused on the interactions of bats and wind turbines and she has published extensively on the issue. Dr. Baerwald is a member of the North American Society of Bat Research, the American Society of Mammalogists, the Canadian Society for Ecology and Evolution, the Society for Conservation Biology, and the Wildlife Society. She is also a member of the International Union for Conservation of Nature (IUCN)’s bat specialist group and a migratory-bat expert for the United Nation’s Convention of Migratory Species.
Abstract
As concerns over rising costs and environmental impacts of fossil fuels grow, wind energy is increasingly popular. However, large numbers of bats are killed at some wind energy facilities, which raises concerns about... [ view full abstract ]
As concerns over rising costs and environmental impacts of fossil fuels grow, wind energy is increasingly popular. However, large numbers of bats are killed at some wind energy facilities, which raises concerns about cumulative impacts on bat populations. An estimated 0.84 and 1.7 million bats have been killed in the U.S. and Canada from 2000-2011, and this increases by over 500,000 individuals annually, 38% of which are hoary bats (Lasiurus cinereus). Given these estimates, our objective was to determine whether fatalities threaten the North American populations of hoary bats. We investigated this by using repeated measures analyses to examine how fatality rates change through time at 53 North American wind facilities with two-years of post-construction monitoring. If fatalities consistently decline, then this may indicate declines in population sizes. However, population estimates are lacking for bats, especially for migratory tree-roosting species like hoary bats, so we then used parameters derived from expert elicitation to model population trends of hoary bats. Both of our analyses suggest that fatalities at wind energy facilities may be negatively affecting hoary bat populations. Fatality rates declined over time at 63.5% of wind energy sites examined and the mean fatality rate was significantly lower overall in the second year of studies. Population modelling suggests that current fatality levels could cause a 91% decrease in the continental population of hoary bats within 50 years. Only in the unlikely scenario of an initial population greater than 4 million and baseline growth of at least 3% per year (λ = 1.03) did mortality from wind turbines have no impact on hoary bat populations. Our analyses highlight the need for effective policy and mitigation strategies that embrace adaptive and flexible management and address cumulative impacts.
Authors
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Erin Baerwald
(AWWI)
Topic Areas
Assessing direct and indirect effects on wildlife and their habitats , Bats , Canada , U.S. - No Specific Region , Impact assessment , Land-based
Session
09 » Examining Species' Responses and Vulnerability to Wind Energy (14:00 - Thursday, 1st December, Interlocken Ballroom)
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