Industrial Wind Turbines are now the #2 Killer of Bats in the U.S. and Recent Research Shows the Negative Impact of Industrial Solar on Bat Populations
Our area is unique for bats. We can all remember days not so long ago when the night sky was full of bats. Now their numbers have dwindled from the effect of white nose syndrome, but also their encounters with wind turbines. Turbines in fact, are now the #2 killer of bats in the U.S.
Michigan’s Department of Environment, Great Lakes, and Energy, the U.S. Fish & Wildlife Services, and U.S. Environmental Protection Agency have consistently stated that locating utility scale wind projects so close to multiple bat hibernacula could have significant implications for maintaining bat populations in those areas.
U.S. Fish and Wildlife Service even stated in April 2021 that “What we have tried to consistently highlight is that locating a utility scale wind project so close to multiple bat hibernacula could have significant implications for maintaining bat populations in those areas.”
There are 82 mines identified to be used as bat hibernacula in the Western UP and scientists believe there are more. In Adams Township the Michigan Mine Inventory has identified 8 mines that contain 53 shafts/openings. Maybe you cannot get inside but bats sure can.
The Michigan Department of Natural Resources stated in a letter to the U.S. Environmental Protection Agency that, “overwintering bat populations are likely underestimated” and there are 48 bat hibernacula within the average little brown bat migratory range ( 62 miles) of the proposed wind development project. Thus, placement of an industrial turbine even several miles from a mine is still quite harmful.
Scientists also estimate that perhaps 99% of the cave bats that hibernate in Michigan, do so in the Western U.P. That makes us a nationally significant location for hosting these wonderful creatures.
These abandoned copper and iron ore mines host 4 different species of winter hibernating cave bats, three which are (or are being considered) as threatened or endangered under the Endangered Species Act. The Keweenaw Ridge also hosts two species of tree bats, that either migrate through the area on their way north or spend their summers in the Keweenaw (before migrating to the southern U.S. for the winter). Imagine those poor tree bats as they encounter industrial wind farm after wind farm as they migrate every year.
Bats pose little risk to human health and provide many benefits. They consume a variety of mosquitoes, benefiting human health by reducing the ability of mosquitoes to spread mosquito-borne diseases, some which are now finding their way into Upper Michigan .In terms of benefits to forest and agriculture business, the economic value of bats to forest and agriculture industries is estimated as greater than $3.7 billion per year.
So why place industrial wind turbines in an area where our local bat population lives and hibernates in the winter (in local mines that are located along the Keweenaw Ridge) and is already decimated by fungal disease known as white-nose syndrome?
Besides the little brown bat, our area hosts northern long-eared bats that are already listed as threatened under the Endangered Species Act and FWS is currently considering a 2016 petition to list tricolored bats as endangered or threatened. Up to 95% of our local bat population has been killed by white nose syndrome, bats reproduce slowly, and industrial wind turbines are now the second largest killer of bats in the U.S. Why add to this calamity?
“The estimated number of bats killed per turbine annually was ….. highest at the coast and on forested hills and ridges”
Our area hosts seven species of bats with the little brown bat (Myotis lucifugus), the most common.[1] It is well known that bats are efficient mosquito eliminators. They can consume 1,000 flying insects in an hour and large part of that diet is mosquitos[2] Mosquitoes can transmit the deadly Eastern Equine Encephalitis (to humans and horses) and West Nile Virus (Eastern Equine Encephalitis).
Bats overwinter in abandoned iron and copper mines of the western UP. Many of these mines are located along the Keweenaw Ridge and directly in the location of the proposed industrial wind turbine project.
In one study of mines in the Western UP (see figure below, from Kurt and Smith, Northeastern Naturalists, 27(4):763-772, 2020), before the discovery of the fungus that causes white nose syndrome, there was over 100,000 bats residing in 50 mines. Then during the first 4–6 years after onset of white nose syndrome, the total number of bats at the 50 local mines declined from 138,068 to 13,988 animals. Ninety percent of the original population were little brown bats, Myotis lucifugus). After the arrival of the fungus, we lost 90% of our little brown bats because of white nose syndrome (Kurt and Smith, Northeastern Naturalists, 27(4):763-772, 2020
The evidence … shows that wind turbines kill bats. Lots of them. And in one study, 92% of those kills were little brown bats http://wellingtontimes.ca/little-brown-bat/
Why should wind turbine infrastructure be placed in an area that is full of old mines that provide bats with a winter hibernation location and may be a migration route? And why further reduce our remaining vulnerable little brown bat population that needs all the help they can get to recover back to pre-white nose syndrome populations? Research shows that wind turbines do kill bats. For example, mortality rates as high of 80% to 90% at wind turbines are reported in locations of migrating hoary, red, and silver-haired bats (one concern of turbines placed on the Garden Peninsula and local counters of spring migrating raptors in the Keweenaw report seeing migrating bats as well). Furthermore. white-nose syndrome and wind turbines have killed the largest number of bats in the world since 2000, according to a new study. https://wildlife.org/mortality-survey-shows-leading-causes-of-bat-deaths/
In addition, A 2021 study reports environmental impact assessments conducted before the installation of turbines are poor predictors of actual fatality rates.[3] This is because some species of bats may be attracted to wind turbines (in one study bat activity was 37% higher at turbines than at control locations) [4] Bat mortality also increases with tower height[5] and in locations near places they hibernate[6] Also, we should not extrapolate bat fatality data collected from turbines located near grasslands. This is because studies show the number of bats killed per turbine is highest at the coast and on forested hills and ridges.[7]
Placement of any technological infrastructure is all about context. That is, some locations are just not appropriate for locating large scale industrial wind turbines.
““Bat collisions with tall man-made structures aren’t all that common; they’re mostly limited to wind farms”
“Bats are being found dead beneath wind turbines all over the world. …….. This fairly new and unanticipated problem has moved to the forefront of conservation and management efforts directed toward this poorly understood group of mammals, particularly due to the concurrent effects of a new bat disease, white-nose syndrome.”
“Bats are long-lived and very slow reproducers,” “Their populations rely on very high adult survival rates. That means their populations recover from big losses very slowly.”
“The flying animals run into spinning blades, or the rapid decrease in air pressure around the turbines can cause bleeding in their lungs.”
Read: Bat Killings by Wind Energy Turbines Continue
Read: Humans are terrible at finding bats and birds killed by wind turbines. Dogs are great at it.
[1] https://upbathouses.com/upbats.html
[2] Wray, A. K., Jusino, M. A., Banik, M. T., Palmer, J. M., Kaarakka, H., White, J. P., ... & Peery, M. Z. (2018). Incidence and taxonomic richness of mosquitoes in the diets of little brown and big brown bats. Journal of Mammalogy, 99(3), 668-674.
[3] Lintott, P. R., Richardson, S. M., Hosken, D. J., Fensome, S. A., & Mathews, F. (2016). Ecological impact assessments fail to reduce risk of bat casualties at wind farms. Current Biology, 26(21), R1135-R1136.
[4] Richardson, S. M., Lintott, P. R., Hosken, D. J., Economou, T., & Mathews, F. (2021). Peaks in bat activity at turbines and the implications for mitigating the impact of wind energy developments on bats. Scientific Reports, 11(1), 1-6.
[5] Barclay, R.M., Baerwald, E.F., Gruver, J.C., 2007. Variation in bat and bird fatalities at wind energy facilities: assessing the effects of rotor size and tower height. Can. J. Zool. 85, 381–387.
[6] Thompson, M., Beston, J. A., Etterson, M., Diffendorfer, J. E., & Loss, S. R. (2017). Factors associated with bat mortality at wind energy facilities in the United States. Biological Conservation, 215, 241-245.
[7] Rydell, J., Bach, L., Dubourg-Savage, M. J., Green, M., Rodrigues, L., & Hedenström, A. (2010). Bat mortality at wind turbines in northwestern Europe. Acta Chiropterologica, 12(2), 261-274.
New Science for Potential Significant Negative Impact of Industrial Solar Facilities on Threatened/Endangered Bat Populations in Michigan’s Western Upper Peninsula
The Western U.P. is critically important destination for migratory tree bats and especially hibernating cave bats that utilize abandoned mines as winter hibernacula. Cave bats hibernating in abandoned mines may travel up to 250 miles away, thus making the Western U.P. critically important in protecting bats in the Upper Great Lakes region.
A recently released peer reviewed scientific journal article (Tinsley et al. article sited below) concluded “ground-mounted solar photovoltaic developments have a significant negative effect on bat activity.”
This new study (and others) point to potential adverse impacts from industrial solar projects in the Keweenaw, such as the proposed 300+ acre Groveland Mine industrial solar installation on threatened/endangered bats that hibernate, roost, forage, and commune within proximity to the proposed development location. This is because of the established risks of bats not tolerating human disturbance (that now include ground-mounted industrial solar photovoltaic developments).
Ground-Mounted Solar Photovoltaic Systems have a Significant Negative Effect on Bat Activity. Only recently have studies been conducted to assess the impact of industrial solar farms on bat activity. A 2023 peer reviewed research study published in a high quality scientific journal used bat echolocation call recordings to conclude “ground-mounted solar photovoltaic developments have a significant negative effect on bat activity” (Tinsley et al., Renewable energies and biodiversity: Impact of ground-mounted solar photovoltaic sites on bat activity. Journal of Applied Ecology, 2023,DOI: 10.1111/1365-2664.1447). In fact, the activity of six of eight species/species groups analyzed was negatively affected by solar photovoltaic panels. The authors report their findings share similarities with a 2023 study from Hungary (Szabadi et al., The use of solar farms by bats in mosaic landscapes: Implications for conservation. Global Ecology and Conservation, 44, e02481, 2023).
Why do Ground-Mounted Solar Photovoltaic Systems Impact Bat Activity? Tinsley et al. (2023) summarize that bats are known to be adversely impacted by anthropogenic noise, development associated with urbanized environments, the presence of smooth surfaces, and habitat fragmentation (i.e.., cutting of trees as proposed at the site). All of these factors are associated with ground-mounted industrial solar photovoltaic sites.
“The alteration of land use, land cover, soils and water resources result in changes to microclimate and hydrological conditions, which have direct and indirect impacts on bats.” Indirect impacts include bat collisions “with solar panels, as bats perceive smooth, horizontal surfaces as water, and will approach such surfaces attempting to drink. Indirect impacts of solar panels on bats may be subtler, with panels potentially increasing reflective temperature at night following a day of hot weather and also altering microclimate by blocking sunlight, rainfall and affecting drainage potentially reducing the availability of invertebrate prey. In addition bats may actively avoid solar photovoltaic sites, as a consequence of habitat loss and fragmentation as industrial solar energy can require large land footprints.”