Relating Bat Passage Rates to Wind Turbine Fatalities

Smallwood, K. Shawn; Bell, Douglas A.

doi:10.3390/d12020084

Cited by 9 publications

(15 citation statements)

References 30 publications

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“…California ground squirrel ( Otospermophilus beecheyi ) is a keystone species of wildlife in the APWRA, supporting coyotes ( Canis latrans ), American badgers ( Taxidea taxus ), golden eagles ( Aquila chrysaetos ), and many other species of mammalian Carnivora and raptors. Bats and small birds migrate through APWRA with a distinct peak in nocturnal flight activity in late September and early October (Smallwood and Bell 2020). Elevations ranged 41–280 m at Buena Vista, 115–477 m at Golden Hills, and 54–402 m at Vasco Winds.…”

Section: Study Areamentioning

confidence: 99%

Dogs Detect Larger Wind Energy Effects on Bats and Birds

Smallwood¹,

Bell²,

Standish³

2020

J Wildl Manag

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As wind turbine‐caused mortality of birds and bats increases with increasing wind energy capacity, accurate fatality estimates are needed to assess effects, identify collision factors, and formulate mitigation. Finding a larger proportion of collision victims reduces the magnitude of adjustment for the proportion not found, thus reducing opportunities for bias. We tested detection dogs in trials of bat and small‐bird carcasses placed randomly in routine fatality monitoring at the Buena Vista and Golden Hills Wind Energy projects, California, USA, 2017. Of trial carcasses placed and confirmed available before next‐day fatality searches, dogs detected 96% of bats and 90% of small birds, whereas humans at a neighboring wind project detected 6% of bats and 30% of small birds. At Golden Hills dogs found 71 bat fatalities in 55 searches compared to 1 bat found by humans in 69 searches within the same search plots over the same season. Dog detection rates of trial carcasses remained unchanged with distance from turbine, and dogs found more fatalities than did humans at greater distances from turbines. Patterns of fatalities found by dogs within search plots indicated 20% of birds and 4–14% of bats remained undetected outside search plots at Buena Vista and Golden Hills. Dogs also increased estimates of carcass persistence by finding detection trial carcasses that the trial administrator had erroneously concluded were removed. Compared to human searches, dog searches resulted in fatality estimates up to 6.4 and 2.7 times higher for bats and small birds, respectively, along with higher relative precision and >90% lower cost per fatality detection. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

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Section: Study Areamentioning

confidence: 99%

Dogs Detect Larger Wind Energy Effects on Bats and Birds

Smallwood¹,

Bell²,

Standish³

2020

J Wildl Manag

Self Cite

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show abstract

“…Where dogs were used at the same turbines concurrently searched by humans, and monitoring methods were otherwise the same, 71 bat fatalities were found [112], where humans found one [113]. At another project previously monitored for three years by humans, fatality finds using dogs resulted in a bat fatality estimate that was 11 times higher than the estimate based on human searchers, despite the search interval and maximum search radius being equal [114]. Dogs can find trace evidence of bats that human searchers would unlikely find, and likewise they can find bats hidden in tall vegetation.…”

Section: Discussionmentioning

confidence: 99%

USA Wind Energy-Caused Bat Fatalities Increase with Shorter Fatality Search Intervals

Smallwood¹

2020

Diversity

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Wind turbine collision fatalities of bats have likely increased with the rapid expansion of installed wind energy capacity in the USA since the last national-level fatality estimates were generated in 2012. An assumed linear increase of fatalities with installed capacity would expand my estimate of bat fatalities across the USA from 0.89 million in 2012 to 1.11 million in 2014 and to 1.72 million in 2019. However, this assumed linear relationship could have been invalidated by shifts in turbine size, tower height, fatality search interval during monitoring, and regional variation in bat fatalities. I tested for effects of these factors in fatality monitoring reports through 2014. I found no significant relationship between bat fatality rates and wind turbine size. Bat fatality rates increased with increasing tower height, but this increase mirrored the increase in fatality rates with shortened fatality search intervals that accompanied the increase in tower heights. Regional weighting of mean project-level bat fatalities increased the national-level estimate 17% to 1.3 (95% CI: 0.15–3.0) million. After I restricted the estimate’s basis to project-level fatality rates that were estimated from fatality search intervals <10 days, my estimate increased by another 71% to 2.22 (95% CI: 1.77–2.72) million bat fatalities in the USA’s lower 48 states in 2014. Project-level fatality estimates based on search intervals <10 days were, on average, eight times higher than estimates based on longer search intervals. Shorter search intervals detected more small-bodied species, which contributed to a larger all-bat fatality estimate.

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“…Knowing how bat fatalities occur and assessing their sources of variation are essential for properly designing mitigation measures. For example, research dealing with bat fatalities at wind energy facilities is growing in recent years and increasing focus has been given on developing effective mitigation and minimization strategies [6][7][8][43][44][45]. However, to our knowledge, ours is the first approach dealing with bat electrocutions, from which we can provide some preliminary recommendations.…”

Section: Mitigation Options and Further Researchmentioning

confidence: 99%

Urban Sprawl, Food Subsidies and Power Lines: An Ecological Trap for Large Frugivorous Bats in Sri Lanka?

et al. 2020

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Electrocution is one of the less known anthropogenic impacts likely affecting the bat population. We surveyed 925 km of overhead distribution power lines that supply energy to spreading urbanized areas in Sri Lanka, recording 300 electrocuted Indian flying foxes (Pteropus giganteus). Electrocutions were recorded up to 58 km from the nearest known colony, and all of them were in urbanized areas and very close ( X ¯ = 4.8 m) to the exotic fruiting trees cultivated in gardens. Predictable anthropogenic food subsidies, in the form of cultivated fruits and flowers, seem to attract flying foxes to urban habitats, which in turn become ecological traps given their high electrocution risk. However, electrocution rates greatly varied among the 352 power lines surveyed (0.00–24.6 indiv./km), being highest in power lines with four wires oriented vertically ( X ¯ = 0.92 indiv./km) and almost zero in power lines with wires oriented horizontally. Therefore, the latter design should be applied to projected new power lines and old vertically oriented lines in electrocution hotspots should be substituted. Given that flying foxes are key seed dispersers and pollinators, their foraging habitat selection change toward urban habitats together with high electrocution risk not only may contribute to their population decline but also put their ecosystem services at risk.

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Relating Bat Passage Rates to Wind Turbine Fatalities

Cited by 9 publications

References 30 publications

Dogs Detect Larger Wind Energy Effects on Bats and Birds

Dogs Detect Larger Wind Energy Effects on Bats and Birds

USA Wind Energy-Caused Bat Fatalities Increase with Shorter Fatality Search Intervals

Urban Sprawl, Food Subsidies and Power Lines: An Ecological Trap for Large Frugivorous Bats in Sri Lanka?

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