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Solick DI, Hopp BH, Chenger J, Newman CM. Automated echolocation classifiers vary in accuracy for northeastern U.S. bat species. PLoS One 2024; 19:e0300664. [PMID: 38829847 PMCID: PMC11146688 DOI: 10.1371/journal.pone.0300664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 03/01/2024] [Indexed: 06/05/2024] Open
Abstract
Acoustic surveys of bat echolocation calls are an important management tool for determining presence and probable absence of threatened and endangered bat species. In the northeastern United States, software programs such as Bat Call Identification (BCID), Kaleidoscope Pro (KPro), and Sonobat can automatically classify ultrasonic detector sound files, yet the programs' accuracy in correctly classifying calls to species has not been independently assessed. We used 1,500 full-spectrum reference calls with known identities for nine northeastern United States bat species to test the accuracy of these programs using calculations of Positive Predictive Value (PPV), Negative Predictive Value (NPV), Sensitivity (SN), Specificity (SP), Overall Accuracy, and No Information Rate. We found that BCID performed less accurately than other programs, likely because it only operates on zero-crossing data and may be less accurate for recordings converted from full-spectrum to zero-crossing. NPV and SP values were high across all species categories for SonoBat and KPro, indicating these programs' success at avoiding false positives. However, PPV and SN values were relatively low, particularly for individual Myotis species, indicating these programs are prone to false negatives. SonoBat and KPro performed better when distinguishing Myotis species from non-Myotis species. We expect less accuracy from these programs for acoustic recordings collected under normal working conditions, and caution that a bat acoustic expert should verify automatically classified files when making species-specific regulatory or conservation decisions.
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Affiliation(s)
- Donald I. Solick
- Electric Power Research Institute, Palo Alto, California, United States of America
- Vesper Bat Detection Services, Fort Collins, Colorado, United States of America
| | - Bradley H. Hopp
- Electric Power Research Institute, Palo Alto, California, United States of America
| | - John Chenger
- Bat Conservation and Management, Carlisle, Pennsylvania, United States of America
| | - Christian M. Newman
- Electric Power Research Institute, Palo Alto, California, United States of America
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2
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Voigt CC, Bernard E, Huang JCC, Frick WF, Kerbiriou C, MacEwan K, Mathews F, Rodríguez-Durán A, Scholz C, Webala PW, Welbergen J, Whitby M. Toward solving the global green-green dilemma between wind energy production and bat conservation. Bioscience 2024; 74:240-252. [PMID: 38720909 PMCID: PMC11075649 DOI: 10.1093/biosci/biae023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 01/24/2024] [Accepted: 02/21/2024] [Indexed: 05/12/2024] Open
Abstract
Wind energy production is growing rapidly worldwide in an effort to reduce greenhouse gas emissions. However, wind energy production is not environmentally neutral. Negative impacts on volant animals, such as bats, include fatalities at turbines and habitat loss due to land-use change and displacement. Siting turbines away from ecologically sensitive areas and implementing measures to reduce fatalities are critical to protecting bat populations. Restricting turbine operations during periods of high bat activity is the most effective form of mitigation currently available to reduce fatalities. Compensating for habitat loss and offsetting mortality are not often practiced, because meaningful offsets are lacking. Legal frameworks to prevent or mitigate the negative impacts of wind energy on bats are absent in most countries, especially in emerging markets. Therefore, governments and lending institutions are key in reconciling wind energy production with biodiversity goals by requiring sufficient environmental standards for wind energy projects.
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Affiliation(s)
| | - Enrico Bernard
- Laboratório de Ciência Aplicada a Conservação da Biodiversidade, Universidade Federal de Pernambuco, Recife, Brazil
| | - Joe Chun-Chia Huang
- Department of Life Science at the National Taiwan Normal University, Taipei City, Taiwan
| | | | - Christian Kerbiriou
- Centre d'Ecologie et des Sciences de la Conservation at the Muséum national d'Histoire naturelle and the Centre National de la Recherche Scientifique at Sorbonne Université Station Marine, in Concarneau, France
| | - Kate MacEwan
- Western EcoSystems Technology, in Cheyenne, Wyoming, United States
| | - Fiona Mathews
- School of Life Sciences at the University of Sussex, Falmer, England, United Kingdom
| | | | - Carolin Scholz
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Paul W Webala
- Department of Forestry and Wildlife Management at Maasai Mara University, Narok, Kenya
| | - Justin Welbergen
- The Hawkesbury Institute for the Environment at Western Sydney University, Richmond, Victoria, Australia
| | - Michael Whitby
- Bat Conservation International, Austin, Texas, United States
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3
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Fritts SR, Guest EE, Weaver SP, Hale AM, Morton BP, Hein CD. Experimental trials of species-specific bat flight responses to an ultrasonic deterrent. PeerJ 2024; 12:e16718. [PMID: 38188150 PMCID: PMC10771094 DOI: 10.7717/peerj.16718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 12/04/2023] [Indexed: 01/09/2024] Open
Abstract
Unintended consequences of increasing wind energy production include bat mortalities from wind turbine blade strikes. Ultrasonic deterrents (UDs) have been developed to reduce bat mortalities at wind turbines. Our goal was to experimentally assess the species-specific effectiveness of three emission treatments from the UD developed by NRG Systems. We conducted trials in a flight cage measuring approximately 60 m × 10 m × 4.4 m (length × width × height) from July 2020 to May 2021 in San Marcos, Texas, USA. A single UD was placed at either end of the flight cage, and we randomly selected one for each night of field trials. Trials focused on a red bat species group (Lasiurus borealis and Lasiurus blossevillii; n = 46) and four species: cave myotis (Myotis velifer; n = 57), Brazilian free-tailed bats (Tadarida brasiliensis; n = 73), evening bats (Nycteceius humeralis; n = 53), and tricolored bats (Perimyotis subflavus; n = 17). The trials occurred during three treatment emissions: low (emissions from subarrays at 20, 26, and 32 kHz), high (emissions from subarrays at 38, 44, and 50 kHz), and combined (all six emission frequencies). We placed one wild-captured bat into the flight cage for each trial, which consisted of an acclimation period, a control period with the UD powered off, and the three emission treatments (order randomly selected), each interspersed with a control period. We tracked bat flight using four thermal cameras placed outside the flight cage. We quantified the effectiveness of each treatment by comparing the distances each bat flew from the UD during each treatment vs. the control period using quantile regression. Additionally, we conducted an exploratory analysis of differences between sex and season and sex within season using analysis of variance. Broadly, UDs were effective at altering the bats' flight paths as they flew farther from the UD during treatments than during controls; however, results varied by species, sex, season, and sex within season. For the red bat group, bats flew farther from the UD during all treatments than during the control period at all percentiles (p < 0.001), and treatments were comparable in effectiveness. For cave myotis, all percentile distances were farther from the UD during each of the treatments than during the control, except the 90th percentile distance during high, and low was most effective. For evening bats and Brazilian free-tailed bats, results were inconsistent, but high and low were most effective, respectively. For tricolored bats, combined and low were significant at the 10th-75th percentiles, high was significant at all percentiles, and combined was most effective. Results suggest UDs may be an effective means of reducing bat mortalities due to wind turbine blade strikes. We recommend that continued research on UDs focus on low emission treatments, which have decreased sound attenuation and demonstrated effectiveness across the bat species evaluated in this study.
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Affiliation(s)
| | - Emma Elizabeth Guest
- Department of Biology, Texas State University, San Marcos, Texas, United States
- Bowman, San Marcos, Texas, United States
| | | | - Amanda Marie Hale
- Department of Biology, Texas Christian University, Fort Worth, Texas, United States
- Western EcoSystems Technology, Inc., Cheyenne, Wyoming, United States
| | | | - Cris Daniel Hein
- National Renewable Energy Laboratory, Arvada, Colorado, United States
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4
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Hayes MA, Lindsay SR, Solick DI, Newman CM. Simulating the influences of bat curtailment on power production at wind energy facilities. WILDLIFE SOC B 2022. [DOI: 10.1002/wsb.1399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Mark A. Hayes
- U.S. Fish and Wildlife Service 650 Capital Mall Sacramento CA 95814 USA
| | | | - Donald I. Solick
- Electric Power Research Institute 3420 Hillview Ave. Palo Alto CA 94304 USA
- Vesper Bat Detection Services 1316 Stover St. Fort Collins CO 80524 USA
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5
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Voigt CC, Scherer C, Runkel V. Modeling the power of acoustic monitoring to predict bat fatalities at wind turbines. CONSERVATION SCIENCE AND PRACTICE 2022. [DOI: 10.1111/csp2.12841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Cedric Scherer
- Leibniz Institute for Zoo and Wildlife Research Berlin Germany
| | - Volker Runkel
- Bundesverband für Fledermauskunde Deutschland e.V Erfurt Germany
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6
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Starbuck CA, Dickson BG, Chambers CL. Informing wind energy development: Land cover and topography predict occupancy for Arizona bats. PLoS One 2022; 17:e0268573. [PMID: 35657796 PMCID: PMC9165840 DOI: 10.1371/journal.pone.0268573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 05/02/2022] [Indexed: 11/19/2022] Open
Abstract
Wind energy is a growing source of renewable energy with a 3-fold increase in use globally over the last decade. However, wind turbines cause bat mortality, especially for migratory species. The southwest United States has high bat species diversity and is an important area for migratory species, although little is known about their seasonal distribution. To examine potential risk to bats in areas proposed for wind energy development, we characterized bat occupancy spatially and temporally across northern Arizona, identifying use during summer when bats are reproductively active and fall during the migratory season. Our objectives were to determine occupancy of migratory species and species of greatest conservation need and develop a probability of occupancy map for species to identify areas of potential conflict with wind energy development. We selected 92 sites in 10 clusters with potential for development and used acoustic detectors to sample bats in the summer and fall of 2016 and 2017 for 6 nights per site per year. We predicted response of migratory bat species and species of special concern to 9 landscape variables using Program MARK. During summer, higher densities of forest on the landscape resulted in a higher probability of occupancy of migratory species such as hoary bats (Lasiurus cinereus), silver-haired bats (Lasionycteris noctivagans), big free-tailed bats (Nyctinomops macrotis), and species of conservation need such as spotted bats (Euderma maculatum). During the fall, higher concentration of valleys on the landscape predicted occupancy of hoary bats, big free-tailed bats, and spotted bats. High bat occupancy in the fall was also associated with higher elevation and close proximity to forests. We recommend that wind turbines be placed in open, flat grasslands away from forested landscapes and concentrations of valleys or other topographic variation.
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Affiliation(s)
- Clarissa A. Starbuck
- School of Forestry, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Brett G. Dickson
- Lab of Landscape Ecology and Conservation Biology, Landscape Conservation Initiative, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Carol L. Chambers
- School of Forestry, Northern Arizona University, Flagstaff, Arizona, United States of America
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7
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An Updated Review of Hypotheses Regarding Bat Attraction to Wind Turbines. Animals (Basel) 2022; 12:ani12030343. [PMID: 35158666 PMCID: PMC8833423 DOI: 10.3390/ani12030343] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/21/2022] [Accepted: 01/27/2022] [Indexed: 02/06/2023] Open
Abstract
Patterns of bat activity and mortalities at wind energy facilities suggest that bats are attracted to wind turbines based on bat behavioral responses to wind turbines. For example, current monitoring efforts suggest that bat activity increases post-wind turbine construction, with bats making multiple passes near wind turbines. We separated the attraction hypothesis into five previously proposed explanations of bat interactions at or near wind turbines, including attraction based on noise, roost sites, foraging and water, mating behavior, and lights, and one new hypothesis regarding olfaction, and provide a state of the knowledge in 2022. Our review indicates that future research should prioritize attraction based on social behaviors, such as mating and scent-marking, as this aspect of the attraction hypothesis has many postulates and remains the most unclear. Relatively more data regarding attraction to wind turbines based on lighting and noise emission exist, and these data indicate that these are unlikely attractants. Analyzing attraction at the species-level should be prioritized because of differences in foraging, flight, and social behavior among bat species. Lastly, research assessing bat attraction at various scales, such as the turbine or facility scale, is lacking, which could provide important insights for both wind turbine siting decisions and bat mortality minimization strategies. Identifying the causes of bat interactions with wind turbines is critical for developing effective impact minimization strategies.
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8
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Hale AM, Hein CD, Straw BR. Acoustic and Genetic Data Can Reduce Uncertainty Regarding Populations of Migratory Tree-Roosting Bats Impacted by Wind Energy. Animals (Basel) 2021; 12:81. [PMID: 35011186 PMCID: PMC8749617 DOI: 10.3390/ani12010081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/04/2021] [Accepted: 11/08/2021] [Indexed: 11/17/2022] Open
Abstract
Wind turbine-related mortality may pose a population-level threat for migratory tree-roosting bats, such as the hoary bat (Lasiurus cinereus) in North America. These species are dispersed within their range, making it impractical to estimate census populations size using traditional survey methods. Nonetheless, understanding population size and trends is essential for evaluating and mitigating risk from wind turbine mortality. Using various sampling techniques, including systematic acoustic sampling and genetic analyses, we argue that building a weight of evidence regarding bat population status and trends is possible to (1) assess the sustainability of mortality associated with wind turbines; (2) determine the level of mitigation required; and (3) evaluate the effectiveness of mitigation measures to ensure population viability for these species. Long-term, systematic data collection remains the most viable option for reducing uncertainty regarding population trends for migratory tree-roosting bats. We recommend collecting acoustic data using the statistically robust North American Bat Monitoring Program (NABat) protocols and that genetic diversity is monitored at repeated time intervals to show species trends. There are no short-term actions to resolve these population-level questions; however, we discuss opportunities for relatively short-term investments that will lead to long-term success in reducing uncertainty.
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Affiliation(s)
- Amanda M. Hale
- Department of Biology, Texas Christian University, Fort Worth, TX 76129, USA
| | - Cris D. Hein
- National Renewable Energy Laboratory, Arvada, CO 80007, USA;
| | - Bethany R. Straw
- Fort Collins Science Center, U. S. Geological Survey, Fort Collins, CO 80526, USA;
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9
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Cryan PM, Gorresen PM, Straw BR, Thao S(S, DeGeorge E. Influencing Activity of Bats by Dimly Lighting Wind Turbine Surfaces with Ultraviolet Light. Animals (Basel) 2021; 12:ani12010009. [PMID: 35011115 PMCID: PMC8744972 DOI: 10.3390/ani12010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/03/2021] [Accepted: 12/05/2021] [Indexed: 11/18/2022] Open
Abstract
Simple Summary Bats often fly near wind turbines. The fatalities associated with this behavior continue to be an issue for wind energy development and wildlife conservation. We tested an experimental method intended to reduce bat fatalities at the wind turbines. We assumed that bats navigate over long distances at night by dim-light vision and might be dissuaded from approaching artificially lit structures. For over a year, we experimentally lit wind turbines at night with dim, flickering ultraviolet (UV) light while measuring the presence and activity of bats, birds, and insects with thermal-imaging cameras. We detected no statistical differences in the activity of the bats, insects, or birds at a test turbine when lit with UV light compared with that of unlit nights. Additional experiments to test this or other possible bat-deterrence methods may benefit from considering subtle measures of animal response that can provide useful information on the possible behavioral effects of fatality-reduction experiments. Abstract Wind energy producers need deployable devices for wind turbines that prevent bat fatalities. Based on the speculation that bats approach turbines after visually mistaking them for trees, we tested a potential light-based deterrence method. It is likely that the affected bats see ultraviolet (UV) light at low intensities. Here, we present the results of a multi-month experiment to cast dim, flickering UV light across wind turbine surfaces at night. Our objectives were to refine and test a practical system for dimly UV-illuminating turbines while testing whether the experimental UV treatment influenced the activity of bats, birds, and insects. We mounted upward-facing UV light arrays on turbines and used thermal-imaging cameras to quantify the presence and activity of night-flying animals. The results demonstrated that the turbines can be lit to the highest reaches of the blades with “invisible” UV light, and the animal responses to such experimental treatment can be concurrently monitored. The UV treatment did not significantly change nighttime bat, insect, or bird activity at the wind turbine. Our findings show how observing flying animals with thermal cameras at night can help test emerging technologies intended to variably affect their behaviors around wind turbines.
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Affiliation(s)
- Paul M. Cryan
- U.S. Geological Survey (USGS), Fort Collins Science Center, Fort Collins, CO 80526, USA;
- Correspondence:
| | - Paulo M. Gorresen
- Hawaii Cooperative Studies Unit, University of Hawaii at Hilo, Hilo, HI 96720, USA;
- USGS Pacific Island Ecosystems Science Center, Hawaii Volcanoes National Park, Hilo, HI 96718, USA
| | - Bethany R. Straw
- U.S. Geological Survey (USGS), Fort Collins Science Center, Fort Collins, CO 80526, USA;
| | - Syhoune (Simon) Thao
- U.S. Department of Energy, National Renewable Energy Laboratory, National Wind Technology Center, Boulder, CO 80007, USA; (S.T.); (E.D.)
| | - Elise DeGeorge
- U.S. Department of Energy, National Renewable Energy Laboratory, National Wind Technology Center, Boulder, CO 80007, USA; (S.T.); (E.D.)
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10
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Peterson TS, Mcgill B, Hein CD, Rusk A. Acoustic Exposure to Turbine Operation Quantifies Risk to Bats at Commercial Wind Energy Facilities. WILDLIFE SOC B 2021. [DOI: 10.1002/wsb.1236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Brian Mcgill
- School of Biology and Ecology, 5751 Murray Hall, University of Maine Orono ME 04469 USA
| | - Cris D. Hein
- National Renewable Energy Laboratory Golden CO 80401 USA
| | - Adam Rusk
- Stantec Consulting Services Inc., 6800 College Boulevard Overland Park KS 66211 USA
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11
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de Jong J, Millon L, Håstad O, Victorsson J. Activity Pattern and Correlation between Bat and Insect Abundance at Wind Turbines in South Sweden. Animals (Basel) 2021; 11:ani11113269. [PMID: 34828001 PMCID: PMC8614415 DOI: 10.3390/ani11113269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/08/2021] [Accepted: 11/12/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Wind power is an important energy system in the global transition towards renewable energy. As new wind farms are erected in increasing numbers, they will have an impact on many organisms, e.g., through habitat changes and collision mortalities. In this study, we measure bat activity, insect abundance, and weather conditions to test the hypothesis that insect abundance attracts bats to wind turbines because of feeding opportunities. We found that the relationship between insect abundance and bat activity was relatively weak, providing some support for the feeding-attraction hypothesis. However, we also found a strong correlation between bat passes and weather conditions. This suggests that stop-regulation based on weather conditions might be a solution to avoid collisions. However, this study highlights some of the problems with defining the limits for stop-regulation, as bat activity may be high also at relatively high wind speeds and low temperatures. Abstract We present data on species composition and activity of bats during two years at three different wind- turbines, located in south Sweden, both at the base and nacelle height. To test the hypothesis that bats are attracted to wind turbines because of feeding opportunities, insects were sampled at nacelle height at one wind turbine using a suction trap, simultaneously as bat activity were measured. At this wind turbine, we also compared two different technical systems for ultrasound recordings and collect meteorological data. The variation in bat activity was high between nights and between wind turbines. In addition to the expected open-air foraging species (Pipistrellus, Nyctalus, Vespertilio and Eptesicus), some individuals of unexpected species (Myotis, Barbastella, and Plecotus) were found at nacelle height. There was a weak but significant positive relation between bat activity and insect abundance, so the hypothesis could not be rejected, suggesting there might be other factors than insect abundance explaining the frequency of bat visits at the nacelle. We found a strong correlation between bat passes and weather conditions. A reasonable way to mitigate collisions is with stop-regulation. However, this study highlights some of the problems with defining the limits for stop-regulation based on weather conditions.
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Affiliation(s)
- Johnny de Jong
- Swedish Biodiversity Centre (CBM), Department of Urban and Rural Development, Swedish University of Agricultural Sciences, Box 7012, 75007 Uppsala, Sweden
- Correspondence: ; Tel.: +46-70-2271914
| | - Lara Millon
- Calluna AB, Linköpings Slott, 582 28 Linköping, Sweden;
| | - Olle Håstad
- Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Box 7084, 750 07 Uppsala, Sweden;
| | - Jonas Victorsson
- Kalmar County Administration, Regeringsgatan 1, 39231 Kalmar, Sweden;
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12
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Monitoring and Modeling Tree Bat (Genera: Lasiurus, Lasionycteris) Occurrence Using Acoustics on Structures off the Mid-Atlantic Coast-Implications for Offshore Wind Development. Animals (Basel) 2021; 11:ani11113146. [PMID: 34827878 PMCID: PMC8614452 DOI: 10.3390/ani11113146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/28/2021] [Accepted: 10/30/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary “Tree bats” are North American bats that day-roost in trees year-round and undertake seasonal migration in lieu of hibernation. These bats have been shown to be highly susceptible to collisions with wind energy turbines and are known to fly offshore during migration. Therefore, as offshore wind energy expands off the eastern U.S. coast, there is some concern about potential impacts. We monitored bats in coastal Virginia, USA, using acoustic monitors—devices that collect the unique echolocation call signatures of bat species. We found that nightly tree bat visitation offshore or on barrier islands was associated with wind speed, temperature, visibility, and seasonality. Using statistical modeling, we developed a predictive tool to assess occurrence probabilities at varying levels of wind speed, temperature, and seasonality. Probability of occurrence and therefore assumed risk to collision is highest on high temperature and visibility nights, low wind speed nights, and during the spring and fall seasons. We suggest a similar modeling regime could be used to predict the occurrence of bats at offshore wind sites to inform potential mitigation efforts. Abstract In eastern North America, “tree bats” (Genera: Lasiurus and Lasionycteris) are highly susceptible to collisions with wind energy turbines and are known to fly offshore during migration. This raises concern about ongoing expansion of offshore wind-energy development off the Atlantic Coast. Season, atmospheric conditions, and site-level characteristics such as local habitat (e.g., forest coverage) have been shown to influence wind turbine collision rates by bats onshore, and therefore may be related to risk offshore. Therefore, to assess the factors affecting coastal presence of bats, we continuously gathered tree bat occurrence data using stationary acoustic recorders on five structures (four lighthouses on barrier islands and one light tower offshore) off the coast of Virginia, USA, across all seasons, 2012–2019. We used generalized additive models to describe tree bat occurrence on a nightly basis. We found that sites either indicated maternity or migratory seasonal occurrence patterns associated with local roosting resources, i.e., presence of trees. Across all sites, nightly occurrence was negatively related to wind speed and positively related to temperature and visibility. Using predictive performance metrics, we concluded that our model was highly predictive for the Virginia coast. Our findings were consistent with other studies—tree bat occurrence probability and presumed mortality risk to offshore wind-energy collisions is highest on low wind speed nights, high temperature and visibility nights, and during spring and fall. The high predictive model performance we observed provides a basis for which managers, using a similar monitoring and modeling regime, could develop an effective curtailment-based mitigation strategy.
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13
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Solick DI, Newman CM. Oceanic records of North American bats and implications for offshore wind energy development in the United States. Ecol Evol 2021; 11:14433-14447. [PMID: 34765117 PMCID: PMC8571582 DOI: 10.1002/ece3.8175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/31/2021] [Accepted: 09/10/2021] [Indexed: 11/29/2022] Open
Abstract
Offshore wind energy is a growing industry in the United States, and renewable energy from offshore wind is estimated to double the country's total electricity generation. There is growing concern that land-based wind development in North America is negatively impacting bat populations, primarily long-distance migrating bats, but the impacts to bats from offshore wind energy are unknown. Bats are associated with the terrestrial environment, but have been observed over the ocean. In this review, we synthesize historic and contemporary accounts of bats observed and acoustically recorded in the North American marine environment to ascertain the spatial and temporal distribution of bats flying offshore. We incorporate studies of offshore bats in Europe and of bat behavior at land-based wind energy studies to examine how offshore wind development could impact North American bat populations. We find that most offshore bat records are of long-distance migrating bats and records occur during autumn migration, the period of highest fatality rates for long-distance migrating bats at land-based wind facilities in North America. We summarize evidence that bats may be attracted to offshore turbines, potentially increasing their exposure to risk of collision. However, higher wind speeds offshore can potentially reduce the amount of time that bats are exposed to risk. We identify knowledge gaps and hypothesize that a combination of operational minimization strategies may be the most effective approach for reducing impacts to bats and maximizing offshore energy production.
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14
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Voigt CC, Russo D, Runkel V, Goerlitz HR. Limitations of acoustic monitoring at wind turbines to evaluate fatality risk of bats. Mamm Rev 2021. [DOI: 10.1111/mam.12248] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Christian C. Voigt
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Alfred‐Kowalke‐Str. 1710315Berlin Germany
| | - Danilo Russo
- Wildlife Research Unit Dipartimento di Agraria Universita degli Studi di Napoli Federico II Portici Italy
- School of Biological Sciences University of Bristol Bristol Life Sciences Building, 24 Tyndall Avenue BristolBS8 1TQUK
| | - Volker Runkel
- Bundesverband für Fledermauskunde Deutschland e.V. Schmidtstedter Str. 30a99084Erfurt Germany
| | - Holger R. Goerlitz
- Acoustic and Functional Ecology Max Planck Institute for Ornithology Eberhard‐Gwinner‐Strasse 82319Seewiesen Germany
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