Statistical power of mobile acoustic monitoring to detect population change in southeastern U.S. bat species, a case study
Bat populations in eastern North America have experienced precipitous declines following the spread of white-nose syndrome (WNS) and other population stressors. It is imperative to understand changes in bat populations as WNS spreads to provide appropriate guidance for species management. We develop...
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| Format: | Article |
| Language: | English |
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Elsevier
2021-06-01
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| Series: | Ecological Indicators |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1470160X21001898 |
| _version_ | 1828975440103997440 |
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| author | Kristine O. Evans Adam D. Smith David Richardson |
| author_facet | Kristine O. Evans Adam D. Smith David Richardson |
| author_sort | Kristine O. Evans |
| collection | DOAJ |
| description | Bat populations in eastern North America have experienced precipitous declines following the spread of white-nose syndrome (WNS) and other population stressors. It is imperative to understand changes in bat populations as WNS spreads to provide appropriate guidance for species management. We developed generalized linear mixed-models of population trend and habitat associations for five indicator bat species on U.S. Fish and Wildlife Service Mobile Acoustic Bat Monitoring program routes across 86 sites in the southeastern United States from 2012 to 2017. We estimated substantial declining annual trends in relative abundance of tricolored bat (Perimyotis subflavus; −15.1% [−20.6 to −9.1% 95% CI]) and little brown bat (Myotis lucifugus; −13.9% [−22.9 to −3.8% 95% CI]). Relative abundance of bat species increased throughout the summer, and associated positively with the amount of woody cover along survey routes in all but P. subflavus. Fewer evening bats (Nycticeius humeralis) and eastern red bats (Lasiurus borealis) were detected along more developed routes. Using these models, we conducted a prospective power analysis to examine sampling effort necessary to detect moderate to catastrophic population changes in bat populations. We estimated that it would require 10–20 years of surveys on 50–100 routes to detect 5% annual declines in all species at 80% power and α = 0.1. Detecting a 2.73% annual decline may require >200 surveys over >20 years; whereas a 1.14% annual decline was nearly impossible to detect via our program. We demonstrate and caution that underpowered monitoring programs may misrepresent the magnitude and/or sign of population trajectories. We recommend project-specific power analysis continue to be emphasized as an important study design component for effective long-term monitoring programs. |
| first_indexed | 2024-12-14T14:21:04Z |
| format | Article |
| id | doaj.art-ae037de9f0b44418a0847c5fcfaf1b2d |
| institution | Directory Open Access Journal |
| issn | 1470-160X |
| language | English |
| last_indexed | 2024-12-14T14:21:04Z |
| publishDate | 2021-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Ecological Indicators |
| spelling | doaj.art-ae037de9f0b44418a0847c5fcfaf1b2d2022-12-21T22:58:05ZengElsevierEcological Indicators1470-160X2021-06-01125107524Statistical power of mobile acoustic monitoring to detect population change in southeastern U.S. bat species, a case studyKristine O. Evans0Adam D. Smith1David Richardson2Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Box 9690, Mississippi State, MS 39762, USA; Corresponding author at: Box 9690, Mississippi State, MS 39762, USA.South Atlantic-Gulf & Mississippi Basin Regions, Inventory and Monitoring Branch, National Wildlife Refuge System, U.S. Fish and Wildlife Service, 135 Phoenix Rd., Athens, GA 30605, USASouth Atlantic-Gulf & Mississippi Basin Regions, Inventory and Monitoring Branch, National Wildlife Refuge System, U.S. Fish and Wildlife Service, 2776 Sunset Dr., Grenada, MS 38901, USABat populations in eastern North America have experienced precipitous declines following the spread of white-nose syndrome (WNS) and other population stressors. It is imperative to understand changes in bat populations as WNS spreads to provide appropriate guidance for species management. We developed generalized linear mixed-models of population trend and habitat associations for five indicator bat species on U.S. Fish and Wildlife Service Mobile Acoustic Bat Monitoring program routes across 86 sites in the southeastern United States from 2012 to 2017. We estimated substantial declining annual trends in relative abundance of tricolored bat (Perimyotis subflavus; −15.1% [−20.6 to −9.1% 95% CI]) and little brown bat (Myotis lucifugus; −13.9% [−22.9 to −3.8% 95% CI]). Relative abundance of bat species increased throughout the summer, and associated positively with the amount of woody cover along survey routes in all but P. subflavus. Fewer evening bats (Nycticeius humeralis) and eastern red bats (Lasiurus borealis) were detected along more developed routes. Using these models, we conducted a prospective power analysis to examine sampling effort necessary to detect moderate to catastrophic population changes in bat populations. We estimated that it would require 10–20 years of surveys on 50–100 routes to detect 5% annual declines in all species at 80% power and α = 0.1. Detecting a 2.73% annual decline may require >200 surveys over >20 years; whereas a 1.14% annual decline was nearly impossible to detect via our program. We demonstrate and caution that underpowered monitoring programs may misrepresent the magnitude and/or sign of population trajectories. We recommend project-specific power analysis continue to be emphasized as an important study design component for effective long-term monitoring programs.http://www.sciencedirect.com/science/article/pii/S1470160X21001898Acoustic monitoringBat monitoringHabitat associationsPopulation trendsStatistical powerWhite-nose syndrome |
| spellingShingle | Kristine O. Evans Adam D. Smith David Richardson Statistical power of mobile acoustic monitoring to detect population change in southeastern U.S. bat species, a case study Ecological Indicators Acoustic monitoring Bat monitoring Habitat associations Population trends Statistical power White-nose syndrome |
| title | Statistical power of mobile acoustic monitoring to detect population change in southeastern U.S. bat species, a case study |
| title_full | Statistical power of mobile acoustic monitoring to detect population change in southeastern U.S. bat species, a case study |
| title_fullStr | Statistical power of mobile acoustic monitoring to detect population change in southeastern U.S. bat species, a case study |
| title_full_unstemmed | Statistical power of mobile acoustic monitoring to detect population change in southeastern U.S. bat species, a case study |
| title_short | Statistical power of mobile acoustic monitoring to detect population change in southeastern U.S. bat species, a case study |
| title_sort | statistical power of mobile acoustic monitoring to detect population change in southeastern u s bat species a case study |
| topic | Acoustic monitoring Bat monitoring Habitat associations Population trends Statistical power White-nose syndrome |
| url | http://www.sciencedirect.com/science/article/pii/S1470160X21001898 |
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