Bat activity patterns relative to temporal and weather effects in a temperate coastal environment

Gorman, Katherine M.; Barr, Elaine L.; Ries, Lindsay; Nocera, Tomás; Ford, W. Mark

doi:10.1016/j.gecco.2021.e01769

Cited by 22 publications

(20 citation statements)

References 61 publications

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“…This suggests E. nilssonii may also be sensitive to light during the breeding time, although feeding around street lights is not uncommon later in the summer (Rydell 1992). Activity in both taxa begin decreasing by the end of August and continued to decrease until a drop at the end of the season, most likely due to a drop in ambient temperature limiting bat activity (Gorman et al 2021).…”

Section: Discussionmentioning

confidence: 99%

Large‐scale long‐term passive‐acoustic monitoring reveals spatio‐temporal activity patterns of boreal bats

et al. 2023

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The distribution ranges and spatio-temporal patterns in the occurrence and activity of boreal bats are yet largely unknown due to their cryptic lifestyle and lack of suitable and efficient study methods. We approached the issue by establishing a permanent passive-acoustic sampling setup spanning the area of Finland to gain an understanding on how latitude affects bat species composition and activity patterns in northern Europe. The recorded bat calls were semi-automatically identified for three target taxa; Myotis spp., Eptesicus nilssonii or Pipistrellus nathusii and the seasonal activity patterns were modeled for each taxa across the seven sampling years (2015-2021). We found an increase in activity since 2015 for E. nilssonii and Myotis spp. For E. nilssonii and Myotis spp. we found significant latitude -dependent seasonal activity patterns, where seasonal variation in patterns appeared stronger in the north. Over the years, activity of P. nathusii increased during activity peak in June and late season but decreased in mid season. We found the passive-acoustic monitoring network to be an effective and costefficient method for gathering bat activity data to analyze spatio-temporal patterns. Long-term data on the composition and dynamics of bat communities facilitates better estimates of abundances and population trend directions for conservation purposes and predicting the effects of climate change.

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Section: Discussionmentioning

confidence: 99%

Large‐scale long‐term passive‐acoustic monitoring reveals spatio‐temporal activity patterns of boreal bats

et al. 2023

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“…The count detection model was developed with the same underlying assumptions as MLESite , but can be modified and tuned for different applications. For example, variables that characterize differences in recording conditions (e.g., nightly temperature; Gorman et al, 2021) or deployment locations (e.g., near water features, flyway, and interior forest; Ford et al, 2005) can be exploited to adjust inferences appropriately for nightly recording sessions that had no or very few bat calls detected. Depending on the spatiotemporal sampling design underlying an application, additional parameters can be included that model spatial correlation in the probability of occurrence (Equation ) and/or temporal correlation in relative activity (Equation ) using Gaussian processes (Gelfand & Schliep, 2016; Wright et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

Statistical assessment on determining local presence of rare bat species

et al. 2022

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Surveying cryptic, sparsely distributed taxa using autonomous recording units, although cost‐effective, provides imperfect knowledge about species presence. Summertime bat acoustic surveys in North America exemplify the challenges with characterizing sources of uncertainty: observation error, inability to census populations, and natural stochastic variation. Statistical uncertainty, if not considered thoroughly, hampers determining rare species presence accurately and/or estimating rangewide status and trends with suitable precision. Bat acoustic data are processed using an automated workflow in which proprietary or open‐source algorithms assign a species label to each recorded high‐frequency echolocation sequence. A false‐negative occurs, if a species is actually present but not recorded and/or all recordings from the species are of such poor quality that a correct species identity cannot be assigned to any observation. False positives for a focal species are a direct result of the presence and incorrect identification of a recording from another species. We compare four analytical approaches in terms of parameter estimation and their resulting (in)correct decisions regarding species presence or absence using realistic data‐generating scenarios for bat acoustic data within a simulation study. The current standard for deciding species presence or absence uses a multinomial likelihood‐ratio test p value (maximum likelihood estimate [MLE]‐metric) that accounts for known species misidentifications, but not imperfect detection and only returns a binary outcome (evidence of presence or not). We found that the MLE‐metric had estimated median correct decisions less than 60% for presence and greater than 85% for absence. Alternatively, a multispecies count detection model was equivalent to or better than the MLE‐metric for correct claims of rare species presence or absence using the posterior probability a species was present at a site and, importantly, provided unbiased estimates of relative activity and probability of occurrence, creating opportunities for reducing posterior uncertainty through the inclusion of meaningful covariates. Single‐species occupancy models with and without false‐positive detections removed were insufficient for determining local presence because of substantially biased occurrence and detection probabilities. We propose solutions to potential barriers for integrating local, short‐term and rangewide, long‐term acoustic surveys within a cohesive statistical framework that facilitates determining local species presence with uncertainty concurrent with estimating species–environment relationships.

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“…We included a two-way interaction between distance to forest and relative pest abundance, a two-way interaction between distance to forest and phonic group, and a two-way interaction between phonic group and relative pest abundance as main predictor variables. We also included daily minimum temperature (Tmin) and daily precipitation (Precip) as fixed covariates as these environmental factors have been shown to significantly affect bat activity (Gorman et al, 2021). Lastly, we included a quadratic effect of date as a fixed effect, as we expected bat activity to increase as pups become volant, until mid-August, and decline towards late-September, as bats migrate to hibernation sites.…”

Section: Bat Activitymentioning

confidence: 99%

Far from home: bat activity and diversity in row crop agriculture decreases with distance to potential roost habitat

Hunninck

Coleman

Boman

et al. 2022

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As demand for food increases, agricultural production is poised to increase dramatically. Pesticides are commonly used to maintain high crop yield, though they have several drawbacks, including reduced efficacy over time and harmful effects to human and ecosystem health. Bats are highly effective predators of crop pests and have great potential to reduce crop damage resulting from insects. However, few studies have investigated how pest control by bats might change over large expanses of continuous row crop agriculture, which is common in the Midwest. Agricultural landscapes offer few roosting opportunities and could be difficult for bats to traverse, which might affect the degree of ecosystem services provided by bats. We hypothesized that with increasing distance into uninterrupted row crop agriculture 1) bat activity would decrease and 2) bat species richness would decrease, but that these effects would be buffered when insect pest abundance is high. We deployed 50 acoustic bat detectors over 10 transects in east-central Illinois from July to September 2021. In each transect, we placed detectors on crop field edges at increasing distance from a large riparian corridor assumed to be frequented by bats. Bat activity was high across the landscape but declined by 56% from the forest edge to 4000m into row crop agriculture, while bat diversity decreased by 34%. Pest abundance seemed to decrease overall bat activity but had no effect on bat diversity. These results indicate that bats, although able to have a large effect on crop pest reduction, might not be as efficient in suppressing crop pests in vast uninterrupted agricultural landscapes which offer scant roost availability. Our work will inform recommendations to landowners and private lands managers on ways to increase bat access to roosts and forest cover near agricultural areas, thereby enhancing the potential for bats to provide pest control services.

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Bat activity patterns relative to temporal and weather effects in a temperate coastal environment

Cited by 22 publications

References 61 publications

Large‐scale long‐term passive‐acoustic monitoring reveals spatio‐temporal activity patterns of boreal bats

Large‐scale long‐term passive‐acoustic monitoring reveals spatio‐temporal activity patterns of boreal bats

Statistical assessment on determining local presence of rare bat species

Far from home: bat activity and diversity in row crop agriculture decreases with distance to potential roost habitat

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