Broad-scale geographic and temporal assessment of northern long-eared bat (Myotis septentrionalis) maternity colony-landscape association

Gorman, KM; Deeley, SM; Barr, EL; Freeze, SR; Kalen, Nicholas J.; Muthersbaugh, MS; Ford, W. Mark

doi:10.3354/esr01170

Cited by 11 publications

(6 citation statements)

References 43 publications

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“…Also, local site selection for which habitats are optimal for detecting sensitive species need not be changed; the information (metadata) characterizing the habitat surrounding the detector location can be included in an integrated model as covariates for relative activity and local availability, thereby adjusting for the preferential detector placement within a grid cell. For example, the putative day‐roosting and foraging habitat of M. septentrionalis and M. sodalis in eastern North America is upland and riparian forested conditions (Gorman et al, 2022). The NABat acoustic survey design suggests selecting different habitat features within a grid cell to maximize the potential for detecting the full suite of species.…”

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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Section: Discussionmentioning

confidence: 99%

Statistical assessment on determining local presence of rare bat species

et al. 2022

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“…The bats in our study area switched roosts often, suggesting that this feature may be one of the reasons the colony remained in the snag forest. Additionally, the hydric nature of the snag forest and its proximity to a large forest patch likely provides an optimal foraging habitat for northern long-eared bats [90,95,96].…”

Section: Discussionmentioning

confidence: 99%

Roosting Behavior of Northern Long-Eared Bats (Myotis septentrionalis) in an Urban-Adjacent Forest Fragment

Burrell

Bergeson

2022

Forests

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Throughout the Midwest United States, agricultural and urban development have fragmented natural areas, with a disproportionate effect on forests and wetlands. The resulting habitat loss, compounded with the spread of white-nose syndrome (WNS), has caused precipitous population declines in several forest-obligate bat species. In 2019, we discovered a remnant northern long-eared bat (Myotis septentrionalis Trouessart) maternity colony in a small forest fragment adjacent to a restored wetland in northeastern Indiana, USA. We investigated roost selection in this colony during the summers between 2019 and 2021 by attaching radio transmitters to northern long-eared bats and tracking them to day roosts. We measured tree, plot, and landscape-level characteristics for each roost and for a randomly selected available tree in the same landscape, then compared characteristics using paired t-tests. Over 70 net nights, we captured and tracked 4 individuals (1 juvenile male, 1 post-lactating female, and 2 lactating females) to 12 different roosts. There were, on average, 3.5 times more standing dead trees (snags) in plots around roosts compared to available trees (t = −4.17, p = 0.02). Bats in this maternity colony selected roosts near a stretch of flooded forest (which contained 83% of roosts) dominated by solar-exposed, flood-killed snags. These roosts likely provide warm microclimates that facilitate energy retention, fetal development, and milk production. By describing roosts within this landscape, we provide insight into the resources that enable an endangered bat species to persist in urbanized forest fragments.

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“…In all cases, we placed detectors at least 100 m apart and secured them on poles, elevated ~2 m above the ground. The maximum distance a detector can sample is 30 m (Gorman et al, 2022). Thus, while one bat might be recorded on multiple detectors in an evening, there was no danger of one bat being recorded simultaneously by two recorders.…”

Section: Methodsmentioning

confidence: 99%

Biotic and abiotic factors shaping bat activity in Maryland soybean fields

et al. 2023

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Bats are important pest control agents in agriculture. Yet, the underlying fine‐scale biotic and abiotic mechanisms that drive their foraging behaviors and responses to insect outbreaks are unclear. Herbivore‐induced plant volatiles (HIPVs) can attract both invertebrate and vertebrate natural enemies that use the chemical plant cues to locate insect prey. The ability of HIPVs to attract multiple species raises the question of whether they may also be a biotic factor influencing insectivorous bat activity. Additionally, abiotic factors, such as weather conditions, can affect bat activity in agricultural settings, but little is known about how bats respond to shifting environmental conditions on short timescales in this landscape context. Using a model crop system, soybean (Glycine max), our study asked three questions: (1) Which bat species are active in eastern Maryland soybean fields? (2) Is insectivorous bat activity affected by naturally occurring soybean HIPVs and/or synthetic soybean HIPVs (indole or farnesene)? (3) How is insectivorous bat activity affected by hourly weather conditions in this landscape? In soybean fields in eastern Maryland, we created paired treatment plots: HIPV plots (damaged plants or synthetic HIPV dispensers) and control plots (undamaged plants or empty dispensers). We measured bat activity using ultrasonic recorders, summarizing hourly and nightly activity, and detected 10 total species. The most abundant species were big brown/silver‐haired bats (Eptesicus fuscus/Lasionycteris noctivagans). Bat activity did not significantly differ between control and HIPV plots in any of the three experiments. Thus, our results do not support our expectation that bats in eastern Maryland use soybean HIPVs to locate insect prey. However, bat activity did increase with increasing average hourly temperature and wind speed. This initial study of bats and HIPVs, as well as the fine‐scale examination of weather conditions on bat activity, may serve as a guide for future research on bat–plant interactions that can support the development of new strategies for sustainable pest management.

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Broad-scale geographic and temporal assessment of northern long-eared bat (Myotis septentrionalis) maternity colony-landscape association

Cited by 11 publications

References 43 publications

Statistical assessment on determining local presence of rare bat species

Statistical assessment on determining local presence of rare bat species

Roosting Behavior of Northern Long-Eared Bats (Myotis septentrionalis) in an Urban-Adjacent Forest Fragment

Biotic and abiotic factors shaping bat activity in Maryland soybean fields

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