Estimating Sample Size for Landscape-Scale Mark-Recapture Studies of North American Migratory Tree Bats

Schorr, Robert A.; Ellison, Laura E.; Lukacs, Paul M.

doi:10.3161/150811014x683426

Cited by 20 publications

(13 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ecological research often requires wild‐living individuals to be marked and then recaptured, tracked, or re‐sighted over time. Applying these techniques can be challenging due to low recapture rates, technological constraints, welfare considerations, and the need to minimize disturbance to threatened populations (Cooke et al, ; Schorr, Ellison, & Lukacs, ). A wide range of marking and tagging techniques are available to monitor wildlife, including mutilation (e.g., toe clipping or ear notching), banding, radio‐transmitters, acoustic tags, and bio‐loggers (Bino, Kingsford, Grant, Taylor, & Vogelnest, ; Murray & Fuller, ; O'Mara, Wikelski, & Dechmann, ; Perry, Wallace, Perry, Curzer, & Muhlberger, ; Walker, Trites, Haulena, & Weary, ; Wilmers et al, ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High detectability with low impact: Optimizing large PIT tracking systems for cave‐dwelling bats

Harten

Reardon

Lumsden

et al. 2019

Ecology and Evolution

View full text Add to dashboard Cite

Passive integrated transponder (PIT) tag technology permits the “resighting” of animals tagged for ecological research without the need for physical re‐trapping. Whilst this is effective if animals pass within centimeters of tag readers, short‐distance detection capabilities have prevented the use of this technology with many species. To address this problem, we optimized a large (15 m long) flexible antenna system to provide a c. 8 m2 vertical detection plane for detecting animals in flight. We installed antennas at two roosting caves, including the primary maternity cave, of the critically endangered southern bent‐winged bat (Miniopterus orianae bassanii) in south‐eastern Australia. Testing of these systems indicated PIT‐tags could be detected up to 105 cm either side of the antenna plane. Over the course of a three‐year study, we subcutaneously PIT‐tagged 2,966 bats and logged over 1.4 million unique detections, with 97% of tagged bats detected at least once. The probability of encountering a tagged bat decreased with increasing environmental “noise” (unwanted signal) perceived by the system. During the study, we mitigated initial high noise levels by earthing both systems, which contributed to an increase in daily detection probability (based on the proportion of individuals known to be alive that were detected each day) from <0.2 (noise level ≥30%) to 0.7–0.8 (noise level 5%–15%). Conditional on a low (5%) noise level, model‐based estimates of daily encounter probability were highest (>0.8) during peak breeding season when both female and male southern bent‐winged bats congregate at the maternity cave. In this paper, we detail the methods employed and make methodological recommendations for future wildlife research using large antennas, including earthing systems as standard protocol and quantifying noise metrics as a covariate influencing the probability of detection in subsequent analyses. Our results demonstrate that large PIT antennas can be used successfully to detect small volant species, extending the scope of PIT technology and enabling a much broader range of wildlife species to be studied using this approach.

show abstract

Section: Introductionmentioning

confidence: 99%

“…Exemplifying these challenges is the study of bats, of which a large proportion are small insectivorous species, that are cryptic, highly mobile, and difficult to recapture (Schorr et al, ). These ecological and behavioral traits pose practical challenges and ethical considerations for marking and tracking individuals.…”

Section: Introductionmentioning

confidence: 99%

High detectability with low impact: Optimizing large PIT tracking systems for cave‐dwelling bats

Harten

Reardon

Lumsden

et al. 2019

Ecology and Evolution

View full text Add to dashboard Cite

show abstract

“…For example, using closed-population mark-recapture methods, Nichols et al (1984) marked approximately 80% of a population of voles to estimate abundance, while in our simulations we marked 2-12% of the population. Using a joint live recapture and dead recovery model, Schorr et al (2014) found that detecting a decline in survival would require marking 50,000 migratory bats per year. Another practical advantage to the CR estimator is that an abundance estimate can be generated for a single population, which could be useful for a species with few populations or if a treatment is not replicated (e.g., an oil spill affecting one population).…”

Section: Discussionmentioning

confidence: 99%

“…However, marking a large fraction of an Indiana bat colony is difficult, requires special permission from the U.S. Fish and Wildlife Service, and trap-shyness would likely limit recaptures (Robbins et al 2008, Schorr et al 2014. Therefore, we judged that mark-recapture methods were not feasible for estimating the size of an Indiana bat colony.…”

Section: Example: Indiana Bat Datamentioning

confidence: 99%

A method for estimating abundance of mobile populations using telemetry and counts of unmarked animals

2015

View full text Add to dashboard Cite

While numerous methods exist for estimating abundance when detection is imperfect, these methods may not be appropriate due to logistical difficulties or unrealistic assumptions. In particular, if highly mobile taxa are frequently absent from survey locations, methods that estimate a probability of detection conditional on presence will generate biased abundance estimates. Here, we propose a new estimator for estimating abundance of mobile populations using telemetry and counts of unmarked animals. The estimator assumes that the target population conforms to a fission‐fusion grouping pattern, in which the population is divided into groups that frequently change in size and composition. If assumptions are met, it is not necessary to locate all groups in the population to estimate abundance. We derive an estimator, perform a simulation study, conduct a power analysis, and apply the method to field data. The simulation study confirmed that our estimator is asymptotically unbiased with low bias, narrow confidence intervals, and good coverage, given a modest survey effort. The power analysis provided initial guidance on survey effort. When applied to small data sets obtained by radio‐tracking Indiana bats, abundance estimates were reasonable, although imprecise. The proposed method has the potential to improve abundance estimates for mobile species that have a fission‐fusion social structure, such as Indiana bats, because it does not condition detection on presence at survey locations and because it avoids certain restrictive assumptions.

show abstract

“…However, a number of studies have shown that this assumption may be invalid [ 6 ]. For example, sample size and sample duration have been shown to influence estimates of growth rate [ 13 ], survival probability [ 14 ], population density [ 5 ], annual decline in population [ 15 ], meta-population estimates of interchange among populations [ 16 ], as well as the precision of estimated parameters [ 12 ] in both matrix and CMR modelling.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Mark-Recapture Sampling Effort on Estimates of Rock Lobster Survival

et al. 2016

View full text Add to dashboard Cite

Five annual capture-mark-recapture surveys on Jasus edwardsii were used to evaluate the effect of sample size and fishing effort on the precision of estimated survival probability. Datasets of different numbers of individual lobsters (ranging from 200 to 1,000 lobsters) were created by random subsampling from each annual survey. This process of random subsampling was also used to create 12 datasets of different levels of effort based on three levels of the number of traps (15, 30 and 50 traps per day) and four levels of the number of sampling-days (2, 4, 6 and 7 days). The most parsimonious Cormack-Jolly-Seber (CJS) model for estimating survival probability shifted from a constant model towards sex-dependent models with increasing sample size and effort. A sample of 500 lobsters or 50 traps used on four consecutive sampling-days was required for obtaining precise survival estimations for males and females, separately. Reduced sampling effort of 30 traps over four sampling days was sufficient if a survival estimate for both sexes combined was sufficient for management of the fishery.

show abstract

Estimating Sample Size for Landscape-Scale Mark-Recapture Studies of North American Migratory Tree Bats

Cited by 20 publications

References 49 publications

High detectability with low impact: Optimizing large PIT tracking systems for cave‐dwelling bats

High detectability with low impact: Optimizing large PIT tracking systems for cave‐dwelling bats

A method for estimating abundance of mobile populations using telemetry and counts of unmarked animals

The Influence of Mark-Recapture Sampling Effort on Estimates of Rock Lobster Survival

Contact Info

Product

Resources

About