scholarly journals Integrating telemetry data into spatial capture-recapture modifies inferences on multi-scale resource selection

2017 ◽  
Author(s):  
Daniel W. Linden ◽  
Alexej P. K. Sirén ◽  
Peter J. Pekins
Keyword(s):  
Resource Selection ◽  
Wildlife Conservation ◽  
Coniferous Forest ◽  
Space Use ◽  
Camera Traps ◽  
Telemetry Data ◽  
Multi Scale ◽  
Management Objectives ◽  
Capture Recapture ◽  
Conservation And Management

AbstractEstimating population size and resource selection functions (RSFs) are common approaches in applied ecology for addressing wildlife conservation and management objectives. Traditionally such approaches have been undertaken separately with different sources of data. Spatial capture-recapture (SCR) provides a framework for jointly estimating density and multi-scale resource selection, and data integration techniques provide opportunities for improving inferences from SCR models. Here we illustrate an application of integrated SCR-RSF modeling to a population of American marten (Martes americana) in alpine forests of northern New England. Spatial encounter data from camera traps were combined with telemetry locations from radio-collared individuals to examine how density and space use varied with spatial environmental features. We compared multi-model inferences between the integrated SCR-RSF model with telemetry and a standard SCR model with no telemetry. The integrated SCR-RSF model supported more complex relationships with spatial variation in third-order resource selection (i.e., individual space use), including selection for areas with shorter distances to mixed coniferous forest and rugged terrain. Both models indicated increased second-order selection (i.e., density) for areas close to mixed coniferous forest, while the integrated SCR-RSF model had a lower effect size due to modulation from spatial variability in space use. Our application of the integrated SCR-RSF model illustrates the improved inferences from spatial encounter data that can be achieved from integrating auxiliary telemetry data. Integrated modeling allows ecologists to join empirical data to ecological theory using a robust quantitative framework to better address conservation and management objectives.

How effective are grid trapping, oil cards and track boards in monitoring bush rat populations?

2007 ◽  
Vol 29 (2) ◽  
pp. 149 ◽  
Author(s):  
C.L. Free ◽  
L.K-P. Leung
Keyword(s):  
Wildlife Conservation ◽  
Selection Procedure ◽  
Model Parameters ◽  
Significance Level ◽  
Abundance Indices ◽  
Capture Recapture ◽  
Card Index ◽  
Rattus Fuscipes ◽  
Trapping Grid ◽  
Conservation And Management

Monitoring populations is a key component of wildlife conservation and management. This study aimed to evaluate the effectiveness of abundance indices used for estimating populations of the bush rat Rattus fuscipes. The study was conducted on Fraser Island, Queensland, Australia. A trapping grid consisting of 5 x 5 trap stations, 20 m apart, was used because this configuration was typical of those used for small mammal trapping in Australia. Capture-recapture data were collected from trapping 18 grids over four consecutive nights, immediately followed by two consecutive nights of conducting oil card and track indices. On 11 grids, model Mb was selected by the CAPTURE model selection procedure, indicating increased capture probability after first capture (trap-happy). The estimated trappable population size (�) on these grids was not precise with the standard error on average being 28% of �. On the other seven grids, the number of animals caught was too small (<3) to estimate model parameters.. The main problem of the grid trapping was that some grids caught too few animals to estimate �. Our data suggest that the minimum grid area for estimating useful � is one that would catch more than 8 individuals. The minimum grid area varies depending on the density of rats and should be determined by a pilot trapping study. The number of trapping occasions can be increased until a specific precision of � is reached. The correlation between track index and � was near the 0.05 significance level indicating tracks are potentially a reliable index for monitoring bush rat populations. The oil card index was not significantly correlated with �.

scholarly journals How many giraffes are there? A comparison of abundance estimators at Ongava Game Reserve, Namibia

2021 ◽  
Author(s):  
Christophe Bonenfant ◽  
Ken Stratford ◽  
Stephanie Periquet
Keyword(s):  
Population Size ◽  
Detection Probability ◽  
Wildlife Conservation ◽  
Camera Trap ◽  
Biological Data ◽  
Camera Traps ◽  
Population Abundance ◽  
Visit Frequency ◽  
Game Reserve ◽  
Capture Recapture

Camera-traps are a versatile and widely adopted tool to collect biological data in wildlife conservation and management. If estimating population abundance from camera-trap data is the primarily goal of many projects, what population estimator is suitable for such data needs to be investigated. We took advantage of a 21 days camera-trap monitoring on giraffes at Onvaga Game Reserve, Namibia to compare capture-recapture (CR), saturation curves and N-mixture estimators of population abundance. A marked variation in detection probability of giraffes was observed in time and between individuals. Giraffes were also less likely to be detected after they were seen at a waterhole with cameras (visit frequency of f = 0.25). We estimated population size to 119 giraffes with a Cv = 0.10 with the best CR estimator. All other estimators we a applied over-estimated population size by ca. -20 to >+80%, because they did not account for the main sources of heterogeneity in detection probability. We found that modelling choices was much less forgiving for N-mixture than CR estimators. Double counts were problematic for N-mixture models, challenging the use of raw counts at waterholes to monitor giraffes abundance.

scholarly journals An empirical demonstration of the effect of study design on density estimations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Ali Nawaz ◽  
Barkat Ullah Khan ◽  
Amer Mahmood ◽  
Muhammad Younas ◽  
Jaffar ud Din ◽  
...  
Keyword(s):  
Rare Species ◽  
Sampling Design ◽  
Space Use ◽  
Camera Traps ◽  
Large Carnivores ◽  
Large Mammals ◽  
Spatial Coverage ◽  
Capture Recapture ◽  
Compact Design ◽  
Empirical Demonstration

AbstractThe simultaneous development of technology (e.g. camera traps) and statistical methods, particularly spatially capture–recapture (SCR), has improved monitoring of large mammals in recent years. SCR estimates are known to be sensitive to sampling design, yet existing recommendations about trap spacing and coverage are often not achieved, particularly for sampling wide-ranging and rare species in landscapes that allow for limited accessibility. Consequently, most camera trap studies on large wide-ranging carnivores relies on convenience or judgmental sampling, and often yields compromised results. This study attempts to highlight the importance of carefully considered sampling design for large carnivores that, because of low densities and elusive behavior, are challenging to monitor. As a motivating example, we use two years of snow leopard camera trapping data from the same areas in the high mountains of Pakistan but with vastly different camera configurations, to demonstrate that estimates of density and space use are indeed sensitive to the trapping array. A compact design, one in which cameras were placed much closer together than generally recommended and therefore have lower spatial coverage, resulted in fewer individuals observed, but more recaptures, and estimates of density and space use were inconsistent with expectations for the region. In contrast, a diffuse design, one with larger spacing and spatial coverage and more consistent with general recommendations, detected more individuals, had fewer recaptures, but generated estimates of density and space use that were in line with expectations. Researchers often opt for compact camera configurations while monitoring wide-ranging and rare species, in an attempt to maximize the encounter probabilities. We empirically demonstrate the potential for biases when sampling a small area approximately the size of a single home range—this arises from exposing fewer individuals than deemed sufficient for estimation. The smaller trapping array may also underestimate density by significantly inflating $$\sigma$$ σ . On the other hand, larger trapping array with fewer detectors and poor design induces uncertainties in the estimates. We conclude that existing design recommendations have limited utility on practical grounds for devising feasible sampling designs for large ranging species, and more research on SCR designs is required that allows for integrating biological and habitat traits of large carnivores in sampling framework. We also suggest that caution should be exercised when there is a reliance on convenience sampling.

scholarly journals Population characteristics, space use and habitat selection of two non-migratory caribou herds in central Alaska, 1994 - 2009

Rangifer ◽  
2014 ◽  
Vol 34 (1) ◽  
pp. 1 ◽  
Author(s):  
Jon S. Horne ◽  
Tim Craig ◽  
Kyle Joly ◽  
Glenn W. Stout ◽  
Merben R. Cebrian ◽  
...  
Keyword(s):  
Resource Selection ◽  
Rangifer Tarandus ◽  
Analytical Techniques ◽  
Space Use ◽  
Spatial Separation ◽  
Herd Size ◽  
Population Characteristics ◽  
Home Ranges ◽  
Telemetry Data ◽  
Very High Frequency

Conservation and management of Alaska’s caribou (Rangifer tarandus granti) herds are important for ecological, cultural, social, and economic reasons.  While most research is directed towards the large migratory herds, smaller herds that may or may not be migratory can be an equally valuable component of the state’s faunal resources; but for many of these smaller herds, basic information on herd size, demographics, space use and movements is lacking.  We compiled Very High Frequency (VHF) telemetry data collected from 1994 - 2009 on 2 such herds in central Alaska, the Hodzana Hills Herd (HHH) and the Ray Mountain Herd (RMH) and estimated abundance, survival, resource selection and seasonal home ranges to inform future management of these herds.  We found that both herds were relatively small and stable with approximately 1000 – 1500 individuals; annual survivorship of adult females was high (93% and 94% for RMH and HHH, respectively) and comparable to other stable or increasing herds in Alaska.  Both herds were non-migratory maintaining seasonal ranges with substantial overlap.  Additionally, despite their close proximity, we did not document any exchange of individuals between the 2 herds.  Their spatial separation may be partly due to a strip of non-preferred habitat that somewhat parallels the Dalton Highway.  While the telemetry data we used were not originally collected for the purpose of this study, careful compilation and application of appropriate analytical techniques allowed us to glean important characteristics of these herds that will be of value to regulatory and management agencies in the future.

scholarly journals Effects of Bait on Male White-Tailed Deer Resource Selection

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2334
Author(s):  
James T. Johnson ◽  
Richard B. Chandler ◽  
L. Mike Conner ◽  
Michael J. Cherry ◽  
Charlie H. Killmaster ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Resource Selection ◽  
Spatial Scales ◽  
Space Use ◽  
Second Order ◽  
Camera Traps ◽  
Home Ranges ◽  
Order Selection ◽  
Short Term ◽  
Third Order

Bait is often used to increase wildlife harvest susceptibility, enhance viewing opportunities, and survey wildlife populations. The effects of baiting depend on how bait influences space use and resource selection at multiple spatial scales. Although telemetry studies allow for inferences about resource selection within home ranges (third-order selection), they provide limited information about spatial variation in density, which is the result of second-order selection. Recent advances in spatial capture-recapture (SCR) techniques allow exploration of second- and third-order selection simultaneously using non-invasive methods such as camera traps. Our objectives were to describe how short-term baiting affects white-tailed deer (Odocoileus virginianus) behavior and distribution. We fit SCR models to camera data from baited and unbaited locations in southwestern Georgia to assess the effects of short-term baiting on second- and third-order selection of deer during summer and winter surveys. We found little evidence of second-order selection during late summer or early winter surveys when camera surveys using bait are typically conducted. However, we found evidence for third-order selection, indicating that resource selection within home ranges is affected. Concentrations in space use resulting from baiting may enhance disease transmission, change harvest susceptibility, and potentially bias the outcome of camera surveys using bait.

scholarly journals Where to spot: individual identification of leopard cats (Prionailurus bengalensis euptilurus) in South Korea

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Heebok Park ◽  
Anya Lim ◽  
Tae-Young Choi ◽  
Seung-Yoon Baek ◽  
Eui-Geun Song ◽  
...  
Keyword(s):  
South Korea ◽  
Wildlife Conservation ◽  
Camera Traps ◽  
Individual Identification ◽  
Parameter Estimates ◽  
Population Parameter ◽  
Study Results ◽  
Capture Recapture ◽  
Leopard Cat ◽  
Prionailurus Bengalensis

AbstractKnowledge of abundance, or population size, is fundamental in wildlife conservation and management. Camera-trapping, in combination with capture-recapture methods, has been extensively applied to estimate abundance and density of individually identifiable animals due to the advantages of being non-invasive, effective to survey wide-ranging, elusive, or nocturnal species, operating in inhospitable environment, and taking low labor. We assessed the possibility of using coat patterns from images to identify an individual leopard cat (Prionailurus bengalensis), a Class II endangered species in South Korea. We analyzed leopard cat images taken from Digital Single-Lense Relfex camera (high resolution, 18Mpxl) and camera traps (low resolution, 3.1Mpxl) using HotSpotter, an image matching algorithm. HotSpotter accurately top-ranked an image of the same individual leopard cat with the reference leopard cat image 100% by matching facial and ventral parts. This confirms that facial and ventral fur patterns of the Amur leopard cat are good matching points to be used reliably to identify an individual. We anticipate that the study results will be useful to researchers interested in studying behavior or population parameter estimates of Amur leopard cats based on capture-recapture models.

scholarly journals Leopard Density Estimation within an Enclosed Reserve, Namibia Using Spatially Explicit Capture-Recapture Models

Animals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 724
Author(s):  
Noack ◽  
Heyns ◽  
Rodenwoldt ◽  
Edwards
Keyword(s):  
Management Strategies ◽  
Camera Traps ◽  
Spatially Explicit ◽  
Conservation Areas ◽  
Term Survival ◽  
New Class ◽  
Capture Recapture ◽  
Wildlife Populations ◽  
Effective Conservation

The establishment of enclosed conservation areas are claimed to be the driving force for the long-term survival of wildlife populations. Whilst fencing provides an important tool in conservation, it simultaneously represents a controversial matter as it stops natural migration processes, which could ultimately lead to inbreeding, a decline in genetic diversity and local extinction if not managed correctly. Thus, wildlife residing in enclosed reserves requires effective conservation and management strategies, which are strongly reliant on robust population estimates. Here, we used camera traps combined with the relatively new class of spatially explicit capture-recaptured models (SECR) to produce the first reliable leopard population estimate for an enclosed reserve in Namibia. Leopard density was estimated at 14.51 leopards/100 km2, the highest recorded density in Namibia to date. A combination of high prey abundance, the absence of human persecution and a lack of top-down control are believed to be the main drivers of the recorded high leopard population. Our results add to the growing body of literature which suggests enclosed reserves have the potential to harbour high densities and highlight the importance of such reserves for the survival of threatened species in the future.

scholarly journals Wildlife conservation and management in China: achievements, challenges and perspectives

2021 ◽  
Author(s):  
Guangping Huang ◽  
Xiaoge Ping ◽  
Weihua Xu ◽  
Yibo Hu ◽  
Jiang Chang ◽  
...  
Keyword(s):  
Wildlife Conservation ◽  
Conservation And Management
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