scholarly journals Applying camera traps to detect and monitor introduced mammals on oceanic islands

Oryx ◽  
2020 ◽  
pp. 1-8
Author(s):  
Lucas Lamelas-López ◽  
Iván Salgado
Keyword(s):  
Introduced Species ◽  
Large Scale ◽  
Camera Trap ◽  
Oceanic Islands ◽  
Camera Traps ◽  
Camera Trapping ◽  
Sampling Effort ◽  
Terrestrial Mammals ◽  
Management Actions ◽  
Survey Technique

Abstract The introduction of mammal predators has been a major cause of species extinctions on oceanic islands. Eradication is only possible or cost-effective at early stages of invasion, before introduced species become abundant and widespread. Although prevention, early detection and rapid response are the best management strategies, most oceanic islands lack systems for detecting, responding to and monitoring introduced species. Wildlife managers require reliable information on introduced species to guide, assess and adjust management actions. Thus, a large-scale and long-term monitoring programme is needed to evaluate the management of introduced species and the protection of native wildlife. Here, we evaluate camera trapping as a survey technique for detecting and monitoring introduced small and medium-sized terrestrial mammals on an oceanic island, Terceira (Azores). Producing an inventory of introduced mammals on this island required a sampling effort of 465 camera-trap days and cost EUR 2,133. We estimated abundance and population trends by using photographic capture rates as a population index. We also used presence/absence data from camera-trap surveys to calculate detection probability, estimated occupancy rate and the sampling effort needed to determine species absence. Although camera trapping requires large initial funding, this is offset by the relatively low effort for fieldwork. Our findings demonstrate that camera trapping is an efficient survey technique for detecting and monitoring introduced species on oceanic islands. We conclude by proposing guidelines for designing monitoring programmes for introduced species.

scholarly journals Counting Sunda clouded leopards with confidence: incorporating individual heterogeneity in density estimates

Oryx ◽  
2019 ◽  
pp. 1-10 ◽  
Author(s):  
Azlan Mohamed ◽  
Rahel Sollmann ◽  
Seth Timothy Wong ◽  
Jürgen Niedballa ◽  
Jesse F. Abrams ◽  
...  
Keyword(s):  
Population Density ◽  
Large Scale ◽  
Null Model ◽  
Camera Trap ◽  
Camera Trapping ◽  
Individual Heterogeneity ◽  
Sampling Effort ◽  
Density Estimates ◽  
Clouded Leopard ◽  
Forest Reserves

AbstractEven with intensive sampling effort, data often remain sparse when estimating population density of elusive species such as the Sunda clouded leopard Neofelis diardi. An inadequate number of recaptures can make it difficult to account for heterogeneity in detection parameters. We used data from large-scale camera-trapping surveys in three forest reserves in Sabah, Malaysian Borneo, to (1) examine whether a high-density camera-trap network increases the number of recaptures for females, which tend to be more difficult to detect, thus improving the accuracy of density estimates; (2) compare density estimates from models incorporating individual heterogeneity in detection parameters with estimates from the null model to evaluate its potential bias; and (3) investigate how the size of the camera-trap grid affects density and movement estimates. We found that individual heterogeneity could not be incorporated in the single-site data analysis and only conservative null model estimates could be generated. However, aggregating data across study sites enabled us to account for individual heterogeneity and we estimated densities of 1.27–2.82 individuals/100 km2, 2–3 times higher than estimates from null models. In light of these findings, it is possible that earlier studies underestimated population density. Similar densities found in well-managed forest and recently selectively logged forest suggest that Sunda clouded leopards are relatively resilient to forest disturbances. Our analysis also revealed that camera-trapping grids for Sunda clouded leopard density estimations should cover large areas (c. 250 km2), although smaller grids could be appropriate if density or detectability are higher.

scholarly journals Mammal diversity among vertical strata and the evaluation of a survey technique in a central Amazonian forest

2021 ◽  
Vol 61 ◽  
pp. e20216133
Author(s):  
Alexander Roldán Arévalo-Sandi ◽  
André Luis Sousa Gonçalves ◽  
Kota Onizawa ◽  
Tsuneaki Yabe ◽  
Wilson Roberto Spironello
Keyword(s):  
Camera Trap ◽  
Camera Traps ◽  
Sampling Effort ◽  
Mammal Species ◽  
Lowland Forest ◽  
Survey Technique ◽  
Terrestrial Habitats ◽  
Common Technique ◽  
The Difference ◽  
Mammal Diversity

Mammal groups have a vast variety of habitats, which include aquatic, aerial, arboreal, and terrestrial. For terrestrial habitats, camera traps are used as a common technique to record mammals and other vertebrates and have been recently utilized to observe arboreal animals as well. Here, we compare the difference in mammal diversity between floor and canopy strata and evaluate the use of camera trapping in a lowland forest in central Amazon. We installed nine paired camera traps, one in the canopy stratum and other in the floor stratum, in the Alto Cuieiras Biological Reserve (Brazilian Amazon). With a sampling effort of 720 camera-days, we recorded 30 mammal species: nine in canopy strata, 14 in floor strata, and seven in scansorial strata (sharing both strata). On the forest floor, the species with the greatest abundance was Myoprocta acouchy; in the canopy, Isothrix paguros had the greatest abundance; and among the scansorial species, Proechymis sp. was the most abundant. Our results show the differences in mammal diversity between floor and canopy strata; canopy strata contained more small and frugivorous mammals. Although we obtained a relatively low sampling effort with the camera-trap method compared with other studies utilizing different techniques, our results were especially similar to those of previous studies that worked with canopy and floor strata. Thus, camera trap can be very effective for recording short periods of time, and this method is less physically exhaustive and expensive for researchers to study vertical strata.

scholarly journals A picture is worth a thousand words: the application of camera trapping to the study of birds

2008 ◽  
Vol 18 (S1) ◽  
pp. S144-S162 ◽  
Author(s):  
Timothy G. O'Brien ◽  
Margaret F. Kinnaird
Keyword(s):  
Finite Mixture Models ◽  
Camera Trap ◽  
Camera Traps ◽  
Camera Trapping ◽  
Individual Identification ◽  
Nest Defence ◽  
Primary Forest ◽  
Sampling Effort ◽  
Observation Process ◽  
Capture Recapture

AbstractThis study reviews the use of remotely triggered still cameras, known as camera traps, in bird research and suggests new methods useful for analyzing camera trap data. Camera trapping may be most appropriate for large, ground-dwelling birds, such as cracids and pheasants. Recent applications include documentation of occurrence of rare species and new species records, nest predation studies and behavioural studies including nest defence, frugivory, seed dispersal, and activity budgets. If bird postures are analyzed, it may be possible to develop behavioural time budgets. If birds are marked or individually identifiable, abundance may be estimated through capture-recapture methods typically used for mammals. We discourage use of relative abundance indices based on trapping effort because of the difficulty of standardizing surveys over time and space. Using the Great Argus Pheasant Argus argusianus, a cryptic, terrestrial, forest bird as an example, we illustrate applications of occupancy analysis to estimate proportion of occupied habitat and finite mixture models to estimate abundance when individual identification is not possible. These analyses are useful because they incorporate detection probabilities < 1 and covariates that affect the sample site or the observation process. Results are from camera trap surveys in the 3,568 km2 Bukit Barisan Selatan National Park, Indonesia. We confirmed that Great Argus Pheasants prefer primary forest below 500 m. We also find a decline in occupancy (6–8% yr−1). Point estimates of abundance peak in 2000, followed by a sharp decline. We discuss the effects of rarity, detection probability and sampling effort on accuracy and precision of estimates.

scholarly journals A First Step Towards Automated Species Recognition from Camera Trap Images of Mammals Using AI in a European Temperate Forest

2021 ◽  
pp. 299-310
Author(s):  
Mateusz Choiński ◽  
Mateusz Rogowski ◽  
Piotr Tynecki ◽  
Dries P. J. Kuijper ◽  
Marcin Churski ◽  
...  
Keyword(s):  
Data Processing ◽  
Large Scale ◽  
Species Recognition ◽  
Population Monitoring ◽  
Camera Trap ◽  
Camera Traps ◽  
Camera Trapping ◽  
Classification Model ◽  
Wildlife Monitoring ◽  
Species Classification

AbstractCamera traps are used worldwide to monitor wildlife. Despite the increasing availability of Deep Learning (DL) models, the effective usage of this technology to support wildlife monitoring is limited. This is mainly due to the complexity of DL technology and high computing requirements. This paper presents the implementation of the light-weight and state-of-the-art YOLOv5 architecture for automated labeling of camera trap images of mammals in the Białowieża Forest (BF), Poland. The camera trapping data were organized and harmonized using TRAPPER software, an open-source application for managing large-scale wildlife monitoring projects. The proposed image recognition pipeline achieved an average accuracy of 85% F1-score in the identification of the 12 most commonly occurring medium-size and large mammal species in BF, using a limited set of training and testing data (a total of 2659 images with animals).Based on the preliminary results, we have concluded that the YOLOv5 object detection and classification model is a fine and promising DL solution after the adoption of the transfer learning technique. It can be efficiently plugged in via an API into existing web-based camera trapping data processing platforms such as e.g. TRAPPER system. Since TRAPPER is already used to manage and classify (manually) camera trapping datasets by many research groups in Europe, the implementation of AI-based automated species classification will significantly speed up the data processing workflow and thus better support data-driven wildlife monitoring and conservation. Moreover, YOLOv5 has been proven to perform well on edge devices, which may open a new chapter in animal population monitoring in real-time directly from camera trap devices.

scholarly journals eDNA sampled from stream networks correlates with camera trap detection rates of terrestrial mammals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arnaud Lyet ◽  
Loïc Pellissier ◽  
Alice Valentini ◽  
Tony Dejean ◽  
Abigail Hehmeyer ◽  
...  
Keyword(s):  
Large Scale ◽  
Stream Water ◽  
Spatial Scales ◽  
Environmental Dna ◽  
Camera Trap ◽  
Camera Traps ◽  
Sufficient Information ◽  
Multiple Time ◽  
Detection Rates ◽  
Terrestrial Mammals

AbstractBiodiversity monitoring delivers vital information to those making conservation decisions. Comprehensively measuring terrestrial biodiversity usually requires costly methods that can rarely be deployed at large spatial scales over multiple time periods, limiting conservation efficiency. Here we investigated the capacity of environmental DNA (eDNA) from stream water samples to survey terrestrial mammal diversity at multiple spatial scales within a large catchment. We compared biodiversity information recovered using an eDNA metabarcoding approach with data from a dense camera trap survey, as well as the sampling costs of both methods. Via the sampling of large volumes of water from the two largest streams that drained the study area, eDNA metabarcoding provided information on the presence and detection probabilities of 35 mammal taxa, 25% more than camera traps and for half the cost. While eDNA metabarcoding had limited capacity to detect felid species and provide individual-level demographic information, it is a cost-efficient method for large-scale monitoring of terrestrial mammals that can offer sufficient information to solve many conservation problems.

scholarly journals Long-term monitoring of margays (Leopardus wiedii): Implications for understanding low detection rates

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247536
Author(s):  
Bart J. Harmsen ◽  
Nicola Saville ◽  
Rebecca J. Foster
Keyword(s):  
Detection Rate ◽  
Camera Trap ◽  
Wide Distribution ◽  
Camera Traps ◽  
Detection Rates ◽  
Terrestrial Mammals ◽  
Exclusive Territories ◽  
Carnivore Species ◽  
Density Population

Population assessments of wide-ranging, cryptic, terrestrial mammals rely on camera trap surveys. While camera trapping is a powerful method of detecting presence, it is difficult distinguishing rarity from low detection rate. The margay (Leopardus wiedii) is an example of a species considered rare based on its low detection rates across its range. Although margays have a wide distribution, detection rates with camera traps are universally low; consequently, the species is listed as Near Threatened. Our 12-year camera trap study of margays in protected broadleaf forest in Belize suggests that while margays have low detection rate, they do not seem to be rare, rather that they are difficult to detect with camera traps. We detected a maximum of 187 individuals, all with few or no recaptures over the years (mean = 2.0 captures/individual ± SD 2.1), with two-thirds of individuals detected only once. The few individuals that were recaptured across years exhibited long tenures up to 9 years and were at least 10 years old at their final detection. We detected multiple individuals of both sexes at the same locations during the same survey, suggesting overlapping ranges with non-exclusive territories, providing further evidence of a high-density population. By studying the sparse annual datasets across multiple years, we found evidence of an abundant margay population in the forest of the Cockscomb Basin, which might have been deemed low density and rare, if studied in the short term. We encourage more long-term camera trap studies to assess population status of semi-arboreal carnivore species that have hitherto been considered rare based on low detection rates.

More haste, less speed: pilot study suggests camera trap detection zone could be more important than trigger speed to maximise species detections

2018 ◽  
Vol 40 (1) ◽  
pp. 118 ◽  
Author(s):  
Bronwyn A. Fancourt ◽  
Mark Sweaney ◽  
Don B. Fletcher
Keyword(s):  
Pilot Study ◽  
Wildlife Management ◽  
Detection Probability ◽  
Field Trials ◽  
Camera Trap ◽  
Camera Traps ◽  
Detection Zone ◽  
Trigger Time ◽  
Management Actions ◽  
Context Specific

Camera traps are being used increasingly for wildlife management and research. When choosing camera models, practitioners often consider camera trigger speed to be one of the most important factors to maximise species detections. However, factors such as detection zone will also influence detection probability. As part of a rabbit eradication program, we performed a pilot study to compare rabbit (Oryctolagus cuniculus) detections using the Reconyx PC900 (faster trigger speed, narrower detection zone) and the Ltl Acorn Ltl-5310A (slower trigger speed, wider detection zone). Contrary to our predictions, the slower-trigger-speed cameras detected rabbits more than twice as often as the faster-trigger-speed cameras, suggesting that the wider detection zone more than compensated for the relatively slower trigger time. We recommend context-specific field trials to ensure cameras are appropriate for the required purpose. Missed detections could lead to incorrect inferences and potentially misdirected management actions.

Can camera trapping be used to accurately survey and monitor the Hastings River mouse (Pseudomys oralis)?

2016 ◽  
Vol 38 (1) ◽  
pp. 44 ◽  
Author(s):  
Paul D. Meek ◽  
Karl Vernes
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Survey Methods ◽  
Camera Trap ◽  
Camera Traps ◽  
Camera Trapping ◽  
Common Element ◽  
Computer Assisted ◽  
Survey Tool ◽  
Wide Range

Camera trapping is increasingly recognised as a survey tool akin to conventional small mammal survey methods such as Elliott trapping. While there are many cost and resource advantages of using camera traps, their adoption should not compromise scientific rigour. Rodents are a common element of most small mammal surveys. In 2010 we deployed camera traps to measure whether the endangered Hastings River mouse (Pseudomys oralis) could be detected and identified with an acceptable level of precision by camera traps when similar-looking sympatric small mammals were present. A comparison of three camera trap models revealed that camera traps can detect a wide range of small mammals, although white flash colour photography was necessary to capture characteristic features of morphology. However, the accurate identification of some small mammals, including P. oralis, was problematic; we conclude therefore that camera traps alone are not appropriate for P. oralis surveys, even though they might at times successfully detect them. We discuss the need for refinement of the methodology, further testing of camera trap technology, and the development of computer-assisted techniques to overcome problems associated with accurate species identification.

The history of wildlife camera trapping as a survey tool in Australia

2015 ◽  
Vol 37 (1) ◽  
pp. 1 ◽  
Author(s):  
Paul D. Meek ◽  
Guy-Anthony Ballard ◽  
Karl Vernes ◽  
Peter J. S. Fleming
Keyword(s):  
Quantitative Research ◽  
Reaction Times ◽  
Historical Review ◽  
Camera Trap ◽  
Recent Change ◽  
Camera Traps ◽  
Camera Trapping ◽  
Survey Tool ◽  
Trapping Methods ◽  
Effective Models

This paper provides an historical review of the technological evolution of camera trapping as a zoological survey tool in Australia. Camera trapping in Australia began in the 1950s when purpose-built remotely placed cameras were used in attempts to rediscover the thylacine (Thylacinus cynocephalus). However, camera traps did not appear in Australian research papers and Australasian conference proceedings until 1989–91, and usage became common only after 2008, with an exponential increase in usage since 2010. Initially, Australian publications under-reported camera trapping methods, often failing to provide fundamental details about deployment and use. However, rigour in reporting of key methods has increased during the recent widespread adoption of camera trapping. Our analysis also reveals a change in camera trap use in Australia, from simple presence–absence studies, to more theoretical and experimental approaches related to population ecology, behavioural ecology, conservation biology and wildlife management. Practitioners require further research to refine and standardise camera trap methods to ensure that unbiased and scientifically rigorous data are obtained from quantitative research. The recent change in emphasis of camera trapping research use is reflected in the decreasing range of camera trap models being used in Australian research. Practitioners are moving away from less effective models that have slow reaction times between detection and image capture, and inherent bias in detectability of fauna, to more expensive brands that offer faster speeds, greater functionality and more reliability.

scholarly journals Large- and medium-bodied terrestrial mammals of the Upper Berbice region of Guyana

Check List ◽  
2020 ◽  
Vol 16 (5) ◽  
pp. 1229-1237
Author(s):  
Meshach A. Pierre ◽  
Leroy Ignacio ◽  
Evi A. D. Paemelaere
Keyword(s):  
Relative Abundance ◽  
Forest Ecosystems ◽  
Camera Trap ◽  
Camera Traps ◽  
Large Mammals ◽  
Sensitive Species ◽  
Terrestrial Mammals ◽  
Mammal Community ◽  
Eira Barbara ◽  
Brocket Deer

Large mammals are key contributors to forest ecosystems globally, but Neotropical mammal populations are understudied. We employed remotely triggered camera traps and track surveys to assess the mammal community in the newly accessible upper Berbice region of Guyana. In a cumulative 2,821 trap nights between two camps and 14 km of track surveys we recorded 18 species of mammals. Camera trap records showed that Red-Rumped Agouti (Dasyprocta leporina (Linnaeus, 1758)) featured the highest relative abundance at both camps, while Tayra (Eira barbara (Linnaeus, 1758)), Amazonian Brown Brocket Deer (Mazama nemorivaga (F. Cuvier, 1817)), Giant Anteater (Myrmecophaga tridactyla (Linnaeus, 1758)) and Giant Armadillo (Priodontes maximus (Kerr, 1792)) the lowest. We also report na&iuml;ve occupancy estimates. Detections of threatened and disturbance sensitive species indicate that the study site has a high biodiversity value. We provide recommendations for further study in this recently disturbed ecosystem and other understudied regions of Guyana.

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