scholarly journals Evaluation of the AHDriFT Camera Trap System to Survey for Small Mammals and Herpetofauna

2021 ◽  
Author(s):  
Evan Amber ◽  
Gregory J. Lipps Jr. ◽  
William E. Peterman
Keyword(s):  
Small Mammals ◽  
Camera Trap ◽  
Camera Traps ◽  
Heat Processing ◽  
Vegetative Cover ◽  
Wet Meadow ◽  
Terrestrial Vertebrate ◽  
Drift Fence ◽  
Current Design ◽  
Animal Size

Traditional surveys for small mammals and herpetofauna require intensive field effort because these taxa are often difficult to detect. Field surveys are further hampered by dynamic environmental conditions and dense vegetative cover, which are both attributes of biodiverse wet meadow ecosystems. Camera traps may be a solution, but commonly used passive infrared game cameras face difficulties photographing herpetofauna and small mammals. The Adapted-Hunt Drift Fence Technique (AHDriFT) is a camera trap and drift fence system designed to overcome traditional limitations, but has not been extensively evaluated. We deployed 15 Y-shaped AHDriFT arrays (three cameras per array) in northern Ohio wet meadows from March 10 to October 5, 2019. Equipment for each array cost approximately US$1,570. Construction and deployment of each array took about three hours, with field servicing requiring 15 minutes per array. Arrays proved durable under wind, ice, snow, flooding and heat. Processing two-weeks of images of 45 cameras averaged about 13 person-hours. We obtained 9,018 unique-capture events of 41 vertebrate species comprised of 5 amphibians, 13 reptiles (11 snakes), 16 mammals and 7 birds. We imaged differing animal size classes ranging from invertebrates to weasels. We assessed detection efficacy using expected biodiversity baselines. We determined snake communities from three years of traditional surveys and possible small mammal and amphibian biodiversity from prior observations and species ranges and habitat requirements. We cumulatively detected all amphibians and 92% of snakes and small mammals that we expected to be present. We also imaged four mammal and two snake species where they were not previously observed. However, capture consistency was variable by taxa and species, and low-mobility species or species in low densities may not be detected. In its current design, AHDriFT proved to be effective for terrestrial vertebrate biodiversity surveying.

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.

scholarly journals The Role of Citizen Science and Deep Learning in Camera Trapping

2021 ◽  
Vol 13 (18) ◽  
pp. 10287
Author(s):  
Matyáš Adam ◽  
Pavel Tomášek ◽  
Jiří Lehejček ◽  
Jakub Trojan ◽  
Tomáš Jůnek
Keyword(s):  
Machine Learning ◽  
Citizen Science ◽  
Camera Trap ◽  
Camera Traps ◽  
Public Authorities ◽  
Web Based ◽  
Conservation Policies ◽  
Terrestrial Vertebrate ◽  
New Perspective

Camera traps are increasingly one of the fundamental pillars of environmental monitoring and management. Even outside the scientific community, thousands of camera traps in the hands of citizens may offer valuable data on terrestrial vertebrate fauna, bycatch data in particular, when guided according to already employed standards. This provides a promising setting for Citizen Science initiatives. Here, we suggest a possible pathway for isolated observations to be aggregated into a single database that respects the existing standards (with a proposed extension). Our approach aims to show a new perspective and to update the recent progress in engaging the enthusiasm of citizen scientists and in including machine learning processes into image classification in camera trap research. This approach (combining machine learning and the input from citizen scientists) may significantly assist in streamlining the processing of camera trap data while simultaneously raising public environmental awareness. We have thus developed a conceptual framework and analytical concept for a web-based camera trap database, incorporating the above-mentioned aspects that respect a combination of the roles of experts’ and citizens’ evaluations, the way of training a neural network and adding a taxon complexity index. This initiative could well serve scientists and the general public, as well as assisting public authorities to efficiently set spatially and temporarily well-targeted conservation policies.

scholarly journals Use of a novel camera trapping approach to measure small mammal responses to peatland restoration

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Nick A. Littlewood ◽  
Mark H. Hancock ◽  
Scott Newey ◽  
Gorm Shackelford ◽  
Rose Toney
Keyword(s):  
Animal Welfare ◽  
Small Mammals ◽  
Low Cost ◽  
Camera Trap ◽  
Camera Traps ◽  
Plantation Forestry ◽  
Survey Method ◽  
Flash Intensity ◽  
Peatland Restoration ◽  
Blanket Bog

AbstractSmall mammals, such as small rodents (Rodentia: Muroidea) and shrews (Insectivora: Soricidae), present particular challenges in camera trap surveys. Their size is often insufficient to trigger infra-red sensors, whilst resultant images may be of inadequate quality for species identification. The conventional survey method for small mammals, live-trapping, can be both labour-intensive and detrimental to animal welfare. Here, we describe a method for using camera traps for monitoring small mammals. We show that by attaching the camera trap to a baited tunnel, fixing a close-focus lens over the camera trap lens, and reducing the flash intensity, pictures or videos can be obtained of sufficient quality for identifying species. We demonstrate the use of the method by comparing occurrences of small mammals in a peatland landscape containing (i) plantation forestry (planted on drained former blanket bog), (ii) ex-forestry areas undergoing bog restoration, and (iii) unmodified blanket bog habitat. Rodents were detected only in forestry and restoration areas, whilst shrews were detected across all habitat. The odds of detecting small mammals were 7.6 times higher on camera traps set in plantation forestry than in unmodified bog, and 3.7 times higher on camera traps in restoration areas than in bog. When absolute abundance estimates are not required, and camera traps are available, this technique provides a low-cost survey method that is labour-efficient and has minimal animal welfare implications.

Powerline Easements: Do They Promote Edge Effects in Eucalypt Forest for Small Mammals?

1997 ◽  
Vol 24 (6) ◽  
pp. 737 ◽  
Author(s):  
Ross L. Goldingay ◽  
Robert J. Whelan
Keyword(s):  
Small Mammals ◽  
Edge Effects ◽  
Native Species ◽  
Vegetative Cover ◽  
Mammal Species ◽  
Terrestrial Mammals ◽  
Eucalypt Forest ◽  
Hair Sampling ◽  
South Wales ◽  
Antechinus Stuartii

The distribution and abundance of small terrestrial mammals were assessed in forest adjacent to powerline easements at three different sites in New South Wales. At each site, four transects of 300 m length extended into the forest from the edge of the easement. The abundances of two native species (Antechinus stuartii, Rattus fuscipes) did not differ significantly with distance from the easement but abundances differed markedly among sites. Mammals were captured in only one easement where dense vegetation was present. Feral carnivores, which may mediate edge effects on small mammals, were surveyed by using hair-sampling tubes. Cats and dogs were detected only 50–200 m inside the forest. Foxes were not detected by hair-tubes but were observed on two easements. These results suggest that powerline easements may not create edge effects in eucalypt forest for some native mammal species, although further studies are needed to determine the generality of this conclusion. We recommend that easement management should be more benign to native mammals, given the ubiquity of this form of habitat fragmentation. Promotion of dense vegetative cover and habitat linkages within easements could achieve this.

Changes in small mammal communities after logging in north-central Ontario

1983 ◽  
Vol 61 (5) ◽  
pp. 970-980 ◽  
Author(s):  
Arthur M. Martell
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Vegetative Cover ◽  
North Central ◽  
Clear Cut ◽  
Clear Cutting ◽  
Small Mammal Community ◽  
Small Mammal Communities ◽  
Mammal Community ◽  
Mammal Communities

Changes in small mammal communities following logging were monitored in clear-cut and strip-cut upland black spruce (Picea mariana) stands and in selectively cut mixed wood stands in north-central Ontario. Clear-cutting and subsequent scarification essentially eliminated the vegetative cover. Much of the ground cover recovered within 5 years and shrubs within 12 years, but mosses and lichens took much longer. The small mammal community in both clear-cut and strip-cut stands changed over the first three years after logging from one dominated by southern red-backed voles (Clethrionomys gapperi) to one dominated by deer mice (Peromyscus maniculatus) and then remained relatively stable for up to 13 years after harvest. That shift was not apparent in selectively cut mixed wood stands where the composition of the small mammal community was similar between uncut stands and stands 4–23 years after harvest. There was relatively little change in total numbers of small mammals after logging. In general, the diversity and evenness of small mammals increased or remained stable in the first 1–3 years following harvest, decreased on older (3–16 years) cuts, and then increased to values similar to those in uncut stands on the oldest (19–23 years) cuts.

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.

scholarly journals A sparse observation model to quantify species interactions in time and space

2019 ◽  
Author(s):  
Sadoune Ait Kaci Azzou ◽  
Liam Singer ◽  
Thierry Aebischer ◽  
Madleina Caduff ◽  
Beat Wolf ◽  
...  
Keyword(s):  
Species Interactions ◽  
Activity Patterns ◽  
Niche Partitioning ◽  
Camera Trap ◽  
Camera Traps ◽  
Observation Model ◽  
Occupancy Models ◽  
Time And Space ◽  
Imperfect Detection ◽  
Mobile Species

SummaryCamera traps and acoustic recording devices are essential tools to quantify the distribution, abundance and behavior of mobile species. Varying detection probabilities among device locations must be accounted for when analyzing such data, which is generally done using occupancy models. We introduce a Bayesian Time-dependent Observation Model for Camera Trap data (Tomcat), suited to estimate relative event densities in space and time. Tomcat allows to learn about the environmental requirements and daily activity patterns of species while accounting for imperfect detection. It further implements a sparse model that deals well will a large number of potentially highly correlated environmental variables. By integrating both spatial and temporal information, we extend the notation of overlap coefficient between species to time and space to study niche partitioning. We illustrate the power of Tomcat through an application to camera trap data of eight sympatrically occurring duiker Cephalophinae species in the savanna - rainforest ecotone in the Central African Republic and show that most species pairs show little overlap. Exceptions are those for which one species is very rare, likely as a result of direct competition.

scholarly journals Can citizen science analysis of camera trap data be used to study reproduction? Lessons from Snapshot Serengeti program

2020 ◽  
Author(s):  
Thel Lucie ◽  
Chamaillé-Jammes Simon ◽  
Keurinck Léa ◽  
Catala Maxime ◽  
Packer Craig ◽  
...  
Keyword(s):  
Citizen Science ◽  
Camera Trap ◽  
Camera Traps ◽  
Life History Trait ◽  
List Type ◽  
Breeding Phenology ◽  
Science Data ◽  
Morphological Criteria ◽  
Wide Range ◽  
Trained Observers

AbstractEcologists increasingly rely on camera trap data to estimate a wide range of biological parameters such as occupancy, population abundance or activity patterns. Because of the huge amount of data collected, the assistance of non-scientists is often sought after, but an assessment of the data quality is a prerequisite to their use.We tested whether citizen science data from one of the largest citizen science projects - Snapshot Serengeti - could be used to study breeding phenology, an important life-history trait. In particular, we tested whether the presence of juveniles (less than one or 12 months old) of three ungulate species in the Serengeti: topi Damaliscus jimela, kongoni Alcelaphus buselaphus and Grant’s gazelle Nanger granti could be reliably detected by the “naive” volunteers vs. trained observers. We expected a positive correlation between the proportion of volunteers identifying juveniles and their effective presence within photographs, assessed by the trained observers.We first checked the agreement between the trained observers for age classes and species and found a good agreement between them (Fleiss’ κ > 0.61 for juveniles of less than one and 12 month(s) old), suggesting that morphological criteria can be used successfully to determine age. The relationship between the proportion of volunteers detecting juveniles less than a month old and their actual presence plateaued at 0.45 for Grant’s gazelle and reached 0.70 for topi and 0.56 for kongoni. The same relationships were however much stronger for juveniles younger than 12 months, to the point that their presence was perfectly detected by volunteers for topi and kongoni.Volunteers’ classification allows a rough, moderately accurate, but quick, sorting of photograph sequences with/without juveniles. Obtaining accurate data however appears more difficult. We discuss the limitations of using citizen science camera traps data to study breeding phenology, and the options to improve the detection of juveniles, such as the addition of aging criteria on the online citizen science platforms, or the use of machine learning.

scholarly journals Use of highway culverts by the water opossum (Chironectes minimus) in southeastern Brazil

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Paula Ribeiro Prist ◽  
Guilherme S. T. Garbino ◽  
Fernanda Delborgo Abra ◽  
Thais Pagotto ◽  
Osnir Ormon Giacon
Keyword(s):  
New Records ◽  
Camera Trap ◽  
Sao Paulo ◽  
Riparian Forests ◽  
Camera Traps ◽  
Southeastern Brazil ◽  
São Paulo ◽  
Aquatic Mammal ◽  
Paulo State ◽  
Degraded Area

Abstract The water opossum (Chironectes minimus) is a semi-aquatic mammal that is infrequently sampled in Atlantic rainforest areas in Brazil. Here we report on new records of C. minimus in the state of São Paulo, southeastern Brazil, and comment on its behavior and ecology. We placed nine camera traps in culverts and cattle boxes under a highway, between 2017 and 2019. From a total of 6,750 camera-trap-days, we obtained 16 records of C. minimus (0.24 records/100 camera-trap-days) in two cameras placed in culverts over streams. Most of the records were made between May and August, in the dry season and in the first six hours after sunset. The new records are from a highly degraded area with some riparian forests. The records lie approximately 30 km away from the nearest protected area where the species is known to occur. We suggest that C. minimus has some tolerance to degraded habitats, as long as the water bodies and riparian forests are minimally preserved. The new records presented here also fill a distribution gap in western São Paulo state.

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.

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