Capturing the cryptic: a comparison of detection methods for stoats (Mustela erminea) in alpine habitats

2017 ◽  
Vol 44 (5) ◽  
pp. 418 ◽  
Author(s):  
Des H. V. Smith ◽  
Kerry A. Weston
Keyword(s):  
New Zealand ◽  
Early Summer ◽  
Camera Traps ◽  
Detection Methods ◽  
Monitoring Methods ◽  
Mustela Erminea ◽  
Detection Rates ◽  
Artificial Nests ◽  
Alternative Detection ◽  
Tracking Tunnels

Context The ability to monitor the spatial distribution and abundance of species is essential for detecting population changes, and assessing the progress of conservation management programs. Stoats (Mustela erminea) are a serious conservation pest in New Zealand, but current monitoring methods are not sensitive enough to detect stoats in all situations. Aims We compare the effectiveness of the most commonly employed method for monitoring mustelids in New Zealand, footprint-tracking tunnels, with two alternative detection methods, camera traps and artificial nests. We were interested in determining whether alternative detection methods were more sensitive in detecting stoats than tracking tunnels. Methods We established a network of tracking tunnels, artificial nests and camera traps within alpine habitat. Devices were checked for stoat detections weekly across two seasons, in spring–early summer and autumn. Differences in detection rates and cost effectiveness among methods were analysed among seasons. Key results In spring–early summer, the time to first stoat detection using footprint-tracking tunnels was 61 days, compared with 7 days for camera traps and 8 days for artificial nests. The rate of stoat detection using artificial nests was significantly higher than it was using tracking tunnels (coef = 3.05 ± 1.29, P = 0.02), and moderately higher using camera traps (coef = 1.34 ± 1.09, P = 0.22). In autumn, when overall detectability of stoats was higher, there was no significant difference in detection rates among the three methods, although camera traps again recorded the earliest detection. Artificial nests were the most cost effective detection method in both seasons. Conclusions Artificial nests and camera traps were more efficient at detecting stoats during their spring breeding season (when they are known to be difficult to detect), compared with the more established footprint-tracking tunnel method. Artificial nests have potential to be developed into a monitoring index for small mammals, although further research is required. Both methods provide an important alternative to footprint tracking indices for monitoring stoats. Implications Our study demonstrated the importance of calibration among different monitoring methods, particularly when the target species is difficult to detect. We hypothesise that detection methods that do not rely on conspicuous, artificially constructed devices, may be more effective for monitoring small, cryptic mammals.

Using complementary remote detection methods for retrofitted eco-passages: a case study for monitoring individual koalas in south-east Queensland

2016 ◽  
Vol 43 (5) ◽  
pp. 369 ◽  
Author(s):  
C. E. Dexter ◽  
R. G. Appleby ◽  
J. P. Edgar ◽  
J. Scott ◽  
D. N. Jones
Keyword(s):  
Road Construction ◽  
Primary Objective ◽  
Correlated Data ◽  
Camera Traps ◽  
Detection Methods ◽  
Urban Landscapes ◽  
Monitoring Methods ◽  
Monitoring Method ◽  
Phascolarctos Cinereus ◽  
The Individual

Context Vehicle-strike has been identified as a key threatening process for koala (Phascolarctos cinereus) survival and persistence in Australia. Roads and traffic act as barriers to koala movement and can impact dispersal and metapopulation dynamics. Given the high cost of wildlife mitigation structures such as purpose-built fauna-specific underpasses or overpasses (eco-passages), road construction and management agencies are constantly seeking cost-effective strategies that facilitate safe passage for fauna across roads. Here we report on an array of detection methods trialled to verify use of retrofitted road infrastructure (existing water culverts or bridge underpasses) by individual koalas in fragmented urban landscapes in south-east Queensland. Aims The study examined whether the retrofitting of existing road structures at six sites facilitated safe passage for koalas across roads. Our primary objective was to record utilisation of retrofitted infrastructure at the level of the individual. Methods We used a combination of existing monitoring methods such as GPS/VHF collars, camera traps, sand plots, and RFID tags, along with a newly developed animal-borne wireless identification (WID) tag and datalogging system, specifically designed for this project, to realise the study aims. Key results We were able to verify 130 crossings by koalas involving a retrofitted structure or a road surface over a 30-month period by using correlated data from complementary methods. We noted that crossings were generally uncommon and mostly undertaken by only a subset of our tagged individuals at each site (21% overall). Conclusions An important element of this study was that crossing events could be accurately determined at the level of the individual. This allowed for detailed assessment of eco-passage usage, rather than the more usual approach of simply recording species’ presence. Implications This study underscores the value of identifying the constraints of each individual monitoring method in relation to site conditions. It also highlights the benefits of contingency planning to limit data loss (i.e. using more than one method to collect data). We suggest an approach that uses complementary monitoring methods has significant advantages for researchers, particularly with reference to improving understanding of whether eco-passages are meeting their prescribed conservation goals.

Secondary poisoning of stoats (Mustela erminea) at low mouse (Mus musculus) abundance in a New Zealand Nothofagus forest

1998 ◽  
Vol 25 (4) ◽  
pp. 419 ◽  
Author(s):  
K. P. Brown ◽  
N. Alterio ◽  
H. Moller
Keyword(s):  
New Zealand ◽  
Mus Musculus ◽  
Prey Species ◽  
Rattus Rattus ◽  
Relative Importance ◽  
Trichosurus Vulpecula ◽  
Secondary Poisoning ◽  
Mustela Erminea ◽  
Nothofagus Forest ◽  
Tracking Tunnels

Two different brodifacoum (Talon 20 P™) poisoning regimes effectively killed 100% of resident radio-tagged stoats (Mustela erminea) by secondary poisoning in a New Zealand Nothofagus forest when mice (Mus musculus) were scarce. Resident possums (Trichosurus vulpecula) and ship rats (Rattus rattus) were also killed. The relative importance of different prey species as sources of poison for stoats has not been clearly identified but availability of poisoned prey will determine the efficacy of secondary poisoning in years of low prey abundance. Tracking tunnels did not accurately measure the decline in the stoat population and were probably influenced by immigrant stoats that were kill-trapped and contained high levels of poison. This study corroborates the findings of several other similar studies that secondary poisoning using brodifacoum effectively kills stoats.

Evaluation of camera traps for monitoring European rabbits before and after control operations in Otago, New Zealand

2012 ◽  
Vol 39 (7) ◽  
pp. 621 ◽  
Author(s):  
A. David M. Latham ◽  
Graham Nugent ◽  
Bruce Warburton
Keyword(s):  
New Zealand ◽  
Statistical Power ◽  
Vantage Point ◽  
Camera Traps ◽  
Alternative Methods ◽  
Monitoring Methods ◽  
Control Operation ◽  
Point Counts ◽  
Rabbit Haemorrhagic Disease ◽  
European Rabbits

Context European rabbits (Oryctolagus cuniculus) are reaching plague proportions again in some parts of New Zealand as the effect of rabbit haemorrhagic disease begins to wane. Effective monitoring techniques are required to quantify the success of alternative methods of controlling rabbits, such as poisoning. Aim To evaluate camera traps as a method of estimating the percentage of rabbits killed in a poison control operation, and to compare results obtained from cameras with those from traditional monitoring methods (spotlight transects and vantage-point counts). Methods We deployed cameras and conducted vantage-point counts and spotlight transects to compare a priori statistical power. We then used these monitoring methods to estimate percentage kill from a case study rabbit-control operation using sodium fluoroacetate (compound 1080). Key results Cameras had good statistical power to detect large reductions in rabbit numbers (>90%) and the percentage kill estimated using cameras was comparable with spotlight transects and vantage-point counts. Conclusions Cameras set up at fixed sampling locations can be an effective method of quantitatively assessing rabbit population control outcomes. We recommend that ≥6 cameras per 100 ha should remain active for at least 5 days before and 5 days following control, so as to obtain reliable estimates of percentage kill. Implications Cameras may be preferable to conventional monitoring methods where there is insufficient area to walk or drive transects, terrain is too rugged or scrubby for transects, and there are no or few vantage points from which to count rabbits.

scholarly journals Evaluation of remote cameras for monitoring multiple invasive mammals in New Zealand

2020 ◽  
Author(s):  
V Anton ◽  
Stephen Hartley ◽  
Heiko Wittmer
Keyword(s):  
New Zealand ◽  
Native Species ◽  
Detection Rates ◽  
Remote Cameras ◽  
Ecological Society ◽  
Mammalian Predators ◽  
Invasive Mammals ◽  
Conservation Projects ◽  
Multiple Species ◽  
Tracking Tunnels

© New Zealand Ecological Society. Numerous conservation projects in New Zealand aim to reduce populations of invasive mammalian predators to facilitate the recovery of native species. However, results of control efforts are often uncertain due to insufficient monitoring. Remote cameras have the potential to monitor multiple species of invasive mammals. To determine the efficiency of cameras as a multi-species monitoring tool, we compared the detection rates of remote cameras and tracking tunnels over 4 non-consecutive days across 40 sites in Wellington. On average, cameras detected significantly more hedgehogs (Erinaceus europaeus) and rats (Rattus spp.) than tracking tunnels, and their images could be used to identify rats to the species level in 50% of detections. Cameras also detected more possums (Trichosurus vulpecula) but missed recording mice (Mus musculus) on some occasions where tracking tunnels detected them, and vice-versa. We conclude that remote cameras are well-suited for simultaneously monitoring multiple species of invasive mammals in New Zealand.

Visual lures increase camera-trap detection of the southern cassowary (Casuarius casuarius johnsonii)

2017 ◽  
Vol 44 (3) ◽  
pp. 230 ◽  
Author(s):  
Wren R. McLean ◽  
Ross L. Goldingay ◽  
David A. Westcott
Keyword(s):  
Endangered Species ◽  
Camera Traps ◽  
Population Surveys ◽  
Monitoring Methods ◽  
Detection Rates ◽  
Mobile Species ◽  
Population Sizes ◽  
Cost Efficient ◽  
A Site

Context Monitoring is a key component in managing wildlife populations and is critical for revealing long-term population trends of endangered species. Cryptic or highly mobile species that occur in low densities and in remote terrain require the development of specific monitoring methods. The southern cassowary is an Australian endangered species that poses many challenges for conducting population surveys. Aims The aims of the present study were to determine the effectiveness of camera traps in detecting cassowaries at a site, to determine whether visual lures increased detection rates, and to explore the potential of camera traps in population surveys. Methods Coloured lures (mimicking large blue and red fruit) were placed in front of a set of camera traps and compared with controls (no lures) at 29 survey sites on the Daintree coast, northern Queensland, Australia. Key results Camera traps with lures (1) detected more birds, (2) had a shorter detection latency, (3) had a marginally greater number of captures, (4) experienced a longer capture duration, (5) were more likely to have the cassowary stop in front of the camera, and (6) achieved a 95% probability of detecting cassowaries in 12 trap days, compared with 28 trap days without lures. Conclusions An increase in the number of cassowaries detected, the reduction in camera latency times and the ability to identify the birds enables a more efficient approach to estimating population sizes over existing methods. This is the first published study to use visual lures to conduct camera trapping of birds. Implications The use of camera traps with lures is a practical and cost-efficient technique for the rapid detection of cassowaries at a site and lends itself to studies of population structure, size and trends.

scholarly journals Evaluation of remote cameras for monitoring multiple invasive mammals in New Zealand

2020 ◽  
Author(s):  
V Anton ◽  
Stephen Hartley ◽  
Heiko Wittmer
Keyword(s):  
New Zealand ◽  
Native Species ◽  
Detection Rates ◽  
Remote Cameras ◽  
Ecological Society ◽  
Mammalian Predators ◽  
Invasive Mammals ◽  
Conservation Projects ◽  
Multiple Species ◽  
Tracking Tunnels

© New Zealand Ecological Society. Numerous conservation projects in New Zealand aim to reduce populations of invasive mammalian predators to facilitate the recovery of native species. However, results of control efforts are often uncertain due to insufficient monitoring. Remote cameras have the potential to monitor multiple species of invasive mammals. To determine the efficiency of cameras as a multi-species monitoring tool, we compared the detection rates of remote cameras and tracking tunnels over 4 non-consecutive days across 40 sites in Wellington. On average, cameras detected significantly more hedgehogs (Erinaceus europaeus) and rats (Rattus spp.) than tracking tunnels, and their images could be used to identify rats to the species level in 50% of detections. Cameras also detected more possums (Trichosurus vulpecula) but missed recording mice (Mus musculus) on some occasions where tracking tunnels detected them, and vice-versa. We conclude that remote cameras are well-suited for simultaneously monitoring multiple species of invasive mammals in New Zealand.

Potential for Individual Tree Monitoring in Ponderosa Pine-Dominated Forests Using Unmanned Aerial System Structure from Motion Point Clouds

2021 ◽  
Author(s):  
Matthew B. Creasy ◽  
Wade Travis Tinkham ◽  
Chad M. Hoffman ◽  
Jody C. Vogeler
Keyword(s):  
Forest Structure ◽  
Ponderosa Pine ◽  
Laser Scanning ◽  
Point Clouds ◽  
System Structure ◽  
Detection Methods ◽  
Unmanned Aerial System ◽  
Individual Tree ◽  
Detection Rates ◽  
Ponderosa Pine Forests

Characterization of forest structure is important for management-related decision making, monitoring, and adaptive management. Increasingly, observations of forest structure are needed at both finer resolutions and across greater extents to support spatially explicit management planning. Unmanned aerial system (UAS)-based photogrammetry provides an airborne method of forest structure data acquisition at a significantly lower cost and time commitment than existing methods such as airborne laser scanning (LiDAR). This study utilizes nearly 5,000 stem-mapped trees in ponderosa pine-dominated forests to evaluate several algorithms for detecting individual tree locations and characterizing crown area across tree sizes. Our results indicate that adaptive variable-window detection methods with UAS-based canopy height models have greater tree detection rates compared to fixed window analysis across a range of tree sizes. Using the UAS approach, probability of detecting individual trees decreases from 97% for dominant overstory to 67% for suppressed understory trees. Additionally, crown radii were correctly determined within 0.5 m for approximately two-thirds of sampled trees. These findings highlight the potential for UAS photogrammetry to characterize forest structure through the detection of trees and tree groups in open-canopy ponderosa pine forests. Further work should investigate how these methods transfer to more diverse species compositions and forest structures.

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 Assessing Summer Pond and Lake Inlet Use by Gray Treefrogs (Hyla versicolor/chrysoscelis complex) Using PVC Pipe Traps in Northwest Missouri

2020 ◽  
Vol 48 (2020) ◽  
pp. 17-21
Author(s):  
J. D. McGhee
Keyword(s):  
Sex Ratio ◽  
Hyla Versicolor ◽  
Monitoring Methods ◽  
Contingency Table Analysis ◽  
Detection Rates ◽  
Sampling Locations ◽  
Table Analysis ◽  
Pvc Pipe ◽  
Gray Treefrog

Abstract The widespread decline in amphibian populations highlights the need for establishing rigorous monitoring methods for long-term population studies. In an attempt to launch a long-term monitoring study for a Gray Treefrog complex (Hyla versicolor LeConte /chrysoscelis Cope, hereafter treefrog) population in northwest Missouri, I tested the use of PVC pipe traps in a system of ponds and inlets along a lakeside habitat for three years. For each pond (3) and inlet (2), I established an array of 16 pipes so as to compare differences in use between pipe location, ponds and inlets, and sex ratio between sites. Pipes were checked twice a week during the summer for the presence of treefrogs. Treefrog usage of pipes between ponds and inlets were compared using a contingency table analysis, while an ANOVA was used to assess differences in sex ratios between sites (α = 0.05). A single inlet was used by treefrogs more heavily than the other ponds or inlet (G = 13.61, df = 3, P = 0.0035), however, I found no differences in terms of pipe location within a pond or inlet. Mean sex ratio between water bodies varied but did not significantly differ. There appears to be little effect in terms of pipe placement within our 50 m buffer from the water's edge, but unique habitat effects at sampling locations may significantly affect detection rates or usage.

scholarly journals Active case detection methods for crusted scabies and leprosy: A systematic review

2021 ◽  
Vol 15 (7) ◽  
pp. e0009577
Author(s):  
Miriam Glennie ◽  
Karen Gardner ◽  
Michelle Dowden ◽  
Bart J. Currie
Keyword(s):  
Systematic Review ◽  
Disease Control ◽  
Detection Methods ◽  
Contact Tracing ◽  
Case Detection ◽  
Community Screening ◽  
Detection Rates ◽  
Active Case Detection ◽  
Active Case ◽  
Crusted Scabies

Background Crusted scabies is endemic in some remote Aboriginal communities in the Northern Territory (NT) of Australia and carries a high mortality risk. Improvement in active case detection (ACD) for crusted scabies is hampered by a lack of evidence about best practice. We therefore conducted a systematic review of ACD methods for leprosy, a condition with similar ACD requirements, to consider how findings could be informative to crusted scabies detection. Methods and principle findings We conducted systematic searches in MEDLINE, CINAHL, Scopus and the Cochrane Database for Systematic Reviews for studies published since 1999 that reported at least one comparison rate (detection or prevalence rate) against which the yield of the ACD method could be assessed. The search yielded 15 eligible studies from 511. Study heterogeneity precluded meta-analysis. Contact tracing and community screening of marginalised ethnic groups yielded the highest new case detection rates. Rapid community screening campaigns, and those using less experienced screening personnel, were associated with lower suspect confirmation rates. There is insufficient data to assess whether ACD campaigns improve treatment outcomes or disease control. Conclusion This review demonstrates the importance of ACD campaigns in communities facing the highest barriers to healthcare access and within neighbourhoods of index cases. The potential benefit of ACD for crusted scabies is not quantified, however, lessons from leprosy suggest value in follow-up with previously identified cases and their close contacts to support for scabies control and to reduce the likelihood of reinfection in the crusted scabies case. Skilled screening personnel and appropriate community engagement strategies are needed to maximise screening uptake. More research is needed to assess ACD cost effectiveness, impact on disease control, and to explore ACD methods capable of capturing the homeless and highly mobile who may be missed in household centric models.

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