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 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.

Density and activity patterns of ocelot populations in Yasuní National Park, Ecuador

Mammalia ◽  
2016 ◽  
Vol 80 (4) ◽  
Author(s):  
Julia Salvador ◽  
Santiago Espinosa
Keyword(s):  
Population Density ◽  
Habitat Loss ◽  
National Park ◽  
Conservation Status ◽  
Activity Patterns ◽  
Camera Trap ◽  
Oil Extraction ◽  
Density Estimates ◽  
Yasuni National Park ◽  
Ecuadorian Amazon

AbstractOcelots were historically hunted for their skins but habitat loss is now their most serious threat, causing rapid declines in populations throughout their range. Ocelot abundance has been estimated for various locations across the Neotropics, but we still lack this information from some countries, including Ecuador. Knowing whether ocelot abundance is increasing or decreasing is important to assess the conservation status of this species and the conditions of its habitats in the Ecuadorian Amazon and in the region. To determine whether ocelot abundance and its behavior are affected by human-related activities, camera-trap surveys were carried out in two localities of Yasuní National Park (YNP), one that has experienced hunting, oil extraction, and roads (Maxus Road) and one that is largely unaffected by these activities (Lorocachi). During the survey, 35 and 36 individual ocelots were photographed in Maxus Road and Lorocachi, respectively. Population density estimates were similar for both localities, ranging from 0.31 (SE±6) to 0.85 (SE±17) ocelots/km

scholarly journals Bringing clarity to the clouded leopard Neofelis diardi: first density estimates from Sumatra

Oryx ◽  
2014 ◽  
Vol 48 (4) ◽  
pp. 536-539 ◽  
Author(s):  
Rahel Sollmann ◽  
Matthew Linkie ◽  
Iding A. Haidir ◽  
David W. Macdonald
Keyword(s):  
Mixed Forest ◽  
Camera Trap ◽  
Forest Loss ◽  
Data Sets ◽  
Panthera Tigris ◽  
Density Estimates ◽  
Clouded Leopard ◽  
Data Limitations ◽  
Capture Recapture ◽  
Study Sites

AbstractWe use data from camera-trap surveys for tigers Panthera tigris in combination with spatial capture–recapture models to provide the first density estimates for the Sunda clouded leopard Neofelis diardi on Sumatra. Surveys took place during 2004–2007 in the Kerinci landscape. Densities were 0.385–1.278 per 100 km2. We found no statistically significant differences in density among four study sites or between primary and mixed forest. Because the data sets are too small to account for differences in detection parameters between sexes, density is probably underestimated. Estimates are comparable to previous estimates of 1–2 per 100 km2 from the lowlands of central Sabah, on Borneo. Data limitations suggest that camera-trap surveys for Sunda clouded leopards require traps spaced more closely, to increase the chance of recaptures at different traps. Nevertheless, these first density estimates for clouded leopards on Sumatra provide a benchmark for measuring future conservation impact on an island that is undergoing rapid forest loss.

scholarly journals Density of the Vulnerable Sunda clouded leopard Neofelis diardi in two commercial forest reserves in Sabah, Malaysian Borneo

Oryx ◽  
2012 ◽  
Vol 46 (3) ◽  
pp. 423-426 ◽  
Author(s):  
Andreas Wilting ◽  
Azlan Mohamed ◽  
Laurentius N. Ambu ◽  
Peter Lagan ◽  
Sam Mannan ◽  
...  
Keyword(s):  
Management Practices ◽  
Iucn Red List ◽  
Separate Species ◽  
Density Estimates ◽  
Clouded Leopard ◽  
Forest Reserves ◽  
Protected Forests ◽  
Capture Recapture ◽  
Commercial Forest ◽  
Malaysian Borneo

AbstractRecently the Sunda clouded leopard Neofelis diardi was recognized as a separate species distinct from the clouded leopard Neofelis nebulosa of mainland Asia. Both species are categorized as Vulnerable on the IUCN Red List. Little is known about the newly identified species and, in particular, information from forests outside protected areas is scarce. Here we present one of the first density estimates calculated with spatial capture–recapture models using camera-trap data. In two commercial forest reserves in Sabah (both certified for their sustainable management practices) the density of the Sunda clouded leopard was estimated to be c. 1 per 100 km2 (0.84±SE 0.42 and 1.04±SE 0.58). The presence of the Sunda clouded leopard in such forests is encouraging for its conservation but additional studies from other areas, including protected forests, are needed to compare and evaluate these densities.

scholarly journals Density of the Vulnerable Sunda clouded leopard Neofelis diardi in a protected area in Sabah, Malaysian Borneo

Oryx ◽  
2012 ◽  
Vol 46 (3) ◽  
pp. 427-430 ◽  
Author(s):  
Jedediah Brodie ◽  
Anthony J. Giordano
Keyword(s):  
Population Density ◽  
Primary Forest ◽  
Sampling Effort ◽  
Conservation Area ◽  
Entire Study ◽  
Clouded Leopard ◽  
Geographic Ranges ◽  
Logged Forest ◽  
Entire Study Area ◽  
Malaysian Borneo

AbstractPopulation density is an important parameter for monitoring and guiding conservation of small or threatened wildlife populations. Yet, despite the Vulnerable status of both species of clouded leopard Neofelis spp., and their disappearing tropical forest habitat, information on their population density is lacking from across their broad geographic ranges. Here we estimated population density of the Sunda clouded leopard N. diardi in the Maliau Basin Conservation Area in Sabah, Malaysian Borneo, one of the first such estimates for either species of clouded leopard. With 25 camera-trap stations, each operated for at least 81 trap-nights, we obtained 59 detections of four individual Sunda clouded leopards in undisturbed primary rainforest but only a single detection in logged forest, despite similar sampling effort. Using spatially-explicit mark–recapture models, we estimated a density of 1.9 individuals per 100 km2 (95% confidence interval 0.7–5.4) for primary forest and 0.8 per 100 km2 (0.2–2.6) for the entire study area (including logged forest). These results will contribute to a better understanding of clouded leopard status and serve as a reference for future assessments of the species.

scholarly journals Ocelot Leopardus pardalis in Belize: the impact of trap spacing and distance moved on density estimates

Oryx ◽  
2007 ◽  
Vol 41 (4) ◽  
pp. 469-477 ◽  
Author(s):  
Adam Dillon ◽  
Marcella J. Kelly
Keyword(s):  
Camera Trap ◽  
Pine Forest ◽  
Camera Trapping ◽  
Buffer Size ◽  
Size Analysis ◽  
Wet Season ◽  
Density Estimates ◽  
Leopardus Pardalis ◽  
Broad Leaf ◽  
The Impact

AbstractWe used remote cameras to obtain information on an elusive species and to examine the effects of different camera trapping methodologies on abundance estimates. We determined activity pattern, trail use, trap success, and density of ocelot Leopardus pardalis in seven camera-trap surveys across two habitat types in western Belize: tropical broad-leaf rainforest and tropical pine forest. Ocelots in the rainforest were active mostly at night, in particular immediately after sunset, and they travelled on low-use roads (especially in the wet season) and high-use roads (especially in the dry season) more than established and newly cut trails. Trap success was relatively high in the rainforest (2.11–6.20 captures per 100 trap nights) and low in the pine forest (0.13–0.15 captures per 100 trap nights). Camera trapping combined with mark-recapture statistics gave densities of 25.82–25.88 per 100 km2 in the broad-leaf versus 2.31–3.80 per 100 km2 in the pine forest. Density estimates increased when animals repeatedly captured at the same camera (zero-distance moved animals) were included in the buffer size analysis. Density estimates were significantly negatively correlated with distance between cameras. We provide information on ocelot population status from an unstudied portion of its range and advise that camera trap methodologies be standardized to permit comparisons across sites.

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 Densities of the Eurasian Threetoed Woodpecker Picoides tridactylus calculated from sap row surveys are on par with estimates from fixed route bird censusing

Ornis Svecica ◽  
2021 ◽  
Vol 31 ◽  
pp. 94-106
Author(s):  
Björn Ferry ◽  
Johan Ekenstedt ◽  
Martin Green
Keyword(s):  
Population Density ◽  
Home Range ◽  
Large Scale ◽  
Montane Forest ◽  
Northern Sweden ◽  
Montane Forests ◽  
Density Estimates ◽  
Species Specific ◽  
Different Parts

Species-specific tracks animals can be an effective way of mapping species that are hard to find even if they are present. We used observations of sap rows on trees to calculate densities of Eurasian Three-toed Woodpeckers Picoides tridactylus. We surveyed 14 fixed routes in northern Sweden below the montane forest for sap rows during the autumn of 2020. We used our observations of fresh sap rows together with average home range and proportion of active territories per year derived from the literature, to calculate large-scale woodpecker population density. The density based on sap rows was 0.19 pairs per km2. Densities from fixed route bird observations for different parts of Västerbotten County below the montane forests were 0.13–0.14 pairs per km2, in relative agreement with the estimates from sap rows. We also calculated the population density from fixed route observations in the montane forests, and these were almost three times higher. Our density calculations correspond to 7,900 pairs in Västerbotten County. These results indicate that systematic counts of sap rows can quickly provide credible population density estimates of Eurasian Three-toed Woodpeckers.

scholarly journals Density trends of wild felids in northern Laos

2021 ◽  
Author(s):  
Akchousanh Rasphone ◽  
Jan F. Kamler ◽  
Mathias Tobler ◽  
David W. Macdonald
Keyword(s):  
National Park ◽  
Community Outreach ◽  
Camera Trap ◽  
Panthera Tigris ◽  
Mesopredator Release ◽  
Density Estimates ◽  
Clouded Leopard ◽  
Capture Recapture ◽  
Leopard Cat ◽  
Prionailurus Bengalensis

AbstractDetermining the density trends of a guild of species can help illuminate their interactions, and the impacts that humans might have on them. We estimated the density trends from 2013 to 2017 of the clouded leopard Neofelis nebulosa, leopard cat Prionailurus bengalensis and marbled cat Pardofelis marmorata in Nam Et—Phou Louey National Park (NEPL), Laos, using camera trap data and spatial capture-recapture models. Mean (± SD) density estimates (individuals/100 km2) for all years were 1.77 ± 0.30 for clouded leopard, 1.50 ± 0.30 for leopard cat, and 3.80 ± 0.70 for marbled cat. There was a declining trend in density across the study years for all three species, with a ≥ 90% probability of decline for clouded leopard and leopard cat and an 83% probability of decline for marbled cat. There was no evidence that mesopredator release occurred as a result of tiger (Panthera tigris) and leopard (P. pardus) extirpations. We believe that snaring, the factor that led to the extirpation of tiger and leopard in NEPL, is now contributing to the decline of smaller felids, to an extent that over-rides any potential effects of mesopredator release on their densities and interactions. We recommend that the NEPL managers implement a more systematic and intensified snare removal program, in concert with extensive community outreach and engagement of local people to prevent the setting of snares. These actions might be the only hope for saving the remaining members of the felid community in NEPL.

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