Estimating tiger Panthera tigris populations from camera-trap data using capture—recapture models

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.

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Density trends of wild felids in northern Laos

Biodiversity and Conservation ◽

10.1007/s10531-021-02172-0 ◽

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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Do conservation strategies that increase tiger populations have consequences for other wild carnivores like leopards?

Scientific Reports ◽

10.1038/s41598-019-51213-w ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Ujjwal Kumar ◽

Neha Awasthi ◽

Qamar Qureshi ◽

Yadvendradev Jhala

Keyword(s):

Species Conservation ◽

Camera Trap ◽

Conservation Strategies ◽

Spatially Explicit ◽

Large Carnivores ◽

Catchment Scale ◽

Large Carnivore ◽

Positive Growth ◽

Capture Recapture ◽

Very High

Abstract Most large carnivore populations are declining across their global range except in some well managed protected areas (PA’s). Investments for conserving charismatic apex carnivores are often justified due to their umbrella effect on biodiversity. We evaluate population trends of two large sympatric carnivores, the tiger and leopard through spatially-explicit-capture-recapture models from camera trap data in Kanha PA, India, from 2011 to 2016. Our results show that the overall density (100 km−2) of tigers ranged between 4.82 ± 0.33 to 5.21 ± 0.55SE and of leopards between 6.63 ± 0.71 to 8.64 ± 0.75SE, with no detectable trends at the PA scale. When evaluated at the catchment scale, Banjar catchment that had higher prey density and higher conservation investments, recorded significant growth of both carnivores. While Halon catchment, that had lower prey and conservation investments, populations of both carnivores remained stable. Sex ratio of both carnivores was female biased. As is typical with large carnivores, movement parameter sigma (an index for range size), was larger for males than for females. However, sigma was surprisingly similar for the same genders in both carnivores. At home-range scale, leopards achieved high densities and positive growth rates in areas that had low, medium or declining tiger density. Our results suggest that umbrella-species conservation value of tigers is likely to be compromised at very high densities and therefore should not be artificially inflated through targeted management.

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Spatially explicit capture-recapture method (SECR, SPACECAP): A new approach to determination of the Amur tiger (Panthera tigris altaica) population density by means of camera-traps

Doklady Biological Sciences ◽

10.1134/s0012496613060033 ◽

2013 ◽

Vol 453 (1) ◽

pp. 365-368 ◽

Cited By ~ 9

Author(s):

J. A. Hernandez-Blanco ◽

V. V. Rozhnov ◽

V. S. Lukarevskiy ◽

S. V. Naidenko ◽

M. D. Chistopolova ◽

...

Keyword(s):

Population Density ◽

Camera Traps ◽

Spatially Explicit ◽

Panthera Tigris ◽

Amur Tiger ◽

New Approach ◽

Panthera Tigris Altaica ◽

Capture Recapture

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A Spatially Explicit Capture–Recapture Model for Partially Identified Individuals When Trap Detection Rate Is Less than One

Calcutta Statistical Association Bulletin ◽

10.1177/0008068319837087 ◽

2019 ◽

Vol 71 (1) ◽

pp. 1-20 ◽

Cited By ~ 1

Author(s):

Soumen Dey ◽

Mohan Delampady ◽

K. Ullas Karanth ◽

Arjun M. Gopalaswamy

Keyword(s):

Detection Probability ◽

Credible Interval ◽

Camera Traps ◽

Spatially Explicit ◽

Panthera Tigris ◽

Partial Identity ◽

Proposed Model ◽

Estimation Problems ◽

Capture Recapture ◽

Future Work

Spatially explicit capture–recapture (SECR) models have gained enormous popularity to solve abundance estimation problems in ecology. In this study, we develop a novel Bayesian SECR model that disentangles two processes: one is the process of animal arrival within a detection region, and the other is the process of recording this arrival by a given set of detectors. We integrate this complexity into an advanced version of a recent SECR model involving partially identified individuals (Royle JA. Spatial capture-recapture with partial identity. arXiv preprint arXiv:1503.06873, 2015). We assess the performance of our model over a range of realistic simulation scenarios and demonstrate that estimates of population size N improve when we utilize the proposed model relative to the model that does not explicitly estimate trap detection probability (Royle JA. Spatial capture-recapture with partial identity. arXiv preprint arXiv:1503.06873, 2015). We confront and investigate the proposed model with a spatial capture–recapture dataset from a camera trapping survey of tigers (Panthera tigris) in Nagarahole study area of southern India. Detection probability is estimated at 0.489 (with 95% credible interval (CI) [0.430, 0.543]) which implies that the camera traps are performing imperfectly and thus justifying the use of our model in real world applications. We discuss possible extensions, future work and relevance of our model to other statistical applications beyond ecology. AMS classification codes: 62F15, 92D40

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Predicting preferred prey of Sumatran tigers Panthera tigris sumatrae via spatio-temporal overlap

Oryx ◽

10.1017/s0030605319000577 ◽

2020 ◽

pp. 1-7

Author(s):

Maximilian L. Allen ◽

Marsya C. Sibarani ◽

Miha Krofel

Keyword(s):

Wild Boar ◽

Camera Trap ◽

Critically Endangered ◽

Panthera Tigris ◽

Potential Prey ◽

Encounter Rates ◽

Prey Preferences ◽

Sambar Deer ◽

Composite Scores ◽

Temporal Overlap

Abstract Encounter rates of carnivores with prey are dependent on spatial and temporal overlap, and are often highest with their preferred prey. The Critically Endangered Sumatran tiger Panthera tigris sumatrae is dependent on prey populations, but little is known about its prey preferences. We collected camera-trap data for 7 years (2010–2016) in Bukit Barisan Selatan National Park, Sumatra, to investigate spatial and temporal overlap of tigers with potential prey species. We also developed a novel method to predict predator–prey encounter rates and potential prey preferences from camera-trap data. We documented at least 10 individual tigers, with an overall detection rate of 0.24 detections/100 trap nights. Tigers exhibited a diurnal activity pattern and had highest temporal overlap with wild boar Sus scrofa and pig-tailed macaques Macaca nemestrina, but highest spatial overlap with wild boar and sambar deer Rusa unicolor. We created a spatial and temporal composite score and three additional composite scores with adjustments for the spatial overlap and preferred prey mass. Wild boars ranked highest for all composite scores, followed by sambar deer, and both are known as preferred tiger prey in other areas. Spatial and temporal overlaps are often considered as separate indices, but a composite score may facilitate better predictions of encounter rates and potential prey preferences. Our findings suggest that prey management efforts in this area should focus on wild boar and sambar deer, to ensure a robust prey base for this Critically Endangered tiger population.

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How many tigers Panthera tigris are there in Huai Kha Khaeng Wildlife Sanctuary, Thailand? An estimate using photographic capture-recapture sampling

Oryx ◽

10.1017/s0030605307414107 ◽

2007 ◽

Vol 41 (4) ◽

pp. 447-453 ◽

Cited By ~ 44

Author(s):

Saksit Simcharoen ◽

Anak Pattanavibool ◽

K. Ullas Karanth ◽

James D. Nichols ◽

N. Samba Kumar

Keyword(s):

Tropical Forests ◽

Panthera Tigris ◽

Test Results ◽

Wildlife Sanctuary ◽

Abundance Estimate ◽

Capture Recapture ◽

Tiger Conservation ◽

Tiger Population ◽

Indian Reserves ◽

Closure Assumption

AbstractWe used capture-recapture analyses to estimate the density of a tiger Panthera tigris population in the tropical forests of Huai Kha Khaeng Wildlife Sanctuary, Thailand, from photographic capture histories of 15 distinct individuals. The closure test results (z = 0.39, P = 0.65) provided some evidence in support of the demographic closure assumption. Fit of eight plausible closed models to the data indicated more support for model Mh, which incorporates individual heterogeneity in capture probabilities. This model generated an average capture probability $\hat p$ = 0.42 and an abundance estimate of $\widehat{N}(\widehat{SE}[\widehat{N}])$ = 19 (9.65) tigers. The sampled area of $\widehat{A}(W)(\widehat{SE}[\widehat{A}(W)])$ = 477.2 (58.24) km2 yielded a density estimate of $\widehat{D}(\widehat{SE}[\widehat{D}])$ = 3.98 (0.51) tigers per 100 km2. Huai Kha Khaeng Wildlife Sanctuary could therefore hold 113 tigers and the entire Western Forest Complex c. 720 tigers. Although based on field protocols that constrained us to use sub-optimal analyses, this estimated tiger density is comparable to tiger densities in Indian reserves that support moderate prey abundances. However, tiger densities in well-protected Indian reserves with high prey abundances are three times higher. If given adequate protection we believe that the Western Forest Complex of Thailand could potentially harbour >2,000 wild tigers, highlighting its importance for global tiger conservation. The monitoring approaches we recommend here would be useful for managing this tiger population.

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An assessment of carnivore relative abundance and density in the eastern rainforests of Madagascar using remotely-triggered camera traps

Oryx ◽

10.1017/s0030605309991037 ◽

2010 ◽

Vol 44 (2) ◽

pp. 219-222 ◽

Cited By ~ 29

Author(s):

Brian Gerber ◽

Sarah M. Karpanty ◽

Charles Crawford ◽

Mary Kotschwar ◽

Johnny Randrianantenaina

Keyword(s):

Relative Abundance ◽

National Park ◽

Camera Trap ◽

Camera Traps ◽

Domestic Dog ◽

Likelihood Method ◽

Ranomafana National Park ◽

Carnivore Species ◽

Cryptoprocta Ferox ◽

Capture Recapture

AbstractDespite major efforts to understand and conserve Madagascar’s unique biodiversity, relatively little is known about the island’s carnivore populations. We therefore deployed 43 camera-trap stations in Ranomafana National Park, Madagascar during June–August 2007 to evaluate the efficacy of this method for studying Malagasy carnivores and to estimate the relative abundance and density of carnivores in the eastern rainforest. A total of 755 camera-trap nights provided 1,605 photographs of four endemic carnivore species (fossa Cryptoprocta ferox, Malagasy civet Fossa fossana, ring-tailed mongoose Galidia elegans and broad-striped mongoose Galidictus fasciata), the exotic Indian civet Viverricula indica and the domestic dog Canis familiaris. We identified 38 individual F. fossana and 10 individual C. ferox. We estimated density using both capture-recapture analyses, with a buffer of full mean-maximum-distance-moved, and a spatially-explicit maximum-likelihood method (F. fossana: 3.03 and 2.23 km-2, respectively; C. ferox: 0.15 and 0.17 km-2, respectively). Our estimated densities of C. ferox in rainforest are lower than published estimates for conspecifics in the western dry forests. Within Ranomafana National Park species richness of native carnivores did not vary among trail systems located in secondary, selectively-logged and undisturbed forest. These results provide the first assessment of carnivore population parameters using camera-traps in the eastern rainforests of Madagascar.

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A spatially explicit approach for estimating space use and density of common genets

Animal Biodiversity and Conservation ◽

10.32800/abc.2014.37.0023 ◽

2014 ◽

Vol 37 (1) ◽

pp. 23-33

Author(s):

P. Sarmento ◽

◽

J. Cruz ◽

C. Eira ◽

C. Fonseca ◽

...

Keyword(s):

Spatial Model ◽

Environmental Variables ◽

Camera Trap ◽

Grid Size ◽

Future Research ◽

Spatially Explicit ◽

Density Estimates ◽

Closed Population ◽

Abundance Estimates ◽

Capture Recapture

Many species that occur at low densities are not accurately estimated using capture–recapture methods as such techniques assume that populations are well–defined in space. To solve this bias, spatially explicit capture–recapture (SECR) models have recently been developed. These models incorporate movement and can identify areas where it is more likely for individuals to concentrate their activity. In this study, we used data from camera–trap surveys of common genets (Genetta genetta) in Serra da Malcata (Portugal), designed to compare abundance estimates produced by SECR models with traditional closed–capture models. Using the SECR models, we observed spatial heterogeneity in genet distribution and density estimates were approximately two times lower than those obtained from the closed population models. The non–spatial model estimates were constrained to sampling grid size and likely underestimated movements, thereby overestimating density. Future research should consider the incorporation of cost–weighed models that can include explicit hypothesis on how environmental variables influence the distance metric.

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