Using spatially‐explicit capture–recapture models to explain variation in seasonal density patterns of sympatric ursids

Ecography ◽  
2018 ◽  
Vol 42 (2) ◽  
pp. 237-248 ◽  
Author(s):  
Jeffrey B. Stetz ◽  
Michael S. Mitchell ◽  
Katherine C. Kendall
Keyword(s):  
Spatially Explicit ◽  
Capture Recapture

scholarly journals Leopard Density Estimation within an Enclosed Reserve, Namibia Using Spatially Explicit Capture-Recapture Models

Animals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 724
Author(s):  
Noack ◽  
Heyns ◽  
Rodenwoldt ◽  
Edwards
Keyword(s):  
Management Strategies ◽  
Camera Traps ◽  
Spatially Explicit ◽  
Conservation Areas ◽  
Term Survival ◽  
New Class ◽  
Capture Recapture ◽  
Wildlife Populations ◽  
Effective Conservation

The establishment of enclosed conservation areas are claimed to be the driving force for the long-term survival of wildlife populations. Whilst fencing provides an important tool in conservation, it simultaneously represents a controversial matter as it stops natural migration processes, which could ultimately lead to inbreeding, a decline in genetic diversity and local extinction if not managed correctly. Thus, wildlife residing in enclosed reserves requires effective conservation and management strategies, which are strongly reliant on robust population estimates. Here, we used camera traps combined with the relatively new class of spatially explicit capture-recaptured models (SECR) to produce the first reliable leopard population estimate for an enclosed reserve in Namibia. Leopard density was estimated at 14.51 leopards/100 km2, the highest recorded density in Namibia to date. A combination of high prey abundance, the absence of human persecution and a lack of top-down control are believed to be the main drivers of the recorded high leopard population. Our results add to the growing body of literature which suggests enclosed reserves have the potential to harbour high densities and highlight the importance of such reserves for the survival of threatened species in the future.

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

2019 ◽  
Vol 9 (1) ◽  
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.

Estimating population size by spatially explicit capture-recapture

Oikos ◽  
2012 ◽  
Vol 122 (6) ◽  
pp. 918-928 ◽  
Author(s):  
Murray G. Efford ◽  
Rachel M. Fewster
Keyword(s):  
Population Size ◽  
Spatially Explicit ◽  
Capture Recapture

Applying spatially explicit capture–recapture models to estimate black bear density in South Carolina

2019 ◽  
Vol 43 (3) ◽  
pp. 500-507
Author(s):  
Shefali Azad ◽  
Katherine McFadden ◽  
Joseph D. Clark ◽  
Tammy Wactor ◽  
David S. Jachowski
Keyword(s):  
South Carolina ◽  
Black Bear ◽  
Spatially Explicit ◽  
Capture Recapture

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

2019 ◽  
Vol 71 (1) ◽  
pp. 1-20 ◽  
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

Estimating jaguar (Panthera onca) density in a preserved coastal area of French Guiana

Mammalia ◽  
2018 ◽  
Vol 82 (2) ◽  
pp. 188-192 ◽  
Author(s):  
Matthis Petit ◽  
Thomas Denis ◽  
Ondine Rux ◽  
Cécile Richard-Hansen ◽  
Rachel Berzins
Keyword(s):  
Home Range ◽  
Coastal Area ◽  
French Guiana ◽  
Scale Parameter ◽  
Local Density ◽  
Home Range Size ◽  
Range Size ◽  
Spatially Explicit ◽  
Panthera Onca ◽  
Capture Recapture

AbstractKnowledge of the jaguar population is needed in French Guiana that faces an increase of human-jaguar conflicts. We carried out a camera trap survey to assess jaguar local density and home range size in a preserved coastal area of French Guiana. We ran spatially explicit capture recapture (SECR) models. In our model, the scale parameterσ, that is linked to the home range size, was larger for males (σ=3.87±0.59 SE km) than for females (σ=2.33±0.30 SE km). The assessed jaguar density was 3.22±0.87 SE ind. 100 km−2, which should be considered as an optimal density in a French Guiana coastal area.

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