Modeling Capture, Recapture, and Removal Statistics for Estimation of Demographic Parameters for Fish and Wildlife Populations: Past, Present, and Future

1991 ◽  
Vol 86 (413) ◽  
pp. 225 ◽  
Author(s):  
Kenneth H. Pollock
Keyword(s):  
Demographic Parameters ◽  
Capture Recapture ◽  
Wildlife Populations

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.

Application of photographic capture?recapture modelling to estimate demographic parameters for male Asian elephants

2007 ◽  
Vol 10 (3) ◽  
pp. 391-399 ◽  
Author(s):  
Varun R. Goswami ◽  
M. D. Madhusudan ◽  
K. Ullas Karanth
Keyword(s):  
Demographic Parameters ◽  
Asian Elephants ◽  
Capture Recapture

Modelling survival and breeding dispersal to unobservable nest sites

2016 ◽  
Vol 43 (5) ◽  
pp. 411 ◽  
Author(s):  
Giacomo Tavecchia ◽  
Ana Sanz-Aguilar ◽  
Belinda Cannell
Keyword(s):  
Breeding Site ◽  
Demographic Parameters ◽  
Breeding Dispersal ◽  
Artificial Nests ◽  
Breeding Sites ◽  
Nest Sites ◽  
Local Survival ◽  
Permanent Migration ◽  
Capture Recapture ◽  
Event Capture

Context Demographic parameters in wildlife populations are typically estimated by monitoring a limited number of individuals in observable sites and assuming that these are representative of the whole population. If individuals permanently disperse to unobservable breeding sites, recruitment and immature survival are expected to be negatively biased and breeding-site fidelity cannot be investigated. Aims To develop a method to obtain unbiased estimated of survival, recruitment and breeding dispersal when individuals can move to, or recruit in, unobservable sites. Methods We used the flexibility of multi-event capture–recapture models to estimate dispersal and recruitment to unobservable sites, merging observations made at two sites within the same breeding locations. We illustrated the model with data on little penguin (Eudyptula minor) breeding in artificial as well as in natural nests. Natural nests are unknown or inaccessible and birds in these sites remain unobservable. Encounters at beaches surrounding the colony suggested that marked animals can permanently move to unobservable nests. We built the multi-event model considering two possible states of the individuals (alive breeding in a nest box and alive in a natural nest) and three types of observations (encountered at a nest only, encountered at the beach only and encountered at both places). This model ensured that the breeding dispersal to unobservable places became estimable. Key results Results indicate that the estimated survival was 8% higher than when recaptures at artificial nests were analysed alone. Also, fidelity to artificial nests was 12% lower than to natural nests. This might reflect the greater availability of natural sites or, alternatively, a heterogeneity between these two types of nest. Conclusions We obtained an estimate of local survival of little penguins breeding at Penguin Island that incorporates the permanent migration to unobservable sites and found an asymmetric dispersion towards natural nests. Implication Our conclusions suggest a need for more careful treatment of data derived from artificial sites alone, as demographic parameters might be underestimated if animals prefer natural breeding sites or if they are in greater proportion compared with artificial ones. The analytical approach presented can be applied to many biological systems, when animals might move into inaccessible or unobservable breeding sites.

scholarly journals Estimating demographic parameters from capture-recapture data with dependence among individuals within clusters

2013 ◽  
Vol 4 (5) ◽  
pp. 474-482 ◽  
Author(s):  
Rémi Choquet ◽  
Ana Sanz-Aguilar ◽  
Blandine Doligez ◽  
Erika Nogué ◽  
Roger Pradel ◽  
...  
Keyword(s):  
Demographic Parameters ◽  
Capture Recapture

scholarly journals Dealing with many correlated covariates in capture-recapture models

2016 ◽  
Author(s):  
Olivier Gimenez ◽  
Christophe Barbraud
Keyword(s):  
Principal Component Analysis ◽  
Population Dynamics ◽  
Statistical Significance ◽  
Principal Component ◽  
High Dimensionality ◽  
Demographic Parameters ◽  
Statistical Tools ◽  
Capture Recapture ◽  
New Variables ◽  
Standard Software

SummaryCapture-recapture models for estimating demographic parameters allow covariates to be incorporated to better understand population dynamics. However, high-dimensionality and multicollinearity can hamper estimation and inference. Principal component analysis is incorporated within capture-recapture models and used to reduce the number of predictors into uncorrelated synthetic new variables. Principal components are selected by sequentially assessing their statistical significance. We provide an example on seabird survival to illustrate our approach. Our method requires standard statistical tools, which permits an efficient and easy implementation using standard software.

Modeling Association among Demographic Parameters in Analysis of Open Population Capture-Recapture Data

Biometrics ◽  
2005 ◽  
Vol 61 (1) ◽  
pp. 46-54 ◽  
Author(s):  
William A. Link ◽  
Richard J. Barker
Keyword(s):  
Demographic Parameters ◽  
Open Population ◽  
Capture Recapture

scholarly journals Correction: A Comparison of Grizzly Bear Demographic Parameters Estimated from Non-Spatial and Spatial Open Population Capture-Recapture Models

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0137940
Author(s):  
Jesse Whittington ◽  
Michael A. Sawaya
Keyword(s):  
Demographic Parameters ◽  
Grizzly Bear ◽  
Open Population ◽  
Capture Recapture

scholarly journals Modeling the demography of species providing extended parental care: A capture-recapture multievent model with a case study on Polar Bears (Ursus maritimus)

2019 ◽  
Author(s):  
Sarah Cubaynes ◽  
Jon Aars ◽  
Nigel G. Yoccoz ◽  
Roger Pradel ◽  
Øystein Wiig ◽  
...  
Keyword(s):  
Parental Care ◽  
Litter Size ◽  
Ursus Maritimus ◽  
Reproductive History ◽  
Demographic Parameters ◽  
Capture Recapture ◽  
Breeding Probability ◽  
Extended Parental Care

AbstractIn species providing extended parental care, one or both parents care for altricial young over a period including more than one breeding season. We expect large parental investment and long-term dependency within family units to cause high variability in life trajectories among individuals with complex consequences at the population level. So far, models for estimating demographic parameters in free-ranging animal populations mostly ignore extended parental care, thereby limiting our understanding of its consequences on parents and offspring life histories.We designed a capture-recapture multi-event model for studying the demography of species providing extended parental care. It handles statistical multiple-year dependency among individual demographic parameters grouped within family units, variable litter size, and uncertainty on the timing at offspring independence. It allows to evaluate trade-offs among demographic parameters, the influence of past reproductive history on the caring parent survival status, breeding probability and litter size probability, while accounting for imperfect detection of family units. We assess the model performances using simulated data, and illustrate its use with a long-term dataset collected on the Svalbard polar bears (Ursus maritimus).Our model performed well in terms of bias and mean square error and in estimating demographic parameters in all simulated scenarios, both when offspring departure probability from the family unit occurred at a constant rate or varied during the field season depending on the date of capture. For the polar bear case study, we provide estimates of adult and dependent offspring survival rates, breeding probability and litter size probability. Results showed that the outcome of the previous reproduction influenced breeding probability.Overall, our results show the importance of accounting for i) the multiple-year statistical dependency within family units, ii) uncertainty on the timing at offspring independence, and iii) past reproductive history of the caring parent. If ignored, estimates obtained for breeding probability, litter size, and survival can be biased. This is of interest in terms of conservation because species providing extended parental care are often long-living mammals vulnerable or threatened with extinction.

A Likelihood-Based Approach to Capture-Recapture Estimation of Demographic Parameters under the Robust Design

Biometrics ◽  
1995 ◽  
Vol 51 (1) ◽  
pp. 293 ◽  
Author(s):  
William L. Kendall ◽  
Kenneth H. Pollock ◽  
Cavell Brownie
Keyword(s):  
Robust Design ◽  
Demographic Parameters ◽  
Capture Recapture
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