The Estimation of Population Parameters from Data Obtained by Means of the Capture-Recapture Method: III. An Example of the Practical Applications of the Method

Biometrika ◽  
1953 ◽  
Vol 40 (1/2) ◽  
pp. 137 ◽  
Author(s):  
P. H. Leslie ◽  
Dennis Chitty ◽  
Helen Chitty
Keyword(s):  
Population Parameters ◽  
Practical Applications ◽  
Capture Recapture

scholarly journals Optimal sampling design for spatial capture-recapture

2020 ◽  
Author(s):  
Gates Dupont ◽  
J. Andrew Royle ◽  
Muhammad Ali Nawaz ◽  
Chris Sutherland
Keyword(s):  
Sampling Design ◽  
Spatial Configuration ◽  
Optimal Sampling ◽  
Density Estimates ◽  
Practical Applications ◽  
Industry Standard ◽  
Optimal Sampling Design ◽  
Capture Recapture ◽  
Spatial Locations ◽  
Probability Of Capture

AbstractSpatial capture-recapture (SCR) has emerged as the industry standard for estimating population density by leveraging information from spatial locations of repeat encounters of individuals. The precision of density estimates depends fundamentally on the number and spatial configuration of traps. Despite this knowledge, existing sampling design recommendations are heuristic and their performance remains untested for most practical applications. To address this issue, we propose a genetic algorithm that minimizes any sensible, criteria-based objective function to produce near-optimal sampling designs. To motivate the idea of optimality, we compare the performance of designs optimized using three model-based criteria related to the probability of capture. We use simulation to show that these designs out-perform those based on existing recommendations in terms of bias, precision, and accuracy in the estimation of population size. Our approach allows conservation practitioners and researchers to generate customized and improved sampling designs for wildlife monitoring.

Estimation of apparent survival probability of the harvestman Paranemastoma sillii sillii (Herman, 1871) from two caves

2017 ◽  
Vol 67 (2) ◽  
pp. 165-176 ◽  
Author(s):  
Rodica Plăiaşu ◽  
Arpat Ozgul ◽  
Benedikt R. Schmidt ◽  
Raluca I. Băncilă
Keyword(s):  
Sex Differences ◽  
Weather Conditions ◽  
Monthly Variation ◽  
Population Parameters ◽  
Apparent Survival ◽  
Sex Effect ◽  
Survival Difference ◽  
Surface Weather ◽  
Capture Recapture ◽  
Western Romania

Reliable estimates of population parameters are lacking for most cave-dwelling species. This lack of knowledge may hinder the appropriate management of caves and populations of cave-dwelling species. Using monthly capture-recapture data and Cormack-Jolly-Seber models, we (i) estimated the apparent survival of individuals in two cave populations of the harvestman Paranemastoma sillii sillii (Herman, 1871) from the Mehedinti Mountains in south-western Romania; (ii) investigated temporal variation in apparent survival; (iii) tested if surface weather conditions affect apparent survival of cave-dwelling harvestmen through their influence upon cave environmental conditions and (iv) tested for sex differences in apparent survival. Our results show that the apparent monthly survival estimates were high for both studied cave populations and there was a significant sex effect on survival. Males had lower survival than females, and the survival difference between caves was larger in males than in females. Temporal (i.e., monthly) variation in apparent survival was low and the weather conditions at the surface had little influence on apparent survival as the environment inside the caves is well buffered against weather fluctuations outside the caves. Our results indicate that caves stabilize survival of facultative cave-dwelling species and may serve as microrefugia for epigean species. We suggest that caves should be considered for conservation because they may serve as a refuge for some epigean species during harsh weather conditions.

On the reliability of enumeration for mark and recapture census of voles

1976 ◽  
Vol 54 (6) ◽  
pp. 1019-1024 ◽  
Author(s):  
Ray Hilborn ◽  
James A. Redfield ◽  
Charles J. Krebs
Keyword(s):  
Computer Simulation ◽  
Population Size ◽  
Individual Variation ◽  
Population Parameters ◽  
Small Rodents ◽  
Capture Recapture ◽  
Sampling Intervals ◽  
Average Individual ◽  
Probability Of Capture

Some studies of populations in small rodents rely on enumeration of individuals to provide an estimate of population size. A computer simulation of the capture–recapture process was used to examine the influence of five population parameters on the reliability of enumeration. Enumeration is shown to be insensitive to population size, survival between sampling intervals, and individual variation in the probability of capture. Enumeration is sensitive to the probability of capture; if the probability of capture for the average individual falls below 0.5, the enumeration technique provides a poor estimate of population size. Enumeration is also extremely sensitive to reduced probabilities of capture for unmarked animals. Data from capture–recapture studies of five species of Microtus were used in the computer simulation, and it was concluded for these five species that enumerated populations are at least 10–20% smaller than the actual populations.

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