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[ÀÚ·á] Estimation of Population Size Using Open Capture–Recapture Models 




Estimation of Population Size Using Open Capture–Recapture Models
Authors: McDonald T. L.1; Amstrup S. C.2
Source: Journal of Agricultural, Biological & Environmental Statistics, Volume 6, Number 2, 1 June 2001, pp. 206220(15)
Publisher: American Statistical Association
Abstract:
One of the most important needs for wildlife managers is an accurate estimate of population size. Yet, for many species, including most marine species and large mammals, accurate and precise estimation of numbers is one of the most difficult of all research challenges. Openpopulation capturerecapture models have proven useful in many situations to estimate survival probabilities but typically have not been used to estimate population size. We show that openpopulation models can be used to estimate population size by developing a HorvitzThompsontype estimate of population size and an estimator of its variance. Our population size estimate keys on the probability of capture at each trap occasion and therefore is quite general and can be made a function of external covariates measured during the study. Here we define the estimator and investigate its bias, variance, and variance estimator via computer simulation. Computer simulations make extensive use of real data taken from a study of polar bears (Ursus maritimus) in the Beaufort Sea. The population size estimator is shown to be useful because it was negligibly biased in all situations studied. The variance estimator is shown to be useful in all situations, but caution is warranted in cases of extreme capture heterogeneity.
Keywords: JOLLYSEBER; MARK; RADIO TELEMETRY; RESIGHT; TRAP
Language: English
Document Type: Research article
Affiliations: 1: Statistician/Project Manager, Western EcoSystems Technology, Inc., 2003 Central Avenue, Cheyenne,WY 82001. 2: U.S. Geological Survey, Biological Research Division, 1011 East Tudor Road, Anchorage, AK 99503.
http://www.westinc.com/reports/big_game/McDonald%20and%20Amstrup%202001.pdf 


