Mark-recapture methods for monitoring Sonoran populations of the desert tortoise (Gopherus agassizii)

Persistent Link:
http://hdl.handle.net/10150/278380
Title:
Mark-recapture methods for monitoring Sonoran populations of the desert tortoise (Gopherus agassizii)
Author:
Murray, Roy Charles, 1968-
Issue Date:
1993
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
I determined reliable methods for monitoring Sonoran populations of the desert tortoise. Tortoises were significantly clumped (p < 0.001) on three 1-mi² plots in Arizona, but were not significantly different from random (p > 0.05) on a 1-km² plot, supporting the use of smaller plots in mark-recapture population studies. Simulations showed that Program CAPTURE's Jackknife and Darroch estimators are robust to variations in capturability, which confound most commonly used estimators (e.g., Lincoln-Petersen). Mean capturability determines which estimator is most appropriate for a given population. These methods were applied to data from several tortoise populations. CAPTURE's Jackknife method estimated 70 tortoises/km² in a Mazatzal Mountain, Arizona, population surveyed during 1992. Density was corrected with the mean maximum distance moved method. Regression of CAPTURE estimates indicated two separate populations were stable or increasing from 1990 to 1992, while a third declined. Program JOLLY estimated high survivorship for these three populations (87-100%), but recruitment was lowest for the decreasing population (0-17 tortoises/year).
Type:
text; Thesis-Reproduction (electronic)
Keywords:
Biology, Biostatistics.; Agriculture, Forestry and Wildlife.
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Graduate College; Renewable natural resources
Degree Grantor:
University of Arizona
Advisor:
Schwalbe, Cecil R.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleMark-recapture methods for monitoring Sonoran populations of the desert tortoise (Gopherus agassizii)en_US
dc.creatorMurray, Roy Charles, 1968-en_US
dc.contributor.authorMurray, Roy Charles, 1968-en_US
dc.date.issued1993en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractI determined reliable methods for monitoring Sonoran populations of the desert tortoise. Tortoises were significantly clumped (p < 0.001) on three 1-mi² plots in Arizona, but were not significantly different from random (p > 0.05) on a 1-km² plot, supporting the use of smaller plots in mark-recapture population studies. Simulations showed that Program CAPTURE's Jackknife and Darroch estimators are robust to variations in capturability, which confound most commonly used estimators (e.g., Lincoln-Petersen). Mean capturability determines which estimator is most appropriate for a given population. These methods were applied to data from several tortoise populations. CAPTURE's Jackknife method estimated 70 tortoises/km² in a Mazatzal Mountain, Arizona, population surveyed during 1992. Density was corrected with the mean maximum distance moved method. Regression of CAPTURE estimates indicated two separate populations were stable or increasing from 1990 to 1992, while a third declined. Program JOLLY estimated high survivorship for these three populations (87-100%), but recruitment was lowest for the decreasing population (0-17 tortoises/year).en_US
dc.typetexten_US
dc.typeThesis-Reproduction (electronic)en_US
dc.subjectBiology, Biostatistics.en_US
dc.subjectAgriculture, Forestry and Wildlife.en_US
thesis.degree.nameM.S.en_US
thesis.degree.levelmastersen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineRenewable natural resourcesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSchwalbe, Cecil R.en_US
dc.identifier.proquest1356796en_US
dc.identifier.bibrecord.b31459468en_US
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