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A Two-Phase Model for Smoothly Joining Disparate Growth Phases in the Macropodid Thylogale billardierii

Citation

McMahon, CR and Buscot, M and Wiggins, NL and Collier, N and Maindonald, JH and McCallum, HI and Bowman, DMJS, A Two-Phase Model for Smoothly Joining Disparate Growth Phases in the Macropodid Thylogale billardierii, PLoS One, 6, (10) Article e24934. ISSN 1932-6203 (2011) [Refereed Article]


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Licensed under Creative Commons Attribution 2.5 Generic (CC BY 2.5) http://creativecommons.org/licenses/by/2.5/

DOI: doi:10.1371/journal.pone.0024934

Abstract

Generally, sigmoid curves are used to describe the growth of animals over their lifetime. However, because growth rates often differ over an animal’s lifetime a single curve may not accurately capture the growth. Broken-stick models constrained to pass through a common point have been proposed to describe the different growth phases, but these are often unsatisfactory because essentially there are still two functions that describe the lifetime growth. To provide a single, converged model to age animals with disparate growth phases we developed a smoothly joining two-phase nonlinear function (SJ2P), tailored to provide a more accurate description of lifetime growth of the macropod, the Tasmanian pademelon Thylogale billardierii. The model consists of the Verhulst logistic function, which describes pouch-phase growth – joining smoothly to the Brody function, which describes post-pouch growth. Results from the model demonstrate that male pademelons grew faster and bigger than females. Our approach provides a practical means of ageing wild pademelons for life history studies but given the high variability of the data used to parametrise the second growth phase of the model, the accuracy of ageing of post-weaned animals is low: accuracy might be improved with collection of longitudinal growth data. This study provides a unique, first robust method that can be used to characterise growth over the lifespan of pademelons. The development of this method is relevant to collecting age-specific vital rates from commonly used wildlife management practices to provide crucial insights into the demographic behaviour of animal populations.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Population Ecology
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Farmland, Arable Cropland and Permanent Cropland Flora, Fauna and Biodiversity
Author:Wiggins, NL (Dr Natasha Wiggins)
Author:Bowman, DMJS (Professor David Bowman)
ID Code:75904
Year Published:2011
Web of Science® Times Cited:3
Deposited By:Plant Science
Deposited On:2012-02-20
Last Modified:2017-11-01
Downloads:214 View Download Statistics

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