Estimating age-specific survival when age is unknown: open population capture-recapture models with age structure and heterogeneity

Matechou, Eleni and Pledger, Shirley and Efford, Murray and Morgan, Byron J. T. and Thomson, David L. (2013) Estimating age-specific survival when age is unknown: open population capture-recapture models with age structure and heterogeneity. Methods in Ecology and Evolution, 4 . pp. 654-664. ISSN 2041-210X. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)

Abstract

1. When studying senescence in wildlife populations, we are often limited by the sparseness of the available information on the ages of the individuals under study. Additionally, heterogeneity between individuals can be substantial. Ignoring this heterogeneity can lead to biased estimates of the population parameters of interest and can mark senescence. 2. This paper demonstrates the use of a recently developed capture-recapture model for extracting age-dependent estimates of survival probabilities for individuals of unknown age and extends the model by allowing for heterogeneity in survival and capture probabilities using finite mixtures. 3. Using simulation, we show that the estimates of age-dependent survival probabilities when age is unknown can be biased when heterogeneity in capture probabilities is not modelled, in contrast to the case of time-dependent survival probabilities when the estimates are robust to similar violations of model assumptions. 4. The methods are demonstrated using a long-term data set of female brushtail possums (Trichosurus vulpecula Kerr) for which age-specific models for survival probabilities indicating senescence are strongly favoured. We found no evidence of heterogeneity in survival but strong evidence of heterogeneity in capture probabilities. 5 These models have a wide range of applications for estimating age-dependence in survival when age is unknown as they can be applied to any capture-recapture data set, as long as it is collected over a period which is longer, and preferably considerably so, than the lifespan of the species studied.

Item Type: Article
Uncontrolled keywords: Brushtail possums; finite mixtures; senescence
Subjects: Q Science > QA Mathematics (inc Computing science) > QA276 Mathematical statistics
Q Science > QH Natural history > QH541 Ecology
Divisions: Faculties > Sciences > School of Mathematics Statistics and Actuarial Science > Statistics
Depositing User: Byron Morgan
Date Deposited: 20 Feb 2013 14:29 UTC
Last Modified: 02 Jun 2014 11:45 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/33261 (The current URI for this page, for reference purposes)
  • Depositors only (login required):