Extinct or still out there? Disentangling influences on extinction and rediscovery helps to clarify the fate of species on the edge

Lee, Tasmin E. , Fisher, Diana O. , Blomberg, Simon P. and Wintle, Brendan A. (2017) Extinct or still out there? Disentangling influences on extinction and rediscovery helps to clarify the fate of species on the edge. Global Change Biology, 23 2: 621-634. doi:10.1111/gcb.13421


Author Lee, Tasmin E.
Fisher, Diana O.
Blomberg, Simon P.
Wintle, Brendan A.
Title Extinct or still out there? Disentangling influences on extinction and rediscovery helps to clarify the fate of species on the edge
Journal name Global Change Biology   Check publisher's open access policy
ISSN 1365-2486
1354-1013
Publication date 2017-02-01
Sub-type Article (original research)
DOI 10.1111/gcb.13421
Open Access Status Not yet assessed
Volume 23
Issue 2
Start page 621
End page 634
Total pages 14
Place of publication Chichester, West Sussex, United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2018
Language eng
Abstract Each year, two or three species that had been considered to be extinct are rediscovered. Uncertainty about whether or not a species is extinct is common, because rare and highly threatened species are difficult to detect. Biological traits such as body size and range size are expected to be associated with extinction. However, these traits, together with the intensity of search effort, might influence the probability of detection and extinction differently. This makes statistical analysis of extinction and rediscovery challenging. Here, we use a variant of survival analysis known as cure rate modelling to differentiate factors that influence rediscovery from those that influence extinction. We analyse a global data set of 99 mammals that have been categorized as extinct or possibly extinct. We estimate the probability that each of these mammals is still extant and thus estimate the proportion of missing (presumed extinct) mammals that are incorrectly assigned extinction. We find that body mass and population density are predictors of extinction, and body mass and search effort predict rediscovery. In mammals, extinction rate increases with body mass and population density, and these traits act synergistically to greatly elevate extinction rate in large species that also occurred in formerly dense populations. However, when they remain extant, larger-bodied missing species are rediscovered sooner than smaller species. Greater search effort increases the probability of rediscovery in larger species of missing mammals, but has a minimal effect on small species, which take longer to be rediscovered, if extant. By separating the effects of species characteristics on extinction and detection, and using models with the assumption that a proportion of missing species will never be rediscovered, our new approach provides estimates of extinction probability in species with few observation records and scant ecological information.
Keyword Cure rate model
Detectability
Lazarus
Mammalia
Search effort
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Biological Sciences Publications
 
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