• DOI:10.1111/cobi.13187
• Corpus ID: 51894568

Reevaluating sighting models and moving beyond them to test and contextualize the extinction of the thylacine

@article{Carlson2018ReevaluatingSM,
  title={Reevaluating sighting models and moving beyond them to test and contextualize the extinction of the thylacine},
  author={Colin J. Carlson and Alexander L. Bond and Kevin R. Burgio},
  journal={Conservation Biology},
  year={2018},
  volume={32}
}

• C. Carlson, A. Bond, K. Burgio
• Published 1 August 2018
• Environmental Science
• Conservation Biology

In “Estimating the Extinction Date of the Thylacine with Mixed Certainty Data,” we (Carlson et al. 2018a) used the sighting record, including controversial post-1936 sightings, to model the probability that the thylacine has been classified accurately as extinct. We found astronomically low odds that the thylacine is extant and argue that a camera-trap search for the species in Cape York, northern Queensland, may be motivated by false hope. In a response to our article, Brook et al. (2018) suggest we were too hasty to dismiss the thylacine as extinct. The crux of their argument is that, although our models imply “all post-1937 thylacine sightings are erroneous [ . . . ] historical factors and spatiotemporal heterogeneity argue against this conclusion.” We agree with Brook et al. that spatial heterogeneity in sighting rates, and in extinction dates, is a common methodological challenge that must be better addressed. To this end, we recently developed the R package spatExtinct, which interpolates sighting-based extinction date estimators into landscape-level spatiotemporal models that we term “spatial extinction date estimators” (Carlson et al. 2018b). Using data that Sleightholme and Campbell (2016) assembled with such a model could help better reconstruct spatiotemporal heterogeneity in the thylacine’s extinction on Tasmania, and we are eager to facilitate that analysis. But consensus on the valid use of extinction date estimators in this setting seems a deeper and more persistent issue, as Brook et al. also argue.