Prof Barry Brook1, Dr Jessie Buettel1
1University Of Tasmania, Hobart, Australia
Prior to European colonization in the early 1800s, Tasmania supported a small but stable population of the cursorial predatory thylacine (Thylacinus cynocephalus). This ‘marsupial wolf’, often called the ‘Tasmanian tiger’, had been extirpated from mainland Australia during the mid-Holocene, after surviving the earlier wave of Pleistocene megafaunal extinctions. Due to persecution by graziers (encouraged by a government bounty), incidental snaring by fur traders, habitat modification, and perhaps disease, the Tasmanian population of thylacines declined to extreme rarity by 1910, with the last confirmed wild animals trapped in the early 1930s (although hundreds of unverified sightings were reported over subsequent decades). Here we develop a protocol to objectively characterise the type, quality and uncertainty of fossil and observational records of thylacines and use this approach to underpin a reconstruction of the species’ spatio-temporal distributional dynamics, spanning Pleistocene Sahul to 20th century Tasmania. By linking these patterns to a semi-mechanistic niche-distribution model, we also evaluate the potential for spatial refugia and estimate the probability distribution of its regional extinction times. The approach developed for this case study is applicable for integrating information on sightings and the ecology of other threatened taxa, and thereby improve the conservation prioritisation and search efforts of extremely rare species on the move.
Barry Brook, an ecologist and modeller, is an ARC Australian Laureate Professor and Chair of Environmental Sustainability at the University of Tasmania. He researches the impacts of global change on biodiversity, eco-evolutionary dynamics, extinction and energy.