Sugar gliders in Tasmania: an introduced predator or an elusive native? Catriona D. Campbell, Dejan Stojanovic, Anna J. MacDonald, Bernd Gruber, Stephen Harris, Stephen D. Sarre and Clare E. Holleley
Figure 2: Native distribution of P. breviceps (peach) including suggested introduction to Tasmania (yellow).
• Tasmanian sugar gliders (Petaurus breviceps) have been implicated in the predation of the highly endangered swift parrot (Lathamus discolor) in Tasmania, causing nest failures of close to 100% (Figure 1). • At least seven other hollow nesting birds in Tasmania have also been recorded as vulnerable to predation by P. breviceps. • Without intervention L. discolor is predicted to go extinct within two decades. • Petaurus breviceps are recorded as being introduced to Tasmania (Figure 2). In 1835 individuals were transported to Launceston from Port Phillip in Victoria, as part of the pet trade. • There is an urgent need to establish the provenance of Tasmanian P. breviceps for appropriate management of this presumed novel predator to be applied.
To test divergence hypothesis (Figure 3) we sequenced mitochondrial genes ND2 and ND4 from 20 Tasmanian P. breviceps and 10 mainland samples and combined them with samples from a previous study by Malekian et al. (2010). • All Tasmanian sequences are identical across both ND2 and ND4 genes. • Tasmanian sequences were separated by only two nucleotides from mainland sequences originating from Victoria and South Australia at the ND2 gene (Figure 4). • Tasmanian sequences were identical to more than 20 individual sequences originating from Victoria and South Australia at the ND4 gene (Figure 5).
Figure 1: Evidence of P. breviceps predating on L. discolor nest. Photos courtesy of Dejan Stojanovic. Divergence Hypothesis
Figure 3: Four possible divergence scenarios, adapted from Burridge et. al, based on the last glacial period and the suspected introduction of P. breviceps to Tasmania. (A&B) a recent divergence mediated by the proposed introduction in 1835, with or without gene flow. (C&D) an earlier divergence based on the last glacial period and land bridge between Tasmania and the mainland, with and without gene flow.
Figure 4: Median joining network, ND2 gene (popart) showing haplotypes across the native range of P. breviceps. The Tasmanian haplotype branches alone and is just two nucleotides different from Pb022_SA containing 19 individuals from both Victoria and South Australia. Maximum likelihood tree (MEGA 6.0).
Figure 5: Median joining network, ND4 gene (popart) showing the single haplotype Tasmanian individuals fall into, Pb043-VIC, which consists of 20 Tasmanian and 29 Victoria and South Australian individuals. Maximum likelihood tree (MEGA 6.0).
• The lack of variation in Tasmanian sequences and their similarity with mainland haplotypes provides strong evidence in support of a recent introduction of P. breviceps to Tasmania from the southern mainland population. Burridge C, Brown WE, Wadley J, Nankervis DL, Olivier L, Gardner MG, et al. (2013) Did postglacial sea-level changes initiate the evolutionary divergence of a Tasmanian endemic raptor from its mainland relative? Proc R Soc Biol Sci Malekian M, Cooper SJB, Norman J a, Christidis L, Carthew SM. (2010) Molecular systematics and evolutionary origins of the genus Petaurus (Marsupialia: Petauridae) in Australia and New Guinea. Mol Phylogenet Evol
For further information please contact Catriona Campbell @
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Acknowledgements: Elise Dewar, Matt Young, Elise Furlan, Peter Unmack, Aaron Adamack, QVMAG, TMAG, ANWC, DPIPWE.
