Table S1. Ecological indicators used to suggest whether each of the 27 currently recognized varanid lizard species on the Australian mainland are likely to compete with the introduced mammalian predators, red fox Vulpes vulpes and feral cat Felis catus. The distributions of foxes and cats are taken from Van Dyck & Strahan (2008); varanid species distributions, snout-vent lengths (SVL), habitat types and foraging habits from Pianka et al. (2004). Foraging habits are as defined in Greer (1989).

species / distribution overlap with fox / size class (maximum SVL) / habitat type / foraging habit / dietary overlap with cats / dietary overlap with foxes / non-empty diet samples / references for dietary intake
V. acanthurus / no / 250 / rocky outcrop / ambush / 0.518 / 0.308 / 315 / (King 2008; Losos & Greene 1988; Pianka et al. 2004)
V. baritji / no / 250 / rocky outcrop / active / 0
V. brevicauda / low / 110 / ground / ambush / 0.516 / 0.303 / 132 / (King & Pianka 2007; Pianka 1970; Pianka 1994)
V. bushi / yes / 140 / arboreal / ? active / 0
V. caudolineatus / yes / 120 / arboreal / active / 0.519 / 0.305 / 34 / (Pianka 1969)
V. doreanus / no / 460 / ground / active / 0
V. eremius / yes / 160 / ground / wide-ranging / 0.347 / 0.175 / 128 / (Pianka 1968; Pianka 2007)
V. giganteus / yes / 880 / ground / wide-ranging / 0.655 / 0.588 / 32 / (James et al. 1992; King et al. 1989; MacDonald 2007)
V. gilleni / yes / 190 / arboreal / active / 0.530 / 0.302 / 69 / (James et al. 1992; Pianka 1969)
V. glauerti / no / 250 / rocky outcrop / arboreal / active / 0.521 / 0.305 / 29 / (James et al. 1992)
V. glebopalma / no / 400 / rocky outcrop / ambush / 0.361 / 0.183 / 30 / (James et al. 1992)
V. gouldii / yes / 360 / ground / wide-ranging / 0.588 / 0.374 / 268 / (Douglas & Ride 1962; Losos & Greene 1988; Pengilley 1981; Rowles 2008; Shine 1986; Sutherland, unpubl. data; Thompson 1996)
V. indicus / no / 480 / arboreal/
aquatic / active / 0.568 / 0.361 / 41 / (Losos & Greene 1988)
V. keithhornei / no / 260 / arboreal / active / 0
V. kingorum / no / 110 / rocky outcrop / active / 0.494 / 0.297 / 3 / (James et al. 1992)
V. mertensi / no / 520 / arboreal/
aquatic / aquatic / 0.528 / 0.333 / 142 / (Mayes et al. 2005; Shine 1986)
V. mitchelli / no / 320 / arboreal/
aquatic / active/aquatic / 0.526 / 0.328 / 43 / (Shine 1986)
V. panoptes / low / 740 / ground / wide-ranging / 0.546 / 0.332 / 77 / (Shine 1986)
V. pilbarensis / low / 170 / rocky outcrop / unknown / 0.520 / 0.297 / 6 / (James et al. 1992; Losos & Greene 1988)
V. primordius / no / 120 / rocky outcrop / unknown / 0.508 / 0.290 / 6 / (Losos & Greene 1988)
V. rosenbergi / yes / 400 / ground / wide-ranging / 0.645 / 0.435 / 219 / (King & Green 1979; Pianka et al. 2004; Sutherland, unpubl. data)
V. scalaris / no / 250 / arboreal / active / 0.518 / 0.305 / 44 / (Losos & Greene 1988; Pianka et al. 2004)
V. semiremex / low / 250 / arboreal/
aquatic / aquatic / 0.470 / 0.282 / 4 / (James et al. 1992)
V. spenceri / low / 550 / ground / wide-ranging / 0.811 / 0.659 / 10 / (Jackson & Lemm 2009; Pengilley 1981; Valentic 1997)
V. storri / no / 130 / rocky outcrop / active / 0.523 / 0.305 / 26 / (James et al. 1992)
V. tristis / yes / 300 / arboreal / active / 0.497 / 0.274 / 75 / (Pianka 1994)
V. varius / yes / 760 / arboreal/
ground / wide-ranging / 0.982 / 0.957 / 144 / (Guarino 2001; Jessop et al. 2010; Weavers 1989)
Felis catus / yes / 1.000 / 0.961 / 1157 / (Bayly 1978; Catling 1988; Dickman 1996 and references within; Jones & Coman 1981; Lapidge & Henshall 2001; Molsher 1999; Risbey et al. 1999; Triggs et al. 1984)
Vulpes vulpes / 0.961 / 1.000 / 1867 / (Bayly 1978; Catling 1988; Lapidge & Henshall 2001; Mitchell & Banks 2005; Molsher 1999; Risbey et al. 1999; Triggs et al. 1984)

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