128 J. L. Silcock et al.


PLATE 1 Petrogale xanthopus celeris at Pete’s Hill South, Wallaroo Range, August 2022 (photo: I.C. Gynther) and, clockwise from top right, favoured habitat of the species: terraced boulder fields with complex vegetation structure, Lisburne (photo: P.D. McRae) and Pete’s Hill South, Lynbrydon (photo: I.C. Gynther); and deep boulder-strewn gorge, Bosses Gorge, north of Adavale (photo: P.D. McRae).


water. The mean effective distance to water was similar for presence and absence sites at both the local scale (means of 2.5 and 2.6 km for presence and absence, respectively) and regional scale (means of 2.8 and 3.0 km). A significant rela- tionship existed between goat presence and effective dis- tance to water (U= 901,P,0.05) at the regional scale for the 2020s survey period (sites without goats had a higher mean effective distance to water than sites with goats) but not for the 2010s survey period. There were no significant differences in mean effective distance to water between sites where P. xanthopus celeris was absent in all survey per- iods, those where local extinctionswere followed by recolon- ization or those where P. xanthopus celeris had maintained its presence (Fig. 3).


Changes in range and abundance over the past century


Petrogale xanthopus celeris was located at seven of the eight historical (pre-1970s) localities searched but was not seen at one of them (Orient, west of Thargomindah). The rediscov- ery of the subspecies at three southern sites (Terrachie, Mount Canaway and the McGregor Range, west of Eromanga), where it had been considered locally extinct in the 1970s–1980s, greatly increases the known range of P. xanthopus celeris. The last of these sites is c. 120 km west of the closest record (Terrachie), and surveys in re- sidual habitat between these points found scant suitable habitat and no sign of rock-wallabies (Fig. 1).


The subspecies was reported to occur in the Warrego and


Enniskillen ranges at the north-eastern extent of its distribu- tion (Fig. 1) until the 1960s (I. Walker, pers. comm., August 2019). There was no sign of P. xanthopus celeris in this area in 1974, although low densities of dung were recorded on Forest Hill 20kmto the south-west in the same range system in 1984, and there were also reports in 1988 from Milray and Lumeah to the south (P.D. McRae, unpubl. data, 1988). No evidence of P. xanthopus celeris was detected at 10 sites sur- veyed in these range systems during 2013–2014 and in 2021, but the subspecies was found to be common at one of these sites and uncommon at two of them in 2023, indicating that it had apparently recolonized these sites at some point dur- ing the current decade. The locality of the anecdotal report from Orient, west of Thargomindah, was searched in 1973 and 2013 but did not appear to be suitable habitat. Thirty-nine of the 68 sites surveyed during 1973–1987


(57%) were revisited between 2010 and 2023. Of the total of 162 sites surveyed during 1973–2023, 88 were visited once, 45 were visited twice, 27 were visited three times and two were visited four times (Table 1, Fig. 4). Of the 74 sites visited multiple times, P. xanthopus celeris was never de- tected at seven; these were excluded from further consider- ation. Of the 67 remaining revisited sites, no change in abundance was detected at 28 (42%). Petrogale xanthopus celeris was absent in 2022 from two sites where it had been uncommon during 2011–2012; these sites are within range systems where the subspecies remained common


Oryx, 2025, 59(1), 123–135 © The Author(s), 2024. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605324000760


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