Kroombit Tinker Frog

Population and DistributionThe distribution of Taudactylus pleione is extremely restricted and is confined to twelve small (up to 25 ha) unconnected patches of rainforest (totalling about 200 ha) above 500 m at Kroombit Tops, s.w. of Gladstone (Clarke et al. 1999; J. Clarke pers. comm.). It is believed that T. pleione is a relict species, restricted to Kroombit Tops through habitat fragmentation that disrupted rainforest connections between s. and n.e. Qld (Czechura 1986a). Within the rainforest patches, populations of T. pleione are clumped around drainage lines and seepage areas (J. Clarke pers. comm.). The extent of occurrence is estimated to be 700 ha and the area of occupancy is estimated to be 120 ha (J. Clarke pers. comm). Surveys in February 1997 and regular surveys since 1998 have greatly expanded the known distribution of the species bringing the total number of known populations to 12; 9 in Kroombit Tops NP and 3 in Kroombit Tops SF (Clarke et al. 1999; J. Clarke pers. comm.). All potential sites on the Kroombit Tableland and escarpment have been searched at least once during the calling season although additional potential habitat for the species exists on the Dawes Range and Mt Roberts (M. Cunningham pers. comm.). The only regularly monitored population, in the head of Kroombit Ck, appears to have declined (Hines et al. 1999). The species was regularly encountered at this site prior to 1997 but T. pleione was not heard or seen at this site during the 1997/98 season despite systematic monitoring (Clarke et al. 1999). Data from recent annual searches also indicate a decline in numbers of T. pleione on Kroombit Plateau (E. Meyer pers. comm.). During 1997/98 little other monitoring work was undertaken in the area but the species was heard calling at three recently discovered sites (Hines et al. 1999). Estimates of population size are highly conjectural with no more than 13 individuals being recorded from one site at any one time, and only three females have ever been recorded (J. Clarke pers. comm.). No information is available on population structure or genetic variation (Hines et al. 1999)Known from Kroombit Tops NP and Kroombit Tops SF Scientific Area No. 48 (Clarke et al. 1999). HabitatTaudactylus pleione is highly cryptic and is mainly associated with Piccabeen Palm (Archontophoenix cunninghamiana) rainforest and boulder scree gullies (Czechura 1986a; Clarke et al. 1999; Meyer et al. 2001). Taudactylus pleione is found around rocky shelves and boulders, under rocks or in deep rock piles near temporary stream lines, seepage zones and in sheltered rocky scree (Clarke et al. 1999). Most sites have little or no surface water (J. Clarke pers. comm.). Unlike other species of Taudactylus it has never been observed basking (Czechura 1986b).

ReproductionActivity seems to be initiated by the first heavy falls of rain during the spring-summer period (Czechura 1996a). Calling has been heard between Sep. and Mar., with calling peaks on warm, wet nights from Sep. to Feb. (Clarke et al. 1999; J. Clarke pers. comm.). Calling is usually most intense at dusk and early evening (Czechura 1986a; Borsboom et al. 1997; Clarke et al. 1999) although the species will call all night and all day if conditions are suitable (J. Clarke pers. comm.). The males call partially or completely concealed in rock crevices or under leaf litter and often exhibit territorial behaviour by segregating themselves along the stream (Czechura 1986a), although T. pleione is frequently recorded away from streams or seepages (J. Clarke pers. comm.). Only three gravid female T. pleione have ever been found: one (the holotype) in early February, another in mid-January and a third (partly gravid) in early December (Clarke et al. 1999; E. Meyer pers. comm.). Large unpigmented eggs were visable through the abdominal wall of specimens found in late January and December (Meyer et al. 2001). Eggs, tadpoles and oviposition sites have not been observed (Clarke et al. 1999). Taudactylus pleione almost certainly does not breed in streams (H. Hines & E. Meyer pers. comm.). Despite regular searching along creeks, tadpoles of the species have never been found (E. Meyer pers. comm.). The large eggs moreover suggest direct or partially direct development (E. Meyer pers. comm.). Taudactylus pleione occurs in situations where water is highly ephemeral, or doesn’t pool above the ground (eg. steep rocky slopes) (E. Meyer pers. comm.). Thus, it seems likely that breeding takes place at the bottom of rock piles, which retain water even when there is little or no surface water available (E. Meyer pers. comm.). FeedingFeeding has not been reported but males have been observed moving about, possibly searching for prey, after cessation of calling (J. Clarke pers. comm.). Invasive speciesClarke et al. (1999) and Borsboom et al. (1998) list domestic cattle, horses and feral pigs as potential threats to the species. The majority of the Kroombit Tops SF is under grazing lease and stock pose a threat to T. pleione mainly through the destruction of habitat and fouling of water (Clarke et al. 1999). A fence has been constructed to exclude stock, but impacts at the head of Kroombit Ck continue. Feral pigs, which may prey upon T. pleione, destroy habitat and act as potential vectors of Chytrid fungus (by carrying infected mud to new sites) have recently been found near breeding sites (J. Clarke pers. comm.). MovementsTaudactylus pleione has not been observed between Apr. and Aug. and is presumed to retreat into deep cracks and bolder piles (M. Cunningham pers. comm.). In summer when the frogs are active, individuals may be found in leaf-litter or under stones along water courses where ephemeral pools and soaks form (Czechura 1986a). In the height of the breeding season individuals are increasingly found away from obvious rock refuges and can be found under small stones, palm fronds, surface debris and leaf-litter alongside both permanent and temporary streams (Czechura 1986b). The species is regularly found away from watercourses where seepages are common (J. Clarke pers. comm.).

The apparent low population, isolation and extremely restricted distribution of the species make it highly susceptible to demographic instability, disturbance and extinction. Clarke et al. (1999) and Borsboom et al. (1998) list five main potential threats to the species. These are wildfire, domestic and feral animals (as mentioned above), unknown agent(s) responsible for declines of other Qld frogs, visitor pressure and timber harvesting. Timber harvesting has ceased in the catchments above all known populations (Hines et al. 1999), but may be a threat to any new populations on leasehold land. Visitor numbers are low at present, but increased visitation may disrupt breeding or impact on habitat. A high intensity wildfire in 1994 burned into many rainforest patches used by the species (Hines et al. 1999). A later flood altered stream hydrology and removed leaf litter in the area (Clarke et al. 1999). The wildfire may be partially responsible for the decline of the species at the monitoring site (Hines et al. 1999). Modified fire management procedures have now been put in place to reduce the risk of further high intensity fires (Hines et al. 1999).Four species of Taudactylus from similar habitat elsewhere in Qld have also declined dramatically or disappeared due to unknown causes (eg. Ingram & McDonald 1993). In May 1998, several dead L. pearsoniana were found at Kroombit Tops (Hines and Clarke unpubl. data). Chytrid fungus, a disease found by Berger et al. (1998) to be associated with frog deaths and declines elsewhere in Australia and Central America, was isolated from these animals (Berger unpubl. data). This, in conjunction with the apparent decline of T. pleione at the monitoring site has heightened concern for this species.

The Kroombit tinker frog (Taudactylus pleione), also sometimes referred to as Pleione's torrent frog, is a species of frog in the family Myobatrachidae. It is endemic to Central Queensland in Australia. It lives among rocks and leaf litter near small flowing streams.