Mixophyes fleayi Corben & Ingram 1987

Population and DistributionMixophyes fleayi is narrowly and disjunctly distributed in wet forests from the Conondale Range in s.e. Qld, s. to Yabbra Scrub in n.e. NSW (Hines et al. 1999). The area of occurrence of the species is about 7000 km2 (map in Hines et al. 1999). While the majority of records for the species are from altitudes above 400 m, M. fleayi is also known from lowland rainforest (200 m, Goldingay et al. 1999; 90 and 150 m, H. Hines & L. Shoo unpubl. data). Corben (in McDonald 1991) reported that M. fleayi declined in the Conondale Range in the late 1970’s. Ingram and McDonald (1993) reported that the species has not been seen in the Conondale Range since the summer of 1990-1991. Since Ingram and McDonald’s (1993) review, targeted surveys have been undertaken (Hines et al. 1999; Goldingay et al. 1999). In Qld, populations are currently known from the Conondale Range, Lamington Plateau and the n. section of Main Range, Mt Barney area and Currumbin and Tallebudgera Ck below Springbrook Plateau (Hines et al. 1999). Despite targeted surveys, there have been no records of the species from the extensively developed Mt Tamborine area since 1976 (Hines et al. 1999). There is a museum specimen of M. fleayi collected from Bunya Mt in 1970 (H. Hines unpubl. data), however, recent surveys have failed to locate the species from this area (H. Hines pers. comm.). In NSW the species is known from Lever’s Plateau (Border Ranges), Yabbra and Tooloom Scrubs, Mt Warning, Terania Ck in Nightcap Range and Sheepstation Ck in the Border Ranges (Mahony et al. 1997; Hines et al. 1999). Mixophyes fleayi has disappeared from some locations, though whether populations have declined at other locations is difficult to assess due to a lack of information on the abundance of the species at historical sites (Hines et al. 1999). The very low numbers recorded from many well surveyed sites suggests that declines in abundance may have occurred (Hines et al. 1999; Goldingay et al. 1999).Mixophyes fleayi is known from Qld: Lamington, Main Range NP, Goomburra SF , Conondale Range (Hines et al. 1999), Springbrook, Mt Barney NP (J-M. Hero pers. comm.); and from NSW: Mebbin NP, (J-M. Hero pers. comm.), Yabbra SF (Hines et al. 1999), Border Ranges, Mt Warning, Nightcap, Tooloom NP (Goldingay et al. 1999). HabitatMixophyes fleayi is associated with montane rainforest (Corben & Ingram 1987) and open forest communities adjoining rainforest (H. Hines pers. comm.). The species occurs along stream habitats from first to third order streams (ie. small streams close to their origin through to permanent streams with grades of 1 in 50) and is not found in ponds or ephemeral pools (Mahony et al. 1997). At some locations where the species has been recorded, riparian vegetation has been disturbed and replaced by weeds, however this is considered marginal habitat (Mahony et al. 1997). Tadpoles do occur with several species of native fish, however no introduced fish species have been observed in sympatry with M. fleayi (Mahony et al. 1997; H. Hines unpubl. data).

ReproductionBreeding has been recorded in all months between Jul. and Mar. (Corben & Ingram 1987; H. Hines unpubl. data). Males call from under leaf litter, from exposed rocks in stream beds or from the edges of pools beside streams (Corben & Ingram 1987). Calling activity is related to temperature and stream conditions (W. O’Reilly & H. Hines unpubl. data). Reproductive biology is very similar to that of Mixophyes balbus (Gillespie & Hines 1999). Both species construct a nest in the shallow running water that occurs between pools in relatively wide, flat sections of mountain streams (Knowles et al. 1998). Between 652 and 1290 (C. Morrison pers. comm.) eggs are deposited in a shallow excavation in the stream bed or pasted directly onto bed rock (Knowles et al. 1998). Mixophyes fleayi does not appear to breed during and immediately after heavy rain when water flow is high, presumably due to the lack of suitable oviposition sites and the threat of nests and tadpoles being washed down stream (W. O’Reilly & H. Hines unpubl. data). A written description of the tadpole is presented in Meyer et al. (2001).Invasive speciesLarge areas of the species’ habitat have been and continue to be degraded by feral animals (eg. pigs in the Conondale Range), domestic Stock (Main Range) and invasion of weeds (i.e. Mistflower Ageratina riparia and crofton weed A. adenophora ) (Hines et al. 1999). Damage from feral pigs has increased greatly in recent years (H. Hines pers. comm.). While there is potential for direct predation by pigs, the greatest impact is likely to be from increased silt on embryos and tadpoles (H. Hines pers. comm.). Trampling by domestic stock is likely to have deleterious impacts on oviposition sites of the species (Knowles et al. 1998). MovementsFemales and subadults have been found hundreds of meters from breeding sites in Lamington NP (H. Hines unpubl. data). Preliminary radio-tracking studies on movement have found males moved up to 35 m, and females moved up to 50 m away from the stream (N. Doak pers. comm.).

The reason(s) for declines or disappearance of M. fleayi populations are not known. Large areas of the species’ habitat have been and continue to be degraded by feral animals (eg. pigs in the Conondale Range), domestic Stock (Main Range) and invasion of weeds (Hines et al. 1999). Upstream clearing, timber harvesting and urban development (eg. Mt Tamborine) are all likely to have affected flow regimes and water quality (Hines et al. 1999). A chytrid fungal infection has been identified as the cause of illness and death of M. fleayi on Main Range and Lamington Plateau (Berger et al. 1998). Populations of M. fleayi tend to be characterised by low density and are often isolated from other populations (Hines et al. 1999; Goldingay et al. 1999). The stability of small populations and the effect of isolation on genetic variation within each population is unknown.