Nangur skink Photo: A Borsboom (EHP)
Common name: Nangur skink; Nangur spiny skink
Scientific name: Nangura spinosa
Conservation status: This species is listed as Endangered in Queensland (Nature Conservation Act 1992) and is Critically Endangered nationally (Environment Protection and Biodiversity Conservation Act 1999). It is ranked as a medium priority under the Department of Environment and Heritage Protection Back on Track species prioritisation framework.
Description: The Nangur skink has a robust build and grows to approximately 19 cm in length (9.5 cm snout-vent). Adults can weigh in excess of 30 grams with newly-born skinks weighing 1.5 grams. It has spiny scales along its back, tail and flanks. The limbs are well developed and the tail tapers to a point. It is dark brown in colour with irregular cross-bands on the body and its underside is cream (Covacevich et al. 1993). The scales along its mouth are edged with black. The mid body scales are in 28 rows and strongly keeled, forming longitudinal ridges.
Habitat and distribution
Nangur skink habitat Photo: L Connell (EHP)
The Nangur skink was first discovered in 1992 (Covacevich et al. 1993) with a second population found approximately 38 km away in 1997 (Hannah et al. 1997). It is confined to remnant dry rainforest, including semi-evergreen vine thicket at two locations in south-east Queensland. Current estimates suggest a total population size of less than 200 adults with an extent of occurrence of approximately 45 km2 (Borsboom et al. 2005). Intensive surveys have failed to find further populations of the Nangur skink at any location other than the original two sites.
To date all known Nangur skinks have been recorded at between 315 m and 600 m altitude on basaltic soil in semi-evergreen vine thickets, hoop pine plantations and araucarian notophyll vine forest (Covacevich et al. 1993; Hannah et al. 1997; Borsboom et al. 2005).
The most common tall tree species growing in Nangur skink habitat are hoop pine Araucaria cunninghammii, red kamala Mallotus philippensis and scrub poison tree Excoecaria dallachyana. Regional ecosystems which occur in known skink locations include:
Araucarian complex microsphyll vine forest on Cainozoic igneous rocks
Semi-evergreen vine thicket with Brachychiton rupestris on Cainozoic igneous rocks
Araucarian complex microphyll to notophyll vine forest on Mesozoic to Proterozoic igneous rocks
Notophyll vine forest on Mesozoic to Proterozoic igneous rocks
Semi-evergreen vine thicket on Mesozoic to Proterozoic igneous rocks
Table 1: Regional ecosystems occurring in known locations of the Nangur skink (Source: Queensland Herbarium 2009. Regional Ecosystem description database Version 6.0b: Department of Environment and Resource Management)
Life history and behaviour
Nangur skink and burrow Photo: A Borsboom (EHP)
The Nangur skink lives in single-entrance burrows which may be shared with adults, sub-adults and/or young (Borsboom et al. 2005). Burrows have been measured up to 60 cm in length, terminating in an oval chamber of approximately 5 cm. The burrow entrance can measure 8 cm wide by 3 cm high.
Burrows are generally well-concealed, with entrances located at the base of rocks, beneath tree roots, along road embankments or on open ground (Covacevich et al. 1993; Hannah et al. 1997; Borsboom et al. 2005). The rocks and tree roots associated with burrows may prevent predators digging out entrances.
Nangur skinks appear to prefer burrows with overhanging vegetation but little vegetation at ground level. A large number of burrows are located where there is significant plant density and forest structure. Soil composition is also likely to play a role in habitat suitability as it needs to be suitable for the construction and maintenance of burrows (Borsboom et al. 2005).
There is often a smooth ‘resting platform’ in front of the burrow where skinks have been observed basking in the sunlight during warmer months (Wilson & Swan 2008).
The Nangur skink has a varied diet consisting of ground-dwelling invertebrates, in particular beetles and spiders (Covacevich et al. 1993). Some of the invertebrates are active at night, suggesting that the skink is also active at this time (Borsboom 2007).
Currently little is known of the growth, maturation and reproduction of Nangur skinks, though indirect evidence suggests the skink may bear live young (Covacevich et al. 1993). Very young skinks have been recorded in February and April (Covacevich et al. 1993; Hannah et al. 1997; Wilson & Swan 2008).
Knowledge of threatening processes that may impact on the Nangur skink is limited due to the recent discovery of this species. More research is necessary to improve our understanding of threats and how they impact on the skink.
The following threatening processes are believed to have an impact on the Nangur skink:
- Clearing of habitat
- The harvesting and re-planting of hoop pine plantations
- Illegal collection
Potential threatening processes may include:
- Feral animals (cane toads, feral cats, foxes, dingoes and pigs)
Any reduction in the population of the Nangur skink may have a dramatic impact on the population viability of this species. The Nangur skink is particularly vulnerable to threatening processes as it is only known to occur at two locations.
A recovery plan for the Nangur skink has been prepared. The recovery objective is to improve the status of Nangur skink populations in the wild by implementing informed management decisions based on a thorough understanding of the species’ biology and habitat requirements.
The following actions are recommended:
- Undertake surveys to determine the full extent and area of occupancy of the Nangur skink;
- Monitor ecological and biological parameters considered important for the survival of wild populations;
- Implement threat abatement programs, including weed and feral animal control;
- Modify the harvesting and re-establishment hoop pine plantations at sites where the skink occurs; and
- Implement a fuel management program to protect the Nangur skink's habitat from fire.
Borsboom, A, Smyth, G and Rider, E 2005. The rare Queensland skink Nangura spinosa: Surveys, distribution, habitat, threats, management and conservation status. Internal report. Environmental Protection Agency, Brisbane.
Covacevich, JA, Couper, PJ and James, C 1993. A new skink, Nangura spinosa GEN. ET SP. NOV. from a dry rainforest of southeatern Queensland. Memoirs of the Queensland Museum 34(1): 159-167.
Curtis, L, Dennis, A, McDonald, KR, Kyne, PM and Debus, SJS. 2012. Queensland’s Threatened Animals. CSIRO Publishing, Collingwood, Victoria
Department of Environment and Resource Management. 2009. Survey and Mapping of 2006 Remnant Vegetation Communities and Regional Ecosystems of Queensland, Version 6b (September 2009). Queensland Herbarium, Department of Environment and Resource Management, Brisbane.
Department of Environment and Resource Management 2010. Recovery plan for the Nangur spiny skink (Nangura spinosa). Report to the Department of Sustainability, Environment, Water, Population and Communities, Canberra. Department of Environment and Resource Management, Brisbane.