NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. The Alpine She-oak Skink Cyclodomorphus praealtus Shea, 1995 (family Scincidae) is a slender medium-sized lizard reaching a maximum length of around 350 mm, with a snout to vent length up to 130 mm (Wells 2007). Above, it is olive-green to reddish-brown, and has smooth, overlapping scales with dark lateral edges that create a series of thin, longitudinal dark lines (Cogger 2000). Scales may have black and grey flecks. The tail is tapered and is relatively short compared to similar species from coastal areas (Green & Osborne 1994). The Alpine She-oak Skink has four distinct but short limbs, each with five fingers or toes, with the third and fourth toes sub-equal, or the third toe slightly longer than the fourth (Wells 2007). The species can be distinguished from other She-oak Skinks in Australia (Cyclodomorphus casuarinae and C. michaeli) on the basis that C. praealtus has fewer than 60 subcaudal scales on the underside of any original tails (Shea 1995).
2. The Alpine She-oak Skink is endemic to NSW and Victoria, where it is restricted to sub-alpine and alpine grasslands (Swan et al. 2004). In NSW, the Alpine She-oak Skink has only been observed within Kosciuszko National Park between Smiggin Holes and Kiandra (Swan et al. 2004; D. Hunter pers. comm. 2010; NSW Wildlife Atlas, accessed Sept 2010). In Victoria, the species is found in the north east of the state, extending as far south as Lankey Plain on the Dargo High Plains (Shea 1995). The species is listed as Threatened under the Victorian Flora and Fauna Guarantee Act 1988 and as Endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.
3. The Alpine She-oak Skink appears to have specific habitat requirements, preferring tree-less or very lightly treed areas that contain tussock grasses, low heath or a combination of both (Clemann 2003). Within this habitat the species shelters beneath litter, rocks, logs and other ground debris, and has been observed basking on grass tussocks (Clemann 2003). In NSW, Alpine She-oak Skinks have been observed in alpine to sub-alpine grasslands in flat to gently sloping areas (D. Hunter pers. comm. 2010). Within the Kosciuszko region of NSW, general fauna surveys have been conducted in a range of other habitats considered suitable to the Alpine She-oak Skink, including bogs, woodlands and herbfields, but the species has not yet been reported from these surveys (D. Hunter pers. comm. 2010).
4. Little is known about the breeding biology of the species as it is difficult to detect, spending much of its time sheltering within tussock clumps (Swan et al. 2004). The species gives birth to live young and a study conducted by Shea (1995) of preserved museum specimens found several females, which had been collected during summer, pregnant with between two and nine embryos, suggesting a summer breeding period.
5. There are no data on age at first breeding or longevity for the Alpine She-oak Skink and no information on the relationship between size of an individual and its age (N. Clemann pers. comm. 2010).
6. The diet of the Alpine She-Oak Skink is largely carnivorous, mostly consisting of small invertebrates, such as molluscs and insects (Wells 2007; G. Shea pers. comm. 2010). The species has also been recorded to occasionally feed on small lizards and snakes (Shea 1988) and potentially consumes a limited amount of plant material (N. Clemann pers. comm. 2010).
7. Based on mark-recapture studies conducted in Victoria over several years, adults appear to have relatively small home ranges, and remain in the same general area for long periods of time (N. Clemann unpub. data). The largest distance recorded between sightings of the same individual is roughly 45 m (N. Clemann unpub. data). No marked juveniles have yet been recaptured (N. Clemann unpub. data). As a result of its narrow altitudinal range and specific habitat requirements, the Alpine She-oak Skink is considered to have a limited capacity for dispersal (Koumoundouros et al. 2009).
8. Within some known locations in NSW, the species’ distribution is fragmented by alpine resort buildings and/or groomed ski slopes, roads and tracks (i.e. Perisher Valley/Smiggin Holes). In addition, most known sites in NSW are separated by distances that are beyond the only recorded adult dispersal distance of the species (N. Clemann unpub. data). Hence, populations of the Alpine She-oak Skink would be considered to be fragmented.
9. Insufficient data are available with which to estimate total population size or historic or current population trends of the Alpine She-oak Skink in NSW (D. Hunter pers. comm. 2010). There are 11 records of the species in the state, however no systematic surveys have been undertaken in habitat considered suitable for the species. Most records in NSW are of single individuals (D. Hunter pers. comm. 2010). However, a record of 15 animals was made after fire in Kosciuszko National Park in 2008. This is by far the largest number of individuals so far reported from a single location in NSW (D. Hunter pers. comm. 2011).
10. The geographic range of the species in NSW is considered highly restricted. Based on known records (NSW Wildlife Atlas, accessed Sept 2010; D. Hunter pers. comm. 2010), the Extent of Occurrence (EOO) can be estimated as 873 km2 (based on a minimum convex polygon encompassing all known locations, the method recommended by IUCN (2010) for assessment of EOO). However, the area of suitable habitat available for the species in NSW is estimated to be less than 250 km2 (K. McDougall pers. comm. 2010). Systematic surveys conducted in areas of potentially suitable habitat in Victoria have failed to detect any Alpine She-oak Skinks (N. Clemann pers. comm. 2010), suggesting that even within suitable habitat, the species has, at best, a patchy distribution. In addition, preferred habitat areas in NSW generally have a disjunct occurrence and are within a matrix of other alpine and sub-alpine habitats in which the Alpine She-oak Skink is not known to occur. On the basis of all known records for the species in NSW, the Area of Occupancy (AOO) may be estimated as 24 km2 (i.e. using 2 x 2 km grid cells, the scale recommended by IUCN (2010) for assessment of AOO) but, given that systematic surveys for the species have not yet occurred in NSW and that it may be difficult to detect the species during general fauna surveys, a more conservative assessment would be to place AOO between 24 and 250 km2.
11. Some habitat of the Alpine She-oak Skink would have been destroyed as alpine resort villages were established and expanded in the Kosciuszko region. Construction of associated infrastructure such as roads, tracks and ski runs has also resulted in loss and fragmentation of subalpine and alpine habitat. Construction of dams has also destroyed some habitat likely to be occupied by the species (D. Hunter pers. comm. 2010). This loss of habitat has likely reduced the area of occupancy of this species and probably isolated some populations. ‘Clearing of native vegetation’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.
12. Current grazing and trampling by feral horses, deer and pigs and past trampling by cattle have all contributed to the degradation of Alpine She-oak Skink habitat in NSW, leading to the direct loss of individuals and further fragmentation of populations (D. Hunter pers. comm. 2010). ‘Herbivory and environmental degradation caused by Feral Deer’ and ‘Predation, habitat degradation, competition and disease transmission by Feral Pigs, Sus scrofa Linnaeus 1758’ are listed as Key Threatening Processes under the Threatened Species Conservation Act 1995.
13. Potential threats to the species in NSW are all associated with changes in vegetation structure within preferred habitat brought about by wildfire, weed invasion, and climate change. Available evidence is unclear as to the specific effect of wildfire on the Alpine She-oak Skink. Sections of Kosciuszko National Park have been invaded by Hieracium aurantiacum (Orange Hawkweed), a declared class 1 Noxious Weed in NSW, which has the ability to out-compete native species within grassland in sub-alpine areas (Williams & Holland 2007). As a result of climate change, sub-alpine grasslands are likely to face increasing pressure from plant invasions (McDougall et al. 2005; Williams et al. 2008), which may further reduce the extent of suitable habitat for the Alpine She-oak Skink (D. Hunter pers. comm. 2010). Climate change may also cause the migration of lower elevation shrubs and heaths to higher elevations, resulting in their dominance over tussock grassland (Halloy & Mark 2003). As the Alpine She-oak Skink is specially adapted to low heath tussock grass habitats on the alpine plateau, the species has limited scope for uphill migration in response to changes to habitat. ‘Anthropogenic Climate Change’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.
14. Exotic predators such as rats, foxes, cats and dogs, which are present in developed alpine areas, may prey on the Alpine She-oak Skink, although the extent of this impact is currently unknown.
15. The Alpine She-oak Skink Cyclodomorphus praealtus Shea, 1995 is not eligible to be listed as a Critically Endangered species.
16. The Alpine She-oak Skink Cyclodomorphus praealtus Shea, 1995 is eligible to be listed as an Endangered species as, in the opinion of the Scientific Committee, it is facing a very high risk of extinction in New South Wales in the near future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2010:
Clause 7 Restricted geographic distribution and other conditions
The geographic distribution of the species is estimated or inferred to be:
a projected or continuing decline is observed, estimated or inferred in the key indicator:
the geographic distribution, habitat quality or diversity, or genetic diversity of the species.
Dr Richard Major
Proposed Gazettal date: 02/12/11
Exhibition period: 02/12/11 – 03/02/12
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