South Sister St. Marys, Tasmania

environmental assessment

south sister coupe (NI 114A)

Vegetation

The bushland present on this site represents an excellent example of Eucalyptus delegatensis forest. There is also a small patch of Eucalyptus brookeriana forest. Vegetation in such good ecological condition is becoming increasingly rare as a result of various human induced disturbances including too frequent fires, land clearing, forestry, weed invasion, diseases (such as root-rot fungus) and infrastructure development.

This loss and fragmentation of habitat threatens the long-term viability of native ecosystems. Apart from the roads and the corridor cleared to supply power to infrastructure on the peak of South Sister the remaining bush that was surveyed displayed little evidence of any significant disturbance. The lack of weeds, Bracken Fern, stumps and introduced fauna observed all indicated a forest in relatively undisturbed condition.

The diverse understorey provides top quality habitat for many native animals. In spring and summer there is a profusion of wildflowers and fruits providing a striking display of colour and form. A botanical survey is provided but does not include fungi, mosses or lichen. In addition more species of ferns and orchids are likely to occur on the site.

Threatened Species

Euphrasia

The threatened plant species Euphrasia collina ssp. deflexifolia was located on the coupe. Locations: (0598480/5400300) 20 plants, (05998347/5400940) 6 plants, (0598260/5401134) 31 plants, (0598050/5400980) 8 plants plus 20 plants further down the road from this last site. There is also a number of plants along the road to private property (Derricks Marsh).

I am not aware of any research into the impact of forestry on this species.

Velvet Worms

The Giant and Blind Velvet Worms have been recorded in this area. The line of parapatry that delineates the range of these two species may run through the proposed logging coupe. A previous decision by the Resource Management and Planning Appeal Tribunal (Giles, Weston and Dudley vs Denney and Break O'Day Council) found that selective logging was detrimental to Giant Velvet Worm habitat. It is my understanding that selective logging is on an 80year rotation basis. If this is the case then it will mean that future habitat (rotten, fallen logs) for the species will be diminished because eucalypts will not reach sufficient maturity to develop large branches which will fall to the forest floor. In addition the disturbance of the rocky terrain in the area may impact on the Blind Velvet Worm which are known to inhabit 'micro caverns' as well as rotten logs.

The area does not appear to have been subject to fire for in excess of twenty years. This combined with the abundance of rotting logs constitutes excellent habitat for these species.

Spotted Tailed Quoll

One of the key threats to this species is clearing of native vegetation. The Tasmanian Threatened Fauna Handbook (Bryant) recommends retention of large areas of undisturbed native bush and areas with a natural diversity of fallen logs, dense understorey, rocks (and Wombat burrows) because of their value as refuge sites for Quolls.

The recent report Linking Landscape Ecology and Management to Population Viability Analysis (2004) found that Spotted Tailed Quolls did not reinhabit clearfelled forests for up to 50 years and that habitat value for Quolls did not fully recover until 100 years after logging. While clearfelling is not proposed in this coupe selective logging will have a detrimental impact on Quoll habitat. The report suggests that Quoll numbers may decline by up to 59-65% over the next 200 years. If this is correct then high quality habitat such as found on this site should be protected.

Birds,

The site provides numerous feeding opportunities for native birds including seeds, fruits, insects and nectar. The following birds were sighted or heard during my visit to the land: Green Rosella, New Holland Honeyeater, Spinebill, Pink Robin, Black-faced Cuckoo Shrike, Grey Fantail, Superb Blue Fairy Wren, Thornbill, Currawong, Beautiful Firetail, Yellow Wattlebird, Crescent Honeyeater, Bassian Thrush, Golden Whistler and Spotted Pardalote.

The dense understorey provides cover, shelter and nesting sites for many native birds. The proposed logging operation will damage much of this understorey resulting in loss of habitat for many birds. It is likely that the level of disturbance will result in an increase in Bracken Fern at the expense of the current diverse understorey. It is also worth noting that no introduced birds were observed, another indication of the ecological health of the forest.

Other Fauna

Other fauna observed included echidna, tiger snake, numerous skinks and native snails.

CONCLUSION

This is a forest in excellent ecological condition with outstanding habitat attributes. Logging will result in major disturbance to the site including compaction of the soil, increased risk of introduction of weeds and diseases, destruction/crushing of understorey species (with likely increase in bracken fern), disturbance of rocky habitats and of course loss of mature trees. Forests which contribute so much to biodiversity should be protected.

- Todd Dudley, December 2004

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50419-4882 (1, 1, 10, 310)