Macquarie University – Turpentine/Ironbark forest Regeneration

John Macris 

Key words: Bush Regeneration, Privets, Pittosporum, in-situ conservation.

Less than 5% of the original extent of Turpentine/Ironbark forest of the Sydney Basin Bioregion remains and so this forest type is listed is listed as critically endangered under the Commonwealth EPBC Act. Weed management and rehabilitation of remnants are priority conservation actions under the Act.

A 3.5 ha remnant of Turpentine/Ironbark forest located on the Macquarie University Campus has been the focus of a bush regeneration program that commenced in 2010.  Prior to the works, the site was variable in condition, with a core area near a watercourse having relatively high species diversity including Blackthorn (Bursaria spinosa) and the rare shrub Epacris purpurascens, while edges of this area contained a diversity of weed species.  An upslope area was more highly disturbed as it had been used as a breeding enclosure for research into rare rock wallabies until around 2005.

Works to date. Commencing in Autumn 2010, contract bush regeneration works included culling of the over-represented native Sweet Pittosporum (Pittosporum undulatum) in the core area, and removal of invasive weeds, principally a dense mid-story of the woody weeds Large-leaved Privet (Ligustrum lucidum) and Small-leaved Privet (L. sinense) throughout the treatment area.  Any large Privet logs were retained as habitat. Pampas Grass was removed from around the perimeter and, in a few places, Lantana  (Lantana camara) was also removed, although some has been retained as an interim small bird habitat in a few locations. Follow up work has mainly focused on a range of herbaceous weeds including Ehrhardta (Ehrhardta erecta), and gradual exhaustion from the seed bank of the problem woody weed species.

Results Prior to works, we estimated that about 10% of remnant was in relatively good condition.  About 2.5 years on, we now estimate that about 15% – 20% of the area is now in a resilient condition. Native species regenerating include a range of native grasses and forbs including Blady Grass (Imperata cylindrica), Basket Grass (Oplismenus aemulus), Weeping Grass (Microlaena stipoides), Tufted Hedgehog Grass (Echinopogon caespitosus),Blue Flax Lily (Dianella caerulea), Plume Grass (Dichelachne sp.), Finger Grass (Digitaria parviflora) Bordered Panic Grass (Entolasia marginata), Pastel Flower (Pseuderanthemum variabile) and Kidney Weed (Dichondra repens). Tree saplings including Turpentine (Syncarpia glomulifera) and Smooth-barked Apple (Angophora costata) have been uncovered and are developing in height. The colonizing shrub Kangaroo Apple Solanum aviculare has rapidly developed a rudimentary native mid story in the areas cleared of dense Privet.

Woody weed domination of the understorey before the works commenced

Same view 2years later (2012) showing ground stratum regeneration

Lessons learned. To create a robust weed buffer to the regeneration area, we decided it was important to start work in upslope areas, even though they were disturbed by the previous animal research enclosure (e.g. artificial soil profiles).  Due to same competing uses, such areas have been challenging stablise against weed resurgence, but a management edge is being established gradually.

Acknowledgements.  Sixty per cent of the first 15 months funding for the project was provided by Sydney Metropolitan CMA through their Saving Sydney’s Biodiversity Program with the rest covered by the University.  Subsequent work has been funded under Macquarie University’s Biodiversity restoration programs. Warren Jack from the contractor Sydney Bush Regeneration Company contributed much of the above species list of ground layer regeneration.

Contact: John Macris, Macquarie University. Tel: +61 (0)2 9850 4103

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