Indicative distribution
The areas shown in pink and/purple are the sub-regions where the species or community is known or predicted to occur. They may not occur thoughout the sub-region but may be restricted to certain areas.
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click here to see geographic restrictions).
The information presented in this map is only indicative and may contain errors and omissions.
Scientific name: Eucalyptus aggregata - endangered population
Gazetted date:
30 Aug 2013
Profile last updated:
13 Jan 2022
Description
Black Gum is a small to medium-sized woodland tree growing to 18 m tall. The the bark on the trunk and main branches is dark greyish-black, deeply fibrous or flaky. The bark does not shed annually. Only the uppermost branches and twigs have smooth whitish, cream or greyish bark that sheds yearly. The juvenile leaves are narrow or oval-shaped, dull green and arranged opposite to one another. The adult leaves are slightly curved and round-ended, about 12 cm long and 1 to 2 cm wide. They are glossy dark green and have the same colour on each surface. The buds, flowers and fruits occur in tight clusters of 7; the clusters are on stalks 3 to 4 mm long. The buds are egg-shaped, 3 to 5 mm long and 2 to 3 mm wide. The flowers are white and are followed by gum-nuts which are cone- or cup-shaped, 2 to 4 mm long and 3 to 5 mm wide. The disc on the surface of the gum-nut has processes (valves) which emerge from the disc.
Distribution
This endangered population is located in the Wingecarribee local government area. Three sub populations, comprising less than 100 plants in total, are located in Berrima, Medway and Sutton Forest.
Habitat and ecology
- Grows in the lowest parts of the landscape.
- Grows on alluvial soils, on cold, poorly-drained flats and hollows adjacent to creeks and small rivers.
- Often grows with other cold-adapted eucalypts, such as Snow Gum or White Sallee (Eucalyptus pauciflora), Manna or Ribbon Gum (E. viminalis), Candlebark (E. rubida), Black Sallee (E. stellulata) and Swamp Gum (E. ovata). Black Gum usually occurs in an open woodland formation with a grassy groundlayer dominated either by River Tussock (Poa labillardierei) or Kangaroo Grass (Themeda australis), but with few shrubs.
- Also occurs as isolated paddock trees in modified native or exotic pastures.
- Many populations occur on travelling stock reserves, though stands and isolated individuals also occur on private land.
- None of the three sub populations are protected in conservation reserves
Regional distribution and habitat
Click on a region below to view detailed distribution, habitat and vegetation information.
Threats
- Clearing for cropping and grazing.
- In small populations, hybridisation with related species (e.g. Candlebark (Eucalyptus rubida) and Manna Gum (E. viminalis)), is causing lowering of genetic fitness, and is increasing the risk of extinction.
- The naturally small area and patchiness of its habitat is under pressure from further reduction in area.
- Small-scale clearing as farming properties are subdivided for rural-residential use
- Lack of recruitment.
- Lack of recruitment under current grazing.
- Lack of recruitment because of competition by weeds, particularly Hawthorn (Crataegus monogyna), Phalaris (Phalaris aquatica), Cocksfoot (Dactylis glomerata) and Yorkshire Fog (Holcus lanatus).
- Climate change effects (i.e. increasing average temperatures and reductions in effective rainfall) may reduce the species' viability by reducing conditions suitable for recruitment and establishment of seedlings.
- Climate change may also lead to increased invasion by seedlings of Candlebark and Manna Gum, which may lead to increased competition with Black Gum.
- At risk of clearing or damage due to roadwork on Oldbury Rd.
Recovery strategies
A Saving Our Species conservation project is currently being developed for this species and will be available soon. For information on how you can contribute to this species' recovery, see the Activities to assist this species section below.
Activities to assist this species
- Fence out mature stands to reduce or eliminate grazing pressures and to allow regeneration.
- Control weeds that inhibit regeneration.
- Reduce small-scale clearing pressures.
- Encourage enhancement plantings around remnants of this species (using local-provenance seed sources).
- Mark locations of this species on maps of catchment, shires, farms and/or reserves, etc.
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