Melaleuca biconvexa

Although the Central Coast region contains many areas of low lying swampy land and different types of paperbark trees, Melaleuca biconvexa is the only vulnerable species of Melaleuca present in the local area.

Locally, this species has a widespread distribution and in some places can be considered a common occurrence along certain drainage lines. However, apart from a few distant isolated populations of M. biconvexa, the Central Coast area is considered the stronghold area for this species.

Conservation Status

Listed as vulnerable under Schedule 2 of the Threatened Species Conservation Act, 1995. 
Also listed as vulnerable under the Commonwealth Environment Protection and Biodiversity Conservation Act, 1999.

Description

This species is a small to medium sized paperbark tree. The leaf characteristics are diagnostic for this species. Leaves are small, up to 18 mm long and 4 mm wide; each leaf has an upper surface where the centre-vein is depressed with the two sides forming two convex curves (bi-convex) to the leaf edge.

Other Characteristic Features

Growth Characteristics: This species has a typical paperbark appearance with dense dark-green foliage and papery bark. It can remain small (8-10m) or can grow to a medium sized tree to 20m tall.² Often occurs as numerous small plants growing at close distances to each other.

Flowering Time: Flowering occurs over just 3-4 weeks in September and October.²

Life Span: This species is a long-lived species.

Reproduction: Reproduces by dispersal of very small seeds.^1&2

Site Characteristics

Vegetation Type: Usually in moist forest, scrub and riparian vegetation.¹

Topography: Wide, poorly drained alluvial flats, or in sheltered gullies.^1&2

Hydrology: Typically found in poorly drained areas in very damp to wet soils. Sometimes in areas of impeded drainage with up to 0.5 metre of standing water.²

Soils: Alluvial soils such as the Wyong and Yarramalong Soil Landscapes - Murphy (1993).^{2 & 1}  

Where this Species can be Found

Map of distribution (PDF file, 446kb)

Gosford: Lisarow Wetland, Holgate, Bensville.

Wyong: Porters Creek Wetland, Ourimbah & Bangalow Creeks near the F3, Dooralong.

Lake Macquarie: Wyee, Mandalong.

Where is this Species Habitat Protected?

• This species occurs mostly on privately held land, and is not known in any great numbers within state conservation areas.¹
• This species often occurs along roadside drains, where it is vulnerable to disturbance by road/drainage works.
• It is generally considered that this species is inadequately represented in conservation reserves.³

Threats to Survival

• Frequent fires.
• Habitat loss due to clearing for urban development and drainage works.
• Alterations to the hydrology of low-lying floodplains and swamps including swamp reclamation.
• Increased pollution and nutrients through adjoining developments and rubbish dumping.
• Grazing and trampling by stock causing root damage, prevention of seedling establishment and erosion.

This Species is listed as being affected by the following Key Threatening Processes:

• Clearing of native vegetation.
• Invasion of native plant communities by exotic perennial grasses.
• High frequency fire resulting in disruption of life-cycle processes.

Management Issues

• Survey thoroughly for the presence of M. biconvexa before the approval of development applications and assess appropriately where present on developable land.
• Ensure staff undertaking hazard reduction burns are able to identify the species and are aware of its habitat.
• Apply fire regimes which maintain floristic and structural diversity.
• Maintain or reintroduce ecologically sustainable water flows into swampland habitat.
• Ensure run-off into swamps is controlled for both water quality and quantity.
• Avoid the introduction of heavy, prolonged grazing on sites where M. biconvexa occurs.

Useful Web links:

• Plant Net – www.rbg.gov.au
• Department of Environment and Climate Change www.environment.nsw.gov.au

Bibliography:

1. C.L. Murphy Ed. (1993) Soil Landscapes of the Gosford/Lake Macquarie 1:100,000 sheet, Soil Conservation Service of NSW.
2. Harden, G.J. 2002, ‘Flora of NSW Volume 2,’ UNSW Press, Kensington, NSW.
3. NPWS – Website (Melaleuca biconvexa Species Profile).