Semi-evergreen vine thicket (SEVT) is considered an extreme form of dry seasonal subtropical rainforest (McDonald 1996). It occurs in areas with a subtropical, seasonally dry climate on soils of high to medium fertility and is generally characterised by the prominence of trees with microphyll sized leaves (2.5–7.5cm long) and the frequent presence of swollen-stemmed “bottle trees” (Brachychiton australis, B. rupestris) as emergents from the vegetation. The thickets typically have an uneven canopy 4–9m high with mixed evergreen, semi-evergreen and deciduous emergent tree species 9–18m high. Vines, twining or scrambling plants are prominent.
The Australian Government has listed “Semi-evergreen vine thickets (SEVT) of the Brigalow Belt (North and South) and Nandewar Bioregions” as an ‘Endangered’ ecological community (EC) under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).
Six of the 10 Regional Ecosystems (REs) that make up the SEVT EC are also listed under Queensland’s Vegetation Management Act 1999 (VMA) as ‘Endangered’ (11.3.11, 11.4.1, 11.8.13 and 11.11.18), or ‘Of Concern’ (11.2.3 and 11.9.4).
The SEVT EC also includes areas of SEVT within the Brigalow Belt South and Nandewar Bioregions within New South Wales. This community corresponds to the Notelaea microcarpa–Ehretia membranifolia–Geijera parviflora vine thicket of Floyd (1990) and western vine thickets of Keith (2004). The community is listed as ‘Endangered’ under the NSW Threatened Species Conservation Act 1995.
Habitat and distribution summary
Remnant semi-evergreen vine thickets, often referred to as softwood scrub or bottle tree scrub are most common on undulating plains on fine-grained sedimentary rocks (frequently shale) and on basalt hills and plains. They also occur on coastal dunes, Quaternary alluvium, Tertiary clay plains, old loamy and sandy plains, or hills and lowlands on metamorphic rocks.
The SEVT EC originally covered almost 900,000ha between 19o and 31o latitude, with an average annual rainfall between 500 and 750mm. The total remnant extent of the SEVT EC in 2003 was less than 150,000ha (17%), with approximately 37,000ha in protected areas such as national parks and state forests (Qld EPA 2005a).
Threats affecting SEVT EC include:
- vertebrate pests; and
- coastal development.
Overall recovery objective
The overall objective of this plan is to maintain and conserve the environmental values of the semi-evergreen vine thicket ecological community over the long term, by minimising the loss of both remnant and regrowth SEVT and improving their condition and management.
Summary of actions
The following actions are recommended:
- Complete and refine mapping of remnant SEVT EC.
- Determine the extent and condition of areas of the SEVT
- Survey poorly known species, especially fungi, herpetofauna and invertebrates.
- Monitor selected populations of the EPBC Act-listed species across their distribution within the EC.
- Identify key areas of the SEVT EC for addition to the Queensland and NSW conservation reserve systems.
- Encourage landholders to enter into conservation agreements over semi-evergreen vine thickets.
- Liaise with landholders to develop appropriate burning practices and other procedures to minimize fire damage to remnant areas of SEVT on private and public lands.
- Determine the impact of grazing animals, both domestic and native, on remnant areas of SEVT. Develop guidelines and recommendations for fencing.
- Develop and implement a pest management program to control or manage feral animals and native animals in SEVT remnants.
- Encourage landholders through appropriate incentive programs to protect and foster regrowth SEVT and associated vegetation in buffer areas.
- Research and develop use of SEVT species for landscape rehabilitation and encourage mining companies, Main Roads and others to use native species in plantings.
- Undertake consultation with traditional owner groups to determine the level of indigenous knowledge of and association with the SEVT EC.
- Develop and implement education programs to increase the awareness of government and non-government organisations regarding SEVT conservation, and their responsibilities for SEVT protection and management.