Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents

Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee (TSSC) on Amendments to the List of Ecological Communities under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)

1. Name

A nomination was received for the Semi-evergreen Vine Thicket (SEVT) of the South-east Queensland (SEQ) and Central Queensland Coast (CQC) Bioregions. The name of the nominated ecological community does not adequately describe the distribution or nature of the national ecological community being assessed. The features of the national ecological community are the vegetation formation of a semi-evergreen vine thicket and the presence of bottle trees (Brachychiton spp.) as characteristic emergent tree species. Consequently, the name of the ecological community has been changed to Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents.

2. National Context

The Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community comprises six Regional Ecosystems. All of these Regional Ecosystems are listed as either endangered (E) or of concern (OC) under the Queensland Vegetation Management Act 1999. The six Regional Ecosystems are:

12.8.21  Semi-evergreen vine thicket with Brachychiton rupestris on Cainozoic igneous rocks. Southern half of bioregion (E);

12.8.22  Semi-evergreen vine thicket with Brachychiton australis on Cainozoic igneous rocks. Northern half of bioregion (E);

12.9/10.15  Semi-evergreen vine thicket with Brachychiton rupestris on sedimentary rocks (E);

12.11.13  Semi-evergreen vine thicket on metamorphics ± interbedded volcanics; northern half of bioregion (OC);

12.12.17  Semi-evergreen vine thicket on Mesozoic to Proterozoic igneous rocks; south of bioregion (OC);

12.12.18  Semi-evergreen vine thicket on Mesozoic to Proterozoic igneous rocks; north of bioregion (OC).

The nomination also included an additional three Regional Ecosystems that are excluded from the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community, as defined in the Description. The reasons for their exclusion are outlined below.

8.12.16  Low microphyll vine forest of dry subcoastal hillsides on intermediate volcanics (OC). This Regional Ecosystem was excluded because it is not described as a semi-evergreen vine thicket. Although RE 8.12.16 includes bottle trees, many of the other species cited as being characteristic are not common to the national ecological community.

8.12.28 Dry vine thicket with emergent Acacia fasciculifera and/or Araucaria cunninghamii on islands and headlands (OC). During the assessment period, RE 8.12.28 was distinguished as a separate Regional Ecosystem and split from RE 8.12.16. This Regional Ecosystem was excluded because it is not described as a semi-evergreen vine thicket and does not include bottle trees as a characteristic emergent species. Also, it occurs on islands and headlands rather than undulating hills and plains.

12.11.4  Semi-evergreen vine thicket on metamorphics ± interbedded volcanics (OC). This  Regional Ecosystem is excluded because it does not include bottle trees as a characteristic emergent tree species, and many of the other species cited as being characteristic are not common to the national ecological community.

The Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community occurs in disjunct patches, primarily in the central-western parts of the South-east Queensland Bioregion. Some patches, however, extend across the Bioregion boundary into the extreme eastern parts of the Brigalow Belt South Bioregion. The extent of occurrence ranges from Kroombit Tops National Park to the east of Biloela, south to Main Range National Park to the east of Warwick.  Patches also occur in or near Coulstoun Lakes, Goodnight Scrub National Park and Bunya Mountains National Park. The ecological community does not extend into NSW.

Although the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community could be distinguished from similar ecological communities in southern Queensland and northern NSW, its precise affinities with other semi-evergreen vine thicket ecological communities are not clear at present. It is possible that Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents is part of a broader national ecological community that includes other semi-evergreen vine thicket ecological communities, such as the already listed Semi-evergreen vine thickets of the Brigalow Belt (North and South) and Nandewar Bioregions. The definition of what constitutes the national ecological community needs to be investigated further.

3. Description

The Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community is a type of dry rainforest. The structure of the ecological community consists of an open canopy of stunted trees over a dense understorey.  It comprises a mix of semi-evergreen and evergreen species, with a few deciduous emergent trees (Table 1). The height of the canopy is typically to ten metres tall, except for some emergent trees. Bottle trees (Brachychiton australis, B.discolor, B rupestris) are typical emergent tree species for this ecological community. Other common plant species present in the ecological community are listed in Table 1. 

The landforms on which the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community occurs are undulating hills, lowlands and plains. The ecological community is present on a range of soil types in Queensland land zones 8 (black earths, kraznozems, shallow clays and lithosols), 9/10 (in-situ earths and textured contrast soils/fine textured soils), 11 (lithosols and shallow textured contrast soils of usually low-moderate fertility) and 12 (lithosols and textured contrast soils of usually low fertility).

A range of native vertebrate fauna have been observed within the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community (Table 2). These include three animal species listed as nationally vulnerable under the EPBC Act.

4. How judged by TSSC in relation to the EPBC Act criteria.

The TSSC judges the ecological community to be not eligible for listing under the EPBC Act.  The justification against the criteria is as follows:

Criterion 1 - Decline in geographic distribution

The Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community has declined from its estimated pre-clearing extent of 77,485 ha.  By 1999, the extent of the ecological community had declined to 19,360 ha, a reduction of 75% (Accad et al. 2001).  A minimum decline of 70% is required for an ecological community to be listed as vulnerable. This would ordinarily indicate that the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community, as here defined, is eligible for listing as vulnerable under this criterion.

However, the affinities of the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents to other semi-evergreen vine thicket ecological communities is not clear, at present. Further investigation is required into the limits and status of a possible broader national ecological community. Therefore, the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community is not eligible for listing under this criterion.

Criterion 2 - Small geographic distribution coupled with demonstrable threat

The Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community mostly occurs in disjunct patches within the South-eastern Queensland Bioregion with some patches extending to the eastern extremity of the Brigalow Belt South bioregion. The extent of occurrence lies between Kroombit Tops National Park, to the east of Biloela, and Main Range National Park, to the east of Warwick, a distance of about 450 km.  The pre-clearing area of occupancy for the ecological community was approximately 774.5 km2 (Accad et al. 2001), which indicates that the ecological community had a naturally limited geographic distribution.

The nomination indicated that extant patches of the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community generally are less than 100 ha in size. The existing patchiness of the ecological community is a result of extensive clearing for agriculture and crop production. (Accad et al. 2001).

Accad et al. (2001) also noted that patches require intensive management because of invasion by weeds and fire damage on margins. The combined threats of fragmentation, weed invasion and fire damage have important adverse consequences for the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community. Smaller patches are more likely to be disturbed by the weeds and fire than larger patches.  Rainforests are poorly adapted to fire and dry rainforests, of which the national ecological community is an example, are particularly prone to fire due to their increased flammability. (Floyd 1990). Overly frequent fire regimes can limit the extent or regeneration of rainforest vegetation, especially at the edges of patches. Another adverse impact of inappropriate fire regimes in rainforests is enhanced establishment of weeds (Floyd 1990; Muyt 2001). The nomination notes the presence of nine species of weeds in the national ecological community. Excessive growth of weeds retards the regeneration of the ecological community by crowding out native seedlings and preventing their establishment. Increased presence of weeds also increases the flammability of the ecological community. It is the combination of these threats that is particularly damaging to the ecological community.

All of these threats require intensive management (Accad et al. 2001). The land tenure under which such intensive management is applied to achieve conservation outcomes is primarily in National Parks. However, in 1999, only 1,580 ha (or 8.2%) of the ecological community was conserved in National Parks (Accad et al. 2001). Almost half (49.4%) of the ecological community occurred on freehold land, with remainder mainly in State Reserves (34.4%) or leasehold lands (5.4%). Consequently the existing threats can be presumed to be exerting an adverse influence over most of the extant range of the ecological community.

It is recognised that the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community has a naturally limited distribution and that there are continuing threats to the ecological community. Despite this recognition, there is a lack of data that indicates the severity and timeframes over which existing threats are operating. Therefore, this ecological community is not eligible for listing under this criterion.

Criterion 3 - Loss or decline of functionally important species

The nomination provides no information under this criterion.

Criterion 4 - Reduction in community integrity

The nomination provides no information under this criterion. (The information presented in the nomination under Criterion 4 is pertinent to Criterion 2.)

Criterion 5 - Rate of continuing detrimental change

Accad et al. (2001) provide data by which the rate of clearing for the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community can be estimated. Between 1997 and 1999, 146 ha of this ecological community were lost, mainly from freehold lands. Given that the ecological community covered 19,506 ha in 1997, this represents an average loss rate of 73 ha/year and a proportional loss of 0.75%, for the period 1997-1999. A minimum detrimental change of 30% over the immediate past, or projected for the immediate future, is required for an ecological community to be listed as vulnerable. Therefore, the low rate of detrimental change for the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community indicates that it is not eligible for listing under this criterion.

Criterion 6 - Quantitative analysis showing probability of extinction

The nomination provides no information under this criterion.

5. Conclusion

TheSemi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community is not eligible for listing under the EPBC Act, pending further investigation into its affinities with other semi-evergreen vine thicket ecological communities.

6. Recommendation

TSSC recommends that:

  • the name of the nominated ecological community be changed to Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents to reflect the nature of the ecological community;
  • the nomination for the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community be rejected; and
  • the national extent of the nominated ecological community be reassessed within the context of a broader, national ecological community, Sub-tropical Semi-evergreen Vine Thickets.

Table 1 Plant species present within the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community.  Sources:  1 Accad et al. (2001).  2 Nomination.

Characteristic species 1 Common name
Acacia fasciculifera Rosewood
Alectryon diversifolius  

Alectryon subdentatus

 

Archidendropsis thozetiana

Southern siris

Arytera microphylla

 

Atalaya salicifolia

Brush whitewood

Brachychiton australis

Broad-leaved bottle tree

Brachychiton rupestris

Narrow-leaved or Queensland bottle tree

Bridelia exaltata

 
Bursaria incana Prickly pine
Canthium buxifolium

Shiny canthium

Canthium odoratum

 

Croton insularis

Queensland cascarilla

Diospyros geminata

Scaly ebony

Elattostachys xylocarpa

White tamarind

Erythroxylum australe

 

Flindersia australis

Teak

Flindersia collina

Borad-leaved leopard tree

Geijera paniculata

Axe-breaker

Grevillea helmsiae

 

Melaleuca bracteata

Black tea tree

Planchonella cotinifolia  
Turraea brownii  
Other species present 2  

Acacia aulacocarpa

Hickory wattle

Acacia harpophylla

Brigalow

Acacia maideni

Maiden's wattle

Acalypha capillipe

Small-leaved acalypha

Acronychia laevis

Hard aspen

Alchornea ilicifolia

Native holly

Araucaria cunninghamii

Hoop pine

Arytera foveolata

Gap axe

Austrosteenisia blackii

Bloodvine

Brachychiton discolor

Lacebark tree

Capparis sarmentosa

Scrambling pomegranate

Casearia multinervosa

 

Citriobatus linearis

Black-fruited thronbush

Croton acronychioides

Thick-leaved croton

Cupaniopsis parvifolia

Small-leaved tuckeroo

Geijera salicifolia

Broad-leaved scrub wilga

Gymnema micradenium

 

Maytenus bilocularis

Orangebark

Parsonsia leichhardtii

Black silkpod

Parsonsia lenticellata

Narrow-leaved parsonia

Pavetta australiensis

Butterfly bush

Plantago myosuros

 

Pouteria cotinifolia

Small-leaved coondoo

Streblus brunonianus

Whalebone tree

Tragia novae-hollandiae

 
Vitex lignum-vitae Satinwood
Zanthoxylum brachyacanthum Thorny yellowwood

Table 2  Vertebrate species known to occur within the Semi-evergreen Vine Thickets with Bottle Tree (Brachychiton spp.) Emergents ecological community.  Source:  Nomination. 

Bold = listed as a nationally threatened species under  the EPBC Act.

Scientific name Common name
Accipiter fasciatus Brown Goshawk
Accipiter novaehollandiae Grey Goshawk
Alectura lathami Australian Brush-turkey
Alisterus scapularis Australian King-Parrot
Anomalopus brevicollis Skink
Aviceda subcristata Pacific Baza
Cacatua galerita Sulphur-crested Cockatoo
Calyptorhynchus magnificus Red-tailed Black-Cockatoo
Chalcophaps indica Emerald Dove
Colluricincla harmonica Grey Shrike-thrush
Demansia vestigiata Black Whip Snake
Denisonia maculata Ornamental Snake
Eroticoscincus graciloides Elf Skink
Gerygone mouki Brown Gerygone
Hoplocephalus stephensii Stephen's Banded Snake
Lerista cinerea Skink
Leucosarcia melanoleuca Wonga Pigeon
Litoria caerulea Common Green Tree Frog
Litoria nasuta Striped Rocket Frog
Meliphaga lewinii Lewin's Honeyeater
Melomys cervinipes Fawn-footed Melomys
Miniopterus australis Little Bent-wing Bat
Morelia maculosa Spotted Python
Morelia spilota Carpet Python
Myzomela sanguinolenta Scarlet Honeyeater
Nangura spinosa Nangur Skink
Ninox novaeseelandiae Southern Boobook
Ninox strenua Powerful Owl
Oedura sp.nov Velvet Gecko
Oriolus sagittatus Olive-backed Oriole
Perameles nasuta Long-nosed Bandicoot
Phyllurus caudiannulatus Banded Leaf-tailed Gecko
Pitta versicolor Noisy Pitta
Podargus ocellatus plumiferus Marbled Frogmouth
Pseudocheirus peregrinus Common Ringtail Possum
Psophodes olivaceus Eastern Whipbird
Pteropus poliocephalus Grey-headed Flying-fox
Ptilinopus regina Rose-crowned Fruit-Dove
Rattus fuscipes Bush Rat
Rhinolophus megaphyllus Eastern Horseshoe-bat
Rhipidura fuliginosa Grey Fantail
Rhipidura rufifrons Rufous Fantail
Sericornis frontalis White-browed Scrubwren
Sphecotheres viridis Figbird
Trichoglossus haematodus Rainbow Lorikeet
Trichosurus caninus Mountain Brushtail Possum
Turnix melanogaster Black-breasted Button-quail
Tyto tenebricosa Sooty Owl
Wallabia bicolor Swamp Wallaby

Publications used to assess the nomination

Accad, A., Nelder, V.J., Wilson, B.A. and Neihus, R.E. 2001 Remnant Vegetation in Queensland: Analysis of Pre-clearing Remnant 1997-1999 Regional Ecosystem Information. Brisbane: Queensland Herbarium; Environmental Protection Agency.

Floyd, A.G. 1990 Australian Rainforests in New South Wales. Volume 1.Chipping Norton: Surrey Beatty and Sons Pty Ltd; NSW National Parks and Wildlife Service.

Muyt, A. 2001 Bush Invaders of South-east Australia. Melbourne: R.G. and F.J. Richardson.

Sattler, P.S. and Williams, R.D. (eds). 1999 The Conservation Status of Queensland's Bioregional Ecosystems.  Brisbane: Environment Protection Agency.