NEC 1.1: Bloodwood open woodlands of the northern inland plains Description Key flora and fauna and abiotic elements Woodlands dominated by Corymbia terminalis or C. opaca are grouped together in this NEC because they form communities with broadly similar biotic and abiotic features. There are eight communities in the NVIS data for the arid / semi-arid zone that contribute to its definition (Table 1). These woodlands occur in inland Queensland and Northern Territory. They are generally low open woodlands with a mixed shrub and grass understorey. The dominant bloodwoods are either C. terminalis or C. opaca. The geographic ranges of each of these species are broadly distinct (Figure 1), with C. terminalis to the north and east, and C. opaca more central and south (Hill and Johnson, 1995). Note that there are wide zones of intergradation between the various bloodwood species (Figure 1). Figure 1: Distribution of the bloodwood species: C. opaca (open circles), C. terminalis (plus), C. tumescens (solid circles), C. tumescens - C. terminalis (square), C. opaca - C. terminalis (open diamond) (from Hill and Johnson 1995, Fig 58). Species outside the semi-arid boundary have not been detailed here These woodlands grow on sandy to loamy red earths on flat or undulating sand plains (sub- communities 2, 4, 6, and 7), calcareous clays on plains or low-lying areas (sub-community 3 and 5) and alluvial soils on terraces and floodplains (sub-community 1) (Table 1, Attachment 1-1). The eucalypts in the bloodwood woodlands range from approximately three to 14 metres tall (Attachment 1-1). Some of the Queensland units (eg components of sub-community 2) contain variants that are Acacia dominated, often with emergent C. terminalis. Density of the upper canopy generally varies from 1 to <10%, but may be as high as 20% in variants that are Acacia dominated NEC 1.1: Bloodwood open woodlands of the northern inland plains Page 51 (Attachment 1-1). Other components of the upper storey vary with location, and include ghost gums (C. aparrerinja) in NT and the Mount Isa Inlier of Queensland, Eucalyptus pruinosa in NT, and Acacia aneura (mulga) and Lysiphyllum gilvum (Bauhinia) in Queensland. Neldner (1991) notes, in relation to sub-community 1 (RE 1.3.6) that “Corymbia aparrerinja dominates on deeper soils, while C. terminalis dominates more extensive areas distant from streamline.” The mid-stratum is generally sparse and includes shrubs such as Atalaya hemiglauca, Grevillea striata and various Acacia species in both states, and species of Senna, Hakea, Eremophila and Ventilago. The ground layer often includes spinifexes (Triodia pungens or T. bitextura) and other perennial and annual grasses such as Aristida pruinosa, Aristida latifolia, Eulalia aurea, Bothriochloa ewartiana, Cenchrus pennisetiformis, and Themeda triandra. More details about the floristics and structure of each sub-community are provided in the database accompanying this report and in Attachment 1-1. The above data and those in the tables were compiled from: Wilson et al (1990), Brocklehurst and Gibbons (2003), Sattler and Williams (1999), Environmental Protection Agency, Qld (2003b) and Neldner (1991). There are few data on faunal associations. Sub-community 2 is reported to provide significant provincial fauna habitat due to the number and size of trees with hollows (Sattler and Williams 1999). Further information may be available in the reports listed by Sattler and Williams (1999) for the MII (their Table 1.5, pg 1/25) and the MGD (pg 4/7). Links with other subcommunities or NECs • In NT, to the north, grades into Corymbia terminalis / E. chlorophylla woodlands and Eucalyptus pruinosa, Lysiphyllium low open-woodlands (Wilson et al. 1990) and to the south, grades into arid zone shrublands or grasslands. Because of the broad mapping scale, other map units will occur within the mapped bloodwood woodlands: for example, E. microtheca (perhaps E. victrix) woodlands in depressions in map unit 41, and Triodia spictata hummock grassland on gravely rises within map unit 42 (Wilson et al 1990). Sub-community #7 also occurs as minor component within the Tanami desert hummock grasslands (NT map unit 79; Wilson et al 1990). • In Qld, the tropical savannas mapping incorporates most if not all the Qld subcommunities of this NEC into map unit D46. There are a broad range of other communities included in this group (see Appendix 3.4 in Fox et al (2001) – community Q108 is the woodland matching most Qld subcommunities presented here, but numbers 100, 101, 103, 105 -112, 115, 117 , 203 , 204, 207, 211, 221, 305A, 503 and 506 are also in that group. Most of the latter are primarily tropical. • In Qld, there appear to be floristic and abiotic affinities with: • Archidendropsis basaltica and/or Acacia aneura ± Corymbia terminalis low open woodland on old alluvial sand plains (RE 4.5.4, MGD) • Archidendropsis basaltica and/or Acacia aneura ± Corymbia terminalis low open woodland on sand plains (RE 5.5.6, CHC) • two of the REs (4.5.5 and 1.5.7) grade into RE 4.5.8, a Triodia pungens hummock grassland wooded with Acacia spp. ± Eucalyptus spp. on Quaternary sand sheets (interpreted from Neldner 1991) • C. terminalis also occurs in NEC1.2, in woodlands dominated by E. leucophloia and in NEC1.3, with E. pruinosa and E. leucophylla Bloodwoods (C. tumescens) occur in southern Qld, NW NSW and NE SA, but appear not to form woodlands in most situations. However, the data are sparse and the areas are not well surveyed. The pertinent information for the communities in these states is summarised in Attachment 1-2 NEC 1.1: Bloodwood open woodlands of the northern inland plains Page 52 Table 1: Sub-communities in NEC #1: Bloodwood open woodlands of the inland plains Sub # Name, with source or Regional Ecosystem number for name Other refs for sub State IBRA region Comments (subregion) 1 Ghost gum (Corymbia aparrerinja), bloodwood (Corymbia Christian et al. Qld MII (NWH3) Significant provincial fauna habitat terminalis) open woodland on sandy terraces (RE 1.3.6) (1954), Mount Isa, due to the number and size of Wonorah, Gregory; trees with hollows. Perry et al. (1964), Quamby, Kuridala; (Interpreted as floristic association Neldner (1991), 3 67 in Neldner 1991) 2 Bloodwood (Corymbia terminalis) and/or mulga (Acacia aneura) Christian et al. Qld MII (NWH1) (Interpreted as floristic low open woodland on sandy red earth plains (RE 1.5.7) (1954), Bundella, associations 5 & 10 in Neldner Wonorah; Neldner 1991) (1991), 21, 24 3 Corymbia terminalis ± Lysiphyllum gilvum and Acacia victoriae Neldner (1991), 19d Qld MGD (MGD3) (Interpreted as floristic association low open woodland on alluvium (RE 4.3.10) 44 in Neldner 1991) 4 Corymbia terminalis, Triodia pungens ± Acacia spp., Senna spp., Neldner (1991), 19a Qld MGD (MGD 2) (Interpreted as floristic association Eucalyptus spp. low open woodland on sand plains (RE 4.5.5) 42 in Neldner 1991) 5 Corymbia terminalis low open woodland with Astrebla pectinata ± Neldner (1991), 19b Qld MGD (Interpreted as floristic association Eulalia aurea on plains and low lying areas (RE 4.9.12) (MGD2) 44 in Neldner 1991) 6 C. opaca (Bloodwood) low open-woodland with Triodia bitextura NT DMR, MGD, TAN (Curly Spinifex) hummock grassland understorey (Wilson et al 1990, map unit 41, Brocklehurst and Gibbons 2003 DVT 98) 7 C. opaca (Bloodwood) low open-woodland with Triodia pungens NT DMR, MGD, TAN (Soft Spinifex) hummock grassland understorey (Wilson et al 1990, map unit 42, and Brocklehurst and Gibbons 2003, DVT 116) 8 Corymbia opaca (bloodwood) low open woodland with a NT CHC1 (at Lucy Chrysopogon fallax tussock grassland understorey (Brocklehurst Creek Station) and Gibbons 2003, DVT 126) NEC 1.1: Bloodwood open woodlands of the northern inland plains Page 53 National distribution Known natural distribution (including bioregions, conservation reserves) In Qld, two sub-communities (#1, 2) occurs in the Mt Isa Inlier IBRA region, the other three (#3 to 5) occur in the Mitchell Grass Downs IBRA region (Sattler and Williams, 1999, Figure 2). There is no representation of these communities in protected areas in Qld (Sattler and Williams, 1999). Only one sub-community (#4) is mapped; it covers 830ha in the MGD region. However, the tropical savannas mapping (Fox et al 2001) map the Queensland communities as part of their unit “D46”, this is mapped here (Fig 2) The communities in NT (# 6 and 7, see Figure 2) occur in the Davenport Murchison Ranges, Mitchell Grass Downs and Tanami IBRA regions. None are in conservation reserves or National Parks, according to the CAPAD mapping (Environment Australia 2002). Sub-community#6 (C. opaca low open-woodland with Triodia bitextura hummock grassland understorey) has a naturally restricted distribution and is confined to a distinct area south of the Barkly Tablelands (~ 330 000ha). Sub- community#7 (C. opaca low open-woodland with Triodia pungens hummock grassland understorey) occupies more extensive areas (~2 800 000ha) south of the Barkly Tablelands, and as unmapped small occurrences within hummock grasslands of the Tanami bioregion (Wilson et al. 1990). The remaining NT community (#8) is not in the NVIS data and the original report should be accessed for further details. Figure 2: Indication of location of subcommunities: In the NT, the subcommmunity 6 is indicated in blue, and #7 in yellow. The Qld sub-regions in which the sub-communities occur are shaded (MII horiz lines, MGD pale grey). .Within these, the black patches indicate mapping of the tropical savannas unit D46 in these sub-regions. The CHC1 subregion in NT is indicated because sub-community 8 resides in it. The red line indicates the boundary of the semi-arid areas; grey outlines arid/semi-arid subregions. NEC 1.1: Bloodwood open woodlands of the northern inland plains Page 54 Table 2: Sub-communities in NEC #1: Conservation issues Sub # Name, with source or Regional Ecosystem area % Protected areas Threat status1 Threats number for name (km2) remain ing 1 Ghost gum (Corymbia aparrerinja), bloodwood na >30% no representation Of concern Subject to buffel grass Cenchrus ciliaris (Corymbia terminalis) open woodland on invasion.