Minemakers Wonarah Phosphate Project
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Minemakers Wonarah Phosphate Project Baseline Flora and Fauna Report Prepared for Coffey Natural Systems By Erin Moon, Tom Newsome and Dr Bill Low Low Ecological Service P/L P.O Box 3130 Alice Springs 0871 April 2009 Executive Summary Overview Minemakers Australia Pty Ltd is currently in the pre-feasibility stage of their Wonarah Phosphate Project. Low Ecological Services P/L (LES) was commissioned to broadly characterise the ecology of the area, to identify threatened species of flora and fauna present, or likely to be present in the project area, and determine if there is a potential for the project to have significant impacts on these species. The biodiversity of the area has generally been documented at a regional scale with only occasional incursion to adjacent areas for on-the-ground flora and fauna survey (Wakaya Desert survey - Gibson and Wurst, 1994). Existing data sets were used for a rapid landscape analysis to determine, in a regional context, landforms, geology, drainage systems, vegetation communities or habitats, and compile flora and fauna species lists for the project area. Two landscape, flora and fauna surveys of the project area were conducted by Low Ecological Services between the 18th and 22nd June 2008 (Dry Season 2008) and 20th and 25th March 2009 (Wet Season 2009). A more detailed soil survey was included in the 2009 survey. Regional Context The project area lies within the Davenport and Murchison Ranges Bioregion. The project area overlies the phosphate rich Wonarah beds site, which is classified as significant on a bioregional scale as determined by the NT Parks and Conservation Masterplan (Baker et al., 2005). This was likely due to the variety of habitats resulting from the relative mix of shallow sand covered rocky sub-crop and deeper aeolian sandy and alluvial silty drainage depressions. The project area is dominated by the Yelvertoft land system (Stewart et al. 1954) with minor occurrences of the Wonarah land system (Perry et al. 1962, Stewart et al. 1954). The project area occurs within vegetation community 42 (Wilson et al., 1990) which is described as Corymbia opaca (Bloodwood) low open-woodland with Triodia pungens (Soft Spinifex) hummock grassland understorey. Vegetation community 42 occupies 28095.3 km2 within the Northern Territory of which the Wonarah Phosphate Project area constitutes ~100 km2 and the proposed disturbance (i.e. mine area) equates to 27 km2 (0.1% of vegetation community). i Wonarah Phosphate Project Low Ecological Services P/L Existing Data A search of the NT Parks and Wildlife Flora Atlas (2007) for the project area and surrounding region did not identify any flora species of conservation significance under the EPBC Act. However, fourteen species were listed under the TPWC Act or by White et al. (2000) as significant at the NT or National level. Four of these species occur within the project area, two of which are listed as significant at a national level (Sporobolus latzii and Bonamia alatisemina) by White et al., (2000). Many of these species are essentially data deficient due to lack of surveys in appropriate habitat in the region. No flora species of conservation significance were identified by a protected matters report generated by the Department of Environment Water Heritage and the Arts (DEWHA) web site for the project area and surrounding region. A search of the NT Parks and Wildlife Fauna Atlas (2007) for the project area and surrounding region identified three species of conservation significance under the EPBC Act and TPWC Act, and eight species listed solely under the TPWC Act. Three of these species have been recorded within the project area (Australian bustard, Ardeotis australis, woma, Aspidites ramsayi, and long-haired rat, Rattus villosissimus). Two threatened (vulnerable) fauna species (mulgara, Dasycercus cristicauda or D. blythi, and Australian painted snipe, Rostratula australis); and eight migratory fauna species were identified by a protected matters report (DEWHA) as potentially present in the project area and surrounding region. No endangered or critically endangered species were listed. Field Surveys While the vegetation classification developed by Wilson et al. 1990 is broadly appropriate to the project area, LES desk top and field surveys defined five fine scale vegetation communities within the broader vegetation communities. The fine scale vegetation communities were found to be correlated with land units described by LES, which were verified in the field. Fine scale vegetation communities were mapped by LES for the project area to allow assessment of disturbance at a local scale. The sand plain land units (Alluvial Sand Plains, Shallow Sand Plains and Deep Sand Plains) supported a continuous but variable vegetation community with differing proportions of flora species determined by landscape variables (vegetation community 1 = Eucalypt (coolabah, mallee & bloodwood) and Acacia (dogwood) low open-woodland with Senna sp. low shrublands over hummock grassland). The ii Wonarah Phosphate Project Low Ecological Services P/L Black Soil and Clay Plain land units were grouped, and supported vegetation community 2 = Coolabah low-open woodland with silky browntop (Eulalia aurea) and Mitchell grass grassland understorey. Calcareous Plains supported vegetation community 3 = Supplejack low open woodland with open- grassland understorey. Ephemeral Lakes supported vegetation community 4 = E. victrix (coolabah) low open-woodland with open-grassland understorey. There were limited floristic data for the Rocky rise land units (Limestone Outcrop and Mud Stone Outcrop) due to inaccessibility, but they were grouped with the surveyed rocky rise land units (Silcrete and Ironstone Rocky Rises) which were found to support the same vegetation community with varying proportions of species present. This was defined as vegetation community 5 = Acacia & mallee shrubland over hummock grassland. Fine scale vegetation communities (as classified by LES) 1, 3 & 5 will be the only areas disturbed by the proposed works and the other two communities 2 and 4 are remote and not accessible to the mining operation. No habitats of ecological significance were detected within the project area; however the main ephemeral lake, which is located 5 km north of the Arruwurra Prospect and 13 km south-west of the Main Zone (Wonarah Prospect), is likely to provide important seasonal refuges for fauna and for both annual and perennial plant species adapted to seasonal inundations. This area is outside of the proposed disturbance area. Up to 60% of the project area was burnt prior to the Dry Season 2008 survey, as reflected in the vegetation transects, which, on average, had 48 % bare ground and 23 % litter. Good vegetation growth was recorded during the Wet Season 2009 survey following favourable summer rains, with bare ground along vegetation transects reduced to an average of 19 %. Data from the Wet Season 2009 survey revealed an additional 102 flora species relative to the 42 species identified during the Dry Season 2008 survey, emphasising the importance of a follow-up survey to capture seasonal changes in species composition including those in response to fire. A total of 144 flora species was recorded in the Dry (2008) and Wet (2009) season surveys. No plant species identified during LES field surveys are listed under the EPBC Act; however, two species are listed as Near Threatened (Bergia barklyana and Hibiscus brachychlaenus) and one as Data Deficient (Heliotropium pulvinum) under the TPWC Act. Two environmental weed species were recorded during the Wet Season 2009 survey along road verges and in drainage lines, buffel grass (Cenchrus ciliaris) and kapok bush (Aerva javanica). Neither species is declared under the NT Weeds iii Wonarah Phosphate Project Low Ecological Services P/L Management Act (2001), and Buffel Grass is a useful pasture species. Five declared weeds have been recorded in other studies within the surrounding region (50 km buffer); (Bellyache Bush (Jatropha gossypifolia), Mesquite (Prosopis limensis), Noogoora Burr (Xanthium strumarium), Paddyʹs Lucerne (Sida rhombifolia) and Parkinsonia (Parkinsonia aculeata)). LES field surveys recorded a total of 15 mammal, 14 reptile and 33 bird species. One species listed as Vulnerable under the TPWC Act (2000), the Australian bustard, (Ardeotis australis), and the northern nailtail wallaby (Onychogalea unguifera), listed as Near Threatened under the TPWC Act, were recorded. A further nine species of conservation significance have been recorded within the project area and the surrounding region (50 km buffer) in other studies. LES conducted targeted surveys for species of conservation significance, especially bilby (Macrotis lagotis) and mulgara (Dasycercus cristicauda or D. blythi) where suitable habitat was identified during the Dry Season 2008 survey, but no evidence was found. Traditional owners assisted with tracking surveys and were consulted regarding their knowledge of significant fauna species occurring in the local region, but none were identified. Within the surrounding region over 90 bird species have been recorded and many of these species are likely to occur within the project area. Sand plain habitats are likely to support the greatest bird diversity owing to the micro-topographic diversity and density of habitat, as well as the range of food resources due to the variable phenology of plant species that occur from ridge to flood out. Ephemeral wetland areas are also likely to be important habitats during