Background: Threat abatement plan to reduce the impacts on northern

Australia’s biodiversity by the five listed grasses

DRAFT

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Photographs by Colin G Wilson/Department of Sustainability, Environment, Water, Population and Communities unless otherwise specified.Front cover (left to right): Andropogon gayanus (first three photos), Hymenachne amplexicaulis infestation (photo: Robert Miller), Pennisetum polystachion and P. pedicellatum, P. polystachion.Back cover (left to right): P. polystachion (first three photos), A. gayanus, P. polystachion, A. gayanusInside cover: P polystachion.

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Background: Threat abatement plan to reduce the impacts on 1 northern Australia’s biodiversity by the five listed grasses 2

(DRAFT) 3 4 1. Introduction 5 6 In 2009 the Australian Government listed ‘Ecosystem degradation, habitat loss and species 7 decline due to invasion of northern Australia by introduced gamba grass (Andropogon 8 gayanus), para grass (Urochloa mutica), olive hymenachne (Hymenachne amplexicaulis), 9 mission grass (Pennisetum polystachion) and annual mission grass (Pennisetum pedicellatum)’ 10 (referred to in this document as ‘the five listed grasses’) as a key threatening process under the 11 Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and initiated the 12 development of a threat abatement plan. This document aims to provide the detailed 13 information that underpins the plan. Relevant extracts from the EPBC Act are at Appendix A. 14 15 There are around 10 000 species of grasses worldwide, growing in a range of habitats on all 16 continents. Because many grasses are productive, palatable and competitive, they are desirable 17 as pasture species. However, these qualities also make them one of the weediest plant families 18 in Australia and globally (Booth et al., 2009). 19 20 While the environmental impact for most exotic grass species has not been quantified in 21 Australia, it is generally accepted that these grasses can alter fire regimes, hydrology, soil 22 chemistry, and displace native plant species, resulting in ecosystem degradation, habitat loss 23 and biodiversity decline. 24 25 Many grasses were introduced into Australia primarily for assessment and use in pastoral 26 production. Species were selected for their persistence, high growth rates and nutritional 27 value. From the 1950s, there was a perception that improved pastures were necessary for the 28 viability of the pastoral industry in northern Australia (Christian, 1959 in Grace et al., 2004; 29 Cook and Dias, 2006). Since this time there has been a growing awareness of the high 30 economic costs and significant environmental damage associated with introducing invasive 31 weed species such as some of these grasses. 32 33 Prior to 1996, plants proposed for import into Australia were checked against a ‘prohibited 34 list’ contained in a proclamation of the Quarantine Act 1908. This list included plants that had 35 been identified as a potential risk to Australia due to their weed status elsewhere in the world 36 (DAFF, 2010). A review of quarantine procedures in Australia (Nairn et al., 1996) led to the 37 development of a science-based quarantine risk assessment tool for determining the weed 38 potential of new plants proposed for import into Australia. To further strengthen the 39 quarantine assessment process, the Nairn Review Committee also recommended a ‘permitted 40 list’ for import rather than just a prohibited list. A review of plant seeds permitted entry into 41 Australia (Schedule 5 of the Quarantine Proclamation 1998 – also referred to as the Permitted 42 Seeds List) replaced nearly 3000 genus-level listings with species already present in the 43 country within those genera. In conducting the review, international obligations meant that any 44 species that were already present in Australia and not under ‘official control’1 were included 45 on the Permitted Seeds List. 46 1 ‘Official control’ is defined by the International Plant Protection Convention as ‘the active enforcement of mandatory phytosanitary regulations and the application of mandatory phytosanitary procedures with the objective of eradication or containment of quarantine pests or for the management of regulated non-quarantine pests’.

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In April 1997 the newly developed weed risk assessment (WRA) process was endorsed. Under 47 revised legislation (the Quarantine Proclamation 1998), all plant species are prohibited from 48 import into Australia unless they have been formally assessed under the national WRA system 49 as having a low potential to become weeds and/or are on the Permitted Seeds List. 50 51 In 2010, of the five species listed in the key threatening process, only Hymenachne 52 amplexicaulis was included on the prohibited list. Andropogon gayanus and Urochloa mutica 53 are on neither the permitted nor prohibited lists and therefore would require assessment to 54 determine whether import into Australia would be permitted. The import of Pennisetum spp. 55 other than P. japonicum is permitted under specified conditions and with appropriate permits 56 (ICON, 2010). 57 58 Where grass species with weed potential are already present in Australia, control and 59 management is largely the responsibility of the states and territories. Using the national WRA 60 process as a basis, weed/pest risk assessment processes have been developed by each of the 61 jurisdictions relevant to the threat abatement plan (Northern Territory, Queensland and 62 Western Australia). These processes are used to assess species that may, or have already, 63 become significant weeds. Outcomes of assessments are then used to inform the regulation 64 and management of these species. 65 66 67 2. Species 68

69 2.1 Gamba grass 70 71 2.1.1. Origin and current distribution 72 Gamba grass (Andropogon gayanus) is native to the tropical savannas of Africa, occurring 73 from Senegal in the west to Sudan in the east. Gamba grass in northern Australia is a cultivar 74 known as cv. ‘Kent’ that was developed for use as cattle fodder by crossing material 75 considered to be var. squamulatus and a second unknown variety (Oram, 1990). It was 76 introduced into Australia by the Commonwealth Scientific and Research Organisation 77 (CSIRO) Division of Land Research in 1931 but was not widely used as a pasture grass until 78 1983 when commercial quantities of seed became available (Csurhes, 2005). 79 80 The species is well suited to northern Australian conditions as it is able to establish across a 81 wide range of habitats, from open woodland to closed forests on floodplain margins (Flores et 82 al., 2005). 83 84 In the Northern Territory, preliminary trials on the species were conducted at the Katherine 85 Research Station from 1946. The trials were successful and resulted in widespread plantings in 86 pastoral and agricultural areas of the Top End (NRETAS, 2009). The earliest record of gamba 87 grass in Queensland is a specimen from a CSIRO property near Rockhampton collected in 88 1942. The first record of a naturalised specimen of gamba grass was from Bamaga in 1992, 89 although it was probably naturalised elsewhere in Cape York by that time (Csurhes and 90 Hannan-Jones, 2008). In Western Australia gamba grass is established at a station property in 91 the east Kimberley region. It is rumoured to have been trialled at Derby and Kalumburu but 92 appears not to have persisted (Sinclair, pers. comm., 2010). 93 In the Northern Territory, gamba grass is widely distributed in Darwin and Palmerston, the 94 Litchfield and Coomalie Shires, the Adelaide, Mary, Douglas and Lower Daly River regions 95 and western Arnhem Land. The estimated area of distribution is between 10 000–15 000 km2, 96

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although its potential range is estimated to be 380 000 km2. An estimate by NRETAS (2008) 97 indicated that gamba grass has established in approximately 4 per cent of its potential range. 98 99 The exact area of gamba grass cover in Queensland is unknown. However, it is estimated that 100 there may be up to 18 000 hectares planted (Csurhes and Hannan-Jones, 2008). It is assumed 101 that gamba grass exists as scattered populations across north Queensland, with most sites 102 being in Cape York (Csurhes and Hannan-Jones, 2008). In Western Australia the largest 103 infestation is restricted to El Questro in the east Kimberley region. 104 105 Figure 1: Map indicating known and potential distribution of gamba grass in Australia 106 (DSEWPaC, 2011) 107 108

109 110 2.1.2 Biology and environmental impacts 111 Gamba grass is a perennial tussock-forming species that grows in very dense stands up to 4 112 metres high with tussocks up to 70 centimetres in diameter. These stands cure in June/July, 113 much later than native grass species which cure in April (Rossiter et al., 2004). 114 115 Gamba grass flowers around April with seed reaching maturity in late May/June. It can also 116 seed in October/November after early wet season storms. Seed can be produced in the first 117 year of growth, with production being very prolific. A mature plant has the potential to 118 produce up to 244 000 seeds in one season, with a viability of up to 65 per cent (Flores et al., 119 2005). However, seed banks appear to be short-lived as a seed longevity trial showed that 120 survival rate was less than 1 per cent after 12 months burial (Flores et al., 2005). Native seed 121 banks, although depleted, are not eliminated under gamba grass, thereby providing a natural 122 source of regeneration (Setterfield et al., 2004). 123 124

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Gamba grass can invade undisturbed savanna ecosystems and does not need soil or canopy 125 disturbance to become established, although both these factors will increase its ability to 126 colonise sites (Setterfield et al., 2005). The spread of gamba grass was most obvious along 127 roads and disturbance corridors (Kean and Price, 2003) but riparian corridors are an important 128 and major pathway of spread into remote areas (Petty et al., in prep). 129 130 Compared with native grasses, gamba grass has higher photosynthetic rates, using light more 131 efficiently to produce more leaf area and biomass (Rossiter, 2001). This process results in the 132 replacement of native grass fuel loads with tall, dense fuel beds producing fires of 133 substantially greater intensity than typical native grass fires (up to 48 000 kilowatts per metre 134 compared with 2000 kilowatts per metre) (Rossiter-Rachor et al., 2008; Setterfield et al., in 135 press). These intense fires can result in a dramatic increase in flame height resulting in passive 136 canopy fires (Setterfield et al., in press) and the subsequent decrease in tree cover (Ferdinands 137 et al., 2006; Brooks et al., 2010). Rossiter et al. (2004) also found that available soil nitrate 138 levels were lower, grass water usage trebled and deep drainage of water more than halved in 139 sites invaded by gamba grass compared with native grasses. Therefore, gamba grass has the 140 ability to out-compete native species and alter catchment hydrology, ultimately transforming 141 ecosystem functions and structure. 142 143 2.1.3. Community perception and value 144 Gamba grass is a highly productive and palatable fodder, capable of supporting significantly 145 higher stocking densities of cattle than native grasses. Cattle feeding on gamba grass rather 146 than just native grasses can have increased growth rates, pregnancy rates and weaner rates as 147 well as reduced death rates (NRETAS, 2008). Gamba grass is generally used in a rotational 148 grazing system in combination with native species. Despite the potential benefits to 149 pastoralists, gamba grass is no longer recommended for new plantings as it is difficult to 150 manage, particularly on smaller properties. High stocking densities are required to graze it 151 appropriately, keeping the grass low and palatable. If gamba grass exceeds 90 centimetres in 152 height, de-stocking, followed by slashing or burning is required to regain use (NRETAS, 153 2008). 154 155 Because of its tendency to lead to high intensity fires, gamba grass is increasingly being 156 recognised as dangerous to human health and safety when growing around towns and 157 infrastructure. Once gamba grass fires gain momentum, they can be dangerous and difficult to 158 extinguish due to intense heat and large volumes of smoke produced (NRETAS, 2008). This 159 has led to the Australasian Fire Authorities Council releasing a national position paper on 160 gamba grass (Australasian Fire Authorities Council, 2008). 161 162 2.1.4. Regulation and management 163 Gamba grass has been subject to weed risk assessments in the Northern Territory, Queensland 164 and Western Australia. The results were largely consistent across all jurisdictions. 165 166

• Northern Territory – a very high risk weed where potential exists for successful 167 management (NRETAS, 2009). 168

• Queensland – has the potential to cause significant problems in areas where it is not 169 subject to grazing by cattle. Areas at risk include most of the northern tropical savanna 170 systems (DPIF, 2008). 171

• Western Australia – potentially a high impact for the Kimberley region (Sinclair, pers. 172 comm., 2010). 173

174

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Gamba grass is a declared weed across the Northern Territory, Queensland and Western 175 Australia. See Table 1 for details. 176 177 In the Northern Territory, under the draft gamba grass management plan, there are defined 178 ‘eradication’ and ‘management’ zones for gamba grass. Land managers within the eradication 179 zones are required to actively identify and eradicate existing infestations and prevent the 180 establishment of new infestations. Within the management zones, land managers must control 181 the growth and spread of gamba grass on and between properties. Obligations with respect to 182 management differ between small landholders (less than 20 hectares) and large landholders 183 (greater than 20 hectares). Specific obligations also apply to landholders who wish to use 184 gamba grass as pasture species, and to managers of service and transport corridors. All land 185 users must ensure that there is no further introduction of gamba grass into the Northern 186 Territory or into uninvaded areas. 187 188 Gamba grass is a declared Class 2 pest in Queensland. All landholders are obliged to try to 189 keep their land free of a Class 2 pest and it is an offence to possess, sell or release these pests 190 without a permit (DEEDI, 2010). 191 192 In Western Australia, gamba grass is categorised as a P1 and P2 plant across the entire state. 193 This means that the introduction into, or movement of the plant within the state is prohibited 194 and that all known plants are to be eradicated by land managers. 195 196 2.2 Perennial mission grass 197 198 2.2.1 Origin and current distribution 199 Pennisetum grasses, originating from Africa, were introduced into Australia from the 1930s 200 for testing as pasture species (Cook and Dias, 2006). It is not clear whether introductions of 201 perennial mission grass (Pennisetum polystachion) were deliberate. Given the ability of this 202 species to colonise disturbed sites, escape from ‘semi-controlled’ plots or from introduction 203 plots was highly possible (Cook and Dias, 2006). 204 205 The first record of perennial mission grass as a weed in the Northern Territory was in the 206 1970s. It quickly spread in Darwin and extended its range south to Katherine, east into 207 Arnhem Land, south-west to the Daly River and north to the Tiwi Islands (Miller, 2006). The 208 species was introduced into Queensland in the 1970s (Miller, 2006). 209 210 Perennial mission grass occurs predominantly in the Top End of the Northern Territory and 211 northern Queensland. It also grows in central and south-east Queensland and southern areas of 212 the Northern Territory (Navie and Adkins, 2007). In Western Australia perennial mission 213 grass occurs in the east Kimberley region, with limited patches in the west Kimberley. 214

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Figure 2: Map indicating known and potential distribution of perennial mission grass in 215 Australia (DSEWPaC, 2011) 216 217

218 219 2.2.2. Biology and environmental impacts 220 Perennial mission grass is a tall, perennial, tussock-forming grass growing to 3 metres. It is 221 now a common weed in disturbed areas such as roadsides, pastures and waste sites and it also 222 invades natural bushland (Brooks et al., 2010). Seed heads are dispersed by wind and animals 223 and by attaching to vehicles and equipment. 224 225 In areas invaded by perennial mission grass, fuel loads can be up to five times higher than 226 uninvaded sites, resulting in large fires which can carry into the canopy of trees (Douglas et 227 al., 2004; Brooks et al., 2010). Perennial mission grass displaces native plant species (Brooks 228 et al., 2010) and may alter nitrogen cycling in savanna systems, with up to a 10 per cent 229 reduction in nitrate availability compared with native grasses (Douglas et al., 2004). Perennial 230 mission grass often occurs with gamba grass. 231 232

2.2.3. Community perception and value 233 Perennial mission grass is not considered to be particularly valuable and its use as a pasture 234 species is not promoted. Because of its potential to contribute to intense fires, perennial 235 mission grass is considered by some members of the community to be a problem. Generally 236 speaking, awareness of the species and associated issues is not as widespread as that of gamba 237 grass. 238

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2.2.4. Regulation and management 239 Perennial mission grass is declared in the Northern Territory as a Class B/C weed (Table 1). 240 This means that landholders have a duty to manage the plant on their land, prevent other land 241 from being infested, and to prevent further introductions. 242 243 Perennial mission grass is not declared under state legislation in either Queensland or Western 244 Australia. 245 246 In Western Australia a weed risk assessment concluded that perennial mission grass could 247 potentially have a high biological impact on the Kimberley region. However, there is no 248 formal management program in place for the control of perennial mission grass in Western 249 Australia. 250 251

2.3 Annual mission grass 252 253

2.3.1 Origin and current distribution 254 Annual mission grass was imported into northern Australia from Africa in the 1940s (Cook 255 and Dias 2006). By the 1970s it had become widespread across the north (Setterfield et al., 256 2006). It is found on Cape York in Queensland, the Top End of the Northern Territory and the 257 north-east of Western Australia (GBIF, 2010). 258 259 Figure 3: Map indicating known and potential distribution of annual mission grass in 260 Australia (DSEWPaC, 2011) 261 262

263 264 2.3.2. Biology and environmental impacts 265 Annual mission grass incorporates two sub-species Pennisetum pedicellatum ssp. pedicellatum 266 and Pennisetum pedicellatum ssp. unispiculum (TSSC, 2009). Occurring in high densities, it 267

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grows to 1.5 metres tall and has a high seed output (Setterfield et al., 2006). Mechanisms of 268 spread are thought to be similar to other grass species (via attachment to vehicles and 269 equipment etc). Given its high biomass, it probably has similar impacts to gamba grass and 270 perennial mission grass, out-competing native species and contributing to increased fuel loads, 271 resulting in intense late season fires (TSSC, 2009). It is also reported to grow in shady areas 272 where native grasses do not, thereby facilitating the spread of fires beneath sensitive trees and 273 shrubs that would not normally be subjected to burning (Sinclair, pers. comm., 2010). 274 275

2.3.3. Community perception and value 276 Annual mission grass is not important to the pastoral industry. Community awareness 277 specifically regarding annual mission grass is low. 278 279

2.3.4. Regulation and management 280 This species is not declared in any jurisdiction and no formal management strategies are in 281 place to control its spread. 282 283 In Western Australia the results of a weed risk assessment conclude that the species has the 284 potential to have a high impact in the Kimberley. 285 286 2.4 Olive hymenachne 287 288

2.4.1 Origin and current distribution 289 Olive hymenachne (Hymenachne amplexicaulis) is native to tropical and sub-tropical South 290 and Central America. CSIRO imported olive hymenachne in the early 1970s for assessment as 291 a ponded pasture species for cattle. It was approved for release in 1988. There were reports of 292 this grass invading cane-growing areas soon after it was released. 293 294 Prior to its declaration as a weed, the use of olive hymenachne in Queensland was widely 295 promoted by the grazing industry (Cobon, 2009). In the Northern Territory, small areas were 296 sown during the 1990s. Propagation material was sent to graziers in Western Australia in 1993 297 but it seems that it has failed to establish there (ARMCANZ, 2000). 298 299 In 2010, distribution in the Northern Territory was around Darwin and east Arnhem Land. 300 Infestations are now starting to develop in areas where it has been used in mimosa control 301 programs (as a competitive cover crop). It also occurs in conservation areas such as Kakadu 302 National Park. In 2007, NRETAS reported 5000–6000 hectares of olive hymenachne growing 303 within the territory. 304 305 In Queensland the species occurs in isolated patches on Cape York and extends down the 306 coast to northern New South Wales. 307 308 Olive hymenachne is not known to occur in Western Australia although the Kimberley region 309 is considered to be at high risk of incursion. There is the potential for the species to spread into 310 the Ord region via transport on machinery and equipment (Cobon, 2009). 311 312 In 2007 the area of total occupancy nationally was estimated at 14 000 hectares (Cobon, 313 2009). 314

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Figure 4: Map indicating known and potential distribution of olive hymenachne in 315 Australia (DSEWPaC, 2011) 316 317

318 319

2.4.2. Biology and environmental impacts 320 The name ‘olive hymenachne’ distinguishes it from native hymenachne (Hymenachne 321 acutigluma). Olive hymenachne is a perennial semi-aquatic grass with upright or semi-upright 322 stems growing from a creeping base that reaches up to 2.5 metres tall. Suitable habitat is 323 primarily seasonal, shallow freshwater wetlands and riverbanks in coastal and sub-coastal 324 areas. It reproduces by seed as well as vegetatively from stem fragments. It produces large 325 numbers of viable seeds and reportedly has good germination rates (CRC, 2003). 326 327 Seed is transported during flooding as well as in mud attached to animals and vehicles. It can 328 also be dispersed in contaminated agricultural produce (Navie, 2007). Olive hymenachne 329 poses a severe threat to wetlands as its dense stands reduce plant diversity. It may also affect 330 the recruitment of native trees and exclude native grasses and sedges that provide foraging 331 resources and nesting habitat for native wildlife (NRMW, 2006). Impacts are well documented 332 (Csurhes et al., 1999; NWS, 2000; NRMW, 2006). 333 334

2.4.3. Community perception and value 335 336

Olive hymenachne is recognised as one of Australia’s worst weeds because of its invasiveness. 337 In areas of heavy infestation, it can impact on primary production, water infrastructure, 338 fisheries, public amenity and tourism (NRMW, 2006). Olive hymenachne invades sugarcane 339 fields resulting in crop contamination and increased production costs. It can damage water 340 storage facilities and large floating mats can block drainage channels and pumps. 341 342

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It has been suggested that olive hymenachne may affect recreational and commercial fishing 343 by invading nursery areas for barramundi (Lates calcarifer) (NRMW, 2006). Additionally, as 344 prawns breed in response to natural flood events, disruptions to natural run-off patterns caused 345 by olive hymenachne infestations may impact upon recruitment (NRMW, 2006). 346 347 Olive hymenachne has the potential to affect Indigenous traditional activities (see Section 4: 348 Social and economic impacts). There is awareness of issues surrounding olive hymenachne 349 among some Indigenous communities. For example, the Nywaigi Aboriginal people from the 350 north of Townsville have been working with the CSIRO to manage this weed and restore the 351 health of the Mungalla wetlands. 352 353 2.4.4. Regulation and management 354 Olive hymenachne was listed as a Weed of National Significance (WoNS) in 1999 under the 355 Australian Government’s National Weeds Strategy. It is a declared weed in all jurisdictions 356 relevant to the threat abatement plan. 357 358

• Northern Territory – declared Class B/C. 359 • Queensland – Class 2 pest. 360 • Western Australia – P1 and P2 plant across the entire state. 361

362 Olive hymenachne is also a declared weed in every other Australian state and territory2. 363 364 A weed risk assessment undertaken by Queensland in 1999 determined that olive hymenachne 365 has the potential to dominate shallow, seasonally flooded freshwater wetlands across most of 366 the wet tropics and coastal central Queensland, with serious consequences for native 367 ecosystems and certain fishery habitats. 368 369 In the Northern Territory the main infestations of olive hymenachne occur around the East 370 Alligator River catchment and Arafura Swamp (Cobon, 2009). 371 372 In Western Australia the species was determined to be a high ecological risk for the Kimberley 373 area (Sinclair, pers. comm., 2010). 374 375 As a WoNS there is a significant body of work around the control of this species. A national 376 strategic plan was released in 2001 which outlines a range of management actions aimed at 377 preventing the spread of olive hymenachne and reducing adverse impacts. 378 379 The Hymenachne National Strategic Plan progress review (2008–2009) recommends that 380 given the value of olive hymenachne to the Northern Territory and Queensland cattle industry, 381 an industry code of practice for existing ponded hymenachne pasture management be 382 developed and incorporated in local planning. A zonal control approach is also being pursued 383 by revising the National Hymenachne Strategic Plan to engage all relevant stakeholders in 384 hymenachne management. However, this approach remains to be ratified by relevant 385 jurisdictions (Carter and Dodd, 2009). 386 387

2New South Wales (Noxious Weeds Act 1993), Australian Capital Territory (Pest Plants and Animals Act 2005), Victoria (Catchment and Land Protection Act 1994), South Australia (Natural Resources Management Act 2004) and Tasmania (Weeds Management Act 1999).

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2.5 Para grass 388 389 2.5.1 Origin and current distribution 390

Para grass (Urochloa mutica, also known as Brachiara mutica) is a native grass of Africa and 391 South America that was introduced into Australia around 1880 (Cameron, 2008). It was 392 initially used to control erosion along river banks but has since been promoted as a pasture 393 grass throughout northern Australia (Clarkson, 1995). In the Northern Territory para grass was 394 introduced as a pasture species to the area now known as Kakadu National Park (Douglas and 395 O’Conner, 2004) and to Arnhem Land (Grace et al., 2004). Para grass affects approximately 396 40 000 hectares in the Northern Territory (Low, 1997) and 100 000 hectares in Queensland 397 (NRMW, 2006). In Western Australia, para grass occurs in the north-east and south-west 398 regions of the state. Some believe that para grass has largely occupied its potential range in 399 Australia although within its range there are still many areas where para grass is not present 400 (NRMW, 2006). 401 402 Figure 5: Map indicating known and potential distribution of para grass in Australia 403 (DSEWPaC, 2011) 404 405

406 407 2.5.2 Biology and environmental impacts 408 Para grass is a perennial grass growing up to 1 metre tall. Stems are hollow and robust with a 409 prostrate growth habit, forming dense floating mats. It grows on a range of soil types and is 410 adapted to wet conditions, water-logging and prolonged flooding (Cameron, 2008). It 411 reproduces by seed and stolon fragments both of which are readily transported by floodwaters, 412 waterbirds and vehicles (Gould, 2001). 413 414 In a survey of wetland systems of the Top End in the Northern Territory, para grass was found 415 in dense monocultures which displaced native plants, including ecologically important species 416

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such as wild rice (Oryza meridionalis) (Ferdinands et al., 2005). Fish and bird communities 417 are negatively impacted by para grass (Ferdinands et al., 2005) and Beggs et al. (2003) 418 reported a lower abundance of frogs in areas dominated by para grass compared to those 419 without para grass. A study by Douglas and O’Conner (2004) revealed a lower richness and 420 abundance of terrestrial invertebrates in wetlands dominated by para grass. 421 422 Para grass infestations can provide a significant fuel load resulting in destructive, late season 423 floodplain fires from which para grass can re-establish, but many native species do not 424 (Hunter et al., 2010). 425 426

2.5.3. Community perception and value 427 Despite para grass generally being acknowledged as an aggressive invader of wetland habitats 428 (e.g. Douglas et al., 2004; Ferdinands et al., 2005), it is one of a range of species being used as 429 an alternative pasture grass to olive hymenachne. However, there is increasing community 430 concern about the impacts of para grass and other introduced pasture species that are 431 establishing outside pasture systems (Douglas et al., 2004). As with olive hymenachne, para 432 grass has the potential to significantly impact upon wetlands, affecting a range of activities 433 including recreational, commercial and traditional. 434 435

2.5.4. Regulation and management 436 Para grass is not declared as a weed under any Commonwealth, state or territory legislation. 437 438 Queensland has a ponded pastures policy that covers the management of para grass and other 439 semi-aquatic species utilised by the grazing industry. No other jurisdictions have formal 440 management programs in place. 441 442 Para grass has been assessed in Western Australia as being a high ecological risk for the 443 Kimberley region. 444 445

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Table 1: Classification under state and territory legislation 446 447 Weed State Classification

(see Table 2 for definitions) Legislation

Gamba grass (Andropogon gayanus)

NT Declared as Class A/C and B/C Weeds Management Act 2001

Qld Declared as a Class 2 pest Land Protection (Pest and Stock Route Management) Act 2002

WA Declared as P1 and P2 for whole of the state

Agriculture and Related Resources Protection Act 1976

Perennial mission grass (Pennisetum polystachion)

NT Declared as Class B/C Weeds Management Act 2001

Olive hymenachne (Hymenachne amplexicaulis)

NT Declared as Class B/C Weeds Management Act 2001

Qld Declared as Class 2 pest Land Protection (Pest and Stock Route Management) Act 2002

WA Declared as P1 and P2 for whole of the state

Agriculture and Related Resources Protection Act 1976

448 Table 2: Definitions of classifications under state and territory legislation 449 450 Legislation Definition of classification Northern Territory: Weeds Management Act 2001

Class A – to be eradicated Class B – growth and spread to be controlled Class C – not to be introduced to the Territory

Queensland: Land Protection (Pest and Stock Route Management) Act 2002

Class 2 – a pest that has already spread over substantial areas of the state, but its impacts are considered significant enough to control it and avoid further spread.

Western Australia: Agriculture and Related Resources Protection Act 1976

P1 – introduction of the plant into, or movement of the plant within, an area is prohibited P2 – plant is to be eradicated in the area

451 452 3. Threatened species and ecological communities 453 454 The majority of research to date has focused on the impacts of gamba grass on native species 455 and ecosystems. However, all of the five species of grasses identified in this threatening 456 process have similar impacts e.g. changing native species composition through competition 457 and increasing fuel loads thereby promoting intense, late season fires (Douglas and O’Conner, 458 2004; Ferdinands et al., 2005; Brooks et al., 2010; Setterfield et al., 2010) 459 460 Impacts on native species can occur in a number of ways. For example, in the case of the 461 yellow-snouted gecko, changes to fire regimes are likely to increase mortality of geckos and 462 their eggs through increased predation because of a reduction of the leaf litter cover in which 463 they live (DEWHA, 2006). Introduced grasses can also reduce food resources for granivorous 464

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species such as the Gouldian finch. Monocultures of a single species of grass such as gamba, 465 which seed at only one time of the year as opposed to a mix of native species that provide 466 seeds over extended periods, have the potential to seriously impact on these birds. Increased 467 intensity of fires may also reduce the number of nesting hollows available for breeding 468 (O’Malley, 2006). In wetland environments para grass can replace wild rice (Oryza 469 meriodionalis) and Eleocharis dulcis, both energy-rich resources important to magpie geese 470 for the build up of fat reserves essential for survival through the dry season (Ferdinands et al., 471 2005). 472 473 Gamba grass and perennial mission grass have recently established on the Gove Peninsula and 474 are found within the distribution of the Gove crow butterfly. Altered fire regimes could result 475 in the loss of rainforest patches on which the butterfly is dependant for survival (Braby, 2007). 476 477 Species and ecological communities potentially affected by the spread of introduced grasses 478 are listed at Table A in the Threat abatement plan to reduce the impacts on northern 479 Australia’s biodiversity by the five listed grasses. 480 481 482 4. Social and economic impacts of the five listed grasses 483 484 Native pastures are the primary component of northern Australian grazing systems but 485 environmental and climatic conditions mean there are limits to production in some areas. 486 Native grasses tend to have short growing seasons and produce fodder for only a few months 487 of the year. For pastoralists in northern Australia there is significant benefit in using 488 introduced pasture grasses, however, there are also costs associated with responsible 489 management of these grasses to ensure they do not escape property boundaries. 490 491 Outside of the pastoral industry, introduced grasses are documented as having significant 492 negative economic impacts on other primary producers, for example they can invade 493 sugarcane crops, potentially resulting in increased production costs and reduced yields. Large 494 infestations also lead to loss of amenity and can significantly affect recreational activities and 495 tourism. They can also fuel intense fires which are difficult to control thereby posing a serious 496 threat to human life, property and community safety. 497 498 The social well-being of Indigenous people may be affected by the five listed grasses as they 499 can interrupt both physical and spiritual connections to country. Introduced grass infestations 500 can restrict or prevent Indigenous hunting activities, limit the availability of traditional food 501 such as yams, and render habitat unsuitable for culturally significant species including magpie 502 geese (Hunter et al., 2010). Physical access to sacred sites may also be hindered. 503 504 While there may be significant costs involved with the control of these introduced grasses, 505 these will be offset by the substantial savings resulting from early action against these grasses. 506 As these particular grasses are considered to be in early stages of invasion (TSSC, 2009), 507 prompt intervention will be more cost-effective than if the species are allowed to become more 508 widely established. 509 510 511

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Appendix A 512 513 Environment Protection and Biodiversity Conservation Act 1999 514 515

3 Objects of Act 516

(1) The objects of this Act are: 517 (a) to provide for the protection of the environment, especially those aspects of the 518

environment that are matters of national environmental significance; and 519 (b) to promote ecologically sustainable development through the conservation and 520

ecologically sustainable use of natural resources; and 521 (c) to promote the conservation of biodiversity; and 522 (ca) to provide for the protection and conservation of heritage; and 523 (d) to promote a co-operative approach to the protection and management of the 524

environment involving governments, the community, land-holders and indigenous 525 peoples; and 526

(e) to assist in the co-operative implementation of Australia’s international 527 environmental responsibilities; and 528

(f) to recognise the role of indigenous people in the conservation and ecologically 529 sustainable use of Australia’s biodiversity; and 530

(g) to promote the use of indigenous peoples’ knowledge of biodiversity with the 531 involvement of, and in co-operation with, the owners of the knowledge. 532

533 Threat abatement plans and the Environment Protection and 534 Biodiversity Conservation Act 1999 535 536

Section 271 Content of threat abatement plans 537

(1) A threat abatement plan must provide for the research, management and other actions 538 necessary to reduce the key threatening process concerned to an acceptable level in order 539 to maximise the chances of the long-term survival in nature of native species and 540 ecological communities affected by the process. 541

(2) In particular, a threat abatement plan must: 542 (a) state the objectives to be achieved; and 543 (b) state criteria against which achievement of the objectives is to be measured; and 544 (c) specify the actions needed to achieve the objectives; and 545 (g) meet prescribed criteria (if any) and contain provisions of a prescribed kind (if any). 546

(3) In making a threat abatement plan, regard must be had to: 547 (a) the objects of this Act; and 548 (b) the most efficient and effective use of the resources that are allocated for the 549

conservation of species and ecological communities; and 550 (c) minimising any significant adverse social and economic impacts consistently with 551

the principles of ecologically sustainable development; and 552 (d) meeting Australia’s obligations under international agreements between Australia 553

and one or more countries relevant to the species or ecological community 554 threatened by the key threatening process that is the subject of the plan; and 555

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(e) the role and interests of indigenous people in the conservation of Australia’s 556 biodiversity. 557

(4) A threat abatement plan may: 558 (a) state the estimated duration and cost of the threat abatement process; and 559 (b) identify organisations or persons who will be involved in evaluating the 560

performance of the threat abatement plan; and 561 (c) specify any major ecological matters (other than the species or communities 562

threatened by the key threatening process that is the subject of the plan) that will be 563 affected by the plan’s implementation. 564

(5) Subsection (4) does not limit the matters that a threat abatement plan may include. 565 566

Section 274 Scientific Committee to advise on plans 567

(1) The Minister must obtain and consider the advice of the Scientific Committee on: 568 (a) the content of recovery and threat abatement plans; and 569 (b) the times within which, and the order in which, such plans should be made. 570

(2) In giving advice about a recovery plan, the Scientific Committee must take into account 571 the following matters: 572

(a) the degree of threat to the survival in nature of the species or ecological community 573 in question; 574

(b) the potential for the species or community to recover; 575 (c) the genetic distinctiveness of the species or community; 576 (d) the importance of the species or community to the ecosystem; 577 (e) the value to humanity of the species or community; 578 (f) the efficient and effective use of the resources allocated to the conservation of 579

species and ecological communities. 580

(3) In giving advice about a threat abatement plan, the Scientific Committee must take into 581 account the following matters: 582

(a) the degree of threat that the key threatening process in question poses to the survival 583 in nature of species and ecological communities; 584

(b) the potential of species and ecological communities so threatened to recover; 585 (c) the efficient and effective use of the resources allocated to the conservation of 586

species and ecological communities. 587 588

Section 279 Variation of plans by the Minister 589

(1) The Minister may, at any time, review a recovery plan or threat abatement plan that has 590 been made or adopted under this Subdivision and consider whether a variation of it is 591 necessary. 592

(2) Each plan must be reviewed by the Minister at intervals of not longer than 5 years. 593

(3) If the Minister considers that a variation of a plan is necessary, the Minister may, subject 594 to subsections (4), (5), (6) and (7), vary the plan. 595

(4) The Minister must not vary a plan, unless the plan, as so varied, continues to meet the 596 requirements of section 270 or 271, as the case requires. 597

(5) Before varying a plan, the Minister must obtain and consider advice from the Scientific 598 Committee on the content of the variation. 599

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(6) If the Minister has made a plan jointly with, or adopted a plan that has been made by, a 600 State or self-governing Territory, or an agency of a State or self-governing Territory, the 601 Minister must seek the co-operation of that State or Territory, or that agency, with a view 602 to varying the plan. 603

(7) Sections 275, 276 and 278 apply to the variation of a plan in the same way that those 604 sections apply to the making of a recovery plan or threat abatement plan. 605

606 Threat abatement plans and the Environment Protection and 607 Biodiversity Conservation Regulations 2000 608 609 Part 7 Species and communities 610

Regulation 7.12 Content of threat abatement plans 611 For paragraph 271 (2) (g) of the Act, a threat abatement plan must state: 612 (a) any of the following that may be adversely affected by the key threatening process 613

concerned: 614 (i) listed threatened species or listed threatened ecological communities; 615 (ii) areas of habitat listed in the register of critical habitat kept under section 207A 616

of the Act; 617 (iii) any other native species or ecological community that is likely to become 618

threatened if the process continues; and 619 (b) in what areas the actions specified in the plan most need to be taken for threat 620

abatement. 621 622 623

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