Primary Industries and Fisheries

Minimising the risk of spread of

Mimosa pigra from Peter Faust Dam,

Proserpine

Edward Attard, Cassandra Chopping, Peter Austin, Jason Williams and Tony Pople �

Final report to the Department of Agriculture Forestry and Fisheries and the Department of Environment and Heritage May 2006

Edward Attard and Tony Pople Land Protection, Department of Natural Resources and Water GPO Box 2454, Brisbane Qld 4001

Cassandra Chopping and Peter Austin Land Protection, Department of Natural Resources and Water PO Box 63, Mackay Qld 4740

Jason Williams SunWater, 126 Giddy Road PMB 5013, Ayr Qld 4807

Published by: � ©State of Queensland (Department of Natural Resources and Water) 2006 �

ii Risk of Mimosa pigra spread in Queensland � Contents

Summary and recommendations v �

Section 1–Overview of Mimosa pigra ecology, distribution, impacts and management 1 � 1.1 General introduction 1 � 1.2 Global distribution and history of introduction to Australia 2 � 1.3 M. pigra life history 2 � 1.4 Potential distribution in Australia 4 � 1.5 Current and potential impacts in Australia and overseas 4 � 1.6 Control options and cost 4 �

Section 2–Management of Mimosa pigra in Queensland 5 � 2.1 Introduction 5 � 2.2 State wide strategy 6 � 2.3 Management of M. pigra at Peter Faust Dam 6 � 2.4 Research on M. pigra in Queensland 11 � 2.5 Key stakeholders and their responsibilites 11 �

Section 3–Assessing the risk of Mimosa pigra spread from Peter Faust Dam 13 � 3.1 Introduction 13 � 3.2 Methods 13 � 3.3 Vectors of seed spread 17 � 3.4 Management options 21 � 3.5 Ranking management options 25 � 3.6 Making management decisions 27 � 3.7 Monitoring and performance evaluation 27 �

Acknowledgments 28 �

References 29 �

Appendixes 31 �

Risk of Mimosa pigra spread in Queensland � iii iv Risk of Mimosa pigra spread in Queensland � Summary and A number of preliminary recommendations can be drawn from this risk assessment: recommendations Monitoring and control In February 2001 the first infestation (~100 plants) 1. Current monitoring and control of M. pigra must of Mimosa pigra in Australia outside the Northern be continued, including washdown of vehicles and Territory was found at Peter Faust Dam, near identifying tracks as ‘clean’ and ‘dirty’. However, Proserpine, in central coastal Queensland. This shrub monitoring could be more strategic. Greater effort continues to have major environmental, economic can be directed to periods when germination is and social impacts on the coastal floodplains of most likely and in higher density areas the Top End of the Northern Territory, where it forms (i.e. temporal and spatial stratification). Access dense, almost monospecific stands. At risk of invasion to areas with M. pigra seed and the high detection by M. pigra in are canefields, probability of M. pigra seedlings needs to be cattle-grazing areas and wetlands of conservation maintained by clearing Melaleuca regrowth. significance. 2. Although considered a low priority, monitoring of In 2001 a stakeholder group was assembled, downstream areas is needed if new incursions are comprising the local cattle grazier, SunWater to be identified before their eradication is no longer (which is responsible for management of the dam), feasible. Such delimitation is an important criterion the Queensland Cane Growers Organisation Ltd for eradication. This is likely to be best achieved (Canegrowers), Whitsunday Shire Council and the through a combination of direct monitoring using Queensland Department of Natural Resources and trained surveyors and educating landholders in Water (NRW). Over the next five years the group identifying M. pigra and the risks associated with oversaw a range of on-ground activities to eliminate its spread. M. pigra from the site. This work included describing Livestock management aspects of the biology of M. pigra at the site, investigating control measures and regular monitoring 3. As a high priority, cattle that have been grazed in of the site and removal of plants. However, the M. pigra-infested areas should be held in presence of vast numbers of M. pigra seed in the soil M. pigra-free paddocks for at least seven days at the dam and their likely persistence for more than before transport, as practised in the Northern 20 years means that the potential ways that this seed Territory. A formal agreement is required between could move from the dam (‘vectors’ of seed spread) the local grazier and government to cover need to be identified and managed. These vectors additional costs. include fluctuating water levels, wildlife, cattle and 4. The highest risk (i.e. high M. pigra seed density) recreational users of the dam, particularly fishers. area. on the south-western shoreline, should ideally In mid-2005 a risk assessment involving the major be fenced to exclude cattle, but was considered a stakeholders was therefore conducted to identify and lower priority than other management options. evaluate these vectors and then to canvass a number Restricting access of management options to minimise the risk of 5. Currently recreational users have physical access to M. pigra seed spread. These options were then ranked most areas of the dam. The difficulties of policing according to the risk (likelihood × consequence) of necessitate restricting road access to the higher risk seed spread from a particular vector and the feasibility areas through fencing and locked gates as a high of managing the vector. The latter considered the priority. Access to the western shoreline by boats sociopolitical, economic and technical feasibility of is more problematic, requiring good signage and implementing each management action. identification of the prohibited area perhaps using A further meeting among stakeholders is required to marker buoys. review the risks of potential vectors, the management Education options, their scores and resultant ranks. To be efficient, limited funds should be allocated to 6. Recreational users of the dam need to be made management options that generate the greatest better aware of M. pigra, its impacts and how it can reduction in overall risk of weed spread. Stakeholders, be spread. There are now several warning experts and managers therefore need to compare the signs around the dam, but there needs to be cost of options and their ability to reduce risk. greater exposure of the problem in the media.

Risk of Mimosa pigra spread in Queensland � v Pig control 7. As a high priority, pig hunting (other than by authorised hunters) should be banned and 1080 baiting used to control numbers. Compliance 8. An awareness campaign, restricting access and banning pig hunting will all fail unless they are supported by policing the movement of people within the dam area. Enforcing these restrictions is difficult and could require anemergency quarantine notice that stipulates how the dam can be used and allows authorised officers to police use of the dam and issue fines. Performance evaluation 9. Monitoring is required to determine the effectiveness of management action. Appropriate indicators to monitor are likely to be reductions in the activity of people, pigs and cattle in the M. pigra-infested areas, use of washdown facilities and the survey effort downstream of the dam.

vi Risk of Mimosa pigra spread in Queensland � Section 1

Overview of Mimosa pigra ecology, spreads into its potential distribution area, which distribution, impacts and management includes wetlands throughout northern Australia. Working against this effort is the vast number of 1.1 General introduction M. pigra seed in the soil, some of which may remain viable for more than 20 years (Lonsdale 1992). An infestation of Mimosa pigra was discovered at This long timeframe increases the risk of seed Peter Faust Dam (see Section 2) near Proserpine in being transported outside the site. This report central coastal Queensland (Figure 1) in 2001. This describes an assessment of this risk and how it can is the first known Australian infestation of this weed be best managed. outside the Northern Territory, where it has major Section 1 of this report provides an overview of the environmental, social and economic impacts. Similar problem, including relevant aspects of the ecology impacts are possible in Queensland where it might of M. pigra. Section 2 describes the current invade canefields, cattle-grazing areas and wetlands management of M. pigra at Peter Faust Dam. of conservation importance. Section 3 presents the risk assessment, which uses Fortunately the outbreak at Peter Faust Dam appears stakeholders to identify various hazards, their risks to have been contained in the immediate area around and potential management options. the dam, thus providing a good chance of eradication. Over the five years since 2001 managers undertook monitoring, removal and research of M. pigra at Peter Faust Dam in an attempt to eradicate the weed. The program is costly, but is offset by the cost of potential impact and ongoing control if the weed

Figure 1. Location of Peter Faust Dam in central coastal Queensland

Risk of Mimosa pigra spread in Queensland � 1 1.2 Global distribution and history of 1. M. pigra can withstand the anaerobic conditions of introduction to Australia inundation and flooded soils by having roots near the surface to take up oxygenated water (Miller, The native range of M. pigra is central and southern Nemestothy and Pickering 1981). At Peter Faust America, spanning the tropics from northern Mexico Dam M. pigra was originally found growing in o o (~25 N) to central Brazil (~23 S) (Walden et al. 2004). more than five metres of water (Figure 3) and later It has spread throughout the tropics, including in areas of Melalaeuca with large mats of aerial Australia (Figure 2). It was probably introduced to roots where water levels had receded (Figure 4) Australia in the 1870s, either accidentally in seed (Chopping 2004). samples for the Darwin Botanical Gardens, as seed 2. If cut down, M. pigra can easily resprout from the in cattle intestines or deliberately as an ornamental, stump (Wanichanantakul and Chinawong 1979). although the exact source is unknown (Miller and Following burning, up to 90 per cent of mature Lonsdale 1987). It was confined to Darwin until M. pigra plants and up to 50 per cent of M. pigra the 1950s, but by the 1980s M. pigra had spread seedlings can regrow (Miller 1988). At Peter Faust extensively in the Top End of the Northern Territory. Dam 75 per cent of M. pigra plants were reshooting Today more than 80 000 hectares of native vegetation 21 days after burning (Vitelli and Madigan 2005). in the Northern Territory has been replaced by M. pigra (Walden et al. 2004). 3. Maturity is reached quickly, with seed set in the first year (Lonsdale et al. 1985). At Peter Faust Where it has been introduced M. pigra invades a wide Dam plants can mature and produce seed pods in range of habitats that have been disturbed either a little as 120 days, with flowering (Figure 5) and naturally or anthropogenically and are moist and pod production occurring year round (Vitelli and open (Walden et al. 2004). Typical habitat includes Madigan 2004). The seedpods are covered with floodplains and riverbanks. In the Northern Territory bristles (Figure 6), enabling attachment to animals M. pigra similarly colonises areas that have been and clothing, and flotation on water for extended heavily disturbed by feral or domestic livestock periods (Miller, Nemestothy and Pickering 1981). (Walden et al. 2004). The seeds are also dispersed in soil and mud, adhering to vehicles, other machinery and animals (Lonsdale, Harley and Miller 1985). Livestock and native animals sometimes graze M. pigra (Miller 1988) and pass the seeds in their faeces (Miller and Lonsdale 1987). 4. Seed life span varies with soil depth and soil type, and there are suggestions that it might be up to 23 years in sandy soils (Lonsdale 1992). At Peter Faust Dam an average of more than 5000 seedlings per square metre was observed within the core infestation area in 2002 (Figure 7), although seedbanks are being depleted (Vitelli and Figure 2. Global distribution of M. pigra (after Beckmann 1990). The native range is in dark shading. Locations where Madigan 2005). it has been introduced are shown as solid circles. 5. Average seed production has varied between 9000 and 12 000 per square metre per year in the There are a number of ways M. pigra could have Northern Territory (Lonsdale, Harley and Gillett reached Central Queensland. The most likely source 1988), with up to 220 000 seeds per year for an is the Northern Territory, more than 1500 kilometres individual plant (Lonsdale 1992). At Peter Faust away, with a wide range of potential vectors. While the Dam average monthly seed production per plant cause is unknown, its spread to Peter Faust Dam in ranged from 100 to 100 000 per month in 2004. Queensland highlights the risk of establishment of More than 560 000 seeds were recorded for one M. pigra across large areas of Australia. year from an individual plant (Vitelli and 1.3 M. pigra life history Madigan 2005). 6. M. pigra can grow quickly, at a rate of one M. pigra has many features that have enabled it to centimetre per day, and infestations can double spread rapidly across tropical regions. These are in area in one year. It can also withstand droughts summarised into seven key attributes below (Walden (Lonsdale 1993). At Peter Faust Dam growth rates et al. 2004). Unpublished data for M. pigra growing have ranged from 0.8 to 1.5 centimetres per day at Peter Faust Dam are also presented for comparison (Vitelli and Madigan 2004). with values for these attributes recorded elsewhere.

2 Risk of Mimosa pigra spread in Queensland � 7. In the Northern Territory M. pigra is found on a wide range of soil types, including nutrient-poor sandy soils (Miller 1983). However, seed production, seedling density and plant longevity is higher on heavier soils (Lonsdale 1992), whereas seed longevity is greater in sandier soils (Lonsdale, Harley and Gillett 1988). M. pigra can also tolerate at least moderate levels (~50 per cent) of salinity (Miller 1983).

Figure 3. The original infestation of M. pigra at Peter Faust Figure 5. The distinctive pink flower and sensitive leaves of Dam, Central Queensland, in five metres of water. M. pigra. Photo by A. Doak. Photo by C.Chopping. �

Figure 4. M. pigra growing among Melaleuca shrubs. Figure 6. The seed pods of M. pigraº which are covered with Photo by C.Chopping. bristles. Photo by A. Doak.

Figure 7. Thousands of M. pigra seedlings emerged as the dam water receded. Photo by P. Austin.

Risk of Mimosa pigra spread in Queensland � 3 1.4 Potential distribution in Australia Similar impacts have been reported overseas, even in its native range, where it has expanded its distribution The potential distribution of M. pigra in Australia has in cultivated areas (Walden et al. 2004). been modelled by matching the climate of its overseas distribution with the climate across Australia 1.6 Control options and cost (Figure 8; Lonsdale 1992; Kriticos 2000; Walden et al. 2004). This suggests that approximately 4.2–4.6 Once established, the costs of managing M. pigra million hectares of wetlands in northern Australia is are high (Storrs 1998). Control options include potentially at risk of invasion by M. pigra (Walden et mechanical clearing, spraying with herbicide and al. 2004). burning. The long-term success of control will also depend on subsequent land management to minimise reinvasion (Walden et al. 2004). A number of biological control agents (seven insects and a fungal pathogen) have been released with some impact on M. pigra infestations, and releases of other agents are proposed. Further assessment is required before their full impact will be known (Walden et al. 2004). As outlined in the strategic plan for M. pigra (ARMCANZ 2000), the costs of management have been high. The management and subsequent reduction of an infestation of more than 8000 hectares of M. pigra at Gunbalana, close to Kakadu National Park, has cost $7 million over a five-year period. Kakadu remains free from serious infestation through systematic surveys Figure 8. The potential distribution of M. pigra in Australia and destruction of new outbreaks. This has required (Kriticos 2000). four full-time staff and an annual cost of approximately Given this potential distribution, most (~105) of the $500 000. The current cost of the management of 165 nationally important wetlands in Queensland are M. pigra in the Northern Territory is more than at risk of invasion by M. pigra, with the largest areas $2.5 million per annum, including research, in the Cape York Peninsula and Gulf Plains bioregions on-ground control activities and landholder assistance (Blackman et al. 2000). There are also four Ramsar for herbicides. Given this high cost of ongoing control, sites (i.e., wetlands of international importance eradication of this species from Queensland, at a covered by the Ramsar intergovernmental treaty for predicted cost of just over $3 million (Queensland their conservation) that lie within the potential range Government 2004), is likely to be well worth the of M. pigra (Blackman et al. 2000). investment in the long term.

1.5 Current and potential impacts in Australia and overseas Walden et al. (2004) have discussed the potential impacts of M. pigra in northern Australia, emphasising its damaging effects to wetlands. Although M. pigra shows a preference for disturbed areas, even largely intact landscapes can be transformed into dense, monospecific stands of M. pigra, thus altering both the floristics and structure of the vegetation. The further ramifications can be wide ranging, including: • loss of habitat for native fauna • provision of shelter for feral pigs, and also some native fauna • altered hydrological regimes • loss of agricultural productivity and increased control costs • reduced aesthetics of the landscapes.

4 Risk of Mimosa pigra spread in Queensland � Section 2

Management of Mimosa pigra in by the Queensland Herbarium. A combination of wind Queensland and water dispersal could see M. pigra invade large areas along the over a relatively 2.1 Introduction short time period (Figure 9). This section outlines the ensuing management of M. pigra at Peter Faust Peter Faust Dam (20 41’S, 148 33’E) is located ° ° Dam and provides a context for the risk assessment 25 kilometres west of Proserpine at the headwaters of described in Section 3. the Proserpine River. The discovery of M. pigra at the dam was made by the local grazier and later confirmed

Figure 9. Potential area of infestation of M. pigra assuming omnidirectional wind dispersal at a rate of 76 metres per year from the Proserpine River. Colour bands indicate area of spread after 5, 10, 20 and 50 years (Bryant 2005).

Risk of Mimosa pigra spread in Queensland � 5 As outlined by Austin and Csurhes (2004), M. pigra The current problem is that, while mature plants have is a declared pest in all states except the Australian been destroyed, seedlings continue to germinate, Capital Territory. In Queensland it is declared as a particularly as waters recede. The enormous seed ‘Class 1’ pest under the Land Protection (Pest and bank could contain viable seeds for more than 20 Stock Route Management) Act 2002. By law, all years, so any eradication attempt must continue to landholders must take reasonable steps to keep monitor for at least this long. The location of M. pigra their land free of M. pigra. Introduction, possession plants at Peter Faust Dam suggests it has been present and sale of M. pigra are offences under the Act with since 1996, when the water level was at 32 per cent maximum penalties of $60 000. (Vitelli and Madigan 2005). Since then the water supply increased to about 80 per cent capacity, when 2.2 Statewide strategy M. pigra was discovered, and it has since receded. To protect vulnerable areas in Queensland, a state Masses of seedlings (see Section 1.3) emerged as the strategy was developed to plan an ongoing program water fell from 80 per cent to 32 per cent capacity, but of surveillance and eradication extending across the only isolated plants emerged as water receded further state (Austin and Csurhes 2004). This strategy outlines to 22 per cent in October 2005. five management programs to prevent M. pigra from becoming a significant pest in Queensland: 1. Coordination: Plan, implement, manage, evaluate and revise a statewide, coordinated response to the threat posed by M. pigra. 2. Prevention: Prevent transport of M. pigra seeds into Queensland from the Northern Territory. 3. Surveillance and early detection: Detect new infestations of M. pigra as early as possible. 4. Eradication: Eradicate any M. pigra infestations in Queensland. 5. Research: Develop a capacity to control M. pigra, including an understanding of the plant’s ecology.

2.3 Management of M. pigra at Peter Faust Dam Peter Faust Dam (Figure 10) is a large water body (74-kilometre perimeter at full supply) that provides flood mitigation primarily for canefields downstream, along the Proserpine River. The dam also provides irrigation water for cane farms and supplies domestic water to a number of towns. The dam was constructed in 1990, reaching almost full capacity the following year. A number of recreational activities are popular at the dam, including water sports, camping and pig hunting. However, the dam is particularly renowned as a site for barramundi fishing.

6 Risk of Mimosa pigra spread in Queensland � Figure 10. Peter Faust Dam, showing the water level at full supply and location of the main infestations. Also shown are boundaries of the five sections to aid monitoring and control.

7 A chronology of management actions, as summarised management plan requiring biannual surveys in by Chopping (2004), is given below: February and September. Initial management Control program April 2002 � After discovery of M. pigra in February 2001 at the In April 2002 a second control program was initiated, south-eastern edge of the dam (Figure 10) a series of beginning with further surveys of the dam. management actions were implemented, including: • M. pigra was found to be germinating both in the • an immediate small-scale inspection of the zone of the receding water level and within the thick south-eastern edge of the dam, which located Melaleuca band. approximately 100 M. pigra plants • Plant density (400 M. pigra plants per 25 square • ground and water surveys around the entire metres within heavy infestations; see Figure 11) and perimeter of the dam to identify, map and control soil seed-bank levels were determined. any M. pigra present; this involved the local cattle • The management group re-evaluated control grazier, SunWater, Whitsunday Shire Council and options and a decision was made to clear an NRW access track just off the foreshore within the • a helicopter survey within the dam and surrounding south-western area. Proserpine River catchment, which recorded no • Additional Melaleuca zones with thick M. pigra large (and therefore visible) infestations present were bulldozed, piled and then burned. • a follow-up survey in September 2001, which This provided access to infested sites and recorded 150 recently germinated plants improved detection probabilities of M. pigra plants. • establishment of the Peter Faust Dam Mimosa Approximately 17 kilometres of track was bulldozed. Management Group, now Mimosa pigra Stakeholder Washdown sites were established and guidelines Group (Austin and Csurhes 2004), comprising key developed to minimise the risk of vehicles and stakeholders (see below), which drafted a five-year other machinery moving seed off-site (Figure 12).

Figure 11. High density of M. pigra seedlings in the core infestation area. This small plot is monitored and managed by NRW researchers. Photo by P. Austin.

8 Risk of Mimosa pigra spread in Queensland Figure 12. Washdown facilities, to clean vehicles potentially contaminated with M. pigra seed, have been placed at a number of locations around Peter Faust Dam. � Photos by A. Pople and P. Austin. �

Control program September 2002 Control at the site was again re-evaluated and recommendations were made to: • undertake monthly inspections of the M. pigra- infested, south-western area of the dam and do random checks of the remaining perimeter • undertake triannual surveys of the entire dam perimeter in September, February and May • develop an extension program for minimising the risk of M. pigra spread from the dam (e.g. Figure 13) and highlighting the risk M. pigra poses to the state • undertake feral pig control regularly • hold cattle for at least five days prior to movement off-site by the local grazier • clear Melaleuca throughout the south-western area of the dam where most M. pigra plants were found and the majority of seed is likely to be present • utilise fire management where appropriate.

Risk of Mimosa pigra spread in Queensland � 9 Figure 13. Signs used to warn visitors to the dam of the presence of M. pigra, how to identify it and avoid transporting it away from the dam. Photos by E. Attard and P. Austin.

10 Risk of Mimosa pigra spread in Queensland Management 2002–05 � SunWater � • Two full-time control officers were employed in SunWater is responsible for the management of Peter October 2003 and are able to complete a survey of Faust Dam. It’s role is to: the dam foreshore and control of any emerging • help eradicate M. pigra where it grows on SunWater M. pigra plants every two months. Control involves land a combination of chemical spray using Brush-Off®, maintain human resource capacity to eradicate physical removal of seedlings near and in water and • M. pigra and recognise the need for allocating burning areas, with Atarus® to kill surface seeds. contingency funding � • The foreshore of the dam area was divided into five implement property hygiene practices to avoid operational sections (Figure 10). • seed movement by machinery, people and grazing Clearing of Melaleuca has been completed by • animals. bulldozer and chain in thicker areas and cleared by blade plough along the foreshore. Areas of regrowth Local governments will also require clearing in the future. Local governments have a range of respoinsibilities. • Seed-bank counts have been undertaken within They: M. pigra-infested areas to assist in future • provide advice and assistance with respect to the management planning. � strategic plan including strategic control activities 2.4 Research on M. pigra in Queensland • ensure that eradication is undertaken on any lands under a council’s control including stock routes, Research has focused on the ecology of M. pigra and roadsides and town commons its control at Peter Faust Dam as aspects of these liaise with relevant stakeholders and community to might well be unique to the site. In particular, there • undertake eradication and awareness has been work on (see Section 1.3): • administer and enforce provisions of the Land • quantification of the M. pigra seed-bank depletion Protection (Pest and Stock Route Management) rates and plant growth rates Act 2002 • determination of age at maturity (4–6 months) for recognise the need for resource allocation to M. pigra at Peter Faust Dam • implement the statewide strategy. • evaluation of the efficacy of mechanical, fire and chemical control Other Queensland Government departments Other departments such as Department of Main • chemical registrations for both M. pigra and Roads, Environmental Protection Agency, Department Melaleuca control. of Primary Industries and Fisheries 2.5 Key stakeholders and their • ensure awareness and early-detection programs are responsibilities put in place • ensure departmental staff cooperate to prevent The Mimosa pigra Stakeholder Group (formerly Peter spread of seeds Faust Dam Mimosa Management Group) was formed to direct management activities. The group comprises • ensure eradication is undertaken on all state- the following key stakeholders, with respective managed lands, including national parks and responsibilities (Austin and Csurhes 2004). reserves, state road reserves, rail reserves (state rail authorities) and state forests and forestry reserves. The department of Natural Resources and Water initiates and coordinates the overall response to the SunFish and Faust Dam Fish Stocking Association threat posed by M. pigra. In particular: These organisations: continues to research efficient and effective control • • help raise awareness of the potential for seeds of techniques M. pigra to be spread in nets and other fishing and • provides education services boating equipment • maintains human resource capacity to eradicate • encourage members to take action to help prevent M. pigra spread and to report any suspected plants. • provides financial and administrative support to the Mimosa pigra Stakeholder Group • develops appropriate legislation.

Risk of Mimosa pigra spread in Queensland � 11 Primary producer lobby groups Groups such as Queensland Cane Growers Organisation, AgForce and Queensland Farmers Federation: • help raise awareness of the potential for seeds of M. pigra to be spread by cattle and machinery • encourage members to take action to help prevent seed and plant spread and to report any suspected plants.

Proserpine Chamber of Commerce and Whitsunday Tourism These organisations: • help raise awareness of the potential for seeds of M. pigra to be spread by visitors to the dam • encourage visitors to take action to help prevent seed and plant spread and to report any suspected plants.

12 Risk of Mimosa pigra spread in Queensland �