WEEDS OF NATIONAL SIGNIFICANCE

PRICKLY ACACIA

(Acacia nilotica)

Strategic Plan

© National Weeds Strategy Executive Committee, 2000

ISBN 1 876977 15 9

This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may bereproduced by any process without prior written permission from the National Weeds Strategy ExecutiveCommittee. Requests and inquiries concerning reproduction and rights should be addressed to theProject Manager, National Weeds Strategy Executive Committee.

Supporting information about the National Weeds Strategy, Weeds of National Significance and progressto date may be found at www.weeds.org.au where links and downloads provide contact details for allspecies, their management committees and copies of the strategy.

This strategy was developed under the leadership of the Dept of Natural Resources, Queensland with fullcooperation of all the States and Territories of Australia.

Comments and constructive criticism are welcomed as an aid to improving the process and futurerevisions of this strategy.

Published by: National Weeds Strategy Executive Committee, Launceston

For further information contact:John R Thorp, Project ManagerFor the National Weeds Strategy Executive Committee16 Flowers Court LAUNCESTON Tas. 7250Telephone: (03) 6344 9657 Mobile: 0419 323 400 Fax: (03) 6343 1877Email: jthorp@jta.com.au Web: www.weeds.org.au

Publication date: September 2000

Copies available from:Dept of Natural Resources, QldLand ProtectionLocked Bag 40COORPAROO DC QLD 4151

Preferred way to cite this publication:Agriculture & Resource Management Council of Australia & New Zealand, Australian & New ZealandEnvironment & Conservation Council and Forestry Ministers, (2000) Weeds of National SignificancePrickly Acacia (Acacia nilotica) Strategic Plan. National Weeds Strategy Executive Committee,Launceston.

Cover design by: Grant Flockhart, Queensland Department of Natural Resources

The editors have tried to make the information in this product as accurate as possible. However, they donot guarantee that the information is totally accurate or complete. Therefore, you should not rely solely onthis information when making a commercial decision.

CONTENTS

EXECUTIVE SUMMARY ................................................................................................ 1

THE CHALLENGE.......................................................................................................... 2

1 BACKGROUND ....................................................................................................... 31.1 The biology of prickly acacia........................................................................................................ 31.2 History of spread ......................................................................................................................... 31.3 A weed of national significance.................................................................................................... 41.4 Legislative controls ...................................................................................................................... 51.5 Control to date............................................................................................................................. 51.6 Principles underlying the plan ...................................................................................................... 61.7 Process Followed ........................................................................................................................ 61.8 Relevance to other strategies ...................................................................................................... 6

2 STRATEGIC PLAN .................................................................................................. 82.1 Prevent spread ............................................................................................................................ 82.2 Reduce impact ............................................................................................................................ 92.3 Harness national commitment.................................................................................................... 112.4 Co-ordinate management .......................................................................................................... 13

3 MONITORING AND EVALUATION ....................................................................... 14

4 STAKEHOLDER RESPONSIBILITIES .................................................................. 15

5 ADDITIONAL READING ........................................................................................ 16

6 GLOSSARY ........................................................................................................... 17

Appendix 1Map of the Prickly Acacia Containment Line ........................................ 18

.

September 20001

EXECUTIVE SUMMARY

Prickly acacia (Acacia nilotica subsp. indica)is one of northern Australia’s worst weeds. Itis a woody shrub/tree that aggressivelyreplaces grasslands with thorny thickets. Itcosts primary production over $5 million perannum by decreasing pasture production andhindering mustering. Over 6 million hectaresof arid and semi-arid Queensland are infestedto date. It has potential to infest 50 millionhectares of grasslands in Queensland,Northern Territory and Western Australia.This strategy was developed after extensivecommunity consultation. The majorchallenges for prickly acacia are prevention ofseed spread, managing extensive infestationsand ensuring follow up treatment in infestedareas.

The vision of the strategy is that:

Prickly acacia is confined and itsimpacts reduced to a minimum.

The strategy aims to deliver four desiredoutcomes.

1 Prickly acacia is prevented fromspreading.

• Prevent long and short distancemovement by stock

• Prohibit trade and distribution acrossAustralia

• Develop and maintain early detection anderadication mechanisms

• Maintain a national containment line

• Use enforcement as a management tool.

2 The adverse impacts of establishedprickly acacia infestations areminimised.

• Foster regional and local containmentplanning

• Promote the integration of prickly acaciamanagement

• Identify economic impacts, incentives anddisincentives

• Refine and adopt best practicemanagement

• Improve integrated management

• Introduce and improve the impact ofbiocontrol agents.

3 National commitment to prickly acaciais maintained.

• Adopt a community approach to planningand management

• Maximise the availability and use ofresources

• Develop maps of prickly acacia.

4 Prickly acacia management is co-ordinated at a national level.

• Manage implementation of plan

• Monitor implementation of plan

• Coordinate communication on the plan.aThe extent to which these outcomes are metwill be evaluated as part of a five-year cycleof review and will determine the success ofthis strategic plan.

September 20002

THE CHALLENGE

Prickly acacia (Acacia nilotica ssp. indica) isone of Australia’s worst weeds. It hasreceived national attention because of itsimpacts on the northern Mitchell Grass Downsof Queensland, where it is replacing a grasscommunity with an impenetrable thorny shrubland.

Prickly acacia is a woody shrub/tree,introduced from India and Pakistan. Importedinto Australia as an ornamental and shadetree in the 1900’s this plant was also toutedas a valuable fodder and shade tree from the1920’s to 1960’s. It has progressed to be amajor weed and is known to infest over6,000,000 ha of arid and semi-aridQueensland, with small infestations in threeother states. Most of Australia, north ofapproximately latitude 32oS, (except forSouth Australia, coastal NSW and southeastQueensland) appears to be climaticallysuitable for prickly acacia and must beconsidered as potentially under threat fromthis weed.

Annual costs of $5 million per year areestimated for the grazing industry due toreduced production and increases inmanagement costs. The industry now seesthat the impact of this species significantlyoutweighs the benefits gained from shadeand drought fodder.The environmental cost of prickly acacia hasnot been well quantified. The Mitchell GrassDowns bio-region is known, however, to behome to twenty-five rare and threatened

animal species and two endangered plantcommunities and this community is seriouslyaltered in infested areas. Unless effective andefficient management is implemented andmaintained, prickly acacia will continue toimpact adversely on the biological diversity,agriculture, tourism, other industries andpotential Aboriginal land use across northernAustralia.

Prickly acacia is easily dispersed by stock orhumans and large new infestations canrapidly arise after good seasons. Onceestablished the economic and control costsare high. As with all weeds the cheapestcontrol option is prevention and more work isrequired on protocols and procedures toprevent spread.

Substantial progress has been made on thecontrol of prickly acacia. It can be managedwith a combination of chemical andmechanical control. Introduced biologicalagents have not had a noticeable impact todate. Costs of control may be significantwhen measured against land value. Thechallenge is to find economically feasiblemanagement practices that will be adoptedby land managers. All control measuresrequire follow up due to the regeneration fromthe large seed bank.

Implementation of the Prickly AcaciaStrategic Plan will result in containing thespread of prickly acacia and minimising theimpact of established infestations to Australia.

September 20003

1 BACKGROUND

Prickly acacia is a weed of nationalsignificance (WONS) because it is a woodyshrub that forms thickets that impact onprimary industry and biodiversity. It threatensa major extensive native ecosystem, theMitchell Grass Downs and has the potentialto spread over most of northern Australia.Prickly acacia is easily spread, shows a wideadaptability to climate and results insignificant changes in ecosystemcomposition. Large infestations of pricklyacacia are currently found only inQueensland, however, it poses a potentialrisk to 50 million hectares of Australia’s nativegrassland ecosystems.

Prickly acacia may be confused with nativeacacia species, the genus has over 500species in Australia. Unfortunately thecommon name is also used for some of thesespecies. Native acacia’s include A. farnesiana(known as mimosa bush, mimosa or pricklyacacia) and A. paradoxa (kangaroo thorn).Similar looking woody weeds, also weeds ofnational significance, are Prosopis spp.(mesquites) and Parkinsonia aculeata(parkinsonia).

1.1 The biology of prickly acacia

Prickly acacia, Acacia nilotica ssp. indica, is athorny leguminous shrub or small tree thatgrows to 5 metres. The umbrella shapes ofthe tree and the pods are characteristicfeatures. The young shrubs form densethorny thickets. While mature trees areusually single stemmed, with spreadingbranches which lose most of their thorns.Leaves are finely divided and fern-like, withfour to ten pairs of leaf branches and ten totwenty pairs of narrow green leaflets on eachbranch. Pairs of stout thorns, usually 5-10cmlong, grow at the base of the leaves.

Golden-yellow, ball-shaped flowers, about1cm across, grow on the stems with two tosix flowers per group. Pods are 10-15 cm orlonger, flat, with narrow constrictions betweenthe seeds. The pods turn gray when ripe.One medium sized tree can produce 175 000viable seeds per year. Seeds can remainviable in soil up to 15 years, although lessthan 5% of seed is viable after 2 years(Figure 1).

Stock, particularly cattle, is the main agentsfor dispersing prickly acacia seed. Water is

the second most likely means of dispersal,generally as a result of flooding. Seedgermination is affected by soil type and waterregime. Prickly acacia prefers cracking claysand loam soils due to their high water holdingcapacity.

1.2 History of spread

Prickly acacia was first recorded in Australiagrowing in New South Wales in 1803. It wasnot spread widely until after 1900 when it wasgrown extensively as a shade and ornamentaltree in the Bowen and Rockhampton districtsof Queensland. Initial spread was bybroadcasting seeds from horseback and bydeliberate planting of seedlings. TheDepartment of Agriculture and Stockrecommended it in 1926 as a suitable shadetree for sheep production in westernQueensland. It was subsequently widelyplanted around homesteads, bore drains anddams during the second quarter of this century,not only for shade but also for fodder, becauseof the protein rich pods and leaves.

The wool crash of the 1970's saw a changefrom stocking sheep to cattle in Queensland.The slump in cattle prices during the 1970's inturn led to high stocking rates which may havebeen significant in providing large numbers ofcattle as dispersal agents. This, and the seriesof wet years during the 1950's and again in the1970's promoted massive invasion of pricklyacacia throughout the northern Mitchell GrassDowns and the establishment of dense thornveldts, particularly along bore drains.

Distribution

Prickly acacia is now distributed fromCooktown in Queensland’s north to the NewSouth Wales border and from Bowen on theeast Queensland coast to the Barkly Tablelandand Arnhem Land in the Northern Territory.The major infestation includes 6,000,000hectares of the northern Mitchell Grass Downsof Queensland (Appendix 1). The heaviestinfestations occur along bore drains, watercourses and drainage lines. Infestationsspread from here onto the extensiverangelands.

The potential distribution of prickly acacia inAustralia has been predicted using CLIMEXfrom the ecoclimatic characteristics of theareas of Pakistan and India where prickly

September 20004

acacia is native (Figure 2). All areas north oflatitude 32oS (except for South Australia,coastal NSW and south-east Queensland)appears to be climatically suitable for prickly

acacia and must be considered as potentiallyunder threat by this weed. This potentialdistribution includes over 50 million hectaresof Australia’s native grassland ecosystems.

Figure 1. The life cycle of prickly acacia.

Figure 2. Potential distribution of prickly acacia.(Data is splined from a CLIMEX prediction. EI = Ecoclimaticindex: EI<30 potential for permanent population low, EI>50potential very high).

1.3 A weed of national significance

Prickly acacia currently impacts on a range ofland uses as summarized below.Environmental:

• Potential to replace the Mitchell GrassDowns (area of 320,000 km2) with athorny scrub-land similar to the Africanthorn veldt

• Threatens 25 rare and vulnerable animalsincluding the Julia Creek Dunnart(Sminthopsis douglasi), a form of thelong-tailed planigale (Planigale ingrami)and two skink species

• Prickly acacia infestations result indramatic changes to species diversity ofbirds and reptiles reflecting the decreasein grass cover, increased bare groundand increase in perching sites.

Primary Production:

• Reduced pasture production resulting inreduction in cattle/wool productionestimated at between $2.4 M and $5 Mper year

• Increased difficulty and expense ofmustering stock estimated at $0.4 M peryear

• Impeded movement and access to water

• Water loss from and maintenance of boredrains

• Exacerbates and accelerates soil erosion

• Control costs to primary industryestimated at between $1.4 M and $4 Mper year

• 2-5 years to maturity• mature plants 1.5 m

Pod/seed transportedWater, grazing or importedstock, deliberate planting

Pod/Seed introducedWater, grazing or importedstock, deliberate planting

Pod/Seed transportedWater, grazing or importedstock, deliberate planting

• germination linked to succession of goodseasons

• most germination late spring-early summer

Mature plantFlowering late February toJunePods fall October to January40 years longevity

Seedling Mortality is caused by pasture competition, frost, and low moisture. Most seedlings die in first year

• high seed production (30 000 per plant)• 900 trees / hectare• 40% of seeds passing through cattle viable

Soil seed bankmost surface seeds germinate orbecome unviable within 2 yearsburied seeds can survive up to 7 years

September 20005

• Some property values have beendecreased by as much as 20% due toheavy infestations of prickly acacia acrossthe property.

Tourism:

• The Mitchell Grass Downs are one of theworlds unique grass landscapes. Thevalue of the outback tourism industry isincreasing, infestations reduce the naturalattraction of the outback and the uniquedowns landscape.

Benefits:

• Landholders receive net benefits fromprickly acacia at low densities and duringpoor seasons. This is in the form ofnutrition for stock, shade and shelterresulting in increased lamb survival.

1.4 Legislative controls

Prickly acacia has declared status in 4 states.• Queensland: Plants are to be destroyed (P2

area) and populations to be reduced (P3area).

• Northern Territory: Class A - noxious weed tobe eradicated and Class C - introduction ofspecies prevented.

• Western Australia: P1/P2 - must not beintroduced and eradicated if found.

• New South Wales: W1/P - notifiable weed.This applies to a minority of local governmentareas.

Prickly acacia is not declared in other states,and so it may currently be grown, traded ordistributed from these states. Nationaldeclaration would be required to ensure thatthis does not occur. This species is also regulated byCommonwealth agencies. The AustralianQuarantine and Inspection Service (AQIS)prohibits the introduction of prickly acacia asnursery stock or seed into Australia. TheEnvironment Protection and BiodiversityConservation Act 1999 overseen byEnvironment Australia (EA) may result inprickly acacia becoming a key threateningprocess or its listing in regulations controllingnon-native species.

1.5 Control to date

Prickly acacia was declared as a noxiousplant in Queensland in 1957, but despiteextensive control efforts the weed is wellestablished. In all states, the control of a

declared plant is the responsibility of thelandholder and many landholders are activelyattempting to combat this species. The need to prevent spread into vulnerableriver systems lead QDNR to undertake astrategic control program for prickly acacia.The SWEEP program has spent $2.2M oncontrol of outlying or strategic infestationsfrom 1995/96 to 1998/99. The programoperates in partnership with landholders andlocal governments, 25% of funds supplied bylandholders, and assists with initial controlwork where there is a wide communitybenefit. A prickly acacia containment line(PACL) was established in 1999. Inside theline, integrated control to minimize impact isproposed. Labour barter days, are veryeffective in reducing infestations (see box). Management Chemical and mechanical methods, pasturemanagement and in some situations fire canbe used in an integrated control program forprickly acacia. All methods may be effectivein particular situations depending on: theinfestation density, landform, resources, areacovered and the management objectives(Mackey et al. 1996). Costs range from $2 to$100 per hectare. All programs requireseveral years of follow-up that may increasethe cost several fold. The long-term costsmake control of large dense infestationsuneconomic in some situations. This isaccentuated when there are poor financialreturns from primary industries. Timing is alsovery important for control as some low rainfallseasons may lead to natural mortality whileother seasons result in major seedlingrecruitment. Diuron has successfullycontrolled the densest infestations along boredrains, in dams and borrows pits. Infestationsin creek lines and along natural waterbodiesare more difficult to control. Heavyinfestations away from water bodies can besuccessfully mechanically pulled. Biological control is considered the most costeffective management method for denseareas of many weeds. The seed feedinginsect, Bruchidius sahlbergi was released andattacks the seed in the pod but to date thisagent has not had significant impacts onprickly acacia in the field. A suite of biologicalagents is currently being tested.

September 20006

Barter days tackle prickly acacia

The Upper Landsborough Group in northwestQueensland has adopted the principle oflending your neighbour a hand on a large scale.The group includes 36 properties and 750,000hectares south of Hughenden. Theseproperties form the northern catchment of theLake Eyre Basin.

They meet each month for the purpose of acooperative prickly acacia control day. Thegroup has set a goal of eradicating pricklyacacia within the group’s area by 2006.Mr. Ian McClymont, Chairperson of the groupsaid “To meet this goal, the group has a labourbarter day each month, where landholdersshare their time, experience and skills tocontrol prickly acacia on a property within thegroup. The first day was held in October 1996and only three members turned up for spraying.However, participation levels have gone fromstrength to strength with some control daysnow having to be split between two propertiesto accommodate the large number of

volunteers.”“Natural Resources SWEEP funding hasassisted the group tackle some of their large,dense infestations using mechanical chaining.The benefits of working together have beennumerous for the group, from making the taskless daunting to lifting the community spirit ingeneral. What is really encouraging is thatmany landholders within the group that don’thave a prickly acacia problem are pitching in tohelp properties that do”With an annual budget of less than $90,000made up mostly of man-hours worked, the groupran 16 barter days involving work on 9properties in the 1998/99 financial year. In thelife of the project significant decreases in

prickly acacia have been recorded on 11properties, including some properties are nowcompletely free of this weed”.As well as on-ground work this group has beenimportant in selling the message that “Freedomfrom Prickly Acacia” is possible with the use ofbest practice and a community workingtogether.

1.6 Principles underlying the plan

This plan is based on the recognition andacceptance of the National Weeds Strategyprinciples:

1. Weed management is an essential andintegral part of the sustainablemanagement of natural resources and theenvironment, and requires an integrated,multidisciplinary approach.

2. Prevention and early intervention are themost cost-effective techniques that canbe employed against weeds.

3. Successful weed management requires acoordinated national approach thatinvolves all levels of government inestablishing appropriate legislative,educational and coordination frameworksin partnership with industry, landholdersand the community.

4. The primary responsibility for weedmanagement rests with landholders/landmanagers but collective action isnecessary where the problem transcendsthe capacity of the individuallandholder/land manager to address itadequately.

1.7 Process Followed

The National Prickly Acacia Strategy is theproduct of a stakeholder workshop held inCharters Towers in March 1999. Thisworkshop revised and updated a strategy firstdrafted in November 1997. The draftdocument was the basis of a CommonwealthNatural Heritage Trust project proposal in1997/98. This project funded work on thecontainment line, extension and thedevelopment of an adaptive managementresearch program. This strategy takes inaccount feedback from over fortystakeholders who commented on drafts aswell as input from the management groupand interested parties.

The Prickly Acacia Management Group(PAMG) was formed after a meeting inMuttaburra in May 1998. Its membershipconsists of representatives of industry,landcare, local government, conservation,landholders, government agencies andresearchers. The group’s mission is “Toprovide leadership and guidance to explore,identify and utilise all available and potentialresources for the management of pricklyacacia (a weed of national significance) toachieve sustainable land use”. This group willoversee the implementation of the nationalstrategy.

1.8 Relevance to other strategies

The Prickly Acacia Strategic Plan has beenestablished to provide a framework for

September 20007

coordinated management of the plant acrossthe country. To date most infestations of thisplant are limited to Queensland but pricklyacacia has the potential to spread to other

states. The strategy is linked to other nationaland state resource plans, strategies andgroups already involved in prickly acaciamanagement at regional and local levels.

ScopeScale

Natural Resource Management Pest Management Weed SpeciesManagement

National National Strategy for Conservation ofAustralia's Biological DiversityNational Strategy for EcologicalSustainable Development

National Weeds Strategy Prickly Acacia StrategicPlan

State Qld Biodiversity and Natural ResourceManagement StrategyForest Policy, River, Estuary andWetland policies

Queensland Weed StrategyNorthern Territory WeedManagement StrategyWA Weeds Strategy

Queensland PricklyAcacia ManagementPlan

Regional Regional NRM Plans Regional Pest ManagementStrategies

Prickly AcaciaContainment Line

Catchment Catchment Management Strategies ICM Pest ManagementStrategies

Local Landcare and Roadside ConservationPlans

Local Government PestManagement Plans (Qld.)

Property Property Management Plans Property Pest ManagementPlans

September 20008

2 STRATEGIC PLAN

VISIONPrickly acacia is confined and its impactsreduced to a minimum.

2.1 Prevent spread

Desired outcomePrickly acacia is prevented from spreading.Background Prickly acacia’s current wide distribution isthe product of its deliberate planting as afodder and shade plant for stock. Onceprickly acacia occurs in an area it is possibleto stop some forms of deliberate spread. Themain dispersal vector of prickly acacia seed islivestock that have fed on pods. Stock movedby road transport, is the most importantmechanism for long distance dispersal. Anyattempts to control and contain the weedlocally or regionally must address theproblems posed by stock movement.

Prickly acacia should be declared underlegislation to prevent its trade and distributionand where necessary to support control ofnew or other infestations in all states. Thisauthority must be available to ensure that thegoal of preventing spread is achieved,although, enforcement should be used as alast resort. The primary emphasis of the planis on encouraging landholders throughinvolvement to provide ownership of theissues and consequent outcomes (seeStrategy 2.3.3).

A key component of preventing the impacts ofprickly acacia is early detection of plants inareas outside the PACL. Vast areas ofAustralia are at risk. It is important that thoseareas are prioritised and regular surveyscarried out. Assistance is needed from theindustries and communities of central andnorthern Australia to prevent spread and todetect new infestations. A wide range ofeducation and awareness activities will berequired. These include protocols to reduceseed spread, better management of waterbodies such as borrow pits and bore drainsand more effective awareness campaigns.When new infestations are detected inQueensland, QDNR currently has theresources to respond but this needs to bemaintained and made available in otherStates. The role of the PACL is to prevent the spreadof prickly acacia into the Lake Eyre basin, theGulf catchment and other river systems innorth and central Australia. The PACLconsists of five ‘islands’ of ‘core’ pricklyacacia areas that stretch from Barcaldinenorth to Hughenden and west to Winton andJulia Creek. All prickly acacia outside thePACL is targeted for removal in the long term.Landholder efforts are being supported inQueensland by the SWEEP program with 66projects to date. Small infestations on grazingland in South Australia have beensuppressed in the past and this should occurin other states if they occur.

Strategy Actions Responsibility Rank

2.1.1 Prevent long andshort distancemovement by stock

Develop a code of practice for minimising the dispersal ofprickly acacia through stock transport. A code will:

• Ensure weed seed reduction before dispatch oracceptance of livestock from prickly acacia areas.System proposed includes vendor declarations

• Establish washdown and holding facilities,particularly at sale-yards

• Survey meat works as high risk sites for pricklyacacia establishment

• Develop a “prickly bush” QA system whichemphasises self-regulation and recognition ofproperties that employ such practices.

State agencies,industry groups,landholders

1

Develop and implement prickly acacia education andawareness activities for property owners, stock agents andstock transporters

State agencies, localgovernment,landholders, industry

1

Use risk assessment to determine how and where pricklyacacia is most likely to spread based on its potential forlong distance movement by stock

State agencies 2

Develop monitoring tools to detect new infestations at theproperty level

State agencies,landholders

2

September 20009

Strategy Actions Responsibility Rank

2.1.2

Prohibit trade anddistribution acrossAustralia

Declare prickly acacia to prohibit propagation, trade anddistribution in all States and Territories

Legislative agency ineach State andTerritory, Nurseryindustry, EA

1

2.1.3 Develop and maintainearly detection anderadicationmechanisms

Implement education and awareness activities specific to:mining, tourism, defence, pastoral industry, environmentallysignificant areas, landcare facilitators, government staff,and regular communications for the general public

State/ federalagencies, localgovernment,industry/communitygroups, PAMG

1

Develop and implement an early detection mechanism andimplement regular surveys

State agencies,PAMG, local govt.

1

Determine how and where prickly acacia is likely to spread State agencies, CSIRO 2

Establish state-based procedures for receiving andresponding to reports of prickly acacia (including voucherspecimens in state herbaria) and maintain an earlyeradication capacity

State agencies, localgovernment, EA

3

2.1.4 Maintain a nationalcontainment line

Document the national containment line and makeavailable to general public and review

QDNR, PAMG 1

Regularly review the national containment line PAMG, QDNR 1

Provide criteria for determining areas inside and outsidethe prickly acacia containment line

QDNR, PAMG 2

Eradicate prickly acacia outside the containment line:

(A) Initial control

(B) Follow-up

QDNR, NSWAg,NTDPIF, PIRSA,

Landholders

2

2.1.5 Use enforcement as amanagement tool

Utilise support available from co-operative landholders inencouraging others to meet their eradicationresponsibilities

Local governments,LCMC and Landcaregroups

1

Manage eradication using project planning on anappropriate scale, incorporating long term landholderresponsibilities into each project

State agencies, localgovernment

2

Increase landholder awareness of their currentresponsibilities under legislation.

State agencies, localgovernment

3

Utilise notices where necessary to ensure control aimed ateradication is achieved.

Local government &state agencies

3

2.2 Reduce impact

Desired outcome

The adverse impacts of established pricklyacacia infestations are minimised.

Background

Throughout the region in which prickly acaciahas established, there are still large areasthat are free of the weed or whereinfestations could become denser. Apreventative approach is necessary in thisregion to protect those areas that are free oralmost free of prickly acacia. This needs to betackled locally on an appropriate scale (e.g.sub-catchment). Furthermore, anyopportunities for co-ordinating activities tominimise the impact of established prickly

acacia and other weds should be plannedand implemented regionally or locally,provided consistency is maintained withlarger scale plans (e.g. catchment plans). Prickly acacia management should not beconsidered in isolation from othermanagement activities in a property, region orcatchment. Attention should be given to thetotal requirements of landscape restorationrather than for weed control per se. Pricklyacacia management should be consideredalong with control and management of otherweeds, including other woody weeds such asmimosa bush and mesquite. Further, weedmanagement should be considered as part ofproperty management planning andcoordinated with other management activities

September 200010

to maximize the benefits of control andseasonal fluctuations and minimisingenvironmental impacts. Most major populations of prickly acacia areon pastoral properties characterized by lowreturns per unit area. This represents a majorchallenge in developing economicallyeffective long-term management practices.Landholders do receive benefits from pricklyacacia at low density however, while 1 ha ofprickly acacia yields 75kg of pods, 1 haMitchell grass yields 1-2000 kg grass peryear. Prickly acacia impacts on biodiversityand tourism, ameliorating these effectsshould be taken into account when evaluatingthe returns from control programs. Allstakeholders should consider that notcontaining prickly acacia will result in theirgrandchildren inheriting a thorny shrublandrather than the biologically unique MitchellGrass Downs. A wide range of control options is availablefor prickly acacia including mechanical andchemical control. The effectiveness of these

methods needs continuous dissemination tolandholders. Possible landholdercomplacency to the control of prickly acacianeeds to be specifically targeted. At the sametime landholder input to refining controlmethods and adapting them to localsituations is essential to establish bestpractice management. Integrated control has the potential to providecost effective long-term control of pricklyacacia. There are still information gaps in ourunderstanding of the biology and ecology ofprickly acacia. There is potential to improvethe effectiveness of control methods for somesuch as riparian areas and some value ininvestigating uses of harvested trees.Biological control although not effective todate has the potential to target weaknessesin the lifecycle of the weed. Genetic studieshave recently shown that prickly acacia inAustralia is from the India/Pakistan region, soexploration and collection in this region isrequired.

Strategy Actions Responsibility Rank

2.2.1 Foster regional &local containmentplanning

Incorporate prickly acacia management in:• landholder level property & sub-catchment plans• local government pest management plans• NRM & catchment strategies

State agencies,Catchment and regionalstrategy groups, localgovernment, landholders

1

Promote the establishment of clean areas within theregions of established prickly acacia via these plans

As above 2

Develop and resource management plans forGovernment lands consistent with other plans

State and federalagencies

2

2.2.2 Promote theintegration of pricklyacacia management

Promote integrated weed management to maximizebenefits of prickly acacia control (while alsomonitoring associated costs)

QDNR, industry groups 1

Survey the health of the landscape and ecosystemsand use as an indicator of success of prickly acaciamanagement including reduction of impacts onthreatened ecosystems.

QEPA, CSIRO,community groups, EA

2

Incorporate prickly acacia management within overallweed management in property planning

Landholders 2

Develop a weed planning module for use in theproperty planning process

State agencies 3

2.2.3 Identify economicimpacts, incentivesand disincentives.

Determine the benefits and costs of prickly acaciacontrol for best practice management

QDNR, landholders 1

Update data on the economic impact of prickly acacia QDNR 1

Assess the cost-benefit of SWEEP projects as aninput to planning

QDNR, UQ 1

Assess the economics of prickly acacia managementat different spatial scales (sub-catchment, catchment,regional), including the assessment of SWEEP

QDNR, local government 2

September 200011

Strategy Actions Responsibility Rank

Review, document and distribute information oncurrent and potential incentives and disincentives• Potential “net” benefit of incentives• Impacts on land values/ rates• Forms of assistance available.

QDNR 2

Facilitate removal of identified disincentives QDNR, PAMG 2

Review the use of lease conditions to facilitate pricklyacacia control

QDNR 3

2.2.4 Refine and adopt bestpractice management

Publish best practice options for prickly acaciamanagement

QDNR, PAMG 1

Develop and implement extension andcommunication plans addressing established pricklyacacia infestations

QDNR, PAMG 1

Use adaptive management processes to refine bestpractice for different regions and types of infestations

QDNR, Landholdergroups, PAMG

2

Establish best practice demonstration sites andconduct training in management techniques

QDNR, Landcare 2

2.2.5 Improve integratedmanagementpractices

Improve understanding of prickly acacia biology andspecific control methods as required to supportintegrated management

QDNR/CSIRO

1

Investigate the impact of prickly acacia and itsmanagement on land sustainability (includingbiodiversity and water quality)

QDNR, QEPA, QPWS,community groups

1

Develop best practice control for riparian andwoodland areas and investigate the commercialprocessing of harvested prickly acacia

QDNR/CSIRO

Private industry, localgovernment

Investigate the spread of prickly acacia at alandscape level, including the impact of climate onseedling growth and seed spread

QDNR, CSIRO 1

2.2.6 Introduce andimprove the impact ofbiocontrol agents

Conduct overseas searches for biocontrol agentsbased on - Genetic studies of prickly acacia andpotential effectiveness of the agents

QDNR

1

Maximise introduction and assessment of potentialbiocontrol agents

QDNR 2

Determine impacts of introduced biological agentsand interrelationships between them and other controloptions

QDNR 3

2.3 Harness national commitment

Desired outcome

National commitment to prickly acacia ismaintained.BackgroundCurrent and potential prickly acaciainfestations cover very large areas ofAustralia and so management of this weedrequires a co-ordinated community approach.The major planning processes currentlyoperating are the development of regional,catchment and, in Queensland, localgovernment pest management plans. Theseprocesses involve wide communityrepresentation and thus are a means of

gaining community commitment, as well asincorporating prickly acacia management intoa wider land sustainability framework.Reducing the impact of prickly acacia is anintegral part of land sustainability, includingmanagement of natural vegetation, otheraspects of biodiversity, tourism values andAboriginal land values. Projects addressingthese issues should include prickly acaciamanagement.

The resources required to prevent pricklyacacia spread and to minimise impact ofestablished infestations in the long term areenormous. A cost of $55 million wasestimated for a single treatment of all infestedareas in Queensland. This did not include on-

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going control costs. There is a need toensure that all available resources are utilisedand that all achievements and actions aredocumented as a measure of progress andsuccess. This is also part of accountabilityrequirements on government and privateindustry managers to ensure efficient use ofresources. Approaches for funding should beco-ordinated to maximise potential success.In Queensland SWEEP projects havedemonstrated that government supervisedprojects, including landholder contributions,can reduce infestations. These programs,however, are expensive and require on-goinglandholder commitment to follow-up. The“labour barter days” concept demonstratesthat control programs do not have to begovernment managed but will requiregovernment support.

Information on the distribution of pricklyacacia, including where control works havebeen completed, is critical to supportplanning. The degree of detail required willvary with the scale and purpose of theplanning. QDNR has a system, PestInfo,which is being implemented and evaluated forcommunity group use in Queensland. It willcollate existing data on the present andhistorical distribution of prickly acacia and actas a means of tracking eradication efforts. Itis also desirable to have a whole of Australiarecord of sites where prickly acacia has beendetected and the action taken. Other methodsof obtaining data, such as remote sensingand aerial techniques need to be developedand applied. Collection of landholder mappingdata will significantly add to the current dataset.

Strategy Actions Responsibility Rank

2.3.1 Adopt a communityapproach to planningand management

Provide a map of catchments and regions at risk of pricklyacacia invasion, including the impact of climate change toidentified stakeholder groups

CSIRO, QDNR 1

Incorporate prickly acacia prevention and managementinto regional catchment and local govt plans for all at riskareas and facilitate landholder involvement in planningprocesses

Community groups,local government

1

Incorporate inter-agency and community group co-operation into extension and control projects acrossAustralia

State and federalagencies

2

2.3.2 Maximise theavailability and use ofresources

Include stakeholder consultation in all project development(both ways between government and community)

All stakeholders 1

Maintain the QDNR SWEEP program as a catalyst and co-ordinator for resources from participating stakeholders

QDNR 1

Develop projects which access all appropriate componentsof NHT and other Government programs

QDNR 1

Market the prickly acacia strategy and co-ordinate aplanned approach to funding sources

Project coordinator,PAMG

1

Assist groups to set realistic expectations and objectives,using technical and resource availability information

State agencies,landcare

2

Utilise a project management process for all governmentand community activities - links to 2.4.3.

All stakeholders 2

Document and promote project mechanisms Project coordinator 3

2.3.3 Develop maps ofprickly acacia

Make available prickly acacia distribution and densitymaps at the appropriate scales for stakeholders; regional,catchment or state

QDNR, localgovernment,landholders

1

Develop and implement a procedure for using communitygroup/landholder input to mapping

QDNR, NTDPIF andAGWA

1

Import data from other states into PestInfo. QDNR, NTDPIF andAGWA

1

Complete the implementation of PestInfo in Queensland QDNR, local govt. 2

Investigate new techniques for mapping density and newsites

CSIRO, QDNR 2

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2.4 Co-ordinate management

Desired Outcome

Prickly acacia management is co-ordinated ata national level.

Background

To ensure that weeds of national significanceare effectively managed the National WeedsStrategy outlines the need for thedevelopment, implementation and evaluationof a management program for each species. The planning process outlined in the NationalWeed Strategy requires a number of actions.These are:

• The involvement of all stakeholders indeveloping and implementing the plan

• The integration of the plan with otherexisting, relevant land managementprograms at all levels

• The suitability, availability, requirementsfor, and integration of all available toolsfor control and awareness

• The utilization of coordinated communityaction as the delivery mechanism forimplementation wherever appropriate

• The determination of an appropriatefunding mechanism for the plan, includingidentification of the beneficiaries and theirrelative capacity to pay

• The establishment of performanceobjectives and methods for theirevaluation.

This plan addresses these issues and willprovide a tool in the ongoing coordinatedmanagement of prickly acacia in Australia.

Strategy Actions Responsibility Rank

2.4.1

Manageimplementation of theplan

Establish and maintain a prickly acacia management groupand appoint a project coordinator

QDNR 1

2.4.2Monitorimplementation of theplan

Collate strategic plan milestones and report on progressannually to NWSEC, stakeholders and funding groups

Project coordinator 1

Evaluate projects on outcomes not outputs All stakeholders 1

2.4.3

Coordinatecommunication aboutthe plan

Conduct communication activities to ensure awareness ofthe plan, opportunities and achievements• Ensure linkages with other WONS strategies and other

plans to maximise awareness

Project coordinator 1

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3 MONITORING AND EVALUATION

This strategic plan is subject to a 5-year review. The Prickly Acacia Management Group as acomponent of its quarterly meetings will monitor the implementation of the plan. Annual reportswill be forwarded to the NWSEC and made available to interest groups in a cost efficient manner,possibly a web page. Monitoring will include review of actions outlined and undertaken by groupsimplementing plans:

• State weed strategies

• Queensland local government pestmanagement plans

• Catchment management plans

• Project plans developed from thestrategic plan.

• State of the Environment reportingprocesses.

A set of performance indicators for the plan includes the actions listed below:

• National declaration of prickly acacia

• Increased awareness of prickly acacia asa weed of national significance

• Clear understanding of the social,economic and biodiversity impacts ofprickly acacia

• Increased delivery of extension materialspecific to target groups and sites

• Increases in surveys for isolatedinfestations

• Adoption of vendor declaration andhygiene protocols by industry andlandholder groups

• Decrease in area of prickly acaciaoutside/inside the PACL resulting inrealignment and reduction in the PACLarea

• Eradication of all isolated infestations

• Increased resources for on-groundactions

• Increased action on prickly acacia at alllevels- property, catchment and regional

• Progress on removal of disincentives forcontrol

• Increased use of best managementpractices

• Increased surveys of the conservationstatus and health of Mitchell GrassDowns.

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4 STAKEHOLDER RESPONSIBILITIES

Private landholdersTo control prickly acacia on their ownlands.

• Property management plans includeprickly acacia control

• Implement best practice management

• On-property stock withholding periods toreduce movement of seed with stock

• Eradicate small or strategic infestations.To be aware of the potential for pricklyacacia to spread onto their land

• Be able to identify woody weeds.Department of Natural Resources

• Continuing to develop efficient, effective,and appropriate control techniques

• Providing extension and educationservices to both rural and urbancommunities

• Developing best practice managementunder adaptive management programs

• Support local government enforcement ofcontrols of prickly acacia under the Act

• Liaising with community/industrygroups/local governments to coordinateprickly acacia control

• Facilitate and coordinate prickly acaciaeradication in areas outside the PACL.

Utility companies

• Develop protocols and washdownfacilities

• Become involved in management plans inservice regions.

Agribusiness Industry / Research andDevelopment Corporations

• Support research on the species

• Endorse and implement protocols toprevent the spread of prickly acacia

• Act as conduits for information toproducer groups.

Local Governments (Queensland)To ensure impacts of prickly acacia are keptto a minimum throughout the localgovernment area.

• Ensuring that pest management plansinclude strategic prickly acacia controlactivities

• Ensuring that strategic prickly acaciacontrol is undertaken on all lands underthe Councils control: stock-routes, roadsides and town commons

• Map location and density

• Ensuring that all private landholdersengage in strategic prickly acacia controlactivities

• Liaising with QDNR and communitygroups to undertake strategic pricklyacacia control

• Administering and enforcing theprovisions of the Rural Land ProtectionAct, including notices

• Recognize need for resource allocationon determined priorities for prickly acaciacontrol

• Train other sections of Council on weedissues e.g. environmental health officers.

Other Government Departments inQueensland

• To assist in development of codes ofpractice and ensure uptake byDepartmental staff

• To ensure prickly acacia control isundertaken on all State managed lands.

Other State and Territory governmentagencies

• To ensure awareness and early detectionprograms are put in place

• To eradicate isolated infestations whenfound.

Federal government departments andcorporations

• Ensure quarantine controls on entry ofprickly acacia (AQIS)

• To ensure uptake by Departmental staffto restrict movement of weeds (agenciesthat manage land and travel on non-government land)

• To ensure prickly acacia control isundertaken on all Federally managedlands (Defence, EA and otherCommonwealth departments /corporations that manage land).

• Oversee and manage federal fundsincluding National Heritage Trust andNational Weed Program (EA, Agriculture,Forestry and Fisheries – Australia)

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5 ADDITIONAL READING

Anon 1998 Prickly Acacia. Pest Fact PP9. Department of Natural Resources

Kriticos D 1997 A climatic analysis of the potential distribution of Prickly Acacia in Australia.CRC for Tropical Pest Management.

Mackey AP, Barker M, Dorney W, James P, Jeffrey P, March N, Marohasy J & Panetta D1996 Prickly acacia in Queensland. Pest Status Review Series. Department of NaturalResources Queensland

Mackey AP 1998 Acacia nilotica ssp. indica (Benth.) Brenan. The Biology of AustralianWeeds, Vol. 2. (edited by Panetta FD, Groves RH and Shepherd RCH). RG and FJRichardson.

Parsons WT and Cuthbertson EG 1992 Noxious Weeds of Australia. Inkata Press,Melbourne.

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6 GLOSSARY

AQIS Australian Quarantine and Inspection Service

AGWA Agriculture Western Australia

CLIMEX A simulation modeling system developed by CSIRO

CSIRO Commonwealth Scientific and Industrial Research Organisation

EA Environment Australia

GIS Geographical Information System

ICM Integrated Catchment Management

LCMC Landcare and Catchment Management Council (Queensland)

NHT Natural Heritage Trust

NSWAg New South Wales Agriculture

NRM Natural Resource Management

NTDPIF Northern Territory Department of Primary Industries and Fisheries

NWP National Weed Program

NWSEC National Weed Strategy Executive Committee

PACL Prickly Acacia Containment Line

PAMG Prickly Acacia Management Group

PestInfo GIS based information system

PIRSA Primary Industries and Resources South Australia

QA Quality Assurance

QDNR Queensland Department of Natural Resources

QDPI Queensland Department of Primary Industries

QEPA Queensland Environmental Protection Agency

QPWS Queensland Parks and Wildlife Service

SWEEP Strategic Weed Eradication and Education Program

UQ University of Queensland

WONS Weed of National Significance

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Appendix 1 Map of the Prickly Acacia Containment Line