Distribution, Outbreak Observations and Implications for Management of Bluebell Creeper 'Billardiera heterophylla' (Lindl.) L.Cayzer and Crisp, in the Green Triangle Region of South-Eastern Australia

2010·2.5 MB·English

by  Mark, Johnson Bachmann

Contributions
Distribution, outbreakobservations and implications for
management ofBluebell Creeper Billardiera heterophylla (Lindl.)
&
L.Cayzer Crisp, in the Green Triangle region
ofsouth-eastern Australia
MarkBachmann and Randall Johnson
SouthAustralianDepartmentofEnvironmentandNaturalResources,MtGambier
Abstract
BluebellCreeperBillardieraheterophylla(Lindl.) L.Cayzer&Crisp (syn.Sollyaheterophylla),isaplantnative
tosouth-westernWesternAustralia.ElsewhereinsouthernAustralia,BluebellCreeperisahighlyinvasivespe-
ciesandisaseriousenvironmentalweedinVictoria,TasmaniaandthetemperateregionsofSouthAustralia.
Thelargestknowninfestationofthespeciesoccursinthesouth-eastofSouthAustralia;however,thisisonly
oneofseveralrecentlydiscoveredoutbreaksinthevicinityofthestateborderinthelowersouth-eastofSouth
Australiaandfarsouth-westernVictoria.Thespeciesisconsideredtobeamongthetoppriorityenvironmental
weedspecies for control in the regiongivenwhatisknown ofitsecology, in particularits fecundity, capac-
ity for disturbance-induced seed-bank regeneration and wide range ofpotential dispersalvectors. Bluebell
Creeperisassociatedwithawiderangeofplantassociationsandisalreadywellestablishedatseveraldiscrete
locationsin thelowersouth-east ofSouthAustraliaand thenear-borderzoneoffarsouth-western Victoria;
however, itscapacityfor furtherspread is immense unlessexistingoutbreaks arebrought undercontroland
simplemeasurestopreventnewincursionsareinitiated.Theknowninformationonthespeciesiscollatedand
observationsfrom a range ofinfestationswithdiffering managementhistories, rainfall and edaphic charac-
teristics aresummarised. The implications ofthespecies’ ecologyforbestpracticemanagementare alsodis-
cussed,asarefuturemanagementandresearchrecommendations. (TheVictorianNaturalist127(4)2010,137-145)
Keywords: BluebellCreeper,environmentalweed,invasive,management, ecology
Introduction
Bluebell Creeper Billardiera heterophylla West and Otways regions (DNRE 2002; Ecol-
(Lindl.) L.Cayzer & Crisp, Pittosporaceae is a ogy Australia 2006; G. Carr pers. comm.). In
shrubbyclimberwithtwininghabitanddroop- thelowersouth-eastofSouthAustraliaandad-
ing bell-shaped blue to darkblue flowers with jacent areas offar south-western Victoria, in-
mm
fivelanceolatepetalsupto 10 long(Fig. 1). festationscurrentlyareknownfrom 14discrete
Leaves are narrow-lanceolate, typicalmlymglossy locations (Fig. 3).
greenontheuppersurfaceand 16-60 long,
mm Ecology
2-22 wide,acuteandglabroustopubescent.
BluebellCreeperhaspurplish-greencylindrical Basedon currentdistributionintheGreenTri-
berries up to 20 mm long (Fig. 2). Young fruit angle and elsewhere, Bluebell Creeper appemarms
are denselyhirsute,becomingmoreorlessgla- to require annual rainfall exceeding 550
brouswithmaturity(Bennett 1986). (pers.obs.).Insouth-easternAustralia,Bluebell
Creeper appears to preferlighter (sandy) soils;
Distribution however, plants will establish in heavier soils
Bluebell Creeper (Billardiera heterophylla) is provided drainage is good (Muyt2001). While
endemic to south-western Western Australia. the majorityofsoilsassociatedwiththespecies
Owing to its invasive potential and popularity in Western Australia aresandy, soiltype is not
as a home garden plant, the species has natu- considered a majorfactor limitingdistribution
ralisedinTasmania,Victoriaandthetemperate in its natural range (A Williams pers. comm.).
regions ofSouthAustralia. Bluebell Creeperis reported to tolerate atleast
In South Australia, naturalised Bluebell moderatefrost(ASGAP2006).
CreeperhasbeenrecordedfortheMountLofty In Victoria, Bluebell Creeper is known to in-
Ranges/Fleurieu Peninsula, Kangaroo Island vade heathlandand heathywoodland, lowland
andsouth-eastregions (DEH2006a). InVicto- grassland and grassy woodland, and dry scle-
ria, Bluebell Creeper has been recorded in the rophyll forest andwoodland (Carretal. 1992).
greater Melbourne, Eastern, Gippsland, South In the south-east of South Australia, Bluebell
Vol 127 (4) 2010 137
Contributions
Fig.2.CylindricalberriesofBluebell CreeperBillar-
dieraheterophylla
InWesternAustralia,seedsofthecloselyrelated
Billardierafusiformis are known to be dispersed
bythe followingsmall mammals: Bush RatsRat-
tusfuscipes, Gilberts Potoroos Potorous gilbertii
and Quokkas Setonix brachyurus (Cochrane et
Fliagr.die1r.aBheetlelr-osphhaypleldaflowers ofBluebell CreeperBil- al. 2006). Cochrane et al. (2006) also found that
ingestion by mammals assisted in germination
Creeperis associated with the followingbroad offresh seeds, and germination was greater and
plantcommunities:
more rapid in seeds collected from scats than in
•Eucalyptus arenacea/E. baxteri +/- Pteridium freshlycollected seed. Given the similarityofthe
esculentumwoodland;
• Eucalyptusdiversifolia openmallee; sapneaclioegsocuosncmeercnheadn,iistmisswomratyhbceonastipdlearyinwgitwhheBtlhueer-
•Allocasuarinaverticillatalowwoodland; bell Creeper, and certainly supports the notion
• Eucalyptusfasciculosalowwoodland; thatsmallmammalsarelikelytobeanimportant
•Acacialongifoliavar. sophorae+/-Leucopogon seed-dispersalvectorforthespecies.
parviflorustallshrubland; InVictoriancoastalwoodlands, thousandsof
•Melaleucasquarrosatallshrubland;and, seedlingsofBluebellCreeperemergefollowing
•Eucalyptusovata, E. viminalisssp. cygnetensis firesorsoildisturbanceamongstdenseinfesta-
woodland.
tionsofthespecies (Muyt2001).Thisresponse
Seed often is spread bybirds and other animals, has been observed in Rennick State Forest in
or in dumped garden refuse. Dumping may also south-westernVictoriafollowingfire, asshown
spread the plantvegetatively. SilvereyesZosterops in Fig. 4 (pers. obs.). The same fire response
lateralis, Red Wattlebirds Anthochaera caruncu- in Bluebell Creeper also has been observed in
lata,SingingHoneyeatersLichenostomusvirescens Western Australia (A Williams pers. comm.),
faongdulSarpiisnyar-echkeneokwednHtoonteaykeeaftreuirtssAocfaBniltlhaargdeienryassrpup.- wlahteerdeBiitllhaarsdibereaenfuosbisfoerrmviesd (inCotchheraclnoeseleyt rael-.
(Forde 1986). Seed ofBluebell Creeper also has 2006). Seedtrialsforthisspeciesdemonstrated
beenrecordedfromthescatsofKangaroosMacro- thatB.fusiformisgerminationwassignificantly
pus spp., Brushtail Possum Trichosorus vulpecula enhancedbysmoketreatment(tosimulatefire)
andFox Vulpesvulpes(AWilliamspers. comm.). and aging. In untreated seed fresh from the
Other suspected vectors include large scincoid plant 0% germination was obtained, whereas
lizards Tiliqua spp., Southern Brown Bandicoots around 90% germination was obtained from
IsoodonobesulusandSwampRatsRattuslutreolus seed that was aged for over 15 months and
(AWilliamspers.comm.;pers.obs.). smoketreated(Cochraneetal. 2006).
138 TheVictorian Naturalist
Contributions
Fig.3BillardieraheterophylladistributionintheGreenTriangleregion.
1.TantanoolaForest-MileHillRoadarea(SA). 2.MtBurrRange-BurrSlopesSouthNativeForestReserve
(SA).3.Glencoearea-KalangadooRoadReserve(SA).4.CanundaFrontageRoadReserve-westofMillicent
(SA).5.GillapSouthandKennionNativeForestReserves(SA).6.WooleyLake,BeachportConservationPark
(SA).7.Beachport(SA).8.CullenReserve,Robe(SA).9.ReedyCreek(SA).10.Nelson(Vic). 11.PrincessMar-
garetRoseCave,LowerGlenelgNationalPark(Vic). 12.RennickStateForest,northernend(Vic). 13.Rennick
State Forest, PrincesHighwaysite (Vic). 14. Privatepropertyadjacenttoeastern boundary ofRennickState
Forest(Vic). 15.NaracoorteSouthParklands(SA). 16.CaveRange,nearNaracoorte(SA).
Vol 127 (4) 2010 139
Contributions
Fig.4.RegenerationofBluebellCreeperBillardieraheterophyllaafterfire
Mature plants ofBluebell Creeper are able to Bluebell Creeper is not proclaimed under the
regeneraterapidlyfrombasalstemsfollowinga South Australian Natural Resource Management
spring fire as observed at Glencoe Hill Native Act2004. Likewise,thespecies isnotproclaimed
ForestReserve,SA,2006;however,itis unclear underanyofthe fourcategories in theVictorian
whether mature plants are capable ofregener- CatchmentandLandProtectionAct1994.Assuch,
ating consistently from basal stems following Bluebell Creeper is not prohibited from sale and
summeror autumnfires, andthisrequiresfur- continues to be freely available in both South
ther investigation. Initial observations at the AustraliaandVictoria.Despitethislackofformal
RennickStateForestsite,previouslyreferredto, recognition,arecentweedriskassessmentprocess
appearto indicateahighlevelofadult mortal- forthe SouthEastofSouthAustraliadetermined
ityfromhigherintensityfireduringautumn. BluebellCreeperasamongthehighestweedrisks
forboththeenvironment and the plantation for-
BSltuaetbueslalnCdreaevpaeirlarbeimliatiynsahighlypopularhome estry industry (Anderson et al. 2005). More re-
gardenplantandhasbeencommerciallyavaila- cheenttelryo,phaylhlyabrxipdarfvoifrlmoroaf)BhlausebbeelelnCdreeveepleopred(S,olalnyda
bleinAustraliaandinternationallyforatleasta isknown as Edna WallingBlue Bells. Ithas been
hundredyears. Forexample,Sollya(Billardiera)
bred to keep the original qualities ofthe parent
heterophyllawasavailableforsaleinCinchona, stock,butitisclaimedtobeasterilehybridselec-
cJiatmeadician,Gaosoedarllaynadsa1n88d7H(eJaalmeayic1a99B6u)l.leAtinre1c8e9n2t tsioocniattoedavwoiitdhtohneeeonfviitrsopnamreennttsa,lBwielleadrdiimerpaachtetseraos--
survey ofnurseries and plant suppliers in the
phylla(Austraflora2010).
South EastofSouth Australiafoundthat Blue-
bell Creeper was being sold at nine out of24 OutbreakObservations
supplierssurveyed (DEH2006b). Characteristics observed at the outbreaks in
this region appear to displayan interesting in-
140 TheVictorianNaturalist
Contributions
teraction between time, management history ductive individuals in a population, the back-
andhabitat.Asaresultofthesefactors,theredo ground level ofrecruitment (in the absence of
appearto besome broadlyconsistentoutbreak a high-level disturbance event) is still enough
‘types’thataresuggestedanddescribedinmore eventually to result in a low densitypattern of
detail below; however, it is important to note invasion across relatively large areas ofnative
that it is possible to have two outbreak ‘types’ vegetation, or indeed neighbouring plantation
within one infestation if they have not been forest. As aresult ofthese characteristics, rem-
subjectedtouniformmanagement. Thisoccurs nant native vegetation can appear to retain its
typically where an infestation crosses forestry overallstructuralintegrityandspeciesdiversity
compartmentsorlandtenureboundaries. in the presence ofBluebell Creeper; however,
the fecundity ofthe species means that, in the
1. Mature and apparently ‘stable' - ‘sleeper case of sleeper outbreaks, the live specimens
outbreaks'
represent only the ‘tip ofthe iceberg’ in terms
Sleeper outbreaks occur atsiteswhere Bluebell ofBluebell Creeper density and extent should
Creeper obviously has been present at the site thepotentialofthe seedbankberealised.
for manyyears, butwherethere is no evidence
ofasignificantdisturbanceevent(e.g.fire) dur- 2. Matureandaggressive- \activeoutbreaks'
ing most ofthe time that the species has been Active outbreaks are where the potential ofthe
present. In these conditions, Bluebell Creeper BluebellCreeper seedbankatalong-established
appears somewhat ‘stable’, with large to me- infestation has been manifested. In the most
dium sizedbushy orclimbing shrubs scattered seriouslyaffected sites in this category, Bluebell
across the site ata relativelylowdensity. These Creeper can reach >80% projected cover in the
mature bushes are capable ofproducing mas- understorey; e.g. Windy Hill Native Forest Re-
sive quantities ofseed that, for the most part, serve, south-east SA (see figure on p. 136). At
appear to lie dormant, hence the term ‘sleeper such sites, Bluebell Creeper appears to impact
outbreak’. This seed naturally accumulates in severely on the structural integrity and rich-
higher quantities beneath the leaffall zone of nessoftheunderstoreyinotherwiseintactrem-
each bush; however, a significant number of nantsofnativevegetation.Hence,itappearsthat
seeds also are being transported more widely a single disturbance event such as fire, has the
after faunal species (birds and mammals) have immediate potential to turn a sleeper outbreak
eaten,digestedandexpelledthefruitsandseed. into an active outbreak. A recent example of
These digested (i.e. ‘treated’) seeds may then this has occurred at the Rennick State Forest-
haveagreaterprobabilityofgerminationinthe Princes Highway site, where a prescribed burn
absence ofdisturbance thanthe seed that sim- in Autumn 2003 resulted in the mass germina-
plyfallsfrom thebush(Cochraneetal. 2006). tion of tens of thousands of Bluebell Creeper
The best examples ofthis outbreak type are seedlings over approximately 10 ha ofremnant
in the Naracoorte South Parklands, some na- vegetation.Althoughtheexactnatureofthespe-
tive vegetation c—ompartments within the Tan- ciesatthesitewas not documentedpriorto the
tanoola Forest Mile Hill Road area, and burn to enable a direct comparison, it is inter-
remnant vegetation ofLower Glenelg National esting to note that the pattern ofinfestation in
Parkwithinthevicinityofthe PrincessMarga- anadjacentunburnedcompartmentshowedthe
retRoseCave.Atthelattersite,thelastwildfire typical characteristics ofa sleeper outbreak, as
passed through in 1979, but the current pat- previouslydescribed, with ahandful ofmature,
ternofinvasioninnativevegetationisthatofa heavily fruiting individuals and little or no ap-
sleeperoutbreak. Giventhelonghistoryofgar- parent seedling recruitment. In support ofthis
den style plantings in the vicinity ofthe cave, recentobservationisthefactthatthemostheav-
it is highly likely that the species was present ilyinfestedremnantvegetationcompartmentsin
priorto the fire, but mayhavebeen in anearly theTantanoolaForest-MileHillRoadarea,have
—
stage ofinvasion prior to the establishment a prescribed burning fire management history
ofamoresubstantialseedbank.Hence,ineach thataccounts for, andcloselycorresponds with,
ofthese cases, it is likelythat Bluebell Creeper theirhighlyinfestedcondition.
has been present for decades. Significantly, The other means by which sleeper outbreaks
thesesitesillustratethatgivenenoughtimeand appearto be ‘activated’, althoughperhaps notto
with a large enough number ofmature repro- the same extent as with fire, is through the soil
Vol 127 (4) 2010 141
Contributions
disturbance and additional light penetration Itisalsoimportanttoconsiderthattheremay
associated with plantation forestry operations. be habitats thatare lesssuitablefor thespecies,
It appears that Pinus radiata plantation, adja- where Bluebell Creeper may not establish and
centto LowerGlenelgNational Parkat Princess spread as readily. Possibly fitting this category,
Margaret Rose Cave,while being harvestedand the site at Beachport is unusual in that it is
prepared for replanting, inadvertently stimu- the only known outbreak in a highly exposed
lated the seed bank ofBluebell Creeper. At this coastal dune environment. This site consists of
site,ahighdensityofplantsborderstheedgesof onlyahandfulofindividualsand, interestingly,
tracksthroughthereplantedpines,progressively this appears to be the only location where the
becoming less common with distance from the white-flowered form of Bluebell Creeper has
Cave area; however, scattered plants were still naturalised in the region. Cullen Reserve, at
found over 2 km away. Mechanical disturbance Robe, is another example where a handful of
also appears to have contributed to mass ger- plants have been identified in a patch ofrem-
mination ofthe species at Eagle Quarry in the nant coastal native vegetation immediately in-
Mt LoftyRanges (SA), a site outside the region, land oftheduneenvironment.
resultingfromsiterehabilitationworks(incom- It is important to note, however, that irre-
bination with the presumed use offill contami- spective oftheir location and habitat type, all
natedwithBluebellCreeperseed) (pers.obs.). emerging outbreaks should be treated with
Through the dramatic increase in the number equal priority for eradication, given the mini-
ofindividual plantsina population inarelatively mal resources required for control at this early
shortperiodoftimeafterdisturbance, activeout- stage, and the scale (and future cost) of the
breaksveryquicklyareabletoreachapointwhere problempotentiallybeingprevented.
thescaleoftheinfestationhasthecapacitytoesca-
lateexponentially. Oncethe recruited individuals LikelyOutbreakSources
become reproductiveandcapableofcontributing Given that outbreaks usuallybegin from asin-
toanewseedbank,whichcantakeaslittleasthree glepointsource,it is importanttoconsiderthe
years,thisalarmingprocessisunderway. means bywhich this is likelyto have occurred
in the past. The importance ofthese observa-
3. EarlyPointSource- EmergingOutbreaks’ tions for improving understanding ofhow to
Emerging outbreaks are either one or a hand- best prevent new outbreaks from occurring in
ful ofindividual plants occurring at a site that thefuturecannotbeunderestimated.
isgeographicallyisolatedfromotherknownin- After being sold to the public in nurseries, it
festations.Anemergingoutbreakisessentiallya appears there are two likelyprimary means by
veryearlysleeperoutbreak,butdifferent in that which Bluebell Creeper has, and can continue
it consists ofso few individuals that they have tobecome,established innativevegetation.
not yet been established long enough to have
created a seed bank capable ofthe scale ofre- (a) Deliberateplanting inproximity to native
sponseobservedin triggeringactiveoutbreaks. vegetation
Allknowninfestationsmusthavestartedfrom 1. Princess Margaret Rose Cave: There is evi-
asingle pointsource,atwhichtimetheywould dence from other plantings at the caves to
have fitted this definition ofan emerging out- suggest that Bluebell Creeper was deliber-
break. Left untreated in the right habitat, soil ately planted manyyears ago in the gardens
type and rainfall zone, an emerging outbreak and/or bush in the immediatevicinityofthe
will become a sleeper or active outbreak at cave,whichhasbeenopentothepublicsince
somefuturepoint. Fallingintothiscategoryare the 1930s.
the outbreaks at Cave Range near Naracoorte, 2. Nelson: BluebellCreeperhasbeenseengrow-
consisting of a handful of scattered medium ingingardenswithinthetownshipofNelson,
sized plants, and a single medium sized bush andisnowfoundinbushlandwithinandad-
found on the northern boundary of Rennick jacent to the town, including Lower Glenelg
State Forest. In each case, apparently suitable NationalParkandNelsonStateForest.
habitat occurs in the vicinity, and other more 3. Naracoorte: Bluebell Creeperwas identified
severe outbreaks occur within 10 km, indicat- growing in a works depot adjacent to the
ing that, left untreated, in timethe scale ofthe Parkland.Therearealsoseveralotherhouses
problemwouldmorethanlikelyescalate. andproperties thatbackontothisreserve.
142 TheVictorianNaturalist
Contributions
(b)Dumpinggardenwaste-legalandillegal ManagementImplicationsandRecommen-
1.Rennick State Forest - Highway site: Both dations
sidesofoneofthetracksatthissiteislittered 1. Mature and apparently ‘stable’ - *sleeper
with a significant amount of hard rubbish outbreaks’
and several species oftypical garden weeds Sleeper outbreaks, particularly those that are
that are found in dumped garden waste in relatively restricted in size, provide land man-
bushland, confirming its history of abuse agers with a uniqueopportunityfor the physi-
and the likely source ofthe introduction of cal removal oftheextremelyfecund (andoften
BluebellCreeper. highlyvisible) mature individuals fromthesite
2. Private property adjacent to Rennick State withoutthefearofanuncontrollableseedbank
Forest:Thispropertyshowssignsofpastpri- response. These mature individuals maybe ei-
vate hard rubbish clumping, and the owner ther sprayed with glyphosate and a penetrant,
has confirmedthat it is quite likelythatgar- or cutatthebase and thestump swabbed with
denwastealsomayhavebeendumpedprevi- herbicide, while any seedlings can be hand-
ouslyatthesite. pulled. Ifcompleted successfully, no new seed
3.Nelson: The town rubbish dump still oper- will then be contributedto the seed bank, and
ates on the doorstep ofLower Glenelg Na- the residual rate ofgermination in the absence
tional Park, and is surrounded bybushland. ofdisturbance can be managed with lower in-
Many species of weeds can be seen prolif- tensity human resources over several years, to
erating at the site from previously dumped prevent any seedlings from reaching repro-
garden waste,anditis probable thatthissite ductive age. As our knowledge of seed bank
mayhave contributedto the outbreakatthe ecology for the species improves, additional
town. management options may also emerge, as will
4.Tantanoola Forest-Mile Hill Road area: The amoredetailedunderstandingofhowlongon-
old Glencoe dump site on Mile Hill Road is goingmanagement ofthe sitemaybe required
the most likely point source ofthis infesta- toachieveeradication.
tion, whichatover 1000hectares,isthelarg- Fire as a management tool at sleeper out-
est known outbreak of Bluebell Creeper in breaks should be actively discouraged in light
south-easternAustralia. ofcurrentobservationsandthepresent under-
An additional secondary form ofspread that standing ofthe species’ ecology, as it is clearly
potentially could result in new outbreaks is fire responsive. In all but the smallest sleeper
now also possible given the establishment ofa outbreaks, firehas the potential to escalate the
handful oflargenaturalised populations ofthe labour requirements quickly post-fire beyond
the capacity of the land manager. In such a
speciesintheregion.
(c)Machineryorvehiclespread case, where the appropriate resources are not
Burr Slopes SouthNative Forest Reserve: This deployed post-fire, the outbreak population
outlier outbreak is most likely explained by will have significantly increased in numbers,
a chance dispersal to the reserve of Bluebell and hence is likely to become more active and
Creeper on heavy machinery (e.g. grader or aggressive within a matter ofyears. With our
slasher) usedininfestedforestinthemainTan- currentknowledge, theuse offireis, therefore,
tanoolaForestoutbreakseveralkilometresfur- a management risk not worth taking unless
fullypreparedforthepotentialconsequences.
thertothesouth.
In addition to these potential causes ofpast 2.Matureandaggressive- ‘activeoutbreaks’
andfutureoutbreaks,theexpansionofexisting Managementstyleofan activeoutbreakdepends
outbreaks is facilitated by means ofbiological on scale. For a relatively small active outbreak
vectors, such as birds and mammals. It is as- (suchasatRennickStateForest-PrincesHighway
sumedthatthemajorityofsuchdispersalevents site),theremaybe anopportunitytoremove any
will occurwithin close proximitytothesource remainingmatureplantsandcommenceintensive
material; however, the possibility of chance management before the new generation of fire
long-distance biological dispersal events can- respondent recruits is reproductive. In this case,
not be ruled out and may warrant further in- physical management of plants through hand-
vestigation. pulling, or herbicide spraying with a backpack
maybefeasibleforverydenseareasofseedlings.
Vol 127 (4) 2010 143
Contributions
For active outbreaks that are beyond these c. Machinery/Vehicle Hygiene - particularly
site scale control measures, such as where the machinery such as slashers or graders that
outbreak overlaps compartment boundaries or activelydisturbthesoilorvegetation, should
property tenures, the development of a plan be thoroughly washed down before leaving
initially to contain and prevent further spread an area known to be infested with Bluebell
oftheoutbreakisrecommended. Theemphasis Creeper.
for managers of sleeper and active outbreaks
should beto ensurethaton-groundactions are These three simple preventative measures
aimed at doing everything possible to prevent would dramatically reduce the risk ofnew in-
the outbreakfrom reachinga scale where con- cursions of Bluebell Creeper, as well as many
tainmentbecomes the onlyshort-term feasible other environmentally serious garden escapes,
management option. andallowformanagementeffortstobefocused
ontheearlydetectionandmanagementofsites
3. Earlypointsource- 4emergingoutbreaks' wherethespeciescanreadilybebroughtunder
Emerging outbreaks provide the best oppor- control.
tunity to activate targeted management to SummaryofManagementRecommendations:
elervaedlicbauttesBulsuteabienleldCrreeseopuercrefsraonmdavisigtiel,awnciet,hplroew- 1. Do not burn a bluebell creeper infestation
vheonwteivnegr,theemsepregciinesgforuotbmrreeaaklsisminagdietsuppoteonftifaelw; hunilgehsscossctalceonissevqeureynscmeasl;landbepreparedfor
individualsarebytheirnatureinitiallyverydif- 2. Vigilance in early detection ofemerging or
ficulttodetect. Landmanagers needtobevigi- sleeper outbreaks in south-eastern Australia
lant in ensuring that staff and volunteers are is critical to preventing a broader scale im-
awareof, andreadilyableto identify, thisweed pactbythisspecies;
toensurethatemergingoutbreakscan be iden- 3. Immediate action is required to treatemerg-
tifiedpromptlyandgiventhehighestpriorityin ing outbreaks, dueto the feasibilityoferadi-
workprogramsforimmediatecontrol. cation andtheabilitytopreventescalationin
thescaleoftheoutbreak;
Pre-emptivemeasures 4. Prevention is the first, most basic step re-
Inadditiontoplanningfordealingwithknown quired in planning the control ofemerging
oranticipatednewoutbreaksofBluebellCreep- weeds, hence the following examples ofpre-
er, preventative steps also can be taken to re- ventativeactions are essential:
ducethe riskofnewincursions everbecoming a. Prohibition from saleinnurseries;
establishedinthefirstplace. Forexample: b. Closingrubbishdumpslocatedinsen-
a. Prevention of sale in nurseries - the sim- sitivebushland areas;
plestwaytoreducetheriskofnewoutbreaks c. Bettermachineryhygiene.
inunexpectedlocalitiesistoprohibitthesale ResearchRecommendations
ofhighriskspeciesinnurseries.Government
In addition to utilising the most recent scien-
authoritiesresponsibleforweedmanagement
iVnicmtoarniay,stnaeteesd,itnoclbuedimnogrSeouptrhoaAcutsitvrealiinaathnids tiinfimcaannadgianngecBdlouteable/lolbsCerreveapteiro,naslucihnfaosrmisatoiuotn-
most basic but essential preventative meas- lined in this paper, land managers will require
additional help in developing future manage-
wuriet.hItmhpeorkteayntrleyc,omthmiesnadpaptriooancshoifstchoensSiesntaetnet ment strategies. This is particularly relevant to
enquiryintoinvasivespecies (CofA2004). thoseresponsibleformanagingthelargestscale
ofactive and sleeper outbreaks where manual
b. Closing of unmanaged rubbish dumps - control is now out ofthe question. Some key
particularly those in the immediate vicin-
research questions that have emerged during
ityofremnant native vegetation, as manyin
the region tend to be. The dump at Nelson thecourseofthe authors’investigationinto the
ecologyofBluebell Creeperoutbreaksinclude:
in Victoria, or Canunda in South Australia,
providestandoutexampleswheretwohighly 1. Seedviabilitythrough time
incompatible land uses lie adjacent to one Atsleeper sites where it is possible toeradicate
another, when these dumps are located on the reproductive generation of plants manu-
theboundariesoficonicNationalParks. ally,itisessentialtoknowwhat therateofseed
144 TheVictorian Naturalist
Contributions
bank deterioration is. In this way, managers It should be noted that before work on
could make an informed decision about issues biological control agents is likely to receive
suchas: government grant funding, governments of
• the number of years that ongoing manual south-eastern Australia would need to have
removal ofseedlings is required, and hence proclaimed Bluebell Creeperas aweed species
theongoingworkprogrammingandresource undereachstates relevantlegislation.
implicationsofmanagingoutbreaks;
Acknowledgements
• whether there are a critical number ofyears
aftertheremovalofreproductiveplantswhen TAuhsetraaultihaonrsDetphaarntkmeDnatrrfeonr HEenrvpiircohnmfernotmatnhdeHSeoruitth-
fire exclusion is essential but, after which, age for map production, as well as Anna Williams,
the viability ofpersisting seed drops below a GeoffCarrandRobinAdairforsharingtheirknowl-
thresholdsothat,potentially, firecan be used edgeofthespecies.
as a part ofan eradication strategy- without
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theprohibitivelyhigh costcaused byburning Austraflora(2010)SollyaEdnaWallingBlueBells.(Accessed
earlier, and; online at: httpL//www.austraflora.com/plants_html/ew_
• t(ih.ee.fsoeremdulabtainokn)oefraadirecaaltiisotnic otfargtehtefsorpetcriuees AncRdioeslrklseoAcstnsieoNsn,s/meDewrn_teb:lwuAeJbaewnleldesd_Vmiarritisnuke.haJtsm(s2oe0sn0s5m1)e7n/St3o/u2otf0h1a0Eg)raisctulWteureadl
fromasite. andenvironmentalweedspeciesin theSouthEastofSouth
Australia.(ReporttotheSouthEastNaturalResourceCon-
2. Fireandseason sultativeCommittee)
It is likely that in spite of the recommenda- AsGsoAcPi)ati(o2n00o6f)S.ocSioeltliyeasfhoerteGrropohwyilnlag.Au(sAtcrcaelsisaendPloannltisne(ASat-:
tions in the paper, fire will continue to inter- http://asgap.org.au/shet.htmlon17/3/2010)
act with Bluebell Creeper populations. While Bennett EM (1986) Pittospor—aceae. In Flora ofSouth Aus-
the occurrence ofwildfire is unpredictable, it atrnadliaH,PTaoretlk1eLny.c(oSpooudtihacAeuasetralRioasnaGcoeaveerpn.m4e3n6.t,EdAsdeJlJaeisdseo)p
is important fromamanagementpointofview CatchmentandLandProtectionAct1994(VictorianGovern-
thatits effecton BluebellCreeperoutbreaksbe CamrernGtW),YugovicJVandRobinsonKE(1992)Environmen-
anticipated and planned for. In this way, any tal WeedInvasionsin Victoria. ConservationandManage-
prescribed burns that are planned for areas of mentImplications(DepartmentofConservationandEnvi-
known infestation must be capitalised upon in Cormomnmoennwte/aEclotlhogoifcaAlusHtorratliicau(ltCuorefAP)ty(L2t0d0,4M)eRlebpoourrtneo)nthe
termsoftheopportunitytheyprovide to better regulation, control and management ofinvasive species
understandtheinteractionbetweenfireandthe andtheEnvironmentProtectionandBiodiversityConser-
species, and allow for comparison ofdifferent viaantiGoonvAemrnemnednmte:nCtan(bIenrvarsai)veSpecies)Bill2002. (Austral-
firetreatments,such asintensityandseason. CochraneA,FriendT and HillS (2006) Small mammals as
seeddispersers.AustralianPlantConservation15(2),19-21.
3. Biologicalcontrol DepartmentforEnvironmentandHeritage(2006a) Records
As a Western Australian endemic species re- otrfe)t.he(ESxoturtahctAeudstDreaclieamnbHeerr2b0a0r6i)um(PlantBiodiversityCen-
strictedtothesouth-westofthatstate, Bluebell DepartmentforEnvironmentandHeritage(DEH)(2006b)A
Creeperispotentiallysubjectto,andlimitedby, surveyoftheavailabilityofcertainenvironmentalweedspe-
biological agents (e.g. insects, pathogens) not cDiEesH,inMstouGtahm-beaisetre,rnSoSuotuhthAuAsutsrtarlailai)a. (Unpublished Data,
present across the Nullarbor in the naturalised DepartmentofNatural Resources andEnvironment(2002)
weedy populations ofsouth-eastern Australia. CoastalNotes:BluebellCreeper.(StateofVictoria)
Early work (R Adair and A Williams pers. EcPorlootgeyctAiuosntPrlaalni:aO(v2e00r6v)ieFwarofSEonuvtihroWnemsetntFoarlesWtesedBsio.d(ivReerpsoirtty
comm.) indicates that there are some insect toDepartmentofSustainabilityandEnvironment)
species worth further investigation, although Forde N (1986) Relationships between birds and fruits in
temperate Australia. In The Dynamic Partnership: Birds
theprocess (ifstarted) willbenecessarily slow, andPlants in Southern Australia, pp. 42-58. Eds H Ford
hence this is a longer term option and strate- andDPaton.(SouthAustralianGovernment:Adelaide)
gy. This is because in addition to the work re- GoodlandTandHealeyJR(1996) TheinvasionofJamaican
rainforestsbytheAustralian treePittosporum undulatum.
quired to assess suitability ofpotential control (SchoolofAgriculturalandForestSciences,Universityof
on Bluebell Creeper, any insectsidentified also Wales,Bangor,UK)
would have to be tested thoroughly to ensure Muyt A (2001) Bush Invaders of South-east Australia.
(McPhersonsPrintingGroup:Maryborough,Victoria)
thattheyposeno riskto anycloselyrelatedin- NaturalResourceManagementAct2004(SouthAustralia)
digenous species such as Native Apple-berries
(Billardieraspp.). Received26November2009;accepted8April2010
Vol 127 (4) 2010 145