Starry Stonewort: A Primer on an Aggressive, Invasive Species · Starry Stonewort: A Primer on an...
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Starry Stonewort: A Primer on an Aggressive, Invasive Species • An ancient plant like macro alga which forms large, dense mats. It grows in water from 0.5>10m in depth. Depth of the mats can be 3m. • Mats can be so dense they impede boating or paddling. At the peak of the growing season, late July to late September, they appear like hill-like mounds under the surface of the water. • It is anchored by clear filaments which produce small, white, star shaped bulbils. The bulbils are reproductive structures and organs for hibernation. It is the bulbils which make this alga so difficult to eradicate. • All starry stonewort in N. America is male. This means it is spread by fragmentation and the dispersal of the bulbils.
Transcript of Starry Stonewort: A Primer on an Aggressive, Invasive Species · Starry Stonewort: A Primer on an...
StarryStonewort:APrimeronanAggressive,InvasiveSpecies
• Anancientplantlikemacroalga whichformslarge,densemats.Itgrowsinwaterfrom0.5>10mindepth.Depthofthematscanbe3m.• Matscanbesodensetheyimpedeboatingorpaddling.Atthepeakofthegrowingseason,lateJulytolateSeptember,theyappearlikehill-likemoundsunderthesurfaceofthewater.• Itisanchoredbyclearfilamentswhichproducesmall,white,starshapedbulbils.Thebulbilsarereproductivestructuresandorgansforhibernation.Itisthebulbilswhichmakethisalgasodifficulttoeradicate.• AllstarrystonewortinN.Americaismale.Thismeansitisspreadbyfragmentationandthedispersalofthebulbils.
IdentifyingCharacteristics
• Thebranchletsandstemareverythin (likeheavyfishing line)andhaveacrisptexture.
• Whorls oflong,narrowbranchletsingroupsof4to6comingoffofmainshoots.
• Orangereproductivestructures(male) occuratbranchletnodes.
• Thebranchesareanchoredtothesediment byaclearfilamentwhichproducesmall,white,starshapedbulbils.
• Thesmall,white,star-shapedbulbilsarethedistinguishingfeaturethatgivesitthenamestarrystonewort.
DenseMat
Thelongstemsandbranchletsbecomeentwinedtoformdensemats.
Hill-likemoundscoveringasectionoftheLostChannelonStoneyLake,Sept.2018
IntroductionandSpreadinInvasiveRange
• Nativerange:NorthernEurasian– fromSpaintoJapan.Nativerangehasexpandedwithclimatechange• IntroducedintoNorthAmericathroughtheSt.LawrenceRiver,1974.• Michigan– nowin27bodiesofwater• NewYorkState -14bodiesofwater• Minnestota – confirmedin13lakes• AlsoinPennsylvania,Indiana,andOhio(LakeErie)• 2016– officiallyconfirmedinPresqu’ile Bay,LakeOntario– firstnoteddateinAmericanpublications/websites
KawarthaInfestation
• Officialreports:LakeScugog,LakeSimcoe,LakeCouchiching• Anemail(Sept.2018)fromDr.EricSager,fromTrentUniversitystated:• “Ithinkwedon’tfullyappreciatehowextensivethegrowthofstarrystonewortisthroughouttheKawarthas.We’veseenitinUpperandLowerBuckhorn,TrentRiver,Pigeon,Chemong ...Justaboutanywherewelook.
• SevernRiver/TrentCanal,justpassedLock42toSparrowLake – sawitlastweek
SoitisnosurprisethatstarrystonewortisonSton(e)yLake
• Sofarstarrystoneworthasbeenidentifiedinonly2areasonStoneyLake• IntheareabetweenFairyLakeIslandandthemainlandknownastheLostChannel– andthebaysoneitherend.• ThebayclosesttoSt.Peter’scontainsonecottage• ThebayclosesttoBurleighcontains3cottages,andadockforanislandcottage• Noneofthesecottagescanavoidboatingthroughittogettotheirdocks.Twoarewateraccessonly
• OnWednesdayIdidsomesamplinginanadjacentbayandfoundstarrystonewortthereaswell.
• ThesecondandmoreconcerningareaisGilchristBay– specificallythebayscontainingLittle’sMarina,PineVistaResort,andWildfireGolf. FromthemapputoutbyASLCacoupleyearsagothereareabout8affectedcottages.Themarinawithitsbusyboattrafficisbyfarthebiggestconcernasasourceforfurtherinfestations.
PotentialImpact• Starrystonewortcanspreadataratethatisbothimpressiveandalarming
• Potentiallywecouldbedealingwiththisinmoreandmoreareas.• Whatdoesthismean tothelakeenvironment?
• Reducedbiodiversity – starrystonewortcanoutcompetenativespecies. Italsooutcompetesotherinvasives suchasEurasianwatermilfoil.Itdoesthisbymakingitdifficultforotherplantstoreceivelight.Aswell,themassofstarrystonewortactsasabenthicbarrieraccumulatingphytotoxinsthatmakethesediment inhospitable forotherplantgrowth.
• NostudiesthatIcanfindhavequantifiedthechangeinbiodiversitybutthereisalotofanecdotalsupportforthis.Fromwhatwe’veseenourselves, sections ofthechannelwhichwerefullofamultitudeofaquaticvegetationarenowexclusivelystarrystonewort.ThebaybehindWildfireisalso now largely starrystonewortaswell. This isaresearchgapthatresearchers,particularlyintheUS,arenowtryingtoclose.
• Candegradefishspawninghabitatandcanimpedefishmovement.• ThismaybeespeciallytrueforsunfishandbassthatspawnindensenativeChara.(USgeologicalsurvey,Nonindigenous aquaticspecies database2019)WWW.nas.er.usgs.gov
• Matswhichreachthesurfacemeanthatfishareblockedfrompassingthroughanarea• Adecline infishcouldmeanadecline inbirdsandmammalsthateatthem.Ourloons,herons,ospreyand minkareatrisk. AhabitatfullofSSwillalsobedifficultforturtles.
Impactforcottagersandrecreationallakeusers
• Starrystonewortcoveringyourshoreline,dockandswimmingareasisanightmare.Remember,thiswillhappilygrowinwateruptoapprox.10m,(30ft) deepandwillformdensematsthatare3m (9ft) thick.• Mostdocksareinmuchshallowerwaterwhichmeansswimmingandboatingwillbeaproblem.Atdocksinwaterlessthan9ftdeepitmaybeadensematrighttothesurface.Enjoymentofyourwaterfrontwillbelimited.Thisiswhat’shappeninginareasofLakeScugog.• Fragmentation byboats andfurtherspreading willbehardtoavoid.• SSWatyourdockwill also likelyaffectyourpropertyvalue.
Eradicatingthisfromthelakeisnotanoption.
• Starrystoneworthasnotbeensuccessfullyeradicatedanywhere. ReportsputoutbyvariousStatesandacademicresearchersallreachthesameconclusion.ONCEESTABLISHEDSTARRYSTONEWORTISHERETOSTAY• Harvesting – ofvariousforms willreducethematsbutitwillgrowback.
• Withanymechanicalmethodsthereisalsotheriskofspreadingfragmentsorbulbils.
• Herbicides/algacides reducedthevolumebutagainitistemporary.• Thebulbilsinthesedimentremainviableandwillquicklyre-sprout.• Anotherproblemwithbothmechanicalorchemicaltreatmentisthattheyarenonselective.Theyalsoimpactnativeaquaticspeciesaswell.ThismeansreducedcompetitionfortheSSwhenitbeginstoregrowandthelossofhabitatforotherorganismandfish.
Management• TheconclusionofastudyofvariouscontrolmethodscarriedoutbytheMinnesotaAquaticInvasiveSpeciesResearchCenterwasthat:
• “Wherelargeinfestationshaveestablished,starrystonewortislikelytopersistfortheforeseeablefutureandrealistic,sustainablegoalsshouldbepursued.
• Thosegoalsarereducingabundanceandminimizingriskofspread.
Sowhatcanwedo?
• Weneedtoeitherformagrouporworkwithanexistinggrouptoprepareanorganizedlakecommunityresponse.Thiswouldinvolvethingslikefundraising,communications,lobbyingvariousgovernmentsandagencies,andvolunteerrecruitment,etc.• Wecanlearnfromwhathasbeendoneinvariousstatesthathavebeendealingwiththisforsometime.Minnesota,Vermont,andNewYorkareparticularlygoodatinvolvingtheircitizensinhelpingtoslowthespreadofstarrystonewort.
Actionstoslowthespread:
• Createanawareness/educationplansopeopleonthelake• knowwhatthisis• whereitis,• howtominimizetheriskofspreadingit• Thiswouldincludeappropriatesignagewhichwe’vestartedworkingon.• ItshouldalsoincludeencouragementforpeopletoleavenativeaquaticplantsinplacesoSShascompetition.Discouragelargescale“weed”harvesting.
Actions(cont.)• Inareasalreadyinfestedandwhereboattrafficisunavoidablewecoulddoselectiveharvestingtocreate“clean”marked,pathways.• Thiswouldlikelyhavetoinvolvebothmechanicalandhandpulling.Bestpracticeswouldneedtobedevelopedandhopefullyvolunteerassistancegiventohelpourfellowcottagers.
• Mechanicalharvestingwillneedtobepaidforsowe’dhavetofigurethatout.IbelieveRamaTownshiponLakeSimcoepaysformechanicalharvestinginLagoonCity,andthereisarecentreportfromtheLakeScugogStewardsthattheTrent-SevernWaterwayisgoingtouseacompanyfromPeterboroughtocleanupanareanearPortPerryBay.Sothatisanotheravenuetobeexplored.
Actions(continued)• Areaswhereboattrafficisnotnecessary(smallsecludedbays,LostChannel)arequarantinedparticularlywhentheSShasreachedaheightthatitcanbebrokenwithpaddlesorprops.
• Anorganizedsurveyofhigh-riskareasshouldbedone• Baysnearinfestedareas• Allmarinasandboatlaunches– sincethat’swhereinfestationstraditionallystart.• CheckcottagedocksofpeoplewhodockatorfrequentLittle’sMarinaorWildfire.
• Weneedtocreateareportingandtrackingsystemfornewoccurrences• Activelypromote“Clean,DrainandDry”practicestopreventspreadtootherlakes.
• LargeClean,dryanddrainsignsshouldbepostedatallmarinasandboatlaunchesandsignsindicatingthepresenceofSS.Peopleneedtoknowwhythisisimportant.Notatheoreticalprecautionbutanattempttostopthespreadofanaggressiveinvasivespecies.
• Provideboatwashequipment?• Targetdayswherevolunteerstalktoboaters,helpwashboats?(AsdoneinVermont)
• SpreadthewordtootherlakesnearusandontheTrentSevern– letpeopledealwiththiswhileitisafewsmallpatches.Notoncethey’vegotbaysfullofit.• Unfortunately,ourlakewasnotwarnedaboutthiswhenitwasknowntobeintheTrentsystematleasttwo
yearsbeforeitwasfirstnoticedintheLostChannel.Weneedtobebetterneighboursthanthat.
Conclusion• Starrystonewortisherebutifwegetorganizedtherearethingswecandotohelpourlake.WecanstartbyimplementingsomeofthepracticesdevelopedintheUStohelpslowthespread.• ThereisalotofattentionandresearchhappeningintheUSandnowCanadaaswell.Theresearchisbecomingmoresystematic,emphasizingresearchgapslikecontrolandmanagement,andactuallyquantifyingtheimpact.
• Doingnothingorwaitingforaneradicationmethodtobefoundisnotanoption.Starrystoneworthastheabilitytospreadeverywhere,quitepossiblychangingthecharacterofthelakewelove.
