AnUpdatedAssessmentofManatee
CarryingCapacityintheIRL
PresentedtotheManateeForumbyBobAtkins,PresidentCi@zensforFlorida’sWaterways(CFFW)October2016
Agenda
• Background,GroundRulesandAssump@ons
• AnalysisoftheImpactofUproo@ng
• UpdateonCarryingCapacityandSustainabilityintheIRL
• ConclusionsandaProposedPlanofAc@on
1
Background
2
• ReceivedConstruc@veCri@cismAPertheMay2014DiscussiononIRLCarryingCapacity
• AnImportantOpenQues@onfrommyCarryingCapacityAnalysisPresentedinMay2014WhatisthePoten,alImpactofUprooted/ClearCutForageonCarryingCapacity?
• ThisPresenta@onAddressestheAbove
ManateeManagementFocus
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5000
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7000
EarlyExpertPopula6onEs6matesSynop6cSurveyCounts(FWC)StateAbundanceCalcula6on*Mortality–AllCauses(FWC)Mortality–WatercraI(FWC)
Datainclusive1974throughSeptember30,2016*“Combininginforma-onformonitoringatlargespa-alscales:Firststatewideabundancees-mateofthFloridaManatee”–JulienMarin,etal
ManateeNum
bers
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TheRootCauseofCrisisMentality
TheMostVisibleCon@nuedAgencyFocus
TheMostSignificantRiskRemainsLargelyUnaddressed
BrevardCountyManateeCounts
YEAR
200220032004200520062007200820092010201120122013201420152016
Synop@cSurvey
468596718529389859596108764063316701166
FPLHighCount
5405601464931179219661785
FPLCountAverage
39346470955997713921338
Note:FPLCountsConductedBi-weekly(Oct–Mar)4
Totalseagrassmappedacres,totaltransectlength,andaveragetransectcover Source:SJRWMD
6
IRLSeagrassAcreagebyRegion
≈60%
*
BrevardCo
Source:SJRWMD
7
IRLSeagrassWithinBrevard
≈60%
*
Brevardhas38,000oftheRemaining48,000IRLSeagrassAcres
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IRLSeagrassWithin30kmofCCEC
≈60%
*
About27,000AcresWithinaDay’sManateeSwimofCCEC
• IsThereaPosi@veCorrela@onbetweenObserva@onsofIncreasedManateePresenceandDecreasedIRLSeagrass?
IRLSeagrassAcreage&ManateeNumbers
IRLSeagrassAcreage(SJRWMD)Synop6cSurveyCounts(FWC)PeakBrevardCounts(FPL/Mote)AverageBrevardCounts(FPL/Mote)
9
GroundRulesandAssump@ons• PerSJRWMD
– IRLSeagrassAcreageasof2015Assessment–48,000acres
• PerFWC(Feb2014)– IRLSeagrassDensity:1466-6210lbswetmass/acre
• 1466–SJRWMD(1996–2010)*• 6210-Short,etal(1993)
– IRLSAVGrowthRate:0.5%-4.8%daily• 0.5–1.0%Winter(Nov-Feb)-Provancha,etal(2012)• 4.8%Summer(Mar-Oct)–Virnstein(1982),NearFt.Pierce
– AverageManateeSize:1,000lbs– TypicalManateeConsump6on:4.1–9.4%ofbodyweight
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*ProbablytheMostReliableValue,Butpre2011BasedonmostRecentObserva,ons–CurrentDensityisProbablyLower
GroundRulesandAssump@ons(cont)• CarryingCapacityistheLimita@onofHabitatonPopula@on
• ASustainablePopula@onCanRemainViableIndefinitely
• AnOp@mumSustainablePopula@on:– ExceedstheMinimumPopula6onthatwillSustainItself– DoesnotExceedCarryingCapacity
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GroundRulesandAssump@ons(concl)• WeKnowSomeAmountofUproo@ngOccursDuring
ManateeForaging
• Defini@onsForthePurposesofThisPresenta@on– Uproo,ng-WhennoVisiblePlantRemainsAbovetheRiverbed–PostForaging
– RegrowthTime–NumberofYearsforUprootedSAVtoBecomeViableForage
• Uproo@ngandRegrowthTimeareUnknown– AssumeBothRemainConstantOverTime
• Conserva6veApproach
ThereisanAddi,onalAssump,ononChart24
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Agenda
• Background,GroundRulesandAssump@ons
• AnalysisoftheImpactofUproo@ng
• UpdateonCarryingCapacityandSustainabilityintheIRL
• ConclusionsandaProposedPlanofAc@on
13
AssessingtheEffectofUproo@ngDefini@onsandSetup
• ConsiderUproo@ngasaPercentageofTotalForageLetF=ForageRequirementasDetermined(inAcres)LetR=Uproo6ngasaPercentage(factor)ofForage
• RegrowthTimewillbeRepresentedinYearsBasedon– PropScarStudies(MosquitoLagoonandFLKeys)– WaterManagementDistricts(SJandSWF)andOtherExpert
Observa6ons– 35YearsofPersonalObserva6onsintheIRLLetN=YearsforUprootedAcreagetoRegrow
• HowMuchAcreageisLostAnnuallyduetoUproo@ngDefinePL=NetAnnualPercentageofForagedAcreageLostThenActualAnnualLossisPLxF
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PL=NetAnnualPercentageLostToUnderstandtheCalcula@onofPL
• SupposeR=20%andN=2Years– Eachyear20%oftheforageacreagewouldbeuprooted– Theuprootedacreagewouldgrowbackin2years,
• ½wouldgrowbackeachyear(ratecompoundingnotcalculatedforsimplicity)
– EachYear,WeShouldObserveaPERCENTAGENETLOSSPL=20%-(1/2)(20%)=(1–½)20%PL=10%
• SpecificallyWeCanEs@mate:PL=(1–1/N)R
• RememberPLisapercentageofF– ActualAnnualLossisPLxF(inAcres)
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10%
7.5%
5%
2.5%
NetAnnualPercentSAV
Loss1 2 3 4 5 6 7 8 9 10 11 12 13 14 11
YearstoRegenerateUprootedSAV
PL=(1-)10%1N
PL
N
Case:R=10%
If10%Uproo6ngOccurs(R),andRegrowthTimeis3Years(N),ThenEachYear6.7%(PL)oftheForagedacreswillnotrecoverSo,If1,000acresaregrazedforforage(F)EachYeartheavailableForagewilldeclineby67Acres
Example1,R=10%(Uproo@ng)
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40%
35%
20%
10%
NetAnnualPercentSAV
Loss1 2 3 4 5 6 7 8 9 10 11 12 13 14 11
YearstoRegenerateUprootedSAV
PL=(1-)40%1N
PL
N
Case:R=40%
Example2:R=40%(Uproo@ng)
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If40%Uproo6ngOccurs(R),andRegrowthTimeis3Years(N),ThenEachYear26.7%(PL)oftheForagedacreswillnotrecoverSo,If1,000acresaregrazedforforage(F)EachYeartheavailableForagewilldeclineby267Acres
%UprootCurveComparison–toscale
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R=40%
R=30%
R=20%
R=10%
TheNetEffectofUproo@ng• TheNetEffectofUproo@ngisaCon@nuousLossofSeagrassAcreage– AslongasGrazingRemainsConstant,and– NoAddi@onal“Pasture”is“Created”– ItisCUMULATIVEandPERMANENT
• ThePressingQues@on-HowMuch?– TheAnswerRequiresaBenerUnderstandingof
• HowMuchUproo@ngOccurs,and• HowLongRegrowthRequires
• Conjectures:– Uproo@ngWillLikelyIncreaseasGrazingPressureIncreases– ExceedingCCWillResultinObservableOver-GrazingandSignificant
Uproo@ng
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Agenda
• Background,GroundRulesandAssump@ons
• AnalysisoftheImpactofUproo@ng
• UpdateonCarryingCapacityandSustainabilityintheIRL
• ConclusionsandaProposedPlanofAc@on
20
SeagrassProduc@vityintheIRL• IRLSeagrassDensity
– 1466–6210lbswetmass/ACRE
• IRLProduc@vity-SummerMonths(Apr–Sept)–240days– SeagrassGrowth
• 4.8%/day– TotalProduc6onperAcreofSeagrass
• 1466lbs/acre+(240daysx0.048/dayx1446lbs/Acre)≈18,400lbs/Acre*• 6210lbs/acre+(240daysx0.048/dayx6210lbs/Acre)≈77,700lbs/Acre
• IRLProduc@vity-WinterMonths(Oct–Mar)–120days– SeagrassGrowth
• 0.5%/dayto1.0%/day– TotalProduc6onperAcreofSeagrass
• 1466lbs/acre+(120daysx0.005/dayx1466lbs/Acre)≈2,300lbs/Acre*• 1466lbs/acre+(120daysx0.01/dayx1466lbs/Acre)≈3,200lbs/Acre*• 6210lbs/acre+(120daysx0.01/dayx6210lbs/Acre)≈13,700lbs/Acre
21*ProbablytheMostReliableValues
TypicalManateeSAVConsump@on(lbs)• TypicalAverageManatee
– 1,000lbs
• ManateeSeagrassConsump@on–WinterSeason– 4.1%–9.4%bodyweight/day– (41to94lbsseagrass/day)– x(120days)≈4,900to11,300lbs/manatee/winter
• ManateeSeagrassConsump@on–SummerSeason– 4.1%–9.4%bodyweight/day– (41to94lbsseagrass/day)– x(240days)≈9,800to22,600lbs/manatee/summer
• AnnualConsump@on– ≈14,800to33,840lbsseagrass/manatee/year
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SeasonalIRLSeagrassImpact(R=0%)• ManateeSeagrassConsump@on–Winter(Nov–Feb)
≈4,900to11,300lbs/manatee≈2,300to3,200lbs/Acre(FullProduc@vity)TheTotalProduc@onof≈1.5to4.9acresisconsumedbyeachmanatee
• ManateeSeagrassConsump@on–Summer(Mar–Oct)≈9,800to22,600lbs/manatee/summer≈18,400to77,700lbs/Acre≈0.5to1.2acres/manatee
• WinterRequirementsDetermineCarryingCapacity– LeastAvailableForage
• ShorterTimeFrame• SlowerGrowthRate
– MostManateesPresent
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WinterForageRequirementWinterMinimumManateeForageRequirement• WinterSeasonIRL(Oct–Mar)
– [email protected]/Manatee– BasedontheFPLCountsBetween1500and2000ManateesinBrevardCounty
– TheWinteringHerdRequirestheEquivalentoftheTotalProduc@onof2250and9800AcresOfSeagrass
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HowManyAcres–Really?
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HowmanyActualAcresSAVareRequiredto:– SupplytheEquivalentTotalProduc@onof1Acre?– AndS@llRemainSustainable?
Isn’tTWOtheMinimumReasonableAnswer?– AlltheOtherCreaturesNeedSomeSAVToo– WeHavetoMaintainSomeFilteringFunc@onfortheHealthofthe
Habitat
ASSUMEItTakes2AcrestoSustaintheEquivalentoftheTotalProduc@onof1Acre– ThisDoublesthePreviouslyCalculatedAcreageRequirementforWinter
between– 4,600and19,600acresforthe1,500–2,000Manatees– Equivalently,3.1to9.8AcresSAVperManatee
Re-Calcula@ngCCwithUproo@ng• IRLCarryingCapacitywithZeroUproo@ng
– 3.1to9.8AcresperManatee
• WhatistheAddi@onalImpactofUproo@ng?– AsanExample,Assume5%Uproo@ngand3yearRegrowth– PercentAnnualNetLossis(1–1/3)5%=3.3%– ActualAnnualNetLosswouldbebetween
3.3%(3.1)upto3.3%(9.8)AcresPerManatee0.10to0.32AcresPerManateeLOSTEachYear
• CarryingCapacityRecalculatedforR=5%,N=3– ThisDecreasestheCarryingCapacity– AMinimumof3.2to10.1AcresperManatee– Realis@callytheImpactisGreater– And,IncreasedUproo@ngorLongerRegrowthYieldsLessCapacity
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CC–IncludingUproo@ngImpacts• TheActualAnnualLossofForageisdeterminedby:
– TotalAcreageRequiredforForage(F)– byUproo6ngPercentage(R)and– YearstoRegrow(N)ActualAnnualLossisPL*F,
wherePL=(1-1/N)*R
• SointheIRLcaseabovewhere4,500<F<19,600Ifweassume5%Uproo@ngwith3YearRecoverywecanExpectanAnnualReduc@onof– Between3.3%(4,500)and3.3%(19,600)AcresEachYear– ANetLossBetween150and650AcresSAVeachWinter– Remember,thisisannualandcumula@ve-– Basedonthesevaluesandcurrentpopula@onandforage
Expect750to3,200acrereduc@onover5years
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DataandAnalysisSummary
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• TheObservedBrevard/IRLWinterHerdCon@nuestoGrow
• TheIRLSAVAcreagehasSlightlyIncreasedButDensityhasDeclined– ThisReducesProduc6vity/AcreandPoten6allytheTotalAvailableForage
• TheIRLCon@nuestobeimpactedby“SignificantAnnual”AlgalBlooms– Noreasontobelievewewillexceed75,000acresintheIRL
• BasedontheConserva@veBaselineData,CurrentCondi@onsandVeryConserva@veAnalysis– Between11%and51%oftheTotalBrevardForage(38,000Acres)are
RequiredForWinterForage• Uproo@nghasaNega@ve-YetUndocumentedLongTermImpact
• ManateeMigra@onisaSurvivalIns@nct– ProbablyMoreDrivenbyLong-TermImpactstoForageThanTemperature
Agenda
• Background,GroundRulesandAssump@ons
• AnalysisoftheImpactofUproo@ng
• UpdateonCarryingCapacityandSustainabilityintheIRL
• ConclusionsandaProposedPlanofAc@on
29
Observa@ons
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• WeUrgentlyNeedaClearUnderstandingofLocalAreaCarryingCapacityandOp@mumSustainabilityfortheIRL
• WeMAYS@llhaveQuan@fiableMarginforCapacityintheIRL.
– WeneedtoPro-Ac6velyManagetoPreservethatMargin• DoingNothingandHopingfortheBestisNOTPro-Ac@ve
Management– BasedonTrendsObservedOvertheLongTermweareExtremelyLikely
toSeeaSignificantDetrimentalImpacttotheIRLSeagrassand/ortheEastCoastManateePopula6on
• WeMustRedefineOur“MoreisBener”ManateeManagementApproachandRedirectourEffortsTowardManagementofaStableandGrowingPopula@on
OutdatedManagementApproachManateeManagementisS@llGovernedbyDecadesOldAssump-ons–ThesearetheFabricofOurHistory–ButNOTFacts• TheManateeisanEndangeredSpecies
– Depletedandindangerofex@nc@on– Thebasisfor“MoreisBener”Approach(OverInfluenceoflegaloverscience-ESA,MMPA,etc)
• BoatMortalityistheGreatestThreattotheManateeSpecies– “…watercraP-relatedmortalityhadthegreatestimpactonpopula@ongrowth”–Manatee
ManagementPlan
• SlowBoatSpeedisourBestHopeofSavingtheManateeSpecies– “…Reduc@onsinboa@ngac@vityandspeedisessen@altosafeguardthemanateepopula@on”–
Marmontel,1997
InsufficientAnen@onhasbeenFocusedonCarryingCapacityand/orOp@mumPopula@on• TheseQuan@fiableMeasureswereRepeatedlyRequestedatPublic
Hearingsover30Yearsago• TheObservedPopula@onhasCon@nuedtoGrowatanExplosiveRate
– FarFasterthanwasAssumed;FarFasterthantheBasisforCurrentManagementAc@ons
AFerAlltheseYears,ManateeCarryingCapacityRemains...?
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ProblemDescrip@on–RootCauseHUMANIMPACT• WeHaveEngineeredanEastCoastManateeDistribu@on
ThatJeopardizesNature’sAbilitytoMaintainEquilibrium
• WeCreatedandEncouragedtheAr@ficialWarmWaterOuzlow(s)– CausedtheRapidLocalizedSeasonalManateePopula6onGrowth– Year-RoundPopula6onNumbersnotKnown
• WeCreatedtheHighNutrientLoads(P&N)intheIRL– CausedMuck,AlgalBloomsResul6nginSignificantLossofSeagrass
• TheseTrendsareInDirectConflictandMustbeAddressed– TheConsequenceisanUnacceptableImpacttotheIRL,theManatee
orBoth
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UnacceptableRiskMustBeMi@gated
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Prob
abilityOfA
nUnd
esire
d
Even
tOccurrin
g
ConsequenceoftheEventOccurring
Ac@onsareRequiredtoReducetheProbabilitythatPopula@onandSeagrassTrendsCon@nue
Mi@ga@onPlan–SeagrassLoss
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• TheMul@-LevelGovernmentandCi@zenIRLCOUNCILhasAlreadyTakentheLeadonthisElementoftheProblem
Mi@ga@onPlan–LocalPopula@onMgmnt
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WeCreatedtheProblem–WeCanFixIt
• Ac@on–EliminatetheImpedimentstoPro-Ac@veManateeManagement– ESA–ReclassifytheManateeto“Recovered”– MMPA–Re-EvaluateAllowableTakeBasedon“Recovered”– Amend/RepealanyRestric6veLegisla6on– ReviseGoverningPlans– Organiza6onalObjec6onsMustbeAddressed
• InFact–AllOrganiza6onsMUSTAssistinReshapingPublicOpinion
• Ac@on–DevelopandImplementaPro-Ac@veManateeInterven@onPlan– Respond,Rescue,orRelocate– MonitorPoten6alOvercrowdingatWarmWaterSite– Ac6velySearchforColdStressedorDistressedManateesinthe
SurroundingAreas
Mi@ga@onPlan–LocalPopula@onMgmnt
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• Ac@on–ImposeandEnforceStateorFederalRegula@onsforImmediateReduc@onsandTimelyElimina@onoftheAr@ficialWarmWaterOuzlow– Provide“Cover”fortheOperatorsintheFaceofNega6vePublic
Opinion
• Ac@on...
....Discussion