an updated assessment of manatee carrying capacity in the irl · 1000 2000 3000 4000 5000 6000 7000...

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

0

1000

2000

3000

4000

5000

6000

7000

EarlyExpertPopula6onEs6matesSynop6cSurveyCounts(FWC)StateAbundanceCalcula6on*Mortality–AllCauses(FWC)Mortality–WatercraI(FWC)

Datainclusive1974throughSeptember30,2016*“Combininginforma-onformonitoringatlargespa-alscales:Firststatewideabundancees-mateofthFloridaManatee”–JulienMarin,etal

ManateeNum

bers

3

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

8

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

10

*ProbablytheMostReliableValue,Butpre2011BasedonmostRecentObserva,ons–CurrentDensityisProbablyLower

GroundRulesandAssump@ons(cont)•  CarryingCapacityistheLimita@onofHabitatonPopula@on

•  ASustainablePopula@onCanRemainViableIndefinitely

•  AnOp@mumSustainablePopula@on:–  ExceedstheMinimumPopula6onthatwillSustainItself–  DoesnotExceedCarryingCapacity

11

GroundRulesandAssump@ons(concl)•  WeKnowSomeAmountofUproo@ngOccursDuring

ManateeForaging

•  Defini@onsForthePurposesofThisPresenta@on–  Uproo,ng-WhennoVisiblePlantRemainsAbovetheRiverbed–PostForaging

–  RegrowthTime–NumberofYearsforUprootedSAVtoBecomeViableForage

•  Uproo@ngandRegrowthTimeareUnknown–  AssumeBothRemainConstantOverTime

•  Conserva6veApproach

ThereisanAddi,onalAssump,ononChart24

12

Agenda





13

AssessingtheEffectofUproo@ngDefini@onsandSetup

•  ConsiderUproo@ngasaPercentageofTotalForageLetF=ForageRequirementasDetermined(inAcres)LetR=Uproo6ngasaPercentage(factor)ofForage

•  RegrowthTimewillbeRepresentedinYearsBasedon–  PropScarStudies(MosquitoLagoonandFLKeys)–  WaterManagementDistricts(SJandSWF)andOtherExpert

Observa6ons–  35YearsofPersonalObserva6onsintheIRLLetN=YearsforUprootedAcreagetoRegrow

•  HowMuchAcreageisLostAnnuallyduetoUproo@ngDefinePL=NetAnnualPercentageofForagedAcreageLostThenActualAnnualLossisPLxF

14

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)

15

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)

16

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)

17

If40%Uproo6ngOccurs(R),andRegrowthTimeis3Years(N),ThenEachYear26.7%(PL)oftheForagedacreswillnotrecoverSo,If1,000acresaregrazedforforage(F)EachYeartheavailableForagewilldeclineby267Acres

%UprootCurveComparison–toscale

18

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

19

Agenda





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

22

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

23

WinterForageRequirementWinterMinimumManateeForageRequirement•  WinterSeasonIRL(Oct–Mar)

–  [email protected]/Manatee–  BasedontheFPLCountsBetween1500and2000ManateesinBrevardCounty

–  TheWinteringHerdRequirestheEquivalentoftheTotalProduc@onof2250and9800AcresOfSeagrass

24

HowManyAcres–Really?

25

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

26

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

27

DataandAnalysisSummary

28

•  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





29

Observa@ons

30

•  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...?

31

ProblemDescrip@on–RootCauseHUMANIMPACT•  WeHaveEngineeredanEastCoastManateeDistribu@on

ThatJeopardizesNature’sAbilitytoMaintainEquilibrium

•  WeCreatedandEncouragedtheAr@ficialWarmWaterOuzlow(s)–  CausedtheRapidLocalizedSeasonalManateePopula6onGrowth–  Year-RoundPopula6onNumbersnotKnown

•  WeCreatedtheHighNutrientLoads(P&N)intheIRL–  CausedMuck,AlgalBloomsResul6nginSignificantLossofSeagrass

•  TheseTrendsareInDirectConflictandMustbeAddressed–  TheConsequenceisanUnacceptableImpacttotheIRL,theManatee

orBoth

32

UnacceptableRiskMustBeMi@gated

33

Prob

abilityOfA

nUnd

esire

d

Even

tOccurrin

g

ConsequenceoftheEventOccurring

Ac@onsareRequiredtoReducetheProbabilitythatPopula@onandSeagrassTrendsCon@nue

Mi@ga@onPlan–SeagrassLoss

34

•  TheMul@-LevelGovernmentandCi@zenIRLCOUNCILhasAlreadyTakentheLeadonthisElementoftheProblem

Mi@ga@onPlan–LocalPopula@onMgmnt

35

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

36

•  Ac@on–ImposeandEnforceStateorFederalRegula@onsforImmediateReduc@onsandTimelyElimina@onoftheAr@ficialWarmWaterOuzlow–  Provide“Cover”fortheOperatorsintheFaceofNega6vePublic

Opinion

•  Ac@on...

....Discussion

an updated assessment of manatee carrying capacity in the irl · 1000 2000 3000 4000 5000 6000 7000...

Documents