ThefollowingpresentationwaspresentedtotheScienceCommitteeatitsJune11,2018meetingforinformationalpurposes.ItdoesnotconstituteendorsementofanykindbytheStateofCaliforniaortheScienceCommittee.

SonnyBonoSaltonSeaNWR(ObsidianButte)-September21,2014

SALTONSEAWATERBIRDSURVEYSCURRENTTRENDSANDANALYSISDanOrr–SpatialEcologist,AudubonCaliforniaAndreaJones–DirectorofBirdConservation,AudubonCaliforniaDanCooper–Biologist,CooperEcologicalMonitoringInc.

SaltonSeaEnvironmentalChanges•  Waterlevelandsalinity•  Changinghabitats•  ChangingpreyavailabilityAudubonCaliforniaSaltonSeaWaterbirdSurvey(finescaleshorttermtrends)•  Overview•  Trends

AudubonChristmasBirdCount(largerscalelongtermtrends)•  EaredGrebetrends•  Impactsrelativetoenvironmentalchange

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Salinity ModeledSalinity SeaLevel

SaltonSeaSalinityandWaterLevel2001–2017

Salinity

(TDS

mg/L)

WaterLevel(N

GVD1929)ft

SalinityModelp-value<0.001R2=0.99

SaltonSeaEnvironmentalChangesWaterlevelandsalinity

IncreaseinsalinityanddecreaseinwaterlevelovertimeattheSaltonSea(datafromBureauofReclamation)2013sawincreasedwaterdrawdownsLet’slookattherateofchange(slope)overtimeinsteadoftherawvaluesovertimetoidentifymomentsofchange

MeasuredSalinityModeledSalinity

WaterLevel

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Δ(𝑁

𝐺𝑉𝐷

192

9)𝑓𝑡

/Δ𝑌𝑒

𝑎𝑟 

RateofchangeinSaltonSeaSalinityandWaterLevel

2001–2017

Salinity

RateofChange

Δ(𝑇𝐷

𝑆 𝑚

𝑔/𝐿)

/Δ𝑌

𝑒𝑎𝑟 

RateofChangeinSalinity

RateofChangeinWaterLevel

SaltonSeaEnvironmentalChangesWaterlevelandsalinity

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Δ(𝑁

𝐺𝑉𝐷

192

9)𝑓𝑡

/Δ𝑌𝑒

𝑎𝑟 

RateofchangeinSaltonSeaSalinityandWaterLevel

2001–2017

Salinity

RateofChange

Δ(𝑇𝐷

𝑆 𝑚

𝑔/𝐿)

/Δ𝑌

𝑒𝑎𝑟 

Rateofincreaseinsalinityincreasesdramaticallyafter2013•  2013hadincreaseof887.5mg/L/year•  2014hadanincreaseof1666.7mg/L/year

•  Thatisan88%increase Rateofdecreaseinwaterlevelincreasesdramaticallyafter2013

•  2013haddecreaseof0.192feet/year•  2014hadandecreaseof0.76feet/year

•  Thatisan296%increaseintherateofwaterlevelloss

RateofChangeinSalinity

RateofChangeinWaterLevel

SaltonSeaEnvironmentalChangesWaterlevelandsalinity

Changesinwaterlevelimpacthabitats

ChangesinSalinityimpactpreyspecies•  e.g.Fish

ForBirds

SaltonSeaEnvironmentalChangesHabitatandpreyavailability

Photo:DanCooper

Johnson’sLanding(SaltonCity)June2016

Photo:DanCooper

Johnson’sLanding(SaltonCity)February2015

SaltonSeaEnvironmentalChangesHabitatandpreyavailability

SaltonSeaWaterbirdSurveyOverview

SaltonSeaWaterbirdSurveys•  Nov2016–Mar2018•  14Sites•  1km2surveyboxes•  Surveyedevery2months•  20minutecounts/box

MostAbundantSpecies(>1,000pervisit,November-March)•  California/Ring-billedGull–min.1,840•  RuddyDuck–min.1,673•  NorthernShoveler–min.1,521•  Western/LeastSandpiper–min.1,127

SaltonSeaWaterbirdSurveyOverview

Initialresults:65totalspeciesofwaterbirds

Sample

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AudubonCaliforniaWaterbirdSurveyNovember2016–March2018

Totalnumberofbirdsoverthesurveyperiod

Photo:DanCooper

SaltCreekMouthDecember2015

SaltonSeaWaterbirdSurveyTrendsandanalysis

Sample

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AudubonCaliforniaWaterbirdSurveyNovember2016–March2018

•  Habitatchanges•  Preyavailability

Isthisashiftinfunctionalgroups?

Fewfisheatingbirds(HigherTrophicLevel)

Manyshorebirds(LowerTrophicLevel)

SaltonSeaWaterbirdSurveyTrendsandanalysis

DesignPicsInc.;NationalGeographicCreative

RobinL. CDFW

p-value<0.05 p-value<0.05 p-value<0.05

Decreaseinbirdsfeedingathighertrophiclevels(Nov./Jan./Mar.)•  Statisticallysignificant

SaltonSeaWaterbirdSurveyTrendsandanalysis

Birdsfeedingatlowertrophiclevels(Nov./Jan./Mar.)•  Appeartobestableorincreasingbasedonlimiteddata

SaltonSeaWaterbirdSurveyTrendsandanalysis

Least/WesternSandpiper RuddyDuckDowitcherspp.

AmericanAvocet Black-neckedStilt NorthernShoveler

SaltonSeaWaterbirdSurveyTrendsandanalysis

Couldbeshiftinfunctionalgroups?•  Theseanalysisindicatealossofhigher

trophiclevelbirds•  Trendssuggestwemayseeincreasesin

lowertrophiclevelbirds•  Notallarestatisticallysignificant•  Additionalyearsofdatawillrefineresults

PopulationLevelImpacts•  Unknown•  SaltonSeaisimportanttomigratorybirds•  Severalrelyonsalinelakes

Seawall,September2017DanCooper

LenBlumin

ShortTermandFineTimeScale

Audubon’sChristmasBirdCount•  CommunityScience•  Longtermdataset

•  NorthSaltonSea(1965–Present)•  SouthSaltonSea(1939–Present)

CBCSaltonSeaSouth1989-2017

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EaredGrebeAmericanWhitePelicanDouble-crestedCormorantRuddyDuckIncreasedWaterDrawdowns

Year

LnCou

nt

AudubonChristmasBirdCountTrends

AudubonChristmasBirdCountEaredGrebetrends

LotemTaylor,NationalAudubonSociety

EaredGrebes•  Abundantbutvulnerabletohabitat

change•  Lifehistoryisreliantonsalinelakes•  Est.90%ofCApopulationstoppedin

winterontheSaltonSeainthepast

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Δ(𝑁

𝐺𝑉𝐷

192

9)𝑓𝑡

/Δ𝑌𝑒

𝑎𝑟 

RateofchangeinSaltonSeaSalinityandWaterLevel

2001–2017

Salinity

RateofChange

Δ(𝑇𝐷

𝑆 𝑚

𝑔/𝐿)

/Δ𝑌

𝑒𝑎𝑟 

RateofChangeinSalinity

RateofChangeinWaterLevel

AudubonChristmasBirdCountImpactsrelativetoenvironmentalchange

PairControlandImpactSites•  Impact–SaltonSea•  Control–MonoLake(usedhere)•  MoreControlsitestocomeEliminatesNaturalEnvironmentalVariationinPopulationasCauseTestForDifferencesInChange•  Betweensitesbeforeandafterimpact(2013)•  NOTdifferencesinabundancebetweensites

Difference(Δ)Impact

AudubonChristmasBirdCountImpactsrelativetoenvironmentalchange

DoincreasedDrawdownsLeadToImpactToPopulations?BeforeAfterControlImpactPairedSeries(BACIPS)analysis

Ifbothsitesexperiencethesamegeneralnaturalenvironmentalvariabilityorclimaticanomalies(i.e.drought/ElNiño/LaNiña)

•  Expectdifferencesbetweentwotimeperiodsateachsitetobesimilar

•  Ifdifferent

• Pointstolocalimpactascause• Eliminatesnaturalenvironmentalvariationascause

Difference(Δ)

ImpactExpect

AudubonChristmasBirdCountImpactsrelativetoenvironmentalchange

ControlSite

ImpactSite

ImpactSite

NorthSaltonSeaDifferenceisstatisticallysignificant(p-value<0.001)

SouthSaltonSeaDifferenceisstatisticallysignificant(p-value<0.001)

AudubonChristmasBirdCountImpactsrelativetoenvironmentalchange

PreliminaryResults•  Differencesbetweentimeperiodsat

ControlandImpactsitesaresignificantlydifferent

•  Pointstolocalimpactascause•  Notapopulationorregionaltrend

EnvironmentalChangesAtTheSaltonSeaImpactBirdPopulations•  Impactstospeciesreliantonsalinelakes

•  Mayleadtochangesinfunctionaldiversity

SaltonSeaEcosystemsLoss•  Mosaicofhabitattypes•  Birdsareecologicallyimportant•  Birdsareindicatorspecies

Conclusions

RecoveryWillRequireSpecialManagement•  Prioritizespeciesandhabitatsofhigh

value•  Regionalscale•  Flywayscale

•  Habitatcreationandmaintenance•  Wetlands•  NestingIslands

•  Reliablefishery