Lettershttps://doi.org/10.1038/s41558-018-0312-9

Long-distance migratory birds threatened by multiple independent risks from global changeDamaris Zurell   1,2*, Catherine H. Graham3, Laure Gallien   4,5, Wilfried Thuiller   5 and Niklaus E. Zimmermann   2,6

1Geography Department, Humboldt-Universität zu Berlin, Berlin, Germany. 2Dynamic Macroecology, Department of Landscape Dynamics, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland. 3Department of Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland. 4Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa. 5Univ. Grenoble Alpes, CNRS, Univ. Savoie Mont-Blanc, LECA-Laboratoire d’Écologie Alpine, Grenoble, France. 6Department of Environmental Systems Science, Swiss Federal Institute of Technology ETH, Zurich, Switzerland. *e-mail: damaris.zurell@hu-berlin.de

SUPPLEMENTARY INFORMATION

In the format provided by the authors and unedited.

NaTurE CLimaTE CHaNGE | www.nature.com/natureclimatechange

1

SupplementaryInformation

Long-distancemigratorybirdsthreatenedbymultiple

independentrisksfromglobalchange

DamarisZurell,CatherineH.Graham,LaureGallien,WilfriedThuillerandNiklausE.

Zimmermann.

ThisSupplementaryInformationcontainsthefollowinginformation:

- SupplementaryFigureS1.Projectedchangesinseasonalspeciesrichnessoflong-

distancemigratorybirdsfor2050.

- SupplementaryFigureS2.Relationshipbetweenprojectedchangeinmigration

distanceandcurrent-daymigrationdistance.

- SupplementaryFigureS3.Projectedchangesinseasonalrangesizesand

migrationdistancefordifferentglobalchangescenariosanddispersalbuffers.

- SupplementaryFigureS4.Speciesrichnessinbreedingareasfordifferent

projectedrisksandriskcombinations.

- SupplementaryFigureS5.Projectedchangeinsummerandwinterrangesizeand

inmigratorydistancefordifferentIUCNriskcategories.

- SupplementaryFigureS6.Mapsofmultipleglobalchangerisksfordifferent

emissionscenarios.

- SupplementaryFigureS7.Sensitivityanalysesformultipleandsingleglobal

changerisksfordifferentIUCNcategories.

2

- SupplementaryFigureS8.PredictionaccuracyofSDMscalibratedinsummerand

winterranges.

- SupplementaryFigureS9.Effectofdifferentresolutionsandthinningapproaches

onresidualspatialautocorrelationandonestimatesofglobalchangeimpacts.

- SupplementaryFigureS10.Goodness-of-fitbetweenobservedandpredicted

rangepropertiesfordifferentdispersalbufferdistances.

3

FigureS1.Projectedchangesinseasonalspeciesrichnessoflong-distancemigratorybirdsfor2050.We

presentprojectedchangesinsummer(a,e,i)andwinter(b,f,j)richnessfortheclimateandlandcoverchange

scenariosRCP4.5-SSP1(a-d),RCP8.5-SSP3(e-h)andRCP8.5-SSP5(i-l).Additionally,wehighlightareaswherethe

projectedeffectsfromlandcoverchangewerestrongerthanfromclimatechangeforthedifferentscenarios

(c,d,g,h,k,l).Theprojectedchangeswerederivedfromtheensemblemeansforeachscenario,withamaximum

dispersaldistanceof1000km.

-150 -100 -50 0 50 100 150

-150-100-50050100150

-120

-93.3333333333333

-66.6666666666667

-40

-13.3333333333333

13.3333333333333

40

66.6666666666667

93.3333333333333

120

-110

+110Δspecies

a b

c d

e f

g h

i j

k l

LUCC > CCLUCC > CCLUCC > CCLUCC>CC

4

FigureS2.Relationshipbetweenprojectedchangeinmigrationdistanceandcurrent-daymigrationdistance.

Linesshowthetrendsasestimatedfromphylogeneticregression.Projectionscorrespondtotheensemblemeansfor

thescenarioRCP4.5-SSP1,withamaximumdispersaldistanceof1000km.

Current migration distance [°]

Δ d

ista

nce

[°]

10 30 60 90 120

-10

010

NearcticW PalearcticE Palearctic

5

FigureS3.Projectedchangesinseasonalrangesizesandmigrationdistancefordifferentglobalchange

scenariosanddispersalbuffers.Climateandlandcoverscenariosarecodedasnumbers1-8(1:RCP4.5,2:RCP8.5,

3:RCP4.5+SSP1,4:RCP8.5+SSP3,5:RCP8.5+SSP5,6:SSP1,7:SSP3,8:SSP5).

%Δ

sum

mer

are

a-100

-50

050

100

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

Dispersal 500 km Dispersal 1000 km Dispersal 2000 km Full dispersal

%Δ

win

ter a

rea

-100

-50

050

100

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

Dispersal 500 km Dispersal 1000 km Dispersal 2000 km Full dispersal

%Δ

mig

ratio

n di

stan

ce-50

050

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

Dispersal 500 km Dispersal 1000 km Dispersal 2000 km Full dispersal

6

FigureS4.Speciesrichnessinbreedingareasfordifferentprojectedrisksandriskcombinations.We

distinguishspeciesprojectedtobeatnorisk(a),atriskfromsinglethreats(b-d;S=summerpopulationreduction>

10%,W=winterpopulationreduction>10%,M=migrationdistanceincrease>10%)andatriskfrommultiple

threats(e-h).ProjectionscorrespondtotheensemblemeansfortheRCP4.5-SSP1scenario,withamaximumdispersal

distanceof1000km.

(a)Norisk (b)Risk:S

(c)Risk:W (d)Risk:M

(e)Risks:S+W (f)Risks:S+M

(g)Risks:W+M (h)Risks:S+W+M

102030405060

5101520253035

51015202530

246810

10203040

1234567

123456

12345

7

FigureS5.ProjectedchangeinsummerandwinterrangesizeandinmigratorydistancefordifferentIUCN

riskcategories.IUCNrisksare:LCleastconcern,NTnearthreatened,VUvulnerable,ENendangered,CRcritically

endangered.Outliersarenotshown.Projectionscorrespondtotheensemblemeansforthedifferentemission

scenarios,withamaximumdispersaldistanceof1000km.

RCP4.5-SSP1

RCP8.5-SSP3

RCP8.5-SSP5

%Δ

sum

mer

are

a-75

075

LC NT VU EN CR

%Δ

win

ter a

rea

-75

075

LC NT VU EN CR

%Δ

dis

tanc

e-25

025

LC NT VU EN CR

%Δ

sum

mer

are

a-75

075

LC NT VU EN CR

%Δ

win

ter a

rea

-75

075

LC NT VU EN CR

%Δ

dis

tanc

e-25

025

LC NT VU EN CR

%Δ

sum

mer

are

a-75

075

LC NT VU EN CR

%Δ

win

ter a

rea

-75

075

LC NT VU EN CR

%Δ

dis

tanc

e-25

025

LC NT VU EN CR

8

FigureS6.Mapsofmultipleglobalchangerisksfordifferentemissionscenarios.Venndiagramsillustrate

numberofspeciesprojectedtoexperiencesingleandmultiplerisks(forlegendpleaseseeFig.4andFig.S7).We

classifiedspeciesasatriskifpopulationreductionormigrationdistanceincreaseexceeded10%(a,c,e)or20%

(b,d,f).RGBmapsillustratetherelativenumberofspeciesfacingmultiplerisks(thecolouredareasoftheVenn

diagrams).Darktolightcoloursindicateincreasingspeciesnumbers.Colourbandsrepresentspecificrisk

combinations;mixedcoloursindicatethatspecieswithdifferentriskcombinationsarepresent.Projections

correspondtotheensemblemeansandamaximumdispersaldistanceof1000km.

305 114 71725 317

211 170 1101624 920

290 146 62933 419

(a)RCP4.5-SSP1+10%threshold

(c)RCP8.5-SSP3+10%threshold

(e)RCP8.5-SSP5+10%threshold

(b)RCP4.5-SSP1+20%threshold

(d)RCP8.5-SSP3+20%threshold

(f)RCP8.5-SSP5+20%threshold

S+WS+MW+M

n

222 47 7022 02

173 57 11015 23

209 39 7222 02

9

FigureS7.SensitivityanalysesformultipleandsingleglobalchangerisksfordifferentIUCNcategories.a-d

Numberofspeciesprojectedtoexperiencemultiplerisksfromglobalchangewhena20%thresholdisusedfor

classifyingspeciesasatrisk.e-hNumberofspeciesprojectedtoexperiencesingle(butnotmultiple)risks,thus

concentratingonthoseareasoftheVenndiagramswhererisksdonotoverlap(outsideblackborder).Here,a10%

thresholdwasusedforclassifyingspeciesasatrisk.ProjectionscorrespondtotheensemblemeansfortheRCP4.5-

SSP1scenarioandamaximumdispersaldistanceof1000km.ForfurtherexplanationpleaseseeFig.4inmaintext.

155(51.0%)

46(15.1%) 92

(30.3%)1

(0.3%)5(1.6%)

2(0.7%)

3(1.0%)

S(n=207) W(n=141)

M(n=11)

18(38.3%)

11(23.4%) 18

(38.3%)0

(0.0%)0(0.0%)

0(0.0%)

0(0.0%)

S(n=29) W(n=29)

M(n=0)

b

d

a

c

IUCN:Leastconcern

IUCN:(Near)Threatened

S+WS+MW+M

n

190(38.3%)

143(28.8%) 100

(20.2%)13

(2.6%)24(4.8%)

9(1.8%)

17(3.4%)

S(n=370) W(n=265)

M(n=63)

21(32.8%)

27(42.2%) 10

(15.6%)3

(4.7%)0(0.0%)

0(0.0%)

3(4.7%)

S(n=51) W(n=40)

M(n=6)

b

d

a

c

IUCN:Leastconcern

IUCN:(Near)Threatened

SWM

n

Singleglobalchangeriskswith10%threshold

Multipleglobalchangeriskswith20%threshold

10

FigureS8.PredictionaccuracyofSDMscalibratedinsummerandwinterranges.Modelswereinternally

validatedusinga70-30splitsampleapproachwith3repetitions.AUCistheareaunderthereceiveroperating

characteristiccurve;TSSisthetrueskillstatisticcalculatedasTSS=sensitivity+specificity–1;sensitivityisthetrue

positiverateandspecificitythetruenegativerate.

Summer Winter

0.5

0.7

0.9

AUC

Summer Winter0.5

0.7

0.9

TSS

Summer Winter

0.5

0.7

0.9

Sensitivity

Summer Winter

0.5

0.7

0.9

Specificity

11

FigureS9.Effectofdifferentresolutionsandthinningapproachesonresidualspatialautocorrelationandon

estimatesofglobalchangeimpacts.aInthebaselineSDMs,speciesrangemapsandenvironmentaldatawere

griddedat0.5°resolution.WecomparedthesetoSDMsestimatedatcoarserresolutionof1°andtoSDMsestimated

Baseline0.5°(B) Resolution1°(R1) Thinning250km(T) Thinning500km(T5)

èSpecieswith≥40occurrences:

n=715 n=656 n=174 n=13

èIsspatialautocorrelationSACsignificantlyreduced?

ΔSAC:no ΔSAC:ê ΔSAC:ê

èIstheestimatedarealosssignificantlysmaller? Δarea:no Δarea:no Δarea:no

èIstheestimatedmigrationdistanceincreasesignificantlysmaller?

Δdist:no Δdist:no Δdist:no

B B-1000

1000

3000

5000

SA

C d

ista

nce

[km

]

n=715

B R1 B R1-1000

1000

3000

5000

SA

C d

ista

nce

[km

]

n=656

B T B T-1000

1000

3000

5000

SA

C d

ista

nce

[km

]

n=174

B T5 B T5-1000

1000

3000

5000

SA

C d

ista

nce

[km

]

n=13

b c d e

B B

-60

-20

020

40%Δ

are

a

n=715

B R1 B R1

-60

-20

020

40%Δ

are

a

n=656

B T B T

-60

-20

020

40%Δ

are

a

n=174

B T5 B T5

-60

-20

020

40%Δ

are

a

n=13

f g h i

-60

-20

020

40%Δ

dis

tanc

e

n=715

B R1

-60

-20

020

40%Δ

dis

tanc

e

n=656

B T

-60

-20

020

40%Δ

dis

tanc

e

n=174

B T5

-60

-20

020

40%Δ

dis

tanc

e

n=13

j k l m

a

12

forspatiallythinneddatawithminimumdistanceof250kmand500kmbetweenpresencepoints(at0.5°resolution).

Becausethenumberofspecieswithatleast40presencesinsummerandwinterrangechangesacrossresolutionand

thinningchoices(i.e.speciesnumbersaredecreasingfromlefttorightpanels),theresultsofthe2nd,3rd,and4th

columnsshowonlytherespectivespeciessub-sets.b-eshowthedistanceclassesatwhichspatialautocorrelationin

modelresidualsbecomesinsignificantforspeciesdistributionmodels(SDMs)calibratedinsummer(red)andwinter

ranges(blue).f-ishowtheprojectedchangeinsummer(red)andwinterarea(blue).j-kshowtheprojectedchangein

migrationdistances.Significantdifferencesweretestedusingtwo-sampleWilcoxontestswithasignificancelevelof

0.05.ProjectionscorrespondtotheensemblemeansfortheRCP4.5-SSP1scenario,withamaximumdispersal

distanceof1000km.

FigureS10.Goodness-of-fitbetweenobservedandpredictedrangepropertiesfordifferentdispersalbuffer

distances.aexemplifieshowmigrationdistancebetweenpredictedsummerandwinterrangecentroids(with

1000kmdispersalbuffer)correspondstomigrationdistanceobtainedfromrangemaps.Thepredictionsfromthe

linearmodelexplain99%oftheobservedvariationinmigrationdistance(asindicatedbytheadjustedr2).b

summarisestheexplainedvariances(adjustedr2)fordifferentrangeproperties.

a b

Dispersal buffer [km]

Adj

. r2

500 1000 2000 full

0.50.60.70.80.91.0

Summer range sizeWinter range sizeSummer latitudeWinter latitudeSummer longitudeWinter longitudeMigration distance

Dispersal 1000 km

Migration distance range maps

Mig

ratio

n di

stan

ce p

redi

ctio

ns

20 40 60 80 100 120

2040

6080

120

adj.r2 = 0.985