Bonaccorso et al. 2006. Diversity Distrib. 12: 157-164.

Pleistocene fragmentation of AmazonPleistocene fragmentation of Amazonspeciesspecies’’ rangesranges

Photo: University of KansasPhoto: University of Kansas

HafferHaffer, J. 1969. Speciation in Amazonian forest birds., J. 1969. Speciation in Amazonian forest birds.HafferHaffer, J. 1997. Alternate models of vertebrate speciation., J. 1997. Alternate models of vertebrate speciation.

THE REFUGIA HIPOTHESIS

Speciation in the Amazon had been produced by cycles of Speciation in the Amazon had been produced by cycles of

expansion and contraction of forest environments during the expansion and contraction of forest environments during the

PleistocenePleistocene

During glacial periods, reduced temperature and humidity in the During glacial periods, reduced temperature and humidity in the

lowlands of South America left relatively small lowlands of South America left relatively small ““islandsislands”” of of

tropical rainforests surrounded by xeric habitatstropical rainforests surrounded by xeric habitats

Spatial disjunctions and isolation of populationsSpatial disjunctions and isolation of populations

HafferHaffer, J. 1969. Speciation in Amazonian forest birds., J. 1969. Speciation in Amazonian forest birds.

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IMERIIMERI

GUIANAGUIANA

BELÉMBELÉM

RONDÔNIARONDÔNIA

Haffer’sHaffer’s RefugiaRefugia

HafferHaffer & & Prance’sPrance’s RefugiaRefugia

Haffer & Prance, 2002.

Latter Pleistocene changes evidence Latter Pleistocene changes evidence for savanna expansionfor savanna expansion

Colinvaux et al. (1996, 2000, 2001)

Hoorn, C. (1997)

PalynologicalPalynological EvidenceEvidence

“Western Amazon was forested in the “Western Amazon was forested in the Pleistocene as it is now”Pleistocene as it is now”

““PalynologicalPalynological data give no indication of data give no indication of major major vegetationalvegetational changes in the drainage changes in the drainage basin” (of the Amazon)basin” (of the Amazon)(Amazon Fan)(Amazon Fan)

(“(“LagoLago PataPata”, site in north”, site in north--western western Amazon)Amazon)

Pollen evidencesPollen evidences

“All available Amazonian pollen data, without “All available Amazonian pollen data, without exception and including new data, imply biome exception and including new data, imply biome stability: no pollen data suggest increased stability: no pollen data suggest increased coverage of savanna in glacial times”coverage of savanna in glacial times”

ObjectiveObjective

To study how changes in climatic conditions during

the Last Glacial Maximum** might have affected the

patterns of distribution of Amazonian forest and

savanna species, using ecological niche modeling

****refers to the time of maximum extent of the refers to the time of maximum extent of the ice sheetsice sheets during the last during the last glaciationglaciation, , approximately 21 thousand years ago.approximately 21 thousand years ago.

Predictions:Predictions:

Testing Testing Haffer’sHaffer’s HipothesisHipothesis

Reduction and fragmentation Reduction and fragmentation in the potential distributions of forest speciesin the potential distributions of forest species

Expansion in the potential distributions of Expansion in the potential distributions of savanna speciessavanna species

Collection locality dataCollection locality data

Ecological dataEcological data

Distributional Distributional prediction in the presentprediction in the present

Projection to past scenarioProjection to past scenario

Ecological Niche Modeling: GARPEcological Niche Modeling: GARP

GARPGARPGenetic Genetic Algorithm of Algorithm of RuleRule--set set PredictionPrediction

AspectAspectSlopeSlopeTopographic IndexTopographic Index

3Paleoclimate Modeling Intercomparison Project (http://www-lsce.cea.fr/pmip/)

1US Geological Survey (http://edcdaac.usgs.gov/gtopo30/hydro/)

21,000 Years Ago21,000 Years Ago33

Topographic LayersTopographic Layers11

Hadley Centre for Climate Hadley Centre for Climate Prediction and ResearchPrediction and ResearchCanadian CenterCanadian Center

Environmental data SetEnvironmental data Set

Climatic LayersClimatic Layers TemperatureTemperaturePrecipitationPrecipitation

PresentPresent22

2Intergovernmental Panel on Climate Change (http://www.ipcc.ch)

AutomolusAutomolus infuscatusinfuscatusCampephilusCampephilus rubricollisrubricollisFormicariusFormicarius colmacolmaPhylidorPhylidor pyrrhodespyrrhodesPipraPipra coronatacoronataTangaraTangara mexicanamexicanaRauvolfiaRauvolfia paraensisparaensisR. R. polyphyllapolyphyllaR. R. spruceisprucei

Forest speciesForest species

Species distributionSpecies distribution

AtheneAthene cuniculariacuniculariaSublegatusSublegatus modestusmodestusAmmodramusAmmodramus humeralishumeralisEmberizoidesEmberizoides herbicolaherbicolaSporophilaSporophila plumbeaplumbeaRauvolfiaRauvolfia weddellianaweddellianaR. R. ligustrinaligustrinaCuratellaCuratella americanaamericana

Savanna speciesSavanna species

Species distributionSpecies distribution

Results and DiscussionResults and Discussion

Forest speciesForest species

Results and DiscussionResults and Discussion

LastLast Glacial Glacial MaximumMaximum

CoincidentCoincident mapmap for for forestforest speciesspecies

Results and DiscussionResults and DiscussionSavanna speciesSavanna species

• Potential distribution of forest species contracted and fragmented during the last glacial maximum

• Potential distribution of savanna species expanded during the same period, but all data aren’t conclusive

• Contraction of potential distributions of forest species may have created places that retained suitable habitat during the last Glaciation

Results and DiscussionResults and Discussion

Haffer’sHaffer’s RefugiaRefugia??

Potential Distribution Potential Distribution 21000 Years Ago21000 Years Ago

Forest: All Species Forest: All Species Hadley and CanadianHadley and Canadian Modified from Modified from HafferHaffer (1969) and (1969) and BonaccorsoBonaccorso (2006).(2006).

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BELEMBELEM

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To think about…To think about…

• Contraction of potential distributions of forest species may have created places that retained suitable habitat during the last Glaciation. But, were these changes strong enough to produce speciation in the Amazon Basin?

• Are the ecological niches conservatism over evolutionary time periods?