long-term disequilibrium and short-term equilibrium dynamics in west indian biogeography

Long-term disequilibrium and short-term equilibrium dynamics in West Indian biogeography

Liliana M. Dávalos Ecology and Evolution, SUNY at Stony Brook Amy L. Russell Biology, Grand Valley State University

Equilibrium  vs.  disequilibrium  

Cracra2  1983  Syst.  Biol.  M&W  1963  Evolu.on  

Dynamic  equilibrium    

ETIB   Preston  1962  Ecology  

Disequilibrium  

Iturralde  Vinent  &  MacPhee  1999  Bull.  Amer.  Mus.  Nat  Hist.  

How  to  test  disequilibrium?  •  ETIB  lineage  accumulaKon  

as  a  funcKon  of  Kme  –  FiNed  line  

•  Species  =  f(S  arriving  +  speciaKon  –  exKncKon)  

•  Lineages  =  f(S  arriving)  

Ricklefs  &  Bermingham  2001  Science  

Equilibrium  and  disequilibrium  in  colonizaKon  The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again.

Dumont,  Dávalos  2012  PRS-­‐B  

Also:  Stadelmann  et  al.    2007  Dávalos  2010  

Very  long-­‐term  disequilibrium  

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10 20 30 40 50Time in millions of years

Num

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Figure 6

Colonization ratesSingle rate modelTwo-rate slowTwo-rate fast

Natalidae colonization event

Changes  more  recently  

Dávalos  &  Turvey    2012  Bones,  Clones  &  Biomes  

Buckets  of  Caribbean  fossils  

Why  they  went  exKnct  •  CompeKKon  by  other  

invasive  bats  –  Koopman  &  Williams  1951  

•  Cave  flooding  –  Morgan  2001  

•  Interglacial  floods  –  McFarlane  &  Lundberg  2004  

•  Anthropogenic  habitat  destrucKon  –  Gannon  et  al.  2005  

Can  area  change  explain  species  loss?  

Dávalos  &  Russell  2012  Ecology  &  Evolu.on  

Change  in  area  explains  most  change  in  species  richness  

Log of present/LGM area in the Greater Antilles

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Log of present/LGM area in the Bahamas

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cies

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R2  =  0.83   R2  =  0.85  

Room  for  addiKonal  work  

Observed species richness Greater Antilles

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1 1.6 2.5 4.0 6.3 10 16 25

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prediction

Figure 4Observed species richness Bahamas

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1.6

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1 1.6 2.5 4.0

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6.4

How  to  answer  the  right  quesKon  

•  Equilibrium  null  model  •  StaKsKcal  framework  for  tesKng  long-­‐term  paNerns  –  Requires  mulKple  colonizaKon/exKncKon  events  

–  Floor  on  biodiversity  required  to  apply  widely  

–  ExKncKon?  

Drawing  by  A.  Tejedor