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(NAS Colloquium) The Future of Evolution (2002) / Chapter Skim
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Disrupting Evolutionary Processes: The Effect of Habitat Fragmentation on Collared lizards in the Missouri Ozarks
Pages 38-44

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From page 38...
... Species exist in both space and time, and so does intraspecific genetic diversity. In some species, allelic diversity is widely distributed across a species' entire geographical range, and all local populations contain virtually the same alleles and at similar allele frequencies.
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From page 39...
... On the basis of microsatellite loci, the present populations have extreme population subdivision (FST = 0.40, which measures the proportion of the genetic variation in the Total population that exists as differences between Subpopulations) , with little genetic diversity within any single glade population but many fixed genetic differences among even nearby glade populations (15, 16~.
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From page 40...
... Overall, this combination of low population sizes and no gene flow explains the high FST values observed in the northeastern Ozarks. The genetic data also suggest that the lack of gene flow is a relatively recent phenomenon.
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From page 41...
... The founder population on Stegall Table 2. Recapture data on marked collared lizards in the burned versus unburned areas between 1994 and 1997 on Stegall Mountain Recaptured in glade other than glade of Recaptured in glade of Area original capture original capture Unburned 0 34 Burned 9 9 A two-tailed Fisher's Exact Test is used to test the null hypothesis of no spatial effects.
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From page 42...
... For example, the collared lizards on Stegall Mountain now have the capacity to maintain high levels of genetic diversity available for local adaptation because of the larger population sizes and large amounts of gene flow that unite many glades into a single effective breeding population. The increased gene flow is caused by the lizards' ability to disperse through recently burned forests, which, as we have already noted, also allows colonization of unoccupied glades (another buffer against local extinction)
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From page 43...
... How to Prevent the Disruption of Evolutionary Processes Under extreme fragmentation, adaptive potential is lost as the genetic diversity within local populations is eroded by genetic drift and lack of gene flow. The lack of gene flow also prevents the spread of adaptive genetic complexes.
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From page 44...
... (1986) in Evolutionary Processes and Theory, eds.
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Key Terms

  • genetic diversity
  • collared lizards
  • stegall mountain
  • local populations
  • genetic variation

  • population size
  • local extinction
  • shifting balance
  • genetic drift
  • founder events

  • collared lizard
  • adaptive flexibility
  • fire suppression
  • lizard populations
  • local population

  • allelic diversity
  • fire management
  • population structure
  • founder event
  • population sizes

  • forest fire
  • original capture
  • glade populations
  • population growth
  • sapling density

  • balance theory
  • peck ranch
  • adaptive evolution
  • northeastern ozarks
  • habitat fragmentation


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