Evolutionary Ecology

, Volume 26, Issue 4, pp 909–926

Ecogeographic isolation: a reproductive barrier between species and between cytotypes in Houstonia (Rubiaceae)

Original Paper


‘Ecogeographic isolation’ describes the combined role of ecology and geography as a reproductive barrier, and an important component in speciation. Evidence increasingly shows that this form of isolation is important for maintaining the genetic integrity of populations and species. Further, ecogeographic isolation can be a reproductive barrier between polyploid individuals and their diploid progenitors. New ecoinformatic methods, which includes niche modeling and associated statistical assessments of these models with spatially explicit environmental data, allow us to test if ecogeographic isolation is a contributing isolating barrier between species and between cytotypes within a species. We tested the hypothesis that ecogeographic isolation contributes to isolation of species and cytotypes within species of the plant genus Houstonia. We found that species in this group occupied significantly different niches, which suggests ecogeographic isolation is a contributing reproductive barrier. We also found that diploid and tetraploid forms of H. longifolia show some level of ecogeographic isolation, but H. purpurea diploids and tetraploids did not. Our results suggest that ecogeographic isolation plays a role in reproductive isolation between Houstonia species and between cytotypes of H. longifolia.


Cytotype Geographic isolation Reproductive isolation Rubiaceae Ecological niche 

Supplementary material

10682_2011_9539_MOESM1_ESM.docx (14 kb)
Supplementary material 1 (DOCX 14 kb)

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • K. L. Glennon
    • 1
    • 3
  • L. J. Rissler
    • 2
  • S. A. Church
    • 1
    • 4
  1. 1.Department of Biological SciencesThe George Washington UniversityWashingtonUSA
  2. 2.Department of Biological SciencesUniversity of AlabamaTuscaloosaUSA
  3. 3.Department of BiologySyracuse UniversitySyracuseUSA
  4. 4.Global Wildlife ConservationAustinUSA

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