Photo: Kochia, southwest Montana. © 2020 Delena Norris-Tull
Founder effect: Its role in biological invasions
Summaries of the research and commentary by Dr. Delena Norris-Tull, Professor Emerita of Science Education, University of Montana Western, July 2020, updated November 2024.
“The loss of genetic variation resulting from the sub-sampling and introduction of a small number of individuals from a source population [founder effect],… suggests small populations recently introduced are unlikely to succeed. Such reduction in genetic diversity may be exacerbated once a species starts to spread in the new environment… However, genetic diversity may not be crucial for… successful establishment…If an initial pool of individuals successfully survives and reproduces, the population tends to accumulate new genetic diversity…Multiple independent introductions can coalesce over time in the new range… The larger the population becomes, the greater the chances are that some of the genotypes will successfully produce viable offspring” (Zenni, et al., 2017).
Research on genotype x environment interactions: Most species introductions fail. However, for tree species chosen for intentional introduction, specific genotypes are selected, such as when foresters choose tree genotypes better adapted for specific climatic conditions. The large scale planting of forestry species may give the tree species a competitive advantage. “In the unified framework, genetic diversity helps populations overcome selection pressures and transition from naturalized to invasive by potentially increasing fitness of populations” (Zenni, et al., 2017).
References:
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Founder effect: Its role in biological invasions
Summaries of the research and commentary by Dr. Delena Norris-Tull, Professor Emerita of Science Education, University of Montana Western, July 2020, updated November 2024.
“The loss of genetic variation resulting from the sub-sampling and introduction of a small number of individuals from a source population [founder effect],… suggests small populations recently introduced are unlikely to succeed. Such reduction in genetic diversity may be exacerbated once a species starts to spread in the new environment… However, genetic diversity may not be crucial for… successful establishment…If an initial pool of individuals successfully survives and reproduces, the population tends to accumulate new genetic diversity…Multiple independent introductions can coalesce over time in the new range… The larger the population becomes, the greater the chances are that some of the genotypes will successfully produce viable offspring” (Zenni, et al., 2017).
Research on genotype x environment interactions: Most species introductions fail. However, for tree species chosen for intentional introduction, specific genotypes are selected, such as when foresters choose tree genotypes better adapted for specific climatic conditions. The large scale planting of forestry species may give the tree species a competitive advantage. “In the unified framework, genetic diversity helps populations overcome selection pressures and transition from naturalized to invasive by potentially increasing fitness of populations” (Zenni, et al., 2017).
References:
- Zenni, R.D., Dickie, I.A., Wingfield, M.J., Hirsch, H., Crous, C.J., Meyerson, L.A., Burgess, T.I., Zimmermann, T.G., Klock, M.M., Siemann, E., Erfmeier, A., Aragon, R., Montti, L, & LeRoux, J.J. (Jan., 2017). Evolutionary dynamics of tree invasions: Complementing the unified framework for biological invasions. AoB Plants, 9 (1), 1-14 [plw085; 10.1093/aobpla/plw085].
Next Sections on research on evolutionary dynamics:
Next sections on research on the success of invasive species: