Evol Ecol Res 8: 1061-1075 (2006)     Full PDF if your library subscribes.

The genetic structure of the tropical understory herb Dieffenbachia seguine L. before and after forest fragmentation

Sandra Cuartas-Hernández and Juan Núñez-Farfán*

Laboratorio de Genética Ecológica y Evolución, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, 04510 México, Distrito Federal, Mexico

Author to whom all correspondence should be addressed.
e-mail: farfan@servidor.unam.mx


Hypothesis: Theoretically, forest fragmentation is expected to reduce genetic diversity and increase population differentiation through isolation and reduction of habitat.

Assumption: Assessing the effects of fragmentation on the genetic structure makes it necessary to know the former structure in the undisturbed, continuous habitat.

Organism: Dieffenbachia seguine (Araceae), an understory herb of the primary tropical rain forests.

Field site: Los Tuxtlas Biosphere Reserve, Veracruz, Mexico.

Methods: Four populations of the continuous forest (in an area >700 ha) and six populations in remnant fragments of a different area were sampled. The variability of nine allozyme loci was surveyed for 35 plants in each population.

Conclusions: F-statistics indicated that populations of D. seguine are highly structured as a result of random processes (Fst = 0.3052) and local inbreeding (Fis = 0.2905) both in fragments and in the continuous forest. However, genotypic richness was significantly lower in populations of fragments than in the continuous forest, and positively related to the fragment area. The population in the smallest fragment showed the highest genetic distance from all other populations. This suggests an exacerbation of the random differentiation process in fragments.

Keywords: Araceae, clonality, F-statistics, genetic drift, genotypic richness, isozymes, Los Tuxtlas.

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        © 2006 Juan Núñez-Farfán. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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