Genetic Consequences of Tropical Second-Growth Forest Regeneration

Background

This article is an examination of the genetic impacts of old-growth deforestation among 24 year-old second-growth Iriartea deltoidea, a canopy palm, in a lowland Costa Rican forest. Iriartea is widely distributed throughout neotropical rainforests and displays a diverse range of size classes in mature forests. This species recolonizes second-growth forests with newly generated seeds, which are dispersed by birds and mammals.

Research goals & methods

This study employs parentage analysis and genotyping, using AFLP, of the entire founder generation (130 trees) to determine reproductive dominance and genetic diversity among Iriartea deltoidea re-growth. Genotypically similair trees are organized in spatial patches across 20 hectares of second-growth forest and 10 hectares of adjacent old-growth forest. Genotype diversity, genotype patch size, and parentage of second-growth and old-growth Iriartea deltoidea are compared in this article.

Conclusions & takeaways

The impacts of reproductive dominance in early successional forests are significant. Compared to old-growth trees, second-growth trees had lower genetic diversity and larger patches of similar genotypes. Generations of genetic dispersal will be required to restore diversity in secondary tropical forests.