Rare genotype advantage promotes survival and genetic diversity of a tropical palm

• Published in: The New phytologist Vol. 218; no. 4; pp. 1658 - 1667
• Main Authors: Browne, Luke, Karubian, Jordan
• Format: Journal Article
• Language: English
• Published: England New Phytologist Trust 01.06.2018; Wiley Subscription Services, Inc
• Subjects: Biodiversity; Density; Density dependence; Dynamics; forest ecology and evolution; Forest ecosystems; Forest management; Forests; Genetic diversity; Genetic variation; Genotype & phenotype; Genotypes; intraspecific variation; negative density dependence; negative frequency‐dependent selection; Palm; Plant diversity; plant recruitment; Population genetics; Recruitment; Recruitment (fisheries); Seeds; Species diversity; Survival; Tropical climate; Tropical forests; tropics; genetic diversity; negative frequency-dependent selection; tropics; intraspecific variation; forest ecology and evolution; negative density dependence; plant recruitment
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.15107

Negative density dependence, where survival decreases as density increases, is a well-established driver of species diversity at the community level, but the degree to which a similar process might act on the density or frequency of genotypes within a single plant species to maintain genetic diversity has not been well studied in natural systems. In this study, we determined the maternal genotype of naturally dispersed seeds of the palm Oenocarpus bataua within a tropical forest in northwest Ecuador, tracked the recruitment of each seed, and assessed the role of individual-level genotypic rarity on survival. We demonstrate that negative frequency-dependent selection within this species conferred a survival advantage to rare maternal genotypes and promoted population-level genetic diversity. The strength of the observed rare genotype survival advantage was comparable to the effect of conspecific density regardless of genotype. These findings corroborate an earlier, experimental study and implicate negative frequency-dependent selection of genotypes as an important, but currently underappreciated, determinant of plant recruitment and within-species genetic diversity. Incorporating intraspecific genetic variation into studies and theory of forest dynamics may improve our ability to understand and manage forests, and the processes that maintain their diversity.