Tropical Understory Piper Shrubs Maintain High Levels of Genotypic Diversity Despite Frequent Asexual Recruitment

Many plant species have the capacity to regenerate asexually by resprouting from stem and leaf fragments. In the pan-tropical shrub genus Piper, this tendency is thought to be higher in shade-tolerant than light-demanding species, and to represent a trade-off with annual seed production. Here we use molecular markers to identify clones in five Piper species varying in light requirements. We test predictions that (i) asexual recruitment success is highest in shade-tolerant species, and (ii) that consequently, shade-tolerant species are characterized by lower genotypic diversity than light-demanding Piper. We found that two shade-tolerant Piper species recruited asexually more frequently (36–42% of sampled shoots were of asexual origin) than, two light-demanding and one shade-tolerant species (0–26%). Furthermore, as predicted, genotypic diversity was negatively correlated with the frequency of asexual recruitment in the population. Nonetheless, genotypic diversity of Piper was high compared with other clonal plants. The proportion of unique genotypes found per population ranged from 0.58 to 1.0 and the genotypic Simpson’s diversity ranged from 0.93 to 1.0 for all five species. Our results suggest that even though asexual reproduction plays an important role in maintaining local populations of Piper in the understory, it does not seem to reduce genotypic diversity to levels that will threaten these species ability to respond to environmental change. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp.in Spanish is available at http://www.blackwell-synergy.com/loi/btp.