The dispersal process of asexual propagules and the contribution to population persistence in Marchantia (Marchantiaceae)

Premise of the study: The dispersal process involves emigration from a focal source, dispersal through the landscape, and immigration into a new population or habitat. Despite the fact that dispersal is vital for the long-term persistence of a species, key stages of the process are unknown or understudied for many species, including the importance and contribution of asexual reproduction. Focusing only on a single stage in the dispersal process may give an incomplete and potentially flawed picture of the effects of asexual reproduction on metapopulation dynamics in plant species. Methods: Using a multifaceted approach that combines laboratory experiments, field studies, and mathematical models, we quantify the production, dispersal, and survival of immigrants of water-dispersed asexual offspring (gemmae) of the clonal liverwort Marchantia inflexa. Key results: Compared to female plants, male plants of Marchantia inflexa produce gemmae more quickly and in higher numbers, but due to desiccation have lower gemmae survival rates. Gemmae move up to 20 cm per minute in light rain, suggesting they can leave the source population. Long distance dispersal of gemmae is supported by the mathematical analysis of unisexual metapopulations. Upon reaching the new habitat, gemmae survival is high if they stay moist. Conclusions: By integrating multiple experiments to quantify the effects of gemmae on metapopulation dynamics, we found that different stages of dispersal can lead to different conclusions on which sex has an advantage. Gemmae are critical for the maintenance of both sexes, the persistence of single-sex metapopulations and species, and the invasibility of clonal organisms.