Providing the missing links in fern life history: Insights from a phenological survey of the gametophyte stage

Premise The entire life cycle of ferns has been documented, yet their life histories are still poorly understood. In particular, the phenology of fern gametophytes remains largely unknown. To address this issue, we demonstrated a new ecological approach to explore the phenological link between spore release and gametophyte maturation within the life history of a tree fern species. Methods We conducted a serial survey of Alsophila podophylla gametophyte abundance in the field, and recorded the time of its spore release. Every two months for one year, all terrestrial fern gametophytes in an unsampled subplot were collected and identified using tissue-direct PCR. Results We found temporal differences in gametophyte abundances, with a sevenfold difference between the highest and lowest months. The number of spores released was linked to the gametophyte abundance two months later. The switch from gametophyte to juvenile sporophyte was found to be most correlated with precipitation. Discussion The observed fluctuation in gametophyte abundance and population structure was likely associated with the phenology of spore release and environmental factors. Importantly, these findings provide the first evidence of phenological links between different developmental stages in a fern's life history.

Automated summary

This study investigated the phenological link between spore release and gametophyte maturation in a tree fern species. The results showed temporal differences in gametophyte abundance, with spore release being correlated with gametophyte abundance two months later. Precipitation was found to be the most correlated factor in the transition from gametophyte to sporophyte. These findings provide the first evidence of phenological links between different developmental stages in a fern's life history.