The cycle of seagrass life: From flowers to new meadows

Abstract

Understanding sexual reproduction and recruitment in seagrasses is crucial to their conservation and restoration. Flowering, seed production, seed recruitment, and seedling establishment data for the seagrass Posidonia australis was collected annually between 2013 and 2018 in meadows at six locations around Rottnest Island, Western Australia. Variable annual rates of flowering and seed production were observed among meadows between northern and southern sides of the island and among years. Meadows on the northern shore consistently flowered more intensely and produced more seeds across the years of the survey. Inter‐site variation in clonal diversity and size of clones, seed production, wind and surface currents during pollen and seed release, and the large, but variable, impact of seed predation are likely the principal drivers of successful recruitment into established meadows and in colonizing unvegetated sands. The prolific but variable annual reproductive investment increases the probability of low levels of continuous recruitment from seed in this seagrass, despite high rates of abiotic and biotic disturbance at seedling, shoot, and patch scales. This strategy also imparts a level of ecological resilience to this long‐lived and persistent species.

Posidonia oceanica (L.) Delile, 1813 seedlings as a potential integrative tool for restoring damaged meadows

“…Bottlenecks along the reproductive cycle of seagrasses have been suggested to constrain their reproductive success, particularly in the main steps such as flowering, fruiting, seed production, germination, and seedling development (Hemminga & Duarte 2000). Considering the significant investment of energy (Gobert et al 2005), the reduced flowering rate, and the high pre-dispersal seed losses due to abortion and grazing, like other seagrasses (Kendrick et al 2023), the reproductive success of P. oceanica can be confirmed as low (Balestri & Cinelli 2003).…”

“…Understanding sexual reproduction in seagrasses is crucial for their conservation and restoration (Kendrick et al 2023). To date, information on the flowering biology of seagrasses is still lacking precise and accurate knowledge (Ackerman 2015;Guerrero-Meseguer et al 2018).…”