Vegetative and reproductive phenology of dominant mangrove species: A multi-parametric approach from Indian Sundarbans

Phenology, the timing of different life cycle events of plants, like flushing of new leaves, shedding old leaves, flowering and fruiting are crucial for plant fitness. It is often evolutionarily adapted to maximising utilisation of abiotic conditions and biotic interactions. This study aims to provide first comprehensive report of spatiotemporal variation in phenology of twelve dominant mangrove species from two sites of Indian Sundarbans. Apart from timing, relationship between different phenological parameters; duration, intensity, synchrony etc. and their importance in explaining variation between species was also studied. Significant variation in timing of peak activity was observed for different plant species across all four phenophases. Apart from timing, other phenological parameters like, duration also varied among phenophases with fruiting showing the longest maturation period in mangroves. This in turn constrained the available timing of activity for other phases leading to synchronisation of early season flushing and flowering, enhancing inclusive fitness. Altogether, flushing peaked early in dry season, flowering peaked mid-season, and fruiting peaked during wet season. There was continuous variation, not only in timing, but other parameters like duration, intensity, and synchrony across phenophases that was comparable to those observed in other tropical mangrove communities. Although there was an overall difference in the timing of flushing, flowering, and fruiting, no differences between sites for each species were observed. This study provides significant insight into relationship between timing, and other phenology parameters which might help unravel life-history, and resource acquisition and utilisation strategies of plant species in this vulnerable mangrove communities.