Vegetative and reproductive phenology of the mangrove Xylocarpus mekongensis Pierre in the Sundarbans, Bangladesh: Relationship with climatic variables

Phenological study of mangrove ecosystems through the collection of litterfall using litter traps is crucial to assessing mangrove productivity, management, and restoration under conditions of climate change. We investigated the phenological patterns (both vegetative and reproductive) of Xylocarpus mekongensis Pierre using litterfall in the Sundarbans, Bangladesh, over a period of 2 years. Leaf litterfall released throughout the year showed a distinct seasonal pattern, and no stipules were released in January or February of either year. Vegetative litterfall (1766.7–1943.4 g m−2 yr−1) contributed 76.52% of total litterfall (2292.5–2557.1 g m−2 yr−1). Leaf litterfall contributed the largest amount among the types of vegetative litterfall, followed by branch and stipule litterfall. Peak flowering of X. mekongensis was observed in April (1.72 times mean monthly flower production), and peak fruit maturation was observed in August (1.68 times mean monthly production). Analysis of variance showed significant differences among months for all types vegetative (stipule, leaf and branch) and reproductive (flower, immature fruit and mature fruit) litterfall (p < 0.05). However, t tests indicated no significant differences in vegetative (leaf, stipule, and branch) or reproductive (flower, immature fruit, and mature fruit) litterfall (p > 0.05) between the two successive years of the study period. Monthly mean temperature, day length, and maximum wind speed influenced vegetative, flower, and immature fruit fall. Mature fruit fall was influenced by monthly rainfall, monthly mean temperature, and relative humidity.