Regeneration status of mangrove species under mature stands in the oligohaline zone of the Sundarbans, Bangladesh

Regeneration structure and patterns of mangrove communities along the oligohaline zone of the Sundarbans Reserve Forest (SRF), Bangladesh, were studied at 2 forest sites: Karamjol and Ghagramari. A total of five plots with an area of 2000m2 were sampled and evaluated for tree species and ten regeneration plots with an area of 10m2 for mangrove regeneration. Mature mangrove stands at Karamjol area were structurally more complex than Ghagramari area. The preponderance of Heritiera fomes regeneration gives rise to a high Iv value in the study area. Based on species importance value, the order of dominant regeneration species is Heritiera fomes > Bruguiera sexangula > Excoecaria agallocha > Aglaia cucullata. Regeneration stocking and species diversity were similar between the two studied stands. In terms of individual number of seedling recruitment, Karamjol area had higher regeneration density than Ghagramari area. The occurrence of both RC1 (seedling height <40 cm) and RC2 (seedling height between 40-150 cm) were higher in Karamjol area than those in Ghagramari area. Success rates of seedling recruitment were not similar for all mangrove species under their mature tree layer as compared with the density of their adult trees in both areas. The present study provides information on seedlings' recruitment, structure, and composition under the mature stands indicating their ecological significance that may be considered in future decision making processes for management of the SRF.