Abstract: Mangroves are specialized marine ecosystem which is highly productive. They act as shelter, breeding and nursery grounds for a variety of marine and brackish water invertebrates and fish. Some of the dominant plant species in mangrove vegetation of Nigerian coastline are Rhizophora species and Nypa fruticans. Studies were conducted on the decomposition of Rhizophora species and Nypa fruticans. The objective was to compare their decomposition rates and proffer informed management decisions. Decomposition rates of the two species were monitored for 112 days using litter box experiment. Eight litter boxes were stocked with 20 g of leaves of each species and fortnightly two boxes containing the respective plant species were removed and examined for dry matter, carbon and nitrogen contents. There was no significant difference in the rates of decomposition of Rhizophora and Nypa fruticans leaves (p = 0.05) even though Nypa fruticans showed slightly higher rate of decomposition than Rhizophora. The linear relationship between the loss in dry matter and number of days were expressed as y = 10.1-0.080x in Nypa fruticans and y = 9.0-0.073x in Rhizophora sp. It was concluded that the argument in favour of the eradication of Nypa fruticans for the thriving of Rhizophora is inaccurate. Containment of the population rather than control is the logical strategy for the management of the riparian vegetation in the face of climate change.