A comparative study of the decomposition of Rhizophora racemosa and Nypa fruticans of the great Kwa River, Cross River State, Nigeria

Mangroves are specialized marine ecosystem which is highly productive. They act as shelter, breeding and nursery grounds for a variety of Marine and brackishwater invertebrates and fishes. 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 N. fruticans. The objective was to compare their decomposition rates and proffer informed management decisions. Decomposition rates of the two were monitored for 112 days using litter box experiment. Eight litter boxes were stocked with 10g of leaves of each species and two boxes containing the respective plants 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 N. fruticans leaves (p~.0.05) even though N. fruticans showed slightly higher rate of decomposition than Rhizophora. The linear relationship between the loss in dry matter and number were expressed as Y= 10.1-0.080x in N.fruticans, and Y=9.0-0.073x in Rhizophora sp. It was concluded that the argument in favour of the eradication of N.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