Distribution and diversity of mangrove species in Gokana Local Government Area, Rivers State, Nigeria

Abstract

Analysis of mangrove species distribution and diversity were carried out in Gokana Local Government Area, Rivers State, Nigeria. four transects (100 m x 10 m) with a distance of about 2 km from each other were set up at the mangrove back swamp starting from the waterfront towards upland. Each was divided into four equal plots of 25 m x 10 m. Data collection was based on identification and enumeration of the species. Distribution of the species as classified by Morisita’s index showed a uniform dispersion (id <1) in all plots. Simpson’s diversity index showed that species diversity was highest in Plots 4 (0.1272), followed by Plots 3 (0.2068). Plots 1 and 2 were dominated by Rhizophora racemosa (62.07% and 41.17% respectively). Plots 3 were dominated by R. mangle (4 1.67%) while Plots 4 had 26.56% of Acrostichum aureum and 26.56% of Phoenix reclinata. The overlapping mangrove species occurrence (Laguncularia racemosa and R. mangle) at the waterfronts should not alter the phenomenon of zonation for any form of reforestation project to be carried out in the area. Species for planting a specific mangrove area should be decided by environmental condition according to mangrove zonation principle so that reforestation and sustainable rehabilitation in the deteriorated ecosystem will be successfully achieved.

Keywords: Nigerian mangroves, biodiversity, distribution, assemblage, Niger Delta