Floristic Abundance and Diversity of Mangrove in Polluted Soil of Ikuru Town, Andoni, Rivers State, Nigeria

Abstract

This study investigated into the floristic abundance and diversity of mangrove in polluted soils in Ikuru town, Andoni Local Government Area, Rivers State. The study covered an area of about five hectares (ha) of land. The area was measured using a transect of 100m x 20m in each zone. 10m transects were used in the experimental study. A control was chosen within the mangrove forest at Eagle Island Port Harcourt. Soil samples were randomly collected from subtidal, middle intertidal and lower intertidal zones, and control location using soil augar. Composite soil Samples were carefully placed into well labeled poly bags for laboratory analysis. Standard sampling procedures were adopted for soil physical and chemical analysis. Floristic species richness and diversity were also accessed. The results of the floristic compositions of the mangrove tree species in the hydrocarbon polluted soil of Ikuru Town showed that five (5) species, Avicenmia, Rhizophora mangle, Laguncularia racemosa, Acrostichum aureum, Rhizophora racemosa, four (4) families; namely Avicenmia, Avicenruocerae, Rhizophoraceae, Combitaceae and Pteridaceae. Furthermore, the results also showed that in polluted soil, Avicennia germinas recorded (35); unpolluted (52); Rhizophora mangle polluted (22); unpolluted (35); Lagunculania, racemosa polluted (20); unpolluted (30); Acrostichum aureum polluted (25); unpolluted (25); Rhizophora racemosa polluted (42) and unpolluted (60); Axonopus compresus polluted (15) unpolluted (20) and Cynodon dactylon polluted) (10) unpolluted (22) However, the diversity of the mangrove species in both polluted and contro soils were significantly different (P≤0.05), Avicennia gramina (35.52), Rhizophora mangle (22.35); Laguncularia racemosa (20.30), Acrostichum aureum (25.30) and Rhizophora recemosa (42.60). The results showed that the percentage abundance of the mangrove species differ in the percentage occurrence of the species found in the mangrove ecosystem, Rhizophora racemosa (24.88%, 25.49%) in both polluted and control soils, followed by Avicemmia Africana (20.71%; 21.3%) and the least abundant species was Laguncularia racemosa (11.82%; 12.30%). Therefore, rhizophora racemosa was highly recommended in a crude oil polluted sites and afforestation programmes in the mangrove