Mangrove Ecosystem of the Niger Delta: Distribution and Dynamics

Ita Ewa-Oboho
F. Emile Asuquo
P. Edet
E. J. Emeh
S. Oladimeji


DOI: 10.2190/ES.32.2.e

Abstract

Changes in species composition and distribution of macrobiota were studied during 1985-2004 in the Niger Delta system, Southern Nigeria. Two creeks were selected per estuary, two transects per creek, and two stations per transect for regular sampling of macrobiota. A total of 14 taxa of macrofauna comprising over 60 species were found in the region. Decapod brachyurans tended to decrease in mean densities from 35 individuals m-2 in 1985 to 21 and 18 individuals m-2 in 2000 and 2004 respectively. Phytoplankton and zooplankton decreased in species diversity, specie richness, and abundance in estuaries, notably Bonny, Qua Iboe, Brass, and Escravos where the THC contents of water were > 12 ppm emanating from minor oil spills. With the exception of Nypa palms, mangrove vegetation types displayed a general deterioration in numerical abundance and Nypa-rich vegetation were frequent in the more disturbed estuaries, replacing the indigenous mangroves as a type "A" invader.

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