Onyinyechi Priscilla Okpara, Okechukwu Idumah Okogwu
ABSTRACT. The aim of this study was to determine the species diversity and carbon storage potential of herbaceous plants growing within selected dumpsites in the Abakaliki metropolis. The line transect method was used to collect plants from five study stations: Waterworks (A), Kpirikpiri (B), Newlayout (C), FETHA (D) and Presco (E). At each study station, a 15 m×30 m area was measured using tape and demarcated with pegs and ropes. The identified species were collected, the biomass, species frequency, density, dominance, diversity and carbon uptake were measured. The diversity indices evaluated showed that active dump station A was the most diverse and evenly distributed site (Shannon–Weiner diversity index: A=2.43, B=1.09, C=1.16, D=1.14, E=0.99, Pileou’s evenness index, A=1.53, B=0.70, C=0.68, D=0.66, E=0.69). Additionally, at station D, Simpson’s dominance (A=0.27, B=0.32, C=0.24, D=0.43, E=0.10) and Magalef (species richness) indices (A=1.7, B=4.07, C=3.75, D=4.20, E=3.38) were the highest. The herbaceous Ghomphrena celeisoides had the highest relative dominance, relative frequency and important value index across the studied stations. Analysis of variance of the carbon uptake potentials of species showed significant values for abandoned dump stations C (Newlayout) and D (FETHA) when p<0.05. Therefore, total sequestered carbon in stations C (F=15.97, p<0.001) and D (F=8.33, p<0.001) and sequestered carbon dioxide equivalent at stations C (F=15.96, p<0.001) and D (F=43.68, p<0.001) were significant at 95％ confidence level. The results indicate that species at dormant waste disposal sites sequester significant amounts of carbon; therefore, they are recommended for the phytoremediation of disturbed or destroyed ecosystems. Keywords: carbon uptake; density; diversity; relative frequency.
