Tag Archives: Abundance

Survey of Zooplanktondiversity and Abundance and Its Relationship with Physicochemical Parameters in River Kashimbila Takum, Taraba State, Nigeria (Published)

Zooplankton diversity and abundance and its relationship with physico-chemical parameters in River Kashimbila was carried out for a period of eight (8) months from August, 2016 to March, 2017.Physico-chemical parameters were determined, the identification and abundance of zooplankton were also determined. A total of twenty one (21) species of zooplankton were reported, which was dominated by Ciliophora (34.61%), followed by Rotifera (32.92%) and the least being Cnidaria (0.02%). Shannon Weinner diversity index ranged from 1.40 -2.72, Margalef Index from 2.37 – 2.72 and evenness from 0.45 – 0.60. The data revealed that there was a significant difference among number of species and species count at (P<0.05) between raining and dry season. Zooplankton diversity and abundance were influenced by seasons and sites while species composition varied significantly with season at (P<0.05).Based on the zooplankton diversity and abundance, the rivers holds high possible impact on fish production.

Keywords: Abundance, Diversity, River Kashimbila, Zooplankton

Plankton Dynamics as Pollution Indicator in the Coastal Waters of Ondo State, Nigeria (Published)

The dynamics of planktons in the coastal waters of Ondo State, Nigeria were investigated from April, 2014 to March, 2016. Samples were collected monthly using plankton net of 55 μm-mesh size, preserved in 4% formalin, examined with Olympus microscope and identified using standard guides. Zooplankton was more abundant in the environment in this study with NOI of 55.54% and 53.25% in the wet and dry seasons respectively. A total of twenty-three species of phytoplanktons belonging to two taxonomic groups were recorded. Diatom (65.22%) represented by five phyla consisting of Ochrophyta (7species), Heterokontophyta (6species) and Bacillariophyta (2species) while Dinoflagellates (34.78%) were represented by phylum Dinoflagellata (4species) and Myzozoa (4species). The zooplankton assemblage was composed of twenty-seven species including phylum Arthropoda (10), Rotifera (6), Chordata (3), Chaetognatha (2), Echinodermata (2), Ciliophora (1), Cnidarian (1), Granolereticulosa (1), and Mollusca (1). In wet-season, Fish-eggs (4.69%) (most abundant) Brachionus quadridentatus (3.79%); Coscinodiscus sp (3.67%); Biddulphia mobiliensis (3.31%) and Odonata nymph (3.01%) with Foraminifera (0.60%, the least) while the composition of the dry-season had a descending trend of Asterionellopsis sp (3.25%)>Cerataulina sp and Pseudo-nitzschia sp (3.02%)>Chaetognatha adult (2.86%)>Brachionus falcatus; Ceratium hirundinella sp and Coscinodiscus sp (2.70%)>Gyrodinium spp (2.62%) to Protoceratium reticulatum (0.48%). The Number of Individuals ranged from 26.25±6.86 (Dry-season) to 38.85±16.33 (Wet-Season) while Number of the most abundant species (Nmax) and average number of species (S) (which exhibited seasonal variation at P<0.05) ranged from 2.92±0.87 (Dry-Season) to 3.92±1.18 (Wet-Season) and from 18.10±3.14 (Dry-season) to 20.38±5.72 (Wet-Season) respectively. The Margalef’s Diversity Index and Shannon-Wiener Index which showed no seasonal variation ranged from 5.25±0.70 to 5.35±1.28 and 2.80±0.18 to 2.86±0.29 respectively, while Simpsons-Reciprocal Index ranged from 32.25±12.74 (Wet-Season) to 40.10±15.84 (Dry-season) and exhibited seasonal variation at P<0.05. The abundance and diversity of planktons in this study is an indicator of eutrophic ecosystem that is possibly unstressed.

Keywords: Abundance, Brackish-water; Planktons; Eutrophic; Diversity Index, Composition, Nigeria

The Relative Abundance of Floraspecies in the Tropical Rainforest Ecosystem of Boki Nigeria (Published)

This study was conducted with the view to analysing flora species abundance in the tropical rainforest ecosystem of Boki. Despite the spate of indiscriminate logging, this area still remains one of the few ecosystems that have been highly valued for its species diversity. Two forest formations the protected and the unprotected forest were used for the analysis. Six forest enclaves – Kanyang, Borum, Isobendeghe, Okwa I, Okwa II and Okwango were chosen for the study. Transects were laid from the centre of each forest enclave to the heart of the forest. Actual measurement of the quadrat started at a distance of 2km away from each enclave. A quadrat of 100m by 100m was demarcated for flora species identification and enumeration. The relative abundance was computed using the frequency of each species as percentage of the total species in the quadrat. The mean (x-) proportional abundance was computed to determine levels of flora species abundance. This was also complemented with the lognormal curve. Here, the number of flora species was plotted against individual species. The girth of each flora species was determined at breast height of 1.5m. The result of the analysis revealed that very few flora species were of low and high abundance whereas majority were in moderate abundance. Also majority of the trees in the area were in the category of 6-10 metre girth at breast height in the protected forest and 0-5 metre girth at breast height in the unprotected forest.

Keywords: Abundance, Ecosystem, Forest, Frequency, Species