No abstract

A fi eld research was conducted to assess abundance and distribution of species in relation to soil properties in Sedge-dominated Habitats in Uyo Metropolis, Southern Nigeria Systematic sampling method was used. The result of the study revealed that a total of 12 plant species of which 3 were members of the family Cyperaceae were identifi ed in the habitats studied. The Cyperaceae members found were of the genus: Cyperus. Other associated species found were Sida acuta, Scoparia dulcis, Chromolaena odorata, Eleusine indica, Ludwigia decurens etc. The highest density values obtained in this study is characteristic of Cyperus iria in Habitat 4 (9500 st/ha) while the least density value is characteristic of Plastostoma africanum in Habitat 2 (200st/ha). Multivariate correlation and regression techniques evidenced that these differences in density of the sedges refl ected the functions of various important soil properties such as pH, exchangeable Ca, soil moisture, total nitrogen and available phosphorus. Most specifi cally, the current result concludes that Cyperus iria showed strong affi nity for alkaline soils rich in calcium while Cyperus difformis and Cyperus rotundus showed strong preference for acid soils. Cyperus difformis, Cyperus rotundus and Cyperus haspan fl ourished in soils rich in organic manure while Cyperus iria colonies were found thrived on soils with limiting levels of phosphorus This result lends knowledge and practical application in environmental management, weed science and habitat ecology.

The plankton of Odot Stream, Niger Delta, Nigeria were investigated between June and August, (wet season) and October -December, 2014 (dry season) using standard analytical procedures. The data generated were subjected to descriptive statistics and community structure analysis. A total of 37 species of Phytoplankton belonging to four taxa were identified in ascending order as follows: Xanthophyceae (4.7%), Baccillariophyceae (20.19%), Cyanophyceae (36.34%) and Chlorophyceae (38.71%). Zooplankton belonging to 4 taxa were also identified in ascending order as follows; Cladocera (11%), Copepoda (11%), Larvae (26%), Rotifera (52%). Higher seasonal abundance among the families were recorded in dry season for Chlorophyceae (39.16±14.75), Cyanophyceae (21.83±6.50) and Xanthophyceae (10.66±5.81) while higher wet seasonal abundance were recorded for Baccillariophyceae (22.25±4.59) and Copepoda (0.58± 0.34). Chlorophyceae and Rotifera were found as the dominant group in this present study and indicated that Odot stream was highly productive (eutrophic), which could be attributed to high temperature due to the shallowness of the stream and its high exposure to sunlight. Excessive algal bloom should, therefore, be checked to prevent the stream from anoxia and poor water quality and shift in species composition and fish kill.

No abstract

No abstract