Analysis of Soil-Vegetation Interrelationships in a South-Southern Secondary Forest of Nigeria

Soil-vegetation interrelationships in a secondary forest of South-Southern Nigeria were studied using principal component analysis (PCA) and canonical correlation analysis (CCA). The grid system of vegetation sampling was employed to randomly collect vegetation and soil data from fifteen quadrats of 10 m × 10 m. PCA result showed that exchangeable sodium, organic matter, cation exchange capacity, exchangeable calcium, and sand content were the major soil properties sustaining the regenerative capacity and luxuriant characteristics of the secondary forest, while tree size and tree density constituted the main vegetation parameters protecting and enriching the soil for its continuous support to the vegetation after decades of anthropogenic disturbance (food crop cultivation and illegal logging activities) before its acquisition and subsequent preservation by the Cross River State government in 2003. In addition, canonical correlation analysis showed result similar to PCA, as it indicated a pattern of relationship between soil and vegetation. The only retained canonical variate revealed a positive interrelationship between organic matter and tree size as well as an inverse relationship between organic matter and tree density. These extracted soil and vegetation variables are indeed significantly important in explaining soil-vegetation interrelationships in the highly regenerative secondary forest

ORIGINAL ARTICLE Spatio-temporal Distribution to Phytoplankton in the Industrial Area of Calabar River, Nigeria 1

ABSTRACT Phytoplankton is an important microscopic organism that sustains majority of aquatic life forms with its primary productivity. Literature on the abundance and distributional pattern of phytoplankton in the Calabar River is not readily available. A study was carried out to examine the spatio-temporal distribution, species abundance and diversity of phytoplankton in the Calabar River. Phytoplankton samples were collected by trawling plankton net behind an engine boat across six (6) sampling stations. Result obtained showed that a total of 35 phytoplankton species and 35 taxa representing 6 families were recorded. Chlorophyceae (green algae) and Bacillariophyceae (diatom) were the most abundant phytoplankton families constituting 57.2% of total phytoplankton taxa density, the least encountered families were Cyanophyceae (blue-green algae), Chrysophyceae and Xanthophyceae with 8.6% respectively. The result showed seasonal variation in phytoplankton species, as its abundance increased in the dry season than in the wet season primarily due to the increase in photic depth as well as the reduction in input turbid materials from other tributaries of the Calabar River. The study therefore reveals pollution of the Calabar River characterized by the abundance of phytoplankton taxa