SOURCE:

Faculty: Biosences
Department: Botany

CONTRIBUTORS:

Okereke C. Nkumah
Mbaekwe E. I.
Nnabude P .C.

ABSTRACT:

The ecological characterization of three forest types namely: Community Forest, Shrine Forest and Forest Reserves in three forest zones of Anambra State, were carried out to ascertain their biodiversity, species abundance and composition, using the Point-Center-Quarter Method. Within each forest type, soil samples were collected in three replicates of 0-15cm, 15-30cm and 30-45cm depths. Physical and chemical properties of the soils of the forests were determined using standard Methods. Shannon Weiner Index of diversity was employed to determine the species diversity of the sites. Data analysis was carried out using, ANOVA and Principal component analysis (PCA). Relationships among variables were determined using Regression analysis. Results showed a significant relationship between the number of species and species diversity. Plants with significant difference in importance value index (IVI) in all the forests include: Newbouldia laevis (45.99), Gmelina arborea (68.80), Melicia excelsa (686.69), Pterocarpus sp (26.56), Tectona grandis (62.53), Gambeya albida (247.4), and Ceiba pentandra (25.86). The raking of the species diversity of the forests showed that Ukpor community forest ranked highest (3.555), followed by Mamu forest Reserve (3.472) while the lowest was Achala forest reserve (2.486). In the ordination of the soil variables and the forest sites by Principal Component Analysis, the soil textural classes were positively correlated. The association between the number of species and species diversity showed that species diversity depended on the relative percentage contribution of the most abundant species which also had a great influence on the total number of species in the sites. Many of the soil variables (BD, CEC, OM, OC, P and N) had strong positive correlation with species diversity. Other associations showed the differences and similarities that existed in the soil characteristics of the forest sites. The entire forest zones had similar characteristics in terms of species composition but differed in soil characterization. Results of chemical and physical analysis showed a significant difference in moisture content and Bulk Density in Osomari Forest Reserve (0.1389±0.031%) and (0.89±0.023gcm-3) respectively. In Ukpor community Forest, there was interaction between soil depth and forest in CEC (9.431±0.216). There was also a significant difference in Organic Matter content in Ukpor Community Forest (32.5±2.6) and there was interaction between soil depth and forest, while in OC, there was no interaction between soil depth and forest (0.13±0.08). Percentage sand was highest in Ngene Shrine Forest (74.3±0.5%) and there was a significant different in % sand between the forests. Unenzu Community Forest had the highest in % silt content (28.8±9.5%) and there was also a significant difference of % silt between the forests. % clay was highest in Osomari Forest Reserve (46.5±7.1%), and it was significantly difference. The soil pH of Achala Forest Reserve had highest value (6.3±0.3) but no significant difference between soil depths. Phosphorus was found to be highest in Mamu Forest Reserve (48.2±15.6mg/kg), but no significant difference between the forests. Potassium content was highest in Unenzu Community Forest (44.4±28.9mg/kg), no significant difference between the forests and soil depths. Nitrogen was observed to be highest in Ogugu-Nza Shrine Forest (2.8±0.1g/kg), but no significant difference between the forests and soil depths. Ca was highest in Odengwu Community Forest (52.1±11.0g/kg) and there was a significant difference in the Ca content between the forests and soil. Information from the study showed that sites with less species diversity were over exploited through tree felling and other mismanagement practices. Restocking the forests will boost their species diversity and encourage the chances of plant availability as raw materials for industries. The low BD, high CEC and high OC observed, clearly indicated that the forest lands are potentially good for agriculture, if maintained. Such maintenance could be achieved through zero tillage system and avoiding deforestation practice, applicable to Taungya and ley farming. Regular addition of organic matter is an important way to improve soil quality and productivity. Efforts should therefore be made to manage forest lands sustainably.