Comparative assessment of plant biodiversity among different Taungya agroforestry practices in Ondo State.
Loading...
Date
2012
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Obafemi Awolowo University
Abstract
This study examined the floristic composition of the standing vegetation of four different Taungya agroforestry sites and a natural regrowth forest in Ondo State, Southwestern Nigeria. Also, the soil physico-chemical properties in the sites were determined. This was with a view to assessing the impact of this agroforestry practice on the biodiversity status and species diversity in the study areas. Two sample plots of 25 m x 25 m each were selected in each of the five study sites. All the plants were enumerated and identified to species level. The vegetation parameters such as, the height, the girth at breast height and basal area were determined in each site. Each plant was classified into either a tree, shrub, perennial herb, scrambling shrub, epiphyte or a climber while their families were also identified. Species diversity, similarity and contribution of each species to the total abundance were also well determined. Five soil samples were randomly collected from each plot of agroforest and natural regrowth forest at depths of 0-15 cm and 15-30 cm using a soil auger to give a total of one hundred soil samples which were air-dried and sieved using 2.0 mm sieve. Standard laboratory methods were employed for the determination of the particle size distribution, organic carbon, total nitrogen, pH, available phosphorus, water holding capacity, exchangeable acidity and exchangeable cations in all the sampled soils. Duncan Multiple Range Test was used to compare the means of soil parameters in all the sites examined, while Shannon-Weiner diversity index and Simpson index of similarity were used to compare the plant species diversity. The natural regrowth forest had the highest species diversity index (3.43), number of individual species (54) and families (28). Comparatively, the species diversity index, number of individual species and species families for the agroforestry sites respectively were: Owo 1.58, 19, 11; Ore 1.43, 8, 7; Idanre 1.49, 11, 10 and Aponmu 1.27, 11, 9. Species density gradually reduced from 1392 ha-1 in natural regrowth forest to 1192 ha-1, 848 ha-1, 664 ha-1and 432 ha-1 in Owo, Idanre, Ore, and Aponmu Taungya agroforests respectively. More climber species were encountered in natural regrowth forest compared to the four Taungya agroforest sites. Eight epiphytes were encountered in both Idanre and Owo agroforest sites but were absent in the other study sites. Shrubs species recorded were higher in most of the Taungya sites compared to natural regrowth forest. The soil texture of all sites, except Owo Taungya was sandy clay loam at the two soil depths. The soil pH ranged from 5.3 to 7.1 for the top soil and from 4.0 to 7.0 for the sub soil. Ore Taungya site gave significantly (p < 0.05) highest soil organic carbon (2.46 g/kg) and total nitrogen (0.20 g/kg) when compared with other agroforestry sites. The cation exchangeable capacity (6.77 cmol/kg) was highest at Aponmu site. These values however, decreased with depths. This study concluded that Taungya agroforest enhanced plant biodiversity conservation and improved the soil quality of the study area.
Description
xiii,98p
Keywords
Plant biodiversity, Taungya agroforestry, Agroforestry, Soil quality floristic composition, Vegetation
Citation
Akinbisoye, O.S. (2012). Comparative assessment of plant biodiversity among different Taungya agroforestry practices in Ondo State. Obafemi Awolowo University