Tropentag, October 9 - 11, 2007 in Witzenhausen "Utilisation of diversity in land use systems: Sustainable and organic approaches to meet human needs"

Influence of Land Use System on Diversity and Abundance of Insects in Akure Forest Reserve, Ondo State Nigeria

¹Federal University of Technology, Forestry and Wood Technology, Nigeria
²Federal University of Technology, Crop, Pest and Soil Management, Nigeria

Abstract

The study was carried out to assess the effect of land use system on insect diversity and abundance. Three land use systems (fallow land, cocoa agroforestry land, and untouched forest land) was selected for field work within Akure forest reserve. An hectare block were centrally demarcated in each of the forest type. The block was divided into twenty plots of 20 m × 20 m in size. Ten plots where randomly selected where the collection of insects and the enumeration of trees took place. This enumeration entailed the identification of all woody plants with diameter at breast height (dbh) of at least 10 cm. Monthly collection of insects with sweep net and hand peaking were used in each selected plot.
A total of 13,578 insects was collected. These insects belonged to 30 different families and were distributed among 15 orders. Within fallow land the insects belonged to 8 orders and 46 families; while cocoa agro forestry land consists of 5,884 insect that are distributed within 10 0rders and 50 families; and untouched forest land contain of 2,490 insects distributed within 10 orders and 56 species. The families and order with highest number of individual insects are Lepidoptera (4,000) and Orthopetera (1,260). These insects are mainly defoliators. Shannon-weaver diversity index for insects species for the three land use system were 2.306, 2.448, and 3.622 for fallow land, cocoa agro forestry land and untouched forest respectively. There was a significant difference in tree species diversity in the habitats. The species with highest frequency per hectare was Cordia platythrsa (6) in fallow land, cocoa (50) in cocoa agroforestry land Celtis zenkeri in untouched forest land.
A total of 14, 26, and 41 different species of tree were identified in the fallow land, cocoa agroforestry land and untouched forest respectively.

Keywords: Agroforestry, defoliator, diversity of tree species, cacao, fallow

Contact Address: Sunday Adeduntan, Federal University of Technology, Forestry and Wood Technology, No. 3 Adeniyi Close Behind Osrc Station Off Ijare Road, Akure, Nigeria, e-mail: niyi_gbengayahoo.co.uk