Abundance and Diversity of Tree and Insect Species in International Institute of Tropical Agriculture Arboretum and Forest Reserve

The study was carried out to determine the abundance and diversity of insect and tree species in two forest ecosystems (i.e. natural forest and arboretum). Two forest types (natural forest and arboretum) were selected for the field work. Eight plots were demarcated in the two habitats and four plots were randomly selected in each of the forest types. The size of each plot was 20m x 40m where insect collection and enumeration of trees species took place. The enumeration entailed identification of all woody plants with diameter at breast height (dbh) of at least 10 cm. In the two study sites, monthly collections of insects with sweep net and hand picking were carried out in each selected plots. A total of 5,852 insects were collected and identified from the two habitats: 3,390 from the arboretum while 2,462 from the natural forest habitat. The identified insects belonged to a total of 24 families and distributed among 13 orders. Within the natural forest, a total of 2462 insects belonging to 47 species and 7 orders were identified while for the arboretum have a total insect population of 3390 belonging to 41 species and 6 orders were identified. The Shannon-Weiner diversity index for insect was 3.7 and 2.52 in arboretum and natural forest habitats respectively.