ASSESSMENT OF FAUNAL DIVERSITY OF A NATURAL FOREST AND AN ADJACENT PINUS MIXED PLANTATION FOREST IN YAGIRALA

Abstract

Faunal diversity of the natural forest (Pamaragala Aranya Forest) and the University of SriJaycwardcncpura Pinus-ill ixed forest. in Yagirala forest reserve was assessed. TheUniversity Pinus - mixed forest has a dense undergrowth and tropical lowland tree species.The natural forest is a highly degraded forest due to past logging and prevailing illicitfelling. m. The University Pinus forest is a mixed forest which has a dense undergrowthand tropical lowland tree species.

In this study. random line sampling method was used to enumerate fauna. Five plots oflOll III x 5 III each leaving gaps of 50 Ill. were used as a transect line. Fifteen survey lineshaving 60 plots in the Pinus - mixed forest and II survey lines having 51 plots in thenatural forest were assigned. The study was restricted to some selected faunal groups suchas birds, mammals. reptiles. fishes and some invertebrates (butterflies, land snails etc.).Pitfall trapping was used to assess the diversity of selected ground active invertebrategroups such as ants. beet lcs and spiders. For each forest. 10 survey lines were selected and:2 pitfall sampling points were located in each sampling plot for the location of pitfall traps.Two independent samples t-Tcst and the Wilcoxon Signed Rank Test were used tocompare the faunal diversity between the two forests.

The results showed that there is no significant difference in the diversity of birds,mammals. butterflies. and ground active invertebrates such as ants. beetles and spidersbetween two forests. The diversity of land snails in the natural forest is significantlyhigher than the diversity of land snails in the Pinus - mixed forest. The diversity ofinvertebrates of the Pinus - mixed forest is significantly higher than the natural forest.

According 10 the results of the present study. the Pinus - mixed forest also has a rich faunaldiversity. Therefore. il can he assumed that one or more reasons such as food. nestingplaces. protection for fauna in the Pinus - mixed forest. edge effects of Ihe surroundinghome gardens. and the effect of the rich faunal diversity in the natural have been affectedcousidcrahly 10 increase the diversity of some fauna in the Pinus - mixed forest.