A STUDY ON THE BUTTERFLY FAUNAL DIVERSITY IN VARIOUS FOREST HABITATS IN THE KNUCKLES FOREST RANGE

Abstract

A butterfly faunal survey was conducted in the Deenston-Nawanagala Nature Trail areaon the eastern flank of the Knuckles Forest Range at a 915-1906m of elevation with theobjective of studying the butterfly faunal of the area in different habitat types.

A field survey was carried out one day per month during August 2002 to August 2003period. Data collection was done using the 'long-transect method' containing thetransect width to the 'visible range' that varied according to the atmospheric conditions

The following five major habitat types (Listed in the descending order of extent) wereidentified: Abandoned Tea Lands with Lime Grass, Lowland Semi-evergreen Forest, SubMontane Forest, Montane Forest and Abandoned Cardamom Areas

The total number of species recorded was 40 in seven families

This habitat distribution is as follows: Abandoned Tea Lands with Lime Grass: 27 spp.,Lowland Semi-evergreen Forest; 28, Sub Montane Forest; 18, Montane Forest; 9,Abandoned Cardamom Areas;13.

Their distribution in the families is; Nymphalidae 12 spp., Papilionidae 8, Pieridae 6,Satyridae 6, Danaidae 5, Lycaenidae 2 and Riodinidae 1. Only the Family Nymphalidaeis found in all habitat types.

Three of these species are endemic and altogether five species (Including the threeendemics) are nationally threatened.

In the study area the butterfly fauna facing threats due to human and natural causes. Manmade fires occur in grasslands where 27 species (54%) are found. Cardamom cultivationis another factor. Strong winds in some seasons and forest dieback (especially inNawangala) are natural causes. The need for conserving this butterfly fauna ishighlighted in this paper