Species composition, abundance and distribution of butterflies in a home garden habitat located at Hanguranketha, Nuwara Eliya district, Sri Lanka

Abstract

The species richness, abundance and distribution of butterflies associated with a home garden, which was comprised of three micro-habitats; a grassland [GL], shrubland [SL] and disturbed-forest [DF], at Hanguranketha region, Nuwara Eliya district, was determined for a period of four months from September to December 2021, using a visual encounter survey. At each habitat, a belt transect (100 m x 10 m) was set up, and weekly observations were made within 20 minutes in the morning and the afternoon. Species diversity and the evenness were estimated using the Shannon-Weiner diversity index. A total of 32 species representing five families, Hesperiidae, Lycaenidae, Nymphalidae, Papilionidae and Pieridae were encountered. Two species were reported as endangered, while 10 were endemic sub-species. These families were observed in all the three habitats, with the exception of Papilionidae in the GL. Nymphalidae was the most diverse family in DF (35 %) and SL (48 %) whereas Lycaenidae and Nymphalidae made up the most diversity in the GL (37 %). The DF harbored the highest species richness (88 %) and GL had the lowest (34 %). Altogether, 873 individuals were detected over four months. The abundance was found to be similar (P>0.05) in the DF and SL, but lower (P<0.05) in the grassland compared to the other two habitats. The maximum relative abundance was detected (61 %) in the Nymphalidae, while Hesperiidae showed the second highest abundance. The highest diversity (H=2.91) was recorded in the DF with 0.876 in evenness. Butterfly counts in the morning hours outnumbered the evening hours (P<0.05). A reduction in butterfly counts (P<0.05) was detected during November and December. The findings of this study revealed that this home garden is rich in butterflies and proper conservation mechanisms are essentially needed to protect them.