Diversity of Odonata in the Peak Wilderness Sanctuary, Sri Lanka

Abstract

A preliminary study on the diversity of odonata was carried out for the first time to assess thediversity of odonata in the Peak Wilderness Sanctuary (PWS), Sri Lanka. It is a biologicallyrich area surrounding the Adam's Peak which is located at 6° 48' 33.357 N and 80° 29'58.3182 E. Total area of the sanctuary is about 24,000 ha and the altitude ranges from 50 mto 2238 m.. The study was conducted from August 2012 to August 2013. Visual encountersurvey method was used for the sampling and it was carried out along the existing paths andstreams in the sanctuary covering many different habitats types. Sampling was done in theday time from 0800 h to 1700 h as odonates are most active during the day. 34 species ofodonates representing 11 families were recorded during the study while 30 of them wereidentified to the species level. This represents 28.1% (from 121 species) of the Sri Lankanodonate fauna. 19 of the recorded species (55.9%) belong to Suborder Zygoptera while theremaining 15 (44.1%) belongs to the Suborder Anisoptera. Seven of the identified species areendemic to the country while 13 species are considered to be threatened with extinction at thenational level. 10 of the threatened species are known to be Vulnerable while three speciesare endangered. The nationally data deficient and globally critically endangered damselflySinhalestes orientalis (Hagen in Selys, 1862) which has not been recorded for 154 years wasalso observed during this study. The high species richness of odonata and the presence ofmany threatened species and data deficient species indicate that the PWS is an important areafor the odonata thus more comprehensive studies and suitable conservation actions should bemade.