in Sri Lanka - Ministry of Environment

Another threat of increasing importance is the illicit removal of very young trees about 4–6cm in diameter from the understorey of the wet zone forests for firewood, fences and otheruses. Several small tree species such as Humboldtia laurifolia (larval host plant of Jamidescoruscans) and several species of Polyalthia (larval food plants of Graphium doson andGraphium agamemnon) are entirely understorey plants and their removal along with otherunderstorey plants will not only impact the larval food source but will also alter the compositionof the understorey by influencing its microclimate and thereby impacting shade-loving butterflyspecies (Discophora lepida) and plant species (Thottea siliquosa, the sole larval food plant ofPachliopta jophon).The disappearance of suitable habitats and larval food plants in all climatic zones is reflectedin the reduced size of many populations of butterflies, particularly those that show seasonalmass movements. This is particularly evident during the mass movements of Appias galene, A.libythea, Catopsilia pomona, Hebomoia glaucippe and Papilo crino; the numbers seen todayare but a fraction of what was seen a few decades ago.ConservationOf the 245 species of butterflies in Sri Lanka, 100 species (41%) are listed as threatened species(21 are critically endangered, 38 are endangered and 40 are vulnerable). A further 21 speciesare listed as Near Threatened. The status of 6 species was not analyzed because of lack ofdata on their occurrence and distribution. However, only Pachliopta jophon is listed as a globallythreatened species (critically endangered) by the IUCN. This indicates the need to update theGlobal Red List with respect to the conservation status of the butterfly fauna of Sri Lanka.These statistics also reflect the dire consequences of many of the threats outlined above aswell as the lack of information on the biology of many species of butterflies in Sri Lanka. Thestatus designated to the butterflies in this report has been based on EOO and AOO and hasnot taken into consideration the rate of decline in numbers over several years (because oflack of data), although this is a very important criterion in determining the loss of ground by aspecies in its environment over time. Nonetheless, several species such as Rapala lankana,Horaga onyx, H. albimacula, Gangara lebadea, Nacaduba calauria, Junonia hierta, Tajuriaarida, Spindasis greeni, Appias indra, and Cepora nadina, have been recorded in such lownumbers and in so few locations over many years that these must certainly be consideredthe most critically endangered in the island and their conservation must be addressed witha sense of urgency. These butterflies have been sighted less than a half dozen times overthe past 7 years since detailed records have been kept. Interestingly, these butterflies havealso been historically very rare even 100 years ago (Ormiston, 1924) and the assessment oftheir status given here can be questioned until their biology is understood. They are also veryrare in museum collections and the information available on the specimens is scanty. Thereis little or no information on what habitats they were found in and in which locations. All ofthese species are habitat specialists of the wet zone lowlands or montane forests and cannotsurvive outside pristine or near pristine forests as shown by the data collected by the Ministryof the Environment and several independent researchers. This highlights the importance ofconserving the rain forests of the south and south-west, particularly those forest reserves thatare under state control, which are probably the last refuges of these species. Another butterfly,Catapaecilma major, falls into this category but it flies in the dry and intermediate zones.29