in Sri Lanka - Ministry of Environment

Onthophagus and Panelus were also not recorded during extensive surveys. Five out of theknown six Gymnopleurus species were found except G. Smaragdifer.Shifts in the distribution patterns were also observed for some species. For instance, P.melanarius that was known to be widely distributed across the wet zone in the past wasrecorded only from relatively undisturbed areas and good forests during this survey. Caccobiusunicornis which was only recorded from the wet zone by Arrow (1931) was also found the in dryzone. Likewise, Onthophagus laevigatus that was earlier recorded in the wet-zone, was onlyrecorded from the dry and arid zones during our survey.The distribution of Scarabaeinae beetles can be attributed to species-specific habitatpreferences interacting with climatic/geographic variation across the island and anthropogenicmodifications of habitats. Spatial diversity is influenced primarily by climate, elevation, vegetationtypes, available dung types and microhabitat conditions created by canopy, shrub cover, soiland litter properties. These directly affect predation, foraging and reproduction of dung beetles.Mammals are the major suppliers of dung resources. Although diversity and endemism of themammals are high in the wet and montane zones, the dry zone forests contain most of thelarge mammals that are the primary suppliers of dung. The species richness of dung beetlestends to increase with rainfall. Dung beetles reproduce during rainy reasons, leading to moredung burial for egg laying. Community structure, abundance and diversity, are often negativelycorrelated with elevation. Lower productivity at higher elevations is suggested as one of thereasons for this decline. Further, body size of a species is considered to be a function ofenvironmental productivity. This is consistent with the findings of this survey where smallerspecies were found to dominate the species assemblage in the montane zone while large andmedium sized species were more abundant in all other zones.Threats and conservation prioritiesDung beetles are strongly influenced by climate change, forest modification, deforestation andalteration of microhabitat conditions. Large dung beetles are especially susceptible to the lossof forest cover. For instance, P. melrnarius, is vulnerable to loss of forest cover and populationsdecrease rapidly in open, modified areas. Change of favourable environmental conditions cansignificantly alter forest dung beetle communities. Forest loss results in increased predation bynatural enemies, and loss of mammals providing dung resources. Sri Lanka has undergonemassive loss of forest cover in the last century. With few exceptions, the effects of thesechanges on the insect fauna are virtually unknown. It is known that native, forest-inhabitingdung beetle species undergo local extinction in areas where tree cover has disappeared. Inaddition, deforestation in the wet zone during the 19 th century caused many large mammalsto move to the dry zone. Large mammals in the wet zone are mostly restricted to forests andexist in small populations.Altered habitats are often replaced by different communities that are more adapted to newconditions. In the dry and arid zones, large beetles like Scrabaeus gangeticus appear to behighly adapted to open environments and take advantage of the surfeit of dung. However, inthe wet zone, dung beetle biomass is high in forest habitats compared to open modified areas.Some of the modified open habitats of the lowland wet zone of Sri Lanka are occupied bydung beetle communities that are much less functionally efficient than the forest communitiesoccupying the same area.440