ASSESSMENT OF FLORAL DIVERSITY ASSOCIATED WITH ROCK OUTCROPS IN WET ZONE, SRI LANKA

Abstract

Attached

The wide range of ecosystem diversity in Sri Lanka has resulted in high species diversity. Among them rock out crops are special habitats and are hardly studied. Rocks are being extracted for construction purposes in developmental activities. This may cause loss of endemic, rare, threatened or highly localized species, which may be found in the rock out crops. In this study, the emphasis was given to floral diversity associated with undisturbed or least disturbed rock out crops in wet lowlands. Sites were identified according to visual observations as well as randomly from the map of the Forest Department on Conservation Forests, wet zone. The Plots were identified by a visual reconnaissance survey and several circular plots of different sizes were laid out according to the site. The flora observed and the number of individuals were recorded. The study was concentrated on trees and shrubs but vines, epiphytes, ferns and some herbaceous plants were also recorded excluding grasses. General collection of flora out side the plots were taken. Altogether 15 sites have been surveyed. It was observed that most of the sites consist of similar types of vegetation. Variations among the sites regarding floral diversity were therefore limited. But there were species in rock outcrops that differed from the surrounding vegetation. Further, rock outcrops contained a considerable amount of endemic species, threatened species and rare species. Altitude and the number of species present showed no significant linear relationship. Regarding the degree of disturbance among sites and the diversity, there was no significant relationship shown. The sites showed xeric conditions and some of the species were generally found in dry habitats. Sometimes, plants showed an exposed root system and stunted growth. There is a considerable amount of diversity associated with rock outcrops and as habitats become rare, species associated with them could also become rare, therefore conservation measures should be taken where possible.