DIVERSITY AND DISTRIBUTION OF LICHENS OF AMBULUWAWA MOUNTAIN

Abstract

Ambuluwawa Mountain in Gampola District reaches to a height of 1065 meters and vegetationis mostly disturbed.

To study lichens three sites, each 100m2 in area, at different elevations (high <990m), (mid 950-870m) and (low 700- 650m) were selected. Three trees Alstonia macrophylla, Albizzia lebbek,Macaranga tomentosa were selected to study corticolous lichens. Alstonia macrophylla waspresent in all sites while Albizzia lebbek was present in sites one and three. Macarangatomentosa was present in site two only. Rocks were used for sexicolous species. Totalpercentage lichen cover and the total number of different lichens were recorded by placing250cm2 quadrate randomly on trunks of trees (six trees and four quadrate /tree and three rocksper site). Light intensity, bark pH of trees and relative humidity were measured in all sites.

In site one, Parmotrema reticulatum had the highest percentage cover (29.3%) while Buel/ia sp.I had the second highest coverage value (10.6%) onA macrophylla. On rocks, Diploschistes sp.had the highest coverage value while Aspicilia sp. and Toninia sp. was recorded with fairly highcoverage. On the trunks of A. lebbek, several species (If Usnea were recorded in this site.In site two, on A. macrophyl/a, Pertusaria sp. 1 was recorded with highest coverage (14.3%)while Pyrenula sp. and Letrouitia sp. 1 had coverage values of 11.46 and 6.67 respectively. Onrocks a species of Leotogium, Dirinaria aegialita and Pertusaria species were recorded withhigher coverage values. Pertusaria sp. was recorded from all three substrates in this site.In site three, on A. lebbek, Parmotrema reticulatum gave the highest coverage value whileDrynaria aegilita had the second higher value. Heterodermia sp.3 had the highest percentagecover on rocks.

Twenty-five different lichens were identified in site one while site two and three had lessernumber of lichens. Total number of lichens on A. lebbek and A. macrophylla differ significantlyat lower elevation but not in other two sites at higher elevation,

Statistical analyses of coverage values of lichens on different substrate within a site did not showa significant difference. Coverage values of lichens cn same trees, among sites also did not showa significant difference except on A. macrophylla. Lichen coverage on rocks was notsignificantly different between sites one and three.

Light intensity and relative humidity may be having a grater influence on the distribution oflichens. Effect of bark pH on lichen coverage was difficult to interpret.

Forty-five lichens species, which belong to nine genera, were identified in this locality. Eightlichen species were found to be new records in Sri Lanka.

Presence of indicator species such as Letrouitia, Diploschistes, Leptogium, Heterdermia andPyrenula with good coverage on Ambuluwawa Mountain indicates absence of air pollution inthis area.