Use of lichens as bioindicators in tropical zones has been hampered by lack of taxonomic and ecological knowledge. This study was conducted to assess the variation of lichen diversity in different forest management practices under different environmental conditions for their potential use as bioindicators of environmental alterations in Dotalugala, Knuckles mountain range. Data were analyzed to assess the relationship between lichen diversity and microclimatic conditions. In this study, 192 and 148 lichen species were recorded in natural and disturbed vegetation types respectively. The statistical analysis revealed a significant variation in lichen diversity between disturbed and undisturbed vegetations (F = 6.213, df = 1; p ≤ 0.05). Lichen diversity in different vegetation types indicated a remarkable variation (F =3.21, df = 7; p ≤ 0.05). The regression tree analysis indicated, three important variables that determined the lichen diversity; type of vegetation, altitude and association with other Cryptogamic communities. The significant difference of corticolous lichen communities in the natural and disturbed vegetations may be due to the heterogeneity of microclimatic conditions. Specialist lichen communities found to be associated with pristine forests. Results of the present study suggest that lichens in the Knuckles mountain range could be considered as potential indicators in assessing ecological continuity within different vegetations and in the colonization of the regenerating habitats