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The soil seed bank provides an indication of the regenerative potential of forest ecosystems following disturbances. The present study was conducted to examine the spatial and temporal distribution of soil seed bank in three different forest communities identified in an upper montane forest ecosystem (Dotalugala Forest Reserve) in the Knuckles Range, Sri Lanka. The three forest communities were upper-montane forest (UMF), midelevational wet face forest (MWF) and midelevational dry face forest (MDF), hereafter referred to as UMF, MWF and MDF, respectively. Ten surface soil samples were collected from five, 10 m × 15 m permanent plots (2 composite samples from each plot) established in each of the three forest communities. The soil samples were spread on seed beds in a glasshouse and emerging seedlings were counted and identified into different morphospecies. Two soil samplings were conducted during dry and wet seasons. Seed beds were maintained for nearly 3-4 months until no seedlings emerged. The results revealed higher number of germinable seeds in the wet season (1,157, 1,381 and 1,231 seeds) than in the dry season (507, 641 and 597 seeds) in UMF, MWF and MDF forest communities, respectively. The richness had similar trend between seasons (31, 35 and 34 morphotypes in the wet season and 24, 27 and 27 in the dry season in UMF, MWF and MDF, respectively). However, the density and richness showed no significant differences between forest communities during both seasons. Species composition differed between seasons and forest communities. Woody species dominated the soil seed bank during the dry season, while non-woody species dominated in the soil seed bank during the wet season. These temporal fluctuations in seed banks may possibly be due to site-specific (predation, senescence and germination of seeds) and plant-specific (phenology, dormancy of seeds) factors prevailing in these forest communities. Seeds of invasive species were represented comparatively less in all three communities, indicating no significant threat from invasive species to these forest communities. A number of pioneer species including Maesa indica, Acronychia pedunculata and Macaranga spp. were recorded in all three sites signifying their resilience and regenerative potential following a disturbance.

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Plant species in Tropical Montane Cloud Forests (TMCFs) of Dothalugala Man and Biosphere (MAB) Reserve were recorded in twenty six 10 x 15 m 2 experimental plots, aiming to reveal the total species richness and the richness of endemic and threatened flowering plant species in the forest canopy and the understory and, to find out the impacts of cardamom cultivation on the plant diversity of the study area. One hundred and forty eight plant species (77 tree, 46 shrub, 24 climber and one herbaceous species) belonging to 106 plant genera and 55 plant families have been found from the area examined. A high percentage endemicity of plant species (50%) was revealed in this site due to the presence of 74 (38 tree, 29 shrub, 6 climber and one hebaceous) species endemic to Sri Lanka. Similarly, 68 out of all plant species (45.9%) and 47 out of all endemic plant species (63.5%) in these forests were either globally or nationally threatened. The endemic and 'Critically Endangered' Stemonoporus affinis (Dipterocarpaceae) was also found to be thrive in the area. Cardamom cultivation had caused a tremendous reduction in the floristic diversity (total number of species and the number of endemic and threatened species) and the conservation value of TMCFs in Dothalugala MAB reserve. Therefore, the cardamom cultivation and other related disturbances within and adjacent to Dothalugala MAB Reserve should be arrested for the conservation of plant diversity in this fragile ecosystem and, this will eventually contribute towards the conservation of biodiversity not only in Sri Lanka but also in the globe as a whole.