Forestry and Environment Sympoisum 1998, Sri Lanka

Fourth Annual Symposium organized by Department of Forestry and Environment Science, University of Sri Jayewardenapura, Sri Lanka.

Sunday, October 08, 2006


M M D J Senaratne and B M P Singhakumara
Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Nugegoda.

The composition and distribution of herbaceous plants were investigated at Sinharaja World Heritage site.

Previously unlogged forest areas were selected for the present study. Several transects were marked purposively in each site from valley to ridge to study the topographical variation of herbaceous plant distribution. Circular plots, each 10 m2 were demarcated on each transect to study the herbaceous flora. In addition, 200 m2 plots surrounding the 10 m2 plot were marked to enumerate the tree species in the area. The distance between two, 200 m2 plots was 20 m.

In each plot number of plant species was recorded. Voucher specimens were prepared for identification of species found in plots as well as outside the plots. Dominance diversity curves and Shannon diversity indices were prepared for each transect.

Ninety one species belonging to 40 families were recorded. Twenty nine of 91 species are found outside plots. The estimation of individuals of herbaceous plants per hectare was 21,790. Herbs and herbaceous climbers represented 38.47% of the total herbaceous flora. Fern and fern allies represented 45.67% and grasses and sedges 15.84%, respectively.

Species rich families were Zingiberaceae (6 spp.) and Rubiaceae (5 spp.) Density dominance families were Rubiaceae (6.97%) Zingiberaceae (3.9%), Mysinaceae (3.6%), Polipodiaceae (17.3%), Dennestaediaceae (7.8%) Cyatheoceae (3.8%) and Cyperaaceae (5.5%). Diversity indices in valley and ridge were 0.2153 and 0.1754, respectively.

Results indicate the localized distribution of herbaceous species in understorey vegetation of lowland rain forest. This may he due to the differences in micro habitats from valley to ridge.


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