Abstract:
The study was conducted in the Kaluwamodara tributary and Benthara river situated in
the Kaluthara District of Sri Lanka. A field survey was carried out to find out the
richness of mangrove species, their diversity, abundance and the spatial differences of
their diversity. Sampling for the enumeration of mangrove species was
performed in three transects along the Kaluwamodara tributary, sub canal of
Kaluwamodara tributary and Bentara River. Located sample size is 10 m x 10 mand
200 m gaps were maintained between each sample. Twenty four samples were
selected maintaining vegetation density and distribution of species heterogeneity.
Only mangrove species were enumerated. Shannon-Wiener diversity index and
abundance indexes were calculated to analyse the diversity and abundance of
mangrove species. The Inverse Distance Weighted (IDW) interpolation technique in
ArcGIS was performed to analyse and prepare spatial distribution maps of
mangrove diversity. Total numbers of 1091 mangrove individuals were enumerated
during the survey. A total of 11 species belonging to 11 genera and 11 families were
recorded. Seven actual mangrove species and four mangrove associates were identified
from the area. Rhizophora apiculata, Sonneratia caseolaris, Nypa fruticans,
Acrostichum aureum and Hibiscus tiliaceus are the most common species recorded
during the study. Dolichandrone spathacea (L.f.) K. Schum is the least common species
found in the area. RHIZOPHORACEAE, SONNERATIACEAE, PALME,
PTERIDACEAE and MALVACEAE claim for the most common families in the three
study sites. The highest mangrove species diversity was identified in the
Kaluwamodara tributary and highest species abundance was identified in the sub canal of
Kaluwamodara tributary.
