Diversity of Mangrove Associated Brachyuran Fauna in Panama Lagoon, Eastern Coastal of Sri Lanka
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Date
2020
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Uva Wellassa University of Sri Lanka
Abstract
Mangroves are salt-tolerant plant communities that provide unique habitats for a wide
range of faunal communities. Panama lagoon is pristine with rich mangrove coverage.
The present study was carried out to investigate the diversity of mangrove associated
brachyuran fauna in the Panama lagoon, on the East coast of Sri Lanka. Field sampling
was conducted in six sampling sites, covering the entire lagoon from November 2019
to January 2020. In each site, three belt transects were laid perpendicular to the lagoon.
The belt transects were 10 m to 30 m depending on the length of the mangrove patch. It
was subdivided into 10 m×10 m plots and which had six 1 m×1 m randomly selected
sampling units. The sampling area was dug into the water level until the crabs were
caught and picked by hand. Several crabs from different species were recorded. Crabs
were identified up to species level using external morphological characters. Salinity,
temperature, and pH of mangrove soil were measured. Seven species of brachyuran
crabs belonging to four families were identified up to the species level. They
were Parasesarma plicatum, Metopograpsus thukuhar, Metasesarma obesum,
Episesarma mederi, Episesarma versicolor, Cardisoma armatum, and Varuna litterata.
The Parasesarma plicatum was recorded as the most dominant species due to it was
recorded in whole sites of the lagoon. The lower and middle areas of the lagoon
recorded 1.51 and 1.13 for the Shannon wiener indexes and no species found in the
upper area of the lagoon. The distribution pattern of dominant species up to 10 m, 20
m, 30m level. The salinity showed a negative correlation (p < 0.01) with the increasing
distance from the lagoon. The distribution of Cardisoma armatum showed a positive
correlation (p< 0.01) with the soil salinity. Panama lagoon consists of rich brachyuran
fauna diversity and it plays a virtual role in the ecological process and must be
conserved for the future generation.
Keywords: Brachyuran crabs, Fauna, Mangrove, Panama lagoon, Shannon wiener indexes
Description
Keywords
Ecology, Environmental Science, Animal Sciences, Biodiversity – Sri Lanka, Biology