Phytoplankton Diversity in Six Major Reservoirs of Badulla District, Uva Province, Sri Lanka
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Date
2020
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Uva Wellassa University of Sri Lanka
Abstract
Phytoplanktons are major primary producers and act as a bioindicator in inland waters.
The present study investigated the phytoplankton species composition of six reservoirs
(Ulhitiya, Rathkinda, Mapakada, Nagadeepa, Dambarawa, and Sorabora) with highest
inland fish production in Badulla district. Samples were collected using a plankton net (60
μm mesh size) from five sampling points of each reservoir during November 2019-
January 2020. The taxonomical status of collected samples was identified using previous
literature records, standard pictorial guides (The Genera of the Freshwater Algae of Sri
Lanka). Biodiversity indices were calculated to identify the variations of phytoplankton
diversity among sampling points and reservoirs. Total of 41 phytoplankton species
belonging nine major taxonomic classes; Bacillariophyceae (10), Chlorophyceae (10),
Cyanophyceae (08), Zygnemaphyceae (06), Eugenophyceae (02), Fragilariophyceae (02),
Chryotophyceae (01), Xanthophyceae (01), Dinophyceae (01) were recorded. Diatoms
(Bascillariophyceae) recorded the highest relative abundance (61.57%) from selected
reservoirs. Sampling points of each reservoir had no significant effect (p>0.05) on the
phytoplankton diversity while it showed a significant effect (p>0.05) on phytoplankton
diversity among reservoirs. The highest Shannon-Wiener index (1.61±0.06), Simpson’s
Index (0.71±0.01), evenness (0.52±0.024) and richness (21±1.62) were reported from
Dambarawa, while lowest Shannon-wiener index (1.25±0.19), Simpson’s index
(0.59±0.08), evenness (0.42±0.19) and richness (19±0.89) resulted for Ulhitiya Reservoir.
The current study reveals that Aulacoseira sp, Microcystis sp, Pediastrum sp,
Staurastrum sp, Arthrospira sp shows the highest abundance in all six reservoirs.
Dominant species play a vital role as primary producers, bioindicators (Aulacoseira sp,
Microcystis sp), and feed (Staurastrum sp, Arthrospira sp) for fish. Due to the high
abundance of Microsystis sp. (51.58%) in the Ulhitiya reservoir, the potential to generate
toxic algal blooms was identified by the current study. In conclusion, this study identified
the dynamic phytoplankton community and dominant species which act as the major
autotrophs in studied reservoirs. Further, data collected could be used as the baseline
information for the aquatic ecological studies and inland fishery enhancement programs
Keywords: Shannon-Wiener index, Simpson’s index, Biodiversity, Inland fishery,
Primary producers/autotrophs
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Keywords
Environmental Science, Ecology, Biodiversity – Sri Lanka, Water Falls