Diversity And Some Aspects Of Biology Of Ephemeroptera In Streams Of Royal Belum State Park In Perak
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Date
2012-02
Authors
Ghani, Wan Mohd. Hafezul Wan Abdul
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Abstract
Communities of Ephemeroptera (mayflies) investigated in four rivers; Kejar
River, Tan Hain River, Mes River and Ruok River of Royal Belum State Park
(RBSP) were found to be relatively diverse (H’ = 1.407 – 2.166). Twenty genera of
10 families were represented by 10308 individuals collected by the kick sampling
technique from February 2009 until February 2010. Among the four rivers, Tan Hain
River had the highest abundance (3542) and although Ruok River had the lowest
abundance (1500), it scored the highest Diversity Index (H’ = 2.166, 1-D = 0.839)
and Richness Index (R1= 2.325, R2 = 0.465). Baetis sp. was dominant in all rivers
with an average density of 651.11 individuals m-2 followed by Habrophlebiodes sp.
(Leptophlebiidae) of 187.76 individuals m-2. Cinygmula sp., Drunella sp. and
Teloganella sp. were rare. Most ephemeropterans collected in all rivers were
collector-gatherers; collector-filterers were scarce and scrapers and predators were
uncommon. The scores of Water Quality Index (WQI) classified all rivers into Class
I of very clean water quality. All environmental parameters were weakly associate
with the abundances of ephemeropteran species (Spearman’s rho < 0.3, P=0.05)
except the Chemical Oxygen Demand (COD). The head width-body length scatter
plots of Baetis sp. separated the nymphal stages into 9 instars (F-F-8). Its life cycle
took approximately a month from the youngest instar to the final instar. Adult
emergence took place every month, thus Baetis sp. is speculated to have a
multivoltine life history in both Tan Hain and Mes rivers. The secondary production of Baetis sp. was estimated at 60.33 mg m-2 y-1 in Kejar river and 182.96 mg m-2 y-1
in Tan Hain River. The turnover rate (productivity/biomass) was very low in both
rivers and might not reflect the true rate because the cohort number was not known.
Adults Ephemeroptera were more attracted to high light intensities. Ten families
were collected at 160 watts from 2000 h – 0400 h and only 7 families were
encountered at 90 watts (1900 h - 0000 h) but their abundances were not significantly
different (P = 0.05) at both levels of light intensities.
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Keywords
Mayflies