Spatio-Temporal Variation in Macro Invertebrates of Ghodaghodi lake Far-west Kailali Nepal
Date
Authors
Journal Title
Journal ISSN
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Publisher
Department of Zoology
Abstract
Recently species associated with fresh water ecosystems have steeply declined due to
pollution, over exploitation, habitat modification, environmental degradation and impact of
other developmental activities. The physio-chemical parameters are also changing in these
recent years which are also the cause for the loss in aquatic diversity. Macro-invertebrates
forms important links in food chain and are considered as an indicator of changes in aquatic
habitat. Since Ghodaghodi Lake contributes habitat for wide variety of aquatic species, the
status of macro-invertebrates is yet to be known. Therefore, this study was designed to
investigate the spatio-temporal variations of macro-invertebrates and describe the
relationship between certain environmental variables and assemblage structure of macro invertebrates.
Macro-invertebrates
samples
were
collected
in
seasonal
basis
from
four
sites
of
the
Lake
by
using
bin sampler and then analyzed. Macro-invertebrate community richness,
Shannon-Wiener diversity, and evenness were calculated for each site.Data on the
temperature, depth, pH, conductivity, dissolved oxygen, hardness, free carbon dioxide,
alkalinity and total dissolved solid was recorded.Redundancy analysis (RDA) was performed
to examine the relationship between the Macro-invertebrate assemblages and environmental
variables.Altogether 42families belonging 18 orders, 6 classes and3 phylum’s of macro invertebrates
were
recorded
during
the
study
period.
The
highest
diversity
index
value
(3.16)
was
observed
in winter season and lowest value (3.03) was observed in the autumn season.
The highest diversity index value (3.22) was observed at site C and lowest value (3.10) was
observed at site B. Culicidae family (9.84%)had highest frequency in all four season and four
station.The Scolopendridae (0.22%) and Sphaeriidae (0.22%) familieshad lowest frequency.
The water temperature was found to be highest at site D at summer season i.e., 30.2 °C.
Depth of sampling sites of Lake was highest at site D in summer season i.e., 300 cm. TDS
was maximum at site C in autumn season i.e., 196.1.
Conductivity was recorded maximum at site A in summer season i.e., 236.5 µs. The pH of the
water was alkaline throughout the year i.e., greater than 7 pH. It was recorded 7.1-8.5. The
maximum DO was found to be 5.7 mg/l at site A in winter season. The free CO2 was 3.6
mg/l highest at site B in winter season. Hardness was found to be highest at site A in summer
season i.e., 379 mg/l. The alkalinity of the water was found to be maximum at site C in
winter season i.e., 228 mg/l. Redundancy Analysis (RDA) shows that: Family Culicidae,
lycosidae, Thiardae were most strongly positively correlated with the temperature in summer
season and strongly negatively correlated with alkalinity in autumn and winter
season.Noteridae, Bulinidae, Achatinidae, Lumbricidae, Ephydridae, Hydrometridae are
positively correlated with DO, depth, conductivity and hardness of water. Mutillidae,
Curculionidae, Lymnaeoidae, Notonectidae, Scolopendridae, Pyralidae, Elmidae,
Viviparidae, Corduliidae, Gerridaepreferred positively correlated with pH, total dissolved
solid and CO2
. Seasonal variation and location influence the macro-invertebrates
communities