Bijita Barman | ASSAM UNIVERSITY (Diphu Campus) (original) (raw)

Papers by Bijita Barman

The composition and structure of aquatic Coleoptera and Hemiptera assemblages in a small stream, ... more The composition and structure of aquatic Coleoptera and Hemiptera assemblages in a small stream, Mauriagaon, flowing through Chakrashila Wildlife Sanctuary, a Key Biodiversity Area under the Critical Ecosystem Partnership Fund 2005 situated in Assam, India were analysed. The objectives were to describe the aquatic Coleoptera and Hemiptera from the stream, seasonal variation in their abundance and dominance, and also examine to their relationship with the environmental variables of the water. A total of 7 species (2 Coleoptera and 5 Hemiptera) were recorded from the system. Three Hemipteran species (Ptilomera assamensis, Metrocoris nigrofashioides, Rhagovelia sumatrensis) and one Coleopteran species (Orectogyrus sp.) occurred throughout the year. Shannon Weiner diversity index values in different seasons ranged from 0.36 in post monsoon to 0.52 in pre monsoon, while Berger Parker Index of Dominance ranged from 0.46 in pre-monsoon to 0.72 in post monsoon. Canonical Correspondence Analysis (CCA) showed that the species-environment correlations of axis 1 and 2 were high, and the majority of species responded negatively to total alkalinity. The study on the aquatic insects of a lotic system is a pioneer study in the Sanctuary as no work has been done so far on this and the study add data of the faunal diversity of the Sanctuary. This study suggested that species richness and density of aquatic insects may indicate the conservation value of the habitats because of their significant responses to environmental factors.

Biodiversity is the degree of variations of life forms within biome or ecosystems. Northeastern I... more Biodiversity is the degree of variations of life forms within biome or
ecosystems. Northeastern India is very rich in biodiversity, harboring many
endemic plant and animal species. It falls in Eastern Himalayan region. Knowledge
of the fauna of this region is poor. Most of the information available is on the
larger vertebrates that are easily observed and inventoried. The smaller mammals,
reptiles, amphibians, and fishes have been neglected and the most abundant
taxonomic group, the insects, have been virtually ignored. Chakrashila Wildlife
Sanctuary is the home of the endangered primate Golden langur (Trachypithecus
geei) in India. The sanctuary is also rich in flora and fauna. The water bodies of the
Sanctuary attract many migratory birds in winter season each year. The Sanctuary
is identified as Key Biodiversity Area for addressing the conservation of biodiversity
of the Sanctuary. Very few studies on biodiversity of this Sanctuary have been
carried out so far. The growing population in the surrounding villages is having
immense pressure on the resources of the sanctuary finally leading to habitat
degradation and biodiversity loss. Thus the habitat of the Sanctuary has to be
conserved for the conservation of genetic diversity.

Two new species of water striders in the genus Pleciobates are described from India and compared ... more Two new species of water striders in the genus Pleciobates are described from India and compared with allied species.
Pleciobates bengalensis Jehamalar, Basu & Zettel sp. nov.is described from the Jalpaiguri District, West Bengal and Pleciobates expositus Jehamalar, Chandra & Zettel sp. nov. (Hemiptera: Gerridae) is described from the Dhubri District, Assam. A key to the species of Pleciobates and a distribution map of the species of Pleciobates from India are provided. For
the first time the genitalia of Pleciobates females are described in detail.

This paper represented a preliminary three months data on the aquatic insect diversity of two pon... more This paper represented a preliminary three months data on the aquatic insect diversity of two ponds, one private property pond and one community pond of Irongmara village, district Cachar, Assam. The communitypond (pond1) was characterized by market and household waste disposal site and the privatepond (pond2) was characterized by a community fishery. A total of 16 families belonging to 5orders from pond 1 and 9 families belonging to 4 orders from pond 2 were recorded. The insect order Diptera was found to be abundant and dominant in pond1, while in pond2 the order Hemiptera
was found more abundant and dominant. Dissolved oxygen of water on pond1 was found very low with high Free-CO2 and Electrical Conductivity while in pond2 the dissolved oxygen was found in good concentration with low Free-CO2 and Electrical Conductivity. Different biomonitoring scores were computed to see the water quality of the ponds and statistical analyses were done to find the relationship of environmental variables with insect density and family richness. The present study compared the water quality of the two types of ponds and concluded that the authorities, management and users should come forward with protective measures to save the ponds from deterioration.

Deepor beel (Ramsar Site) is a natural, permanent wetland, in a former channel of Brahmaputra riv... more Deepor beel (Ramsar Site) is a natural, permanent wetland, in a former channel of Brahmaputra river having both biological and environmental importance and richer in floral and faunal diversity. The Deepor beel ecosystem harbours large number of migratory waterfowl each year. But in recent decades several threats introduced in the area like construction, industrial development, large scale encroachment, etc. within the peiphery of the beel. Hence by studying the water quality of the beel the health of the beel could be understood and corresponding measurements could be taken. In the present study physico-chemical variables of the water like, Water temperature (WT), Colour, Odour, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD0, Total Alkalinity (TA), pH, Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Total Solids (TS), turbidity (T), Total Hardness (TH0, Chloride, Calcium and Magnesium had been studied. The result of water variables varies with location, Turbidity found high, i.e., 12.6 TNU at site 7, where DO was very low at site 6 (1.4 mg/l). The BOD ranges (>2 mg/l) of water indicated that the water was moderately polluted at all the sites except site 6 and site 10. TDS shown the upper range of values (150 mg/l -725 mg/l), which was unsuitable for drink. The outcome of ANOVA shown that water variables differ with location (F ration=1.83, p-value<< 0.06). Bray-Curtis Cluster analysis had been performed to find out the similarity among the sites. Where site 1 and site 4 shown highest similarity percentage (96.45%) than other sites. Hence the present study showed that more or less all the sites of the beel were contaminated and a quick action is required to sustain the health of the wetland.

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