Benthic community populations near two adjacent northern pulpmill discharges

Benthic invertebrate communities were investigated as part of the federal Environmental Effects Monitoring programs conducted as required by the amended Pulp and Paper Effluent Regulations (PPER) of the federal Fisheries Act. A Refiner Mechanical (RMP) and larger Kraft pulpmill, both situated on a northern, BC reservoir, discharge secondary-treated effluent within 5 km of each other. Efforts to independently distinguish potential effects associated with these individual discharges were complicated by the proximity of the diffusers, their location within a complex ecological region of a reservoir, and the presence of temporal and spatial confounding influences. A comprehensive examination of the benthic community structure involved the combined assessment of several endpoints (total population numbers, relative proportion of taxonomic groups, and species richness). A tiered, spatial approach, based on a reservoir ecological model (Thornton et al., 1981), was adapted to assess and distinguish community structures and reservoir- and mill-related influences. Results suggested that effects associated with the two different mills could be distinguished based on subtle and distinct differences in benthic community profiles.

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Community structure of benthic macroinvertebrate fauna of river Ichamati, India

Journal of Threatened Taxa ◽

10.11609/jott.3439.10.8.12044-12055 ◽

2018 ◽

Vol 10 (8) ◽

pp. 12044

Author(s):

Arnab Basu ◽

Indrani Sarkar ◽

Siddartha Datta ◽

Sheela Roy

Keyword(s):

Benthic Community ◽

Diversity Index ◽

Abiotic Factors ◽

Benthic Invertebrate ◽

Benthic Macroinvertebrate ◽

Macroinvertebrate Communities ◽

Habitat Conditions ◽

Invertebrate Communities ◽

Benthic Invertebrate Communities ◽

Hydrological Variables

Benthic macroinvertebrate communities are frequently applied as indicators of aquatic ecosystem health as many species are responsive to pollution and abrupt changes in their surroundings. The qualities of benthic invertebrate communities greatly depend on habitat conditions. Thus the diversity in benthic community varies with different habitat conditions. This investigation on the structure of the benthic invertebrate communities was conducted on river Ichamati, a trans-boundary river between India and Bangladesh to assess the cumulative effects of water quality on the aquatic biota. The study period extended from February 2011 to January 2014 at three sites from Majdiah to Hasanabad (in West Bengal, India) a stretch of 124km. A total of 23 macrobenthic species belonging to three phyla, five classes and nine orders were identified. Fifteen species of benthic invertebrates belonging to Mollusca, three species under Annelida and five species under Arthropoda were found. The highest abundance density (3633.33 indiv.m-2) and species richness (18 species) were recorded up-stream (Majdiah) where marginal habitats covered by macrophytes were significantly higher than at other sites. Both the organic carbon (4.41±1.11) and organic matter (7.48±1.56) of soil at this site were the maximum thus influencing the richness of benthic macroinvertebrate communities. Hydrological variables, viz, dissolved oxygen, pH, alkalinity; hardness, salinity, nutrients, calcium, and magnesium were studied to determine their influences on the benthic community in the upper, middle- and down-streams of the river, respectively. Shannon’s diversity index (0.95–2.07; 0.00–0.72; 0.00–0.64), dominance index (0.57–0.86; 0.00–0.44; 0.00–0.44), evenness index (0.72–0.95; 0.61–1.00; 0.00–1.00), Margalef index (0.72–2.23; 0.00–1.32; 0.00-0.28) of the upper, middle- and down-streams were calculated. Benthic macroinvertebrate density was correlated with hydrological variables which indicated that the abiotic factors had either direct or inverse influence on the richness and abundance; however, the abiotic factors did not correlate identically in all three sites.

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