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Development and testing of a biotic index to assess the ecological quality of lakes in Bangladesh

Chowdhury, Gawsia W., Gallardo, Belinda, Aldridge, David C.
Hydrobiologia 2016 v.765 no.1 pp. 55-69
Ephemeroptera, Trichoptera, climate change, habitat destruction, introduced species, lakes, macroinvertebrates, pollution, sewage, species diversity, water management, Bangladesh
Lakes in Bangladesh face many threats including habitat loss, over-exploitation of resources, pollution (e.g. sewage, waste dumping), climate change and the introduction of non-native species. To support effective lake management, we developed and tested the first Bangladesh Lake Biotic Index (BLBI), an index based on macroinvertebrates with the potential to assess and monitor the ecological status of lakes. Twenty sites in each of fourteen representative lakes were surveyed during the wet and dry seasons in 2009 and 2010 (total N = 560) to investigate the variation in macroinvertebrate assemblages, and their response to several physical and chemical parameters. The BLBI of a particular lake was calculated according to taxa tolerance scores, allowing categorization of the studied lakes according to their ecological status: least polluted, moderately polluted and highly polluted. BLBI was positively related to traditional structural metrics including species diversity and richness, evenness, and presence of taxa sensitive to pollution such as Ephemeroptera and Trichoptera. Outcomes from this study provide basic information on the ecological status of lakes in Bangladesh, and encourage the use and development of biomonitoring methods for the assessment and conservation of lakes in developing Asian countries.