A study was conducted to distinguish the likely role of benthic macroinvertebrate as biological indicators in Sungai

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A study on macroinvertebrate diversity was conducted in Sungai Kisap, Langkawi, Kedah. Five stations were selected with a distance of approximately 500 metres apart with three replications of benthos and two replications of water sample. The results classified Sungai Kisap in Class I, which indicates very good water quality based on WQI recommended by the Department of Environment. A total of 2 phyla, 3 classes, 8 orders, 29 families, and 3564 individuals were successfully sampled and recorded. The presence of Hydropsychidae, Baetidae, and Chironomidae with a high abundance of the families show the potential to be used as biological indicators of a clean ecosystem. The analysis showed that the average value of Shannon Diversity Index, H’ (1.28), Pielou Evenness Index, J’ (0.45), and Margaleff Richness Index, DMG (2.80) indicates that Sungai Kisap is in moderate condition and the distribution of macroinvertebrates is uniform between stations. The correlation test showed that the WQI has a strong relationship with the diversity indices involved. BMWP, ASPT, and FBI showed that Sungai Kisap has good water quality.

Aim: This study aims to determine Chironomidae diversity and distribution in three small rivers at Cameron Highlands in relation to their response to water quality conditions. Methodology: Fifteen sites from three rivers (Palas River, Pauh River and Bertam River) were chosen for water quality measurements and Chironomidae sampling. Water quality was analysed following APHA standard methods and chironomid was identified to genus level. The rivers were classified based on Malaysian’s Water Quality Index (WQI) and macroinvertebrates diversity and distribution was analysed using diversity indices. Comparison between sites and river was undertaken using one-way ANOVA and chironomid appearance in relation to water quality was evaluated using Pearson correlation test. Results: Chironomidae (Order: Diptera) distribution at high altitude rivers in Malaysia is not well documented although this group of insect has a wide range of distribution in tropical region. Based on Malaysian water quality index (WQI), result shows all rivers were in Class I. Although still in Class I, Bertam River has slight lower water quality due to higher ammoniacal nitrogen and total suspended solids. The diversity indices also demonstrate that Bertam Rivers was in stress conditions, and other two were in moderate conditions. Three subfamilies (Chironominae, Orthocladiinae and Tanypodinae) were recorded, which comprises of 1963 individuals. Tvetenia (Subfamily: Orthocladiinae) was the most dominant but only dominated Palas River and Pauh River. Another genus from Orthocladiinae (Crocotopus and Rheocrocotopus) also recorded dominant only in Palas River and Pauh River, but lesser in Bertam River. Only Polypedilum (Subfamily: Chironominae) which was second highest recorded, dominated in all rivers, even highest in Bertam River. Amongst dominant genus, only Polypedilum was found dominant in all rivers, others were only dominating Palas River and Pauh River only. Interpretation: This findings exhibit wide range of adaptations and potential use of Polypedilum as biological indicator. Due to availability of incomplete keys, identification to species level cannot be undertaken. However, this study reveals thirteen different sub-group of Polypedilum based mouthpart organs, which represent different species for tropical ecosystems.