Aquatic insect biodiversity and water quality parameters of streams in Northern Thailand

Biodiversity of aquatic insect and physicochemical water quality parameters in Mae Tao and Mae Ku watersheds were assessed bi-monthly from February 2011 to February 2012. A total of 59 families representing 9 orders were recorded. At order level, Trichoptera was found at the highest frequency in total abundance (45.75%) followed by Ephemeroptera (18.06%), Hemiptera (13.45%), Odonata (9.62%), Diptera (8.17%), Coleoptera (4.6%), Megaloptera (0.17%), Lepidoptera (0.11%) and Plecoptera (0.07%). The family Hydropsychidae was the most prominent and the most abundant aquatic insect taxa followed by Chironomidae. Water temperature, dissolved oxygen and ammonia-nitrogen were similar at all sampling stations. Significant variations in pH, electrical conductivity, total dissolved solids, sulfate, nitrate-nitrogen and alkalinity were found at all sampling stations. Taxa richness and diversity index significantly correlated with dissolved oxygen, sulfate, nitrate-nitrogen and ammonia-nitrogen (p<0.05, p<0.01). Physicochemical data and biological data showed that mostly the surface water quality in Mae Tao and Mae Ku watersheds were within Type III of The Surface Water Standard for Agriculture and Water Quality for Protection of Aquatic Resources in Thailand

Caddisflies (Trichoptera, Insecta) as bioindicator of water quality assessment in a small stream in Northern Thailand

The influence of environmental variables and the potential as bioindicators of larval stages of the species of Trichoptera were evaluated in a small stream in northern Thailand from January to November 2017. A total of 1,191 individual caddisfly larvae belonging to 7 families and 13 genus were found. The larvae of the family Glossosomatidae were the most abundant, followed by Hydropsychidae and Calamoceratidae. The genus Glossosoma, Hydromanicus and Hydropsyche were the most abundant genus in this study. Results of the CCA ordination showed that total dissolved solids, electrical conductivity, and water temperature were the most important factors affecting the abundance and diversity of caddisfly larvae. Changes in the caddisfly larvae may indicate changes in physicochemical factors owing to urbanization or other anthropogenic. The results showed that the order Trichoptera, identified to the species or genus level, can potentially be used to assess environmental water quality status in freshwater ecosystems. This study suggested that species richness of aquatic insects may indicate the conservation value of the habitats because of their significant responses to environmental factors