ความสัมพันธ์ระหว่างคุณภาพน้ำกับความหลากหลายของสัตว์ไม่มีกระดูกสันหลังขนาดใหญ่ บริเวณเหนือและท้ายเขื่อนแม่งัดสมบูรณ์ชล จังหวัดเชียงใหม่

Abstract

The objectives of this study are to study the macroinvertebrate diversity in upstream and downstream of Mae Ngat Somboonchol dam and to study some water qualities in upstream and downstream of Mae Ngat Somboonchol dam. The study sites were divided into 7 sites ; 2 sites in upstream and 5 sites in downstream. Macroinvertebrates specimens and physico-chemical parameters were studied for 1 year, since June 2013 to May 2014. The result found the value of conductivity, Total Dissolved Solid (TDS) and Dissolved oxygen (DO) in both upstream study sites in upstream of the dam had higher than other study sites in downstream. The similarity analysis by Cluster Analysis and Principle Component Analysis shown the similarity among the upstream sites and they were differed to the other sites in downstream due to Conductivity and TDS, which were the important factors to determine the difference. Macroinvertebrates specimens for 22,529 individuals from 12 orders within 85 families were found. The highest number of individuals were Ephemeroptera, that were found 8,007 individuals. The 2nd site in upstream of the dam found the highest number of individuals that found 7,833 individuals and the 3rd site in downstream of the dam found the lowest number of individuals that found 299 individuals. The highest number of individual was the family Baetidae, that were found 3,847 individuals. The analyzing of macroinvertebrate diversity by Shannon-Wiener Diversity index shown the 1st site in upstream of the dam in December 2013 was the highest, that was 2.902. And the Evenness of macroinvertebrate was highest in the 7th site in downstream of the dam, that was 0.980. The similarity analysis by Cluster Analysis shown it can divide the study sites into 3 groups; the first group was the 2nd site. The second group member was the 3rd site, the 4th site, the 5th site, the 6th site and the 7th site. And the third group was the 1st site. The considering by Principle Component Analysis (PCA) found the macroinvertebrate in order Trichoptera especially family Helicopsychidae was the important factor that determine the different of 1st site from the others. While order Ephemeroptera especially family Caenidae was the important factor that determine the 2nd site was differed from others. And other sites in downstream were related to the macroinvertebrate in family Hirudinidae (leech), family Thiaridae (Melanoides tuberculata) and family Corixidae (Water Boatman) From the study of the relationship between water quality and macroinvertebrate diversity in upstream and downstream of Mae Ngat Somboonchol dam, DO was the factor that affect to the diversity of macroinvertebrate. Most of macroinvertebrate that found in upstream of the dam were the larvae that prefer the good quality stream such as order Ephemeroptera, Plecoptera and Trichoptera. While the macroinvertebrate that found in downstream of the dam were the adapted groups, that can be lived in moderate- low quality stream such as order Hemiptera, order Coleoptera and order Diptera.