ผลกระทบจากการเปลี่ยนแปลงพื้นที่ชุ่มน้ำเป็นพื้นที่เกษตรกรรมต่อคุณภาพน้ำมวลชีวภาพและความหนาแน่นของปลาน้ำจืดในที่ราบน้ำท่วมถึงของแม่น้ำตาปี อำเภอเคียนซา จังหวัดสุราษฎร์ธานี

Abstract

Fish habitat loss due to floodplain conversion to oil palm and rubber plantation is one of the entire issue in the Tapi River Basin. The present study aims to examine the difference in same environment parameters and fish component between the previous and recent habitat conversion. Collected fishes and measured water quality bimonthly from January 2015 to March 2016 in Tapi River Floodplain, Khian Sa District of Surat Thani Province. The study reveals exceed water quality in previous habitat than recent habitat conversion, Nitrate 3.32 and 5.49 mg NO,-N/L, Nitrite 2.74 and 2.87 mg NO,-N/I, Phosphate 3.57 and 4.17 mg PO-P/l, pH 3.02-7.20 and 3.65- 8.23, Electric Conductivity 125.09 and 186.06 μS/cm, Dissolve Oxygen 3.91 and 6.18 mg/l, Temperature 29.41 and 30.91 °C, Suspended Solid 12.56 and 44.57 mg/l, and Depth 0.96 and 0.64 m., respectively. Two-Way Nested ANOVA showed significance different (P<0.05) in Nitrate, pH, Electric conductivity, Dissolve oxygen, Temperature and Dept. There were 8636 fishes belong to 8 order, 19 family and 55 species. Previous habitat conversion showed higher species number, Species Richness index, Evenness Index and Diversity index, 49 and 41 species, Species Richness 5.56 and 4.99, Evenness index 0.77 and 0.75, Diversity index 2.99 and 2.77, respectively. Biomass and Density also higher than recent habitat conversion, Biomass 176.69 +13.68 and 83.52 +6.37 g/ 50 m2 and Density 103.87 +7.90 and 56.43 ±4.66 ind/50 m2. Two-Way Nested ANOVA showed significance different (P<0.05) in biomass. MANOVA showed significance different (P<0.05) in community of fishes and Canonical Correspondence Analysis reveals most of fishes distribute in previous habitat.