Water Quality Biomonitoring Using Macroinvertebrata in Upper Way Besai, Sumberjaya, West Lampung

摘要

Forest conversion to agriculture such as coffee garden and rice field rapidly occured in the upperWay Besai watershed, Sumberjaya, Lampung, Indonesia which involved activities such as land clearing, soil tillage, planting, weeding and applying fertilizers and pesticides by farmers. Those activities affect the water quality along the stream and river through sedimentation and accumulation of nutrients and pesticide residues. Evaluating the quality of a stream through assessment of macroinvertebrates provides a sensitive and cost effective means on determining stream condition. Macroinvertebrates are sensitive indicators of habitat disturbance, even up to several months after infrequent chemical contamination in contrast to chemical monitoring that provides an idea about the current condition. Samples were taken in April 2005 and August 2005 at 30 spots along the upper Way Besai (WB) catchment along the main river and in three nested streams Way Petai (WP), Way Ringkih (WR) and Air Hitam (AH). Assessment results based on Family Biotic Index (FBI) indicate that water quality in both the forest area and the mixed coffe gardens in the upper Way Besai is excellent. Water quality decrease when converted rice field. Number of macroinvertebrate family and functional feeding group composition changed between seasons, landuse systems and stream order.