Keterkaitan masukan bahan organik dan logam merkuri terhadap struktur komunitas dan produktivitas sekunder larva trichoptera di Sungai Ciliwung (Jawa Barat)

Abstract

Ciliwung River is one of the big rivers in West Java Province which is polluted by organic compound and mercury. Pollution in Ciliwung River could disturb the ecological balance of Trichoptera larvae. The purpose of this study was to reveal the influence of organic compound and mercury contamination on community structure, ecology feeding, secondary productivity of Trichoptera larvae and establish a local biocriteria using multimetric concept. Research was conducted in six stations on high gradient Ciliwung River segment. Trichoptera larvae were collected using surber net with five replications in each study sites. High of organic pollution, mercury contamination, and habitat degradation could decrease number of genus Trichoptera larvae (7-2), diversity index (2.8-0 bits per individu), while increase secondary productivity of Cheumatopsyche sp. larvae (5.9-81.5 g m-2 year-1). Ecology feeding was dominated by filtering collector while disturbance was increasing. Four biological metrics (total taxa number, scores of Stream Invertebrate Grade Number-Average (SIGNAL), % abundance of three dominant taxa, number of sensitive taxa) was successfully created to be a local biocriteria which was called Trichoptera biotic index (IBT). Range the index values were 26-28 classified as least disturbance, 17-18 low disturbance, 7-16 medium disturbance, and 4-6 severe disturbance. Development and refinement of IBT in the future can be used to monitor and evaluate rivers quality in Indonesia especially for high gradient river.