Macroinvertebrate benthic community as rapid quality assessment in Winongo, Code, and Gajahwong Streams inside Yogyakarta City, Special Region of Yogyakarta Province

Abstract

Streams in Yogyakarta City are classified as an urban river, they receive huge amount of organic matter daily from anthropogenic waste. Growing urbanization affected water ecosystem causing water quality and benthic community changes. Macroinvertebrate benthic immediately respond to physic-chemical changes of the stream. Aims of this study are studying urbanization alter macroinvertebrate benthic community, and water quality in Winongo, Gajahwong, and Code streams of Yogyakarta City. Samples were collected at December 2015 and January 2017 in Winongo, Gajahwong, and Code streams inside the administration area of Yogyakarta City using sediment Dredge. Collections perform by dividing each stream into three parts with five replications. Macroinvertebrate benthic were filtered using stratified filter mesh 60, 40, and 20 results showed that macroinvertebrate benthic diversity decreasing from 2015 to 2017 in these three urban streams. There were not much species founded in Yogyakarta City Streams, indicates riparian ecosystem lack of natural habitat. All riparian zone are damage by anthropogenic activities. Their density is also decreasing probably because riparian floodplain embankment caused water velocity faster, leave little sediment for benthic organism. Chironomids larvae dominate in all stations in each river, and the most abundant in Code. They were abundant because streams in Yogyakarta City accept high input of organic matter. They classified as tolerate groups where their abundance indicates water pollution. High waterfall during 2016 most probably caused water quality better in 2017 than 2015. Dissolved oxygen was higher, and water ph is closer to neutral. Thus it cannot be used as an indicator.