Community Structure of Benthos in Gajah Mungkur Reservoir Wonogiri, Central Java

Abstract

Sunarto. 2013. Index of diversity as a basis in determining the benthos community structure influenced by environmental factors in Gajah Mungkur Reservoir, Wonogiri, Central Java. Gajah Mungkur Water Reservoir is a man made body water that serves as a flood control as well as a place for fishery, tourism, hydroelectric, and irrigation. The quality of the water highly depends on the humans’ activities, including their dealing with the waste, tourism activities, and fishery activities making use of cages. Waste can cause hyper-nitrification accompanied by sedimentation, hypoxia, and siltation. The benthos community structure is possibly influenced by environmental factors based on benthos biodiversity index. The purpose of this study was to examine the influence of phisical and chemical invironmental to the community structure of benthos based on the diversity index to figure out the impact of the physical and economical environment factors on the benthos community structure based on diversity index. The sample was collected from six areas at six zones: (i) the inlet (the springhead of Keduang River), (ii)traditional fisheries,(iii) tourism area, (iv) conservation, (v)nerawin area, and (vi) the outlet. The observed environmental factors include temperature, the degree of water’s purity, pH, DO, nitrate, phosphate, calcium and magnesium. The results showed that the environmental factors do have impact on the benthos community structure based on diversity index. Therefore Gajah Mungkur water reservoir was considered  still feasible for the benthos habitat and for other purposes as required in the government regulations.

Keywords: diversity index, community structure, benthos, Gajah Mungkur Reservoir Wonogiri, environmental factors