RESPON KOMUNITAS BENTHIK INSEKTA EMPAT BULAN PASCA-KEBAKARAN HUTAN 2002 DI HULU KALI BOYONG GUNUNG MERAPI

The purpose of this research is to study the response of benthic insect community in the headwater of Boyong River, Mount Merapi, four months post-forest fire in 2002. Energy at the headwater ecosystem was based on the detritus food-chain. The presence of benthic community indicated forest health. The forest fire caused energy which entered into the river changed from allochtonous coarse particulat organic matter (CPOM) to fine particulat organic matter (FPOM). This change would be responded by the functional group of benthic community. Data were collected with Surber Sampler. The result showed that there were 12 genus constituent of benthic insects consisted of functional groups of collector gather, collector filter, predator, dan scrapper. The dominant functional groups were collector gather and collector filters, 2256 individual/m3 or 86.02% and the dominant genus of Baetis and Leutcra. Otherwise, scrapper was founded 111 individual/m3 or 4% and predator 256 individual/m3 or 10%. This condition showed that four months post-forest fire indicated dominant allochtonous in Boyong River was CPOM and FPOM with size of 1 mm. The quality of nutrients in the water was low, otherwise, the sediment nutrients was high. The dominance of functional group of collectors indicated that ecosystem of headwater forest in Boyong River had not been fully recovered