Distribusi dan kepemilikan larva bentonik Chironomidae (Diptera) :: hubungannya dengan Jeluk dan Nutrien di Waduk Sempor, Kebumen, Jawa Tengah

HADISUSANTO, Suwarno, Promotor Prof.Dr. Jusup Subagja, M.Sc

2006 | Disertasi | S3 Ilmu Biologi

Penelitian ini bertujuan untuk mengkaji kualitas air dan sedimen, komunitas larva bentonik Chironomidae (distribusi lokal, kemelimpahan dan komposisi larva), korelasi antara kemelimpahan larva dengan jeluk dan kadar nutrien di Waduk Sempor, Kebumen, Jawa Tengah. Pencuplikan dilakukan pada bulan Februari 2001 — Mel 2002 di lokasi Kedungwringin; Kumambang; Pengantalan; dan Pekuwuan. Rancangan pencuplikan dengan Pencuplikan Acak Stratifikasi Teratur. Pengumpulan data digunakan pencuplik sedimen model Petersen dan sedimen disaring dengan saringan Tyler no. 40, ukuran 425 11m. Larva diisolasi dan diawetkan dalam formalin 2%. Data larva dianalisis dengan indeks Shanon-Wiener dan Simpson serta digunakan ordinasi dua dimensi. Hasil penelitian terdapat 17 genus yang terdin dan 25 spesies. Kemelimpahan larva bentonik pada tahun 2001, Februan (175 individu), Mel (467 md.), September (2.119 i.), Desember (128 md.); pada tahun 2002, Februari (640 md.) dan Mei (1,045 md.). Berdasarkan lokasi kemelimpahan larva tertinggì di PengantaLan (2.140 individu), Kumambang (1.466 md.), Pekuwuan (1.045 md.) dan Kedungwringin (470 md.). Lima spesies yang mempunyai kemelimpalian terbesar: Stictochironomus sp. (7,67 %), Parachironomus sp. (7,08 %), C. concomilahim (6,83 %), D.flexus (6,83 %), Ablabesmyia sp. (6,65 %). Hanya[ 23 spesies saja yang menghuni di keempat lokasi, Spesies paling sering muncul yaitu C. concomitatum di lokasi Pekuwuan dan Pengantalan, C. albiceps di lokasi Kumambang dan C. tenans di Kedungwningin. Spesies paling jarang muncul adalah Larsia sp. Kemelimpahan larva terkonsentrasi pada kedalaman 5 — 10 m, temperatur air (17-32 °C) masih dalam kondisi normal. Nutrien yang berpengaruh pada kemelimpahan larva Chironomidae adalah kadar N- total sedimen, P-total dan N-total air.

The objectives of this research were to study on water and sediment quality, the chironomids benthonic larvae community (local distribution, abundance, and composition), correlation of abundance, water depth and nutrient content at Sempor reservoir, Kebumen, Central Java. Sampling were done in February 2001 to May 2002 at Kedungwringin, Kumambang, Pengantalan and Pekuwuan. The sampling design was stratified purposive random sampling. Material or sediment sampled by Petersen’s dredge was filtered by Tyler no. 40 (mesh size 425 tm). The chironomids larvae were isolated and preserved in 2 % formaldehyde. The larvae data were than analyzed by Shanon Wiener and Simpson indexes and two-dimension ordination. The results showed that there were 17 genera containing 25 species. The larvae abundance was 175 individuals in February 2001, 467 in May 2001, 2,119 in September 2001, 128 in December 2001, 640 in February 2002 and 1,045 in May 2002, Based on the location, the highest abundance at Kedungwringin 470 individuals, Kumambang 1,466, Pengantalan 2,140, and Pekuwuan 1,045. The five species with highest relative abundance were Sticiochironomus sp. (7.67%); Parachironomus sp. (7.08 %); Chironomus concomilaum (6.83 %); D. flexus (6.83 %) and Ablabesmyia sp, (6.65 %). There were 23 species which found at all four sites; the most frequent species were C. concomitatum (Pengantalan and Pekuwuan); C. albiceps (Kumambang); and C. tentans (Kedungwringin). The rarest species was Larsia sp. The larvae were concentrated in the sediment of 5 - 10 m depth. The water temperature was 17 — 32 °C, and was normal conditionain the tropics. The analysis also showed that abundance of the larvae was influenced by sediment total-N, water total-N and water total-P.

Kata Kunci : Chironomidae,Jeluk dan Nutrient, chironomids, distribution, abundance, depth, nutrient