Pengaruh Illegal logging terhadap kemelimpahan komunitas larva insekta akuatik di Hulu Sungai Wain Kalimantan Timur

CHELSI, Yosephin, Dr. Sudibyakto, MS

2005 | Tesis | S2 Ilmu Lingkungan (Magister Pengelolaan Lingkunga

Pada negara yang memiliki 4 musim, kehadiran larva insekta akuatik digunakan sebagai bioindikator kesehatan daerah tangkapan air. Penelitian ini bertujuan mempelajari kemelimpahan komunitas larva insekta akuatik di hulu sungai ekosistem hutan lindung Sungai Wain. Hutan Lindung Sungai Wain dipilah menjadi ekosistem hulu sungai hutan primer dan ekosistem hutan bekas illegal logging. Hulu sungai hutan bekas illegal logging meliputi hulu sungai hutan alang-alang, hulu sungai hutan baru di ileggal logging, dan hulu sungai hutan sekunder. Secara spesifik dipelajari respon komunitas larva insekta akuatik terhadap tekstur sedimen, nutrien sedimen, kualitas air, dan kekritisan lahan dalam stream order 1 pada tiap hulu sungai. Cacah individu komunitas larva insekta akuatik dicuplik dengan metode Stratified Random Sampling menggunakan surber sampler 30 x 30 cm dengan ulangan 30 kali. Hasil penelitian menemukan 36 genus komunitas larva insekta akuatik, tersusun dalam 5 komunitas feeding group, collector gather, collector filter, predator, scrapers dan shredders. Feeding group tersebut tersebar tidak merata dan ditemukan, di semua tipe hutan area kajian. Feeding group dominan pada tiap area kajian adalah gabungan collector gathers dan collector filters sekitar 53 - 82%. Genus penyusun dominan disemua tipe hutan adalah Chironomus sp. dengan densitas 59,25 – 1325,79 ind/m3. Pada hulu sungai hutan primer komunitas feeding group shredders sangat sedikit densitasnya 22.22 ind/m3 dibandingkan collector gather 1822.04 ind/m3. Respon kehadiran collectors di hulu sungai hutan primer mencerminkan hutan primer sudah rusak. Sedangkan hasil perhitungan dengan nilai tingkat kekritisan lahan hutan primer yaitu 500 dan kualitas fisik kimia air yang baik. Dapat disimpulkan hulu sungai hutan primer telah rusak karena kawasan hutan diatas hutan primer sudah mengalami fragmentasi hutan. Sehingga kehadiran komunitas larva insekta akuatik dapat dijadikan bioindikator kesehatan daerah tangkapan air. Artinya dalam pengelolaan hutan di Kalimantan Timur tidak hanya menggunakan parameter lahan kritis, tetapi juga memasukkan komunitas larva insekta akuatik

Aquatic insect larvae community in temprate region has been use as bioindicator good conditions catchment area. This research was to study the abundant of aquatic insect larvae community in primary forest and illegal logging forest, the quality of texture and nutrient water and sediment, land critical and the respon of larvae insect aquatic community in Sungai Wain Protection Forest. The illegal logging forest divided into the secondary forest, the new illegal logging and the grass land ecosystem. Sampling were collected using composite random sampling methods with surber sampler 30 x 30 cm of rapid, pool and edge niches with 10 replicates. The results showed 36 genus consited of 5 community of feeding groups collector gathers, collector filters, predators, scrapers and shredders of the aquatic insect larvae. The collectors were very abundant at all streams 53 - 82 %. However, the shredders community were very less about 4 – 10 %. Include the primary forest streams Chironomus sp. density was between 59,25 to 1325,79 ind/m3. At the primary forest density shredders were 22.22 ind/m3, but collector gathers densities was 1822.04 ind/m3. The high densities of the collectors community reflected primary forest in headwaters of Sungai Wain Protection Forest was disturbed. Community collectors, even the primary forest the catchment area was not in good conditions. Eventhough the land critical level was not critical with value of 500, and the physical chemical water quality are in good conditions. This means the headwaters above the studied areas had fragmented forest. The present of aquatic insect larvae community in east Kalimantan forest can be used as bioindicator on healthy watershed. Therefore, in managing the forest in East Kalimantan not only based on the critical land parameters, but the present aquatic insect larvae community should be used.

Kata Kunci : Lingkungan Hidup,Kerusakan Hutan,Illegal Logging,Larva Insekta Akuatik,headwaters, aquatic insect larvae, primary forest, illegal logging forest