Efek Stres Anthropogenik Terhadap Struktur Komunitas Makrozoobentik Substrat Lunak Perairan Laut Dangkal di Teluk Buyat, Teluk Totok dan Selat Likupang (Semenanjung Minahasa, Sulawesi Utara) - Lawrence J. L. Lumingas; Ruddy D. Moningkey; Alex D. Kambey (Institut Teknologi Bandung, 2011)
Ekosistem perairan laut dangkal di Semenanjung Minahasa diduga telah mengalami tekanan akibat berbagai kegiatan pembangunan dari daratan seperti pertambangan, pertanian dan limbah domestik. Penelitian ini bertujuan untuk menganalisis respon makrozoobentos terhadap berbagai tingkat stres anthropogenik seperti tailing, tambang tradisional dan kegiatan pertanian terhadap struktur komunitas makrozoobentos substrat lunak di Semenanjung Minahasa. Pengambilan sampel (sampling) telah dilaksanakan pada bulan April dan Mei 2010 pada 10 stasiun sampling di zona subtidal di Teluk Buyat, Teluk Totok, dan Selat Likupang. Dalam penelitian ini, telah dikaji variabel komunitas seperti kelimpahan dan keanekaragaman spesies termasuk indeks keanekaragaman spesies Shannon-Wiener (Hâ), indeks kekayaan spesies (SR), indeks kemerataan spesies (Jâ), indeks dominasi Berger-Parker (d), kurva âK-dominanceâ serta âassemblageâ (grup) makrozoobentik dengan analisis multivariat baik analisis klasifikasi maupun analisis faktorial korespondens. Dalam penelitian ini telah diperoleh total 543 individu yang termasuk dalam 114 spesies (takson). Struktur komunitas dan âassemblageâ makrozoobentik substrat lunak di Semenanjung Minahasa ditentukan oleh kondisi substrat danÂ tingkat stres anthropogenik khususnya sedimentasi, baik berasal dari âtailingâ maupun dari kegiatan pertambangan rakyat. Struktur komunitas serta âassemblageâ makrozoobentik di perairan dangkal Selat Likupang umumnya berada pada kondisi alamiah dengan dominasi spesies sensitif, sedangkan yang berada di Teluk Totok khususnya dekat muara Sungai Ratatotok berada pada kondisi buruk (awal suksesi) dengan dominasi spesies oportunis. Berdasarkan karakteristik struktur komunitas serta âassemblageâ makrozoobentiknya, ekosistem bentos di Teluk Buyat belum mencapai tahap akhir suksesi (ekosistem ekuilibrium) kecuali pada kedalaman yang lebih dangkal dekat muara Sungai Buyat. Kata kunci: Komunitas makrozoobentik, Ekologi bentik, Teluk Buyat, Analisis multivariat. The Effect of Anthropogenic Stresses on the Soft Substrate Macrozoobenthic Community Structure in Buyat Bay, Totok Bay and Likupang Strait (Minahasa Pennisular, North Sulawesi) Abstract The ecosystem of shallow marine waters in Minahasa Penninsular has got pressures from various development activities in the land, such as mining, agriculture and or domestic wastes. This study was aimed at analyzing the macrozoobenthos response to various levels of anthropogenic stresses, such as tailing, traditional mining and agricultural activities on the community structure of soft substrate macrozoobenthos, in Minahasa Penninsular. Sampling was carried out in April and May, 2010, at 10 sampling sites in the subtidal zone of Buyat Bay, Totok Bay and Likupang Strait. In this study, the community variables, such as species abundance and diversity using species diversity index of Shannon-Wiener (Hâ), richness index (SR), eveness index (Jâ), dominance index of Berger-Parker (d), âK-dominanceâ curve, were measured. Macrobenthos assemblage was analysed using multivariate analysis, both for classification analysis and factorial correspondence analysis. The study recorded a total of 543 individuals of 114 species (taxa). The soft substrate macrozoobenthic community structure and assemblage in Minahasa Penninsular were determined by the substrate condition and the level of anthropogenic stresses, especially sedimentation from either tailing or traditional mining activities. Both macrozoobenthos community structure and assemblage in shallow waters of Likupang Strait were in natural condition dominated by sensitive species, but those in Totok Bay, near Ratatotok downstream, were in bad condition (early succession) dominated by opportunistic species. Based on the characteristics of macrozoobenthic community structure and assemblage, it was found that the benthic ecosystem of Buyat Bay has not reached the final phase of succession (ecosystem equilibrium), except the shallow waters near Buyat river mouth. Keywords: Macrozoobenthic communities, Benthic ecology, Buyat Bay, Multivariate analysis.