Analisis Tekstur Sedimen terhadap Kelimpahan Gastropoda di Ekosistem Mangrove Desa Pasar Banggi, Rembang

Abstract

Karakteristik sedimen mangrove terdiri dari fraksi pasir, lumpur dan liat. Kelimpahan gastropoda dipengaruhi oleh substrat sebagai habitat dari gastropoda, serta kandungan bahan organik yang berbeda pada tiap fraksi. Oleh karena itu, perlu dilakukan penelitian mengenai analisa tekstur sedimen terhadap kelimpahan gastropoda di kawasan mangrove Desa Pasar Banggi, Rembang, mengingat gastropoda berperan penting dalam menjaga keseimbangan ekologi ekosistem mangrove. Penelitian ini bertujuan untuk menganalisis hubungan tekstur sedimen dengan kelimpahan gastropoda di ekosistem mangrove Desa Pasar Banggi, Rembang yang dilakukan pada bulan Desember 2021. Metode penentuan lokasi sampling menggunakan metode purposive sampling pada 3 lokasi sesuai dengan kerapatan mangrove yang berbeda. Pengukuran ekosistem mangrove menggunakan transek berukuran 15x15 m, dengan 3 subplot gastropoda dalam transek 1x1 m. Hasil penelitian menunjukkan fraksi pasir , lumpur silt dan lempung clay. Genus gastropoda yang ditemukan yaitu Littoria, Nodilittorina, Cerithidea, Trochus, Cassidula dan Telescopium. Nilai rata-rata kelimpahan berkisar antara 106-346 ind/m2. Nilai indeks keanekaragaman dan indeks keseragaman termasuk kedalam kategori rendah. Nilai indeks dominansi menunjukkan adanya pola dominansi dengan pola sebaran mengelompok. Hubungan tekstur sedimen ketiga fraksi dengan kelimpahan gastropoda diperoleh nilai r=0,947–0,991 yang berkorelasi kuat. Semakin tinggi presentasi fraksi diikuti dengan kenaikan kelimpahan gastropoda.   The characteristics of mangrove sediments consists of sand, mud and clay fractions. The abundance of gastropods is influenced by the substrate as the habitat of the gastropods, as well as the different organic matter content in each fraction. Therefore, it is necessary to conduct research on sediment texture analysis of gastropods in the mangrove area of Pasar Banggi Village, Rembang, considering that gastropods are important in maintaining the balance of the mangrove ecosystem. This study aims to determine the relationship between sediment texture and gastropods in the mangrove ecosystem of Pasar Banggi Village, Rembang, which was conducted in December 2021. The sampling location method used the purposive sampling method at 3 locations according to the different mangrove densities. Measurement of the mangrove ecosystem using a transect measuring 15x15 m, with 3 gastropod subplots in a 1x1 m transect. The results showed the fraction of sand, silt and clay. The gastropod genera found were Littoria, Nodilittorina, Cerithidea, Trochus, Cassidula and Telescopium. The average value ranges from 106-346 ind/m2. The diversity index and uniformity index values are included in the low category. The dominance index value indicates a dominant pattern with a clustered distribution pattern. Sediment texture of the three fraction values with gastropod relationship obtained r = 0.947 - 0.991 which is strongly correlated.