Community Structure of Macroalgae in The Waters of Wori Village, Wori District, North Minahasa Regency

Abstract

This study aims to analyze the community structure and species diversity of macroalgae across various habitat conditions represented by three transect lines (T1, T2, and T3). Data collection was conducted using the quadratic transect method with 30 observation plots. Data analysis included the calculation of ecological indices (Shannon-Wiener, Simpson, and Evenness) and inferential statistical tests, specifically Kruskal-Wallis and PERMANOVA, to evaluate differences between locations. The results recorded a total of 15 macroalgae species with a total abundance of 410 individuals. Descriptively, Transect 2 (T2) showed the highest diversity (H' = 2.148) with a species richness of 12 types, while Transect 1 (T1) exhibited the lowest diversity (H' = 1.618), driven by the strong dominance of Padina australis (D = 0.291). The Kruskal-Wallis test results indicated no significant differences in species richness (p = 0.295) and Shannon index (p = 0.272) between transects in terms of alpha diversity. However, the PERMANOVA test revealed highly significant differences in community composition across the three transects (F = 5.143; p = 0.001). This is further supported by a Whittaker's Beta value of 0.364, indicating species turnover between locations. SIMPER analysis revealed that the differences in composition were primarily driven by variations in the abundance of dominant species such as Padina australis, Halimeda opuntia, Sargassum polycystum, Halimeda macroloba, and Turbinaria ornata. Overall, the macroalgae community structure at the study site is heterogeneous, influenced by the distribution of dominant species abundance within each transect zone.

Keywords: macroalgae, community structure, diversity, transect, Wori Village

 Abstrak

Penelitian ini bertujuan untuk menganalisis struktur komunitas dan keanekaragaman spesies makroalga pada berbagai kondisi habitat yang direpresentasikan melalui tiga lintasan transek (T1, T2, dan T3). Pengambilan data dilakukan menggunakan metode transek kuadrat sebanyak 30 plot pengamatan. Analisis data meliputi penghitungan indeks ekologi (Shannon-Wiener, Simpson, dan Kemerataan), serta uji statistik inferensial menggunakan Kruskal-Wallis dan PERMANOVA untuk mengevaluasi perbedaan antar lokasi. Hasil penelitian mencatat total 15 spesies makroalga dengan total kelimpahan mencapai 410 individu. Secara deskriptif, Transek 2 (T2) menunjukkan tingkat keanekaragaman tertinggi (H' = 2,148) dengan kekayaan spesies sebanyak 12 jenis, sedangkan Transek 1 (T1) memiliki nilai keanekaragaman terendah (H' = 1,618) yang dipicu oleh dominansi kuat spesies Padina australis (D = 0,291). Hasil uji Kruskal-Wallis menunjukkan bahwa tidak terdapat perbedaan signifikan pada tingkat kekayaan spesies (p = 0,295) dan indeks Shannon (p = 0,272) antar transek secara alpha diversity. Namun, uji PERMANOVA menunjukkan perbedaan komposisi komunitas yang sangat nyata antar ketiga transek (F = 5,143; p = 0,001). Hal ini diperkuat oleh nilai Beta Whittaker sebesar 0,364 yang mengindikasikan adanya pergantian spesies (species turnover) antar lokasi. Analisis SIMPER mengungkap bahwa perbedaan komposisi tersebut terutama digerakkan oleh variasi kelimpahan spesies dominan seperti Padina australis, Halimeda opuntia, Sargassum polycystum, Halimeda macroloba, dan Turbinaria ornata. Secara keseluruhan, struktur komunitas makroalga di lokasi penelitian bersifat heterogen yang dipengaruhi oleh distribusi kelimpahan spesies dominan di setiap zona transek.

Kata kunci: makroalga, struktur komunitas, keanekaragaman, transek, Desa Wori