Abundance and Diversity of Macrozoobenthos Based on Three Site Characteristics at Lake Tondano, North Sulawesi.

Abstrak

Macrozoobenthos are aquatic organisms that play a crucial role as bioindicators of aquatic environmental quality. This study aims to determine the abundance and diversity of macrozoobenthos at three distinct locations in Lake Tondano, North Sulawesi. Sampling in this study was conducted using the purposive sampling method. Sampling was conducted at three stations: Station I (Inlet), Station II (Near the settlement), and Station III (Outlet). In this study, samples were collected directly from the aquatic substrate using a 30×30 cm Ekman Grab. The results of the study identified 8 species and 7 families belonging to the phyla Mollusca and Annelida in Lake Tondano, with a total of 1,728 individuals. Diversity index values indicated a moderate category at the inlet (H' = 1.22) but a low category at the settlement area (H' = 0.99) and the outlet (H' = 0.58). The highest evenness index value was found at the inlet (E = 0.76) and the lowest at the outlet (E = 0.30), while the highest dominance index value was found at the outlet (C = 0.70). The most abundant species were Filopaludina sumatrensis (1,137 individuals; 65.80%) and Melanoides tuberculata (377 individuals; 21.82%), which dominated the community, particularly in the settlement area and outlet. This indicates a decline in ecological quality from the inlet to the outlet, characterized by increased abundance, low diversity, and high dominance of tolerant species. Macrozoobenthos has proven effective as a bioindicator for assessing the ecological condition of Lake Tondano and can serve as a basis for sustainable lake management efforts.