Alpha diversity of planktonic organisms across stream networks associated with mining activities in Southeast Sulawesi

Abstract

Planktonic organisms are the main biotic components of the food chain of aquatic ecosystems. Little is known about the impact of multiple stressors on plankton community response in mining areas. This study aimed to elucidate the alpha diversity of zooplankton and phytoplankton in different stream networks associated with mining activities in the Molore watershed, Southeast Sulawesi. The research was carried out by taking samples for water quality and plankton analyses in four streams in November 2021 and November 2022. A rarefaction curve approach was used to assess the species richness and diversity trends of the region. Streams were clustered using the Bray-Curtis similarity index of alpha diversity indices, such as the Shannon-Wiener, Simpson, Margalef, Pielou, and Berger-Parker indices. We found six species of zooplankton only in three sites and 21 species of Phytoplankton in the class of Bacillariophyceae, Chlorophyceae, Cyanophyceae, Dinophyceae, and Euglenophyceae across the landscape gradient. The present study showed that the lowest value of the Shannon-Wiener diversity of the plankton community was 0.48, while the maximum expected value based on individuals’ rarefaction curve was 2.24. Species richness is in line with cluster analysis, which shows the similarity of stream groups according to the level of environmental pressure, indicating a valuable ecological indicator for stream management.