Abstract

Phytoplankton communities are excellent indicators of the environmental status of shallow lakes since changes in diversity alert us to potential deterioration. To assess the environmental condition of a shallow lake with strong anthropogenic pressure from forest monocultures, alpha and beta diversities were determined. Three monitoring stations were established in the shallow Kusrupuyewe Lake, southern Chile, which were monitored during the 2021 austral summer and winter. Alpha diversity was high indicating a stable environmental condition. In total, 103 species in summer, 96 species in winter and a high species diversity (Shannon index: H ' > 5 bits/ind) were recorded. Beta diversity indicated that this ecosystem is seasonally heterogeneous, is potentially productive and has a high species turnover. Based on the large species inventory, we conclude that this shallow lake is stable and diverse. Although it is threatened by the presence of forest monocultures, it maintains a stable environmental condition, mainly due to the ability of the phytoplankton present to self-regulate through the species turnover. This study provides the relevant background information to establish conservation measures around the shallow lake, an ecosystem that provides various ecosystem services for the local indigenous communities.