This article examines the cultural diversity of earthen mound–building groups known as Cerritos, spanning from Uruguay to the Patos–Mirim lagoon complex in southern Brazil. Over the past 5,000 years these communities underwent marked transformations, establishing territories, borders and monuments. A shift from hunting to fishing as a primary daily activity underscores the growing importance of aquatic resources in their diets, evidenced by isotopic and lipid analyses and by skeletal pathologies consistent with repetitive fishing tasks. Mobility and visibility data within the lagoon landscape suggest strong interconnections among regions. Collectively, the evidence indicates that Cerriteiros actively shaped aquatic environments, leaving enduring cultural and physical imprints on the Pampas. Their legacies contributed to forms of niche construction that enhanced biodiversity-insights that are highly relevant for contemporary environmental conservation.
