Mapping scientific production in the Tocantins–Araguaia Basin in Brazil Central: application of automated content analysis in freshwater studies

Abstract

The Tocantins–Araguaia Basin, one of the largest and most ecologically significant watersheds in South America, harbors high biodiversity and provides essential ecosystem services. This study offers a comprehensive assessment of the scientific literature on the Tocantins–Araguaia River Basin using automated content analysis. We compared publication trends and research topics across major Brazilian river basins and applied Structural Topic Modeling (STM) to identify dominant themes, their relationships, and temporal dynamics in studies focused on the Tocantins–Araguaia Basin. Publication trends showed a steady increase in scientific output across all basins, with the Amazon and Paraná accounting for the highest number of papers. Keyword analysis revealed distinct thematic profiles, with research terms for the Tocantins–Araguaia Basin closely resembling those of the São Francisco Basin, both emphasizing aquatic biodiversity, hydropower, and land-use change. For the Tocantins–Araguaia Basin specifically, STM identified ten main research themes, with “Fish Morphology” and “Aquatic Communities” being the most frequent. Topics such as “Biodiversity & Fossils”, “Dams & Fisheries”, and “Agricultural Practices” showed high lexical overlap with other themes, indicating broader thematic integration. Temporal analyses revealed the growing prominence of applied and interdisciplinary themes, such as “Aquatic Communities”, “Agricultural Practices”, and “Land Use & Cerrado”, reflecting global scientific priorities in biodiversity conservation and water management. Despite increased scientific output, topics such as invasive species and eDNA remain underrepresented. The analytical framework applied here provides a transferable approach for identifying research trends and gaps in other understudied regions.