The biodiversity crisis is outpacing conservation efforts, with amphibians among the most affected groups due to habitat loss, fragmentation, and disease. We analyzed spatiotemporal records of the Rhinella marina group, i.e., the Achaval's Toad (R achavali), Argentine Toad (R arenarum), Cururu Toad (R diptycha), and Yellow Cururu Toad (R icterica), in the South American Pampa biome. Locality data came from traditional sources (e.g., literature, institutional collections) and the citizen-science platform iNaturalist. We characterized the spatiotemporal distribution of the group, assessed the contribution of iNaturalist to occurrence data, and analyzed land use/cover changes around records. Between 2001-2020, records increased for all species except R icterica, which were largely concentrated before 1980. iNaturalist contributed 48.5% and 39.2% of the grid cells defined for our spatiotemporal analysis of records for R arenarum and R diptycha, respectively, expanding coverage into areas poorly represented by traditional sources. Nevertheless, many areas still lacked recent records, indicating persistent temporal gaps in documentation. In our land-use analysis using 50-km buffered areas around species records, grassland cover declined for all species between 1985 and 2020, most strongly forR achavali (from 68.5% grassland to 52.8%) and R icterica (from 43.2% to 28.2%), coinciding with marked expansion of agriculture or pasture over the same period, especially for R icterica (from 27.8% agriculture/pasture to 37.1%) and R achavali (from 12.8% to 20.3%). Overall, sampling gaps combined with habitat loss may mask local declines. Systematic surveys integrating traditional and citizen science are essential to better assess population trends and threats in the Pampa biome.