The Altillanura is a unique ecosystem within the Colombian Llanos, characterized by well-drained savannas and extensive riparian forests. The Altillanura harbors a rich assemblage of species, largely understudied and currently under threat by large-scale and unplanned agribusiness. Moreover, the number of public protected areas in the Colombian Llanos, particularly in the Altillanura, is insufficient to conserve the threatened habitats and species. Therefore, conservation efforts by private reserves are crucial for the protection of the region’s biodiversity. Here we present the first species list of the Tomogrande, a private nature reserve and scientific research field station in the municipality of Santa Rosalía, Vichada, Colombia. After ten years of ongoing research, we have recorded 299 species of plants, 189 species of birds, and 47 species of mammals. Compared to other private nature reserves in Vichada and the Tuparro National Park, the largest protected area in the region, Tomogrande makes a substantial contribution to the conservation of all three taxonomic groups. We advocate that better landscape planning and sustainable practices should become mandatory in the Altillanura to protect its biodiversity and the livelihoods of all stakeholders that inhabit this region. ; La Altillanura es un ecosistema único de los Llanos colombianos, caracterizado por sabanas bien drenadas y grandes extensiones de bosques ribereños. La Altillanura alberga ricas comunidades poco estudiadas y actualmente amenazadas por la agroindustria a gran escala y no planificada. Además, el número de áreas protegidas públicas en la Altillanura no es suficiente para conservar los hábitats y especies amenazados. Por lo tanto, los esfuerzos de las reservas privadas son cruciales para la conservación de la biodiversidad de la región. Presentamos el primer listado de especies del Tomogrande, reserva natural privada y estación de investigación científica en el municipio de Santa Rosalía, Vichada, Colombia. Después de diez años de ...