The data comprise measurements of abundance of invasive species, illuminance, air temperature, air humidity, specific leaf area, species richness, species diversity, vegetation cover, biomass, decomposition rate and, carbon efflux that was made during filed campaigns to assess the impact of an invasive grass (Urochloa decumbens) on a tropical savanna (Cerrado) in two nature reserve areas in Brazil. The two experimental areas were located within natural reserves in Southeast and Central Brazil; Estação Ecológica de Itirapina in the municipalities of Brotas and Itirapina in São Paulo State, and Parque Nacional de Brasília in the Distrito Federal. Data were collected during multiple field excursions between March and September 2019.