Tree monocultures frequently have a negative impact on biodiversity; however, the adoption of ecologically-sustainable management practices can produce a different outcome. In this study we evaluate how the replacement of Araucaria Forest by ecologically-sustainable monocultures affects the abundance, age structure, sex ratio, and diet of the endemic frog Physalaemus lisei Braun and Braun ( 1977) (Leiuperidae). From October 2003 to April 2005, population samples were taken with pit-fall traps in three 1 ha sites for each of the following habitats: Araucaria Forest, and old monocultures of Araucaria angustifolia, Pinus, and Eucalyptus. The number of individuals captured in Araucaria Forest was similar to that of the monocultures. Population recruitment was higher in the exotic monocultures. Captured individuals were female-biased, the sex ratio being similar for all habitats. Physalaemus lisei was slightly more generalist on the monocultures. These results suggest that the forestry industry, by adopting ecologically-sustainable management practices, can contribute to the conservation of threatened and endemic species.