Statement of the problem: The preservation of ecosystems requires a significant demand for resources, such as personal, financial and infrastructure, which are increasingly difficult to justify due to lack of sustainability and restrictions of use. Tourism could be a good response, however, while goods and services that support visitation are relatively easy to account, other less tangible environmental services, such as biodiversity, can be difficult to be valued. To evaluate these assets is important in order to take the best decisions for ecosystem management. In this work emergy is applied to evaluate the natural capital, in a conservation area in the south of Brazil. The objective is to be able to predict the economic and environmental viability of the study area for a conservation tourism proposal. Methodology & Theoretical Orientation: To place the value of biodiversity in perspective, emergy synthesis of the main storages and ecological processes in the study area are calculated. For the evaluation of renewable inputs to the Peri Lake, solar energy, rainfall, runoff, and wind annual averages are used. Findings: The highest value is recorded for biodiversity ($354 billion), shrub and herbaceous vegetation represents $14 billion emdollars, tree biomass $5.7 billion emdollars, and water extracted for supply $12,4 thousand emdollars. Conclusion & Significance: Biodiversity clearly dominates the environmental assets of the study area. Biodiversity represents the information of the ecosystem reflected in the diversity of the species. It also results in a large input of grants from sponsors, driving most of the research in the area. These results show that the local government strategy, focused only on water extraction is not a good one. Tourism conservation based on natural assets, for example, could be much more attractive