The aim of this paper is to present a case of the application of the Theoretical and Methodological Model for Harmonic Tourism, proposed by Palmas et al, (2014), in order to carry out tourism-based planning tasks through the interaction of communities with both vernacular and rational knowledge, which allows for the analysis and management of harmonic tourism as an alternative to sustainable local development. The methodology applied begins with the theoretical and methodological supports that take into account some analysis categories, such as hommo-ecosystem, systemic elements and sub-elements, harmonic tourism, as well as vernacular and rational knowledge. These categories allow integration from a diagram of vernacular-rational touristic planning with the relevant relationships between biophysical and anthropic subsystems about the use of natural and cultural resources. In order to achieve this goal, 374 questionnaires were randomly distributed, as well as 45 in-depth interviews with key actors, visits and continuous field observations, throughout a period of 4 years (2009-2013). The proposed model was applied in San Pedro Tultepec, which includes the Chimaliapan Lagoon, in the municipality of Lerma, State of Mexico, Mexico. The main results include identification and explanation of environmental problems from the perspective of complex systems, consideration of harmonic tourism as a tool to promote local development, and the importance of spreading of information, regarding the tangible and intangible services offered by the Lagoon to the community in order to promote awareness about the rescue of their current resources
