Grupo Ecológico Sierra Gorda, IAP (Private Assistance Institution), was formed in 1987 by a group of local citizens with deep roots and strong social ties in the region who were concerned about its environmental degradation and selfdestructive land use patterns. Convinced from the outset that they could not hope to conserve the area´s rich biodiversity without the collaboration of civil society, they have worked to implement a new culture of appreciation and respect for the planet within the framework of a sustainable regional development model. The Grupo Ecológico was the head of a campaign that culminated in 1997 with a federal decree designating the region a Biosphere Reserve – the only Mexican reserve whose creation was a product of social initiative. In recognition of the role of civil society, the Mexican president appointed Martha Isabel Ruiz Corzo, co-founder and first director of Grupo Ecológico, as the director of the new Reserve. Grupo Ecológico took on the task of preparing the Reserve Management Program, with input from all sectors of the population. Since its publication in 1999, this document has steered the region´s productive activities and social development under sustainability criteria. The program has fulfilled the commitments undertaken with the local population and is now being updated. As a result of its location at the convergence of two distinct bio-geographical regions, the Sierra Gorda Biosphere Reserve is the protected area with the richest ecological diversity in all of Mexico. Within its 383,567 hectares, the Sierra Gorda harbors 15 types and subtypes of vegetation, as well as over 2,300 vascular plant species, 127 fungi species and 623 vertebrates. The Sierra Gorda Biosphere Reserve is the richest protected area in Mexico in terms of mammal diversity, with 131 species, and the second richest in butterflies and herpetofauna with 650 and 136 species respectively. Furthermore, The Sierra Gorda contains 329 species of birds, which represents approximately 30% of all of the birds found in Mexico . The Sierra Gorda represents a social conservation movement. Its natural resources are in the hands of extremely poor landowners. This presents serious challenges, given the 93,000 residents of 605 communities who claim rights to development, employment, and economic opportunities. The solution requires the collaboration of civil society and government institutions, and the use of innovative mechanisms which combat poverty, halt the degradation of ecosystems, and conserve the region´s biodiversity. The co-management model set in motion by Grupo Ecológico Sierra Gorda in 1999, with responsibilities for the Reserve´s management shared between the Government of Mexico, and civil society, has not only achieved quantifiable results in the restoration of ecosystems and landscapes, but it has also helped to raise over half a million US dollars in additional income for residents by promoting activities compatible with the conservation of the area´s biodiversity in 107 local communities. Furthermore, public investment in sustainable development and conservation has increased 767% since the year 2000. The project has also led to the cleanup of more than 100 communities through the collection of recyclable materials. The first Management Program of the Sierra Gorda Biosphere Reserve (1999-2006) was implemented by the Directors of the Reserve, Grupo Ecológico Sierra Gorda, and its partners, through a “social strategy for conservation,” carrying out numerous actions for the Reserve´s own residents. This model is having great success. It has led to the establishment of strong community networks of voluntary participants and has drawn in over 70 partner organizations, supplying the project with financial or in-kind support. Among other notable results, this program has succeeded in improving conditions for biodiversity (the vegetative cover of the Reserve today is greater than it was in 1970 and threatened species have notably recovered), as well as reducing threats to biodiversity and achieving gains in sustainable development indicators. To ensure the sustainability of future actions, the project has begun transferring experience and responsibilities to other organizations and institutionalizing key programs such as education and environmental cleanup, as well as developing new sources of financing such as the Sierra Gorda Earth Center, which offers courses, workshops, and diploma programs to people of neighboring states, as well as other NGOs and protected areas in Mexico and other Latin American countries in order to share and replicate the experience.