The Osa Peninsula is surrounded by important aquatic and marine resources: To the north, the Terraba-Sierpe Wetland designated as a Ramsar Site of international importance for the protection of aquatic birds contains the largest mangrove forest on the Pacific coast of Central America; to the east, the Golfo Dulce, one out of the only four fjords in the tropics; towards the west, different species of dolphins and whales have been observed; along the Corcovado National Park and the Isla del Caño, run impressive fringes of coral reefs. Finally, many of the beaches of the Peninsula receive four of the world's seven species of endangered sea turtles. We must say that, unfortunately, uncontrolled rapid tourism development and the pressure of commercial and sport fishing fleets are threatening marine life, which requires more aggressive and decisive official protective policies.
The Corcovado National Park in the Osa Peninsula is said to be "the crown jewel" in Costa Rica's park system. Its forests shelter numerous endemic species including mammals, birds, reptiles, amphibians and insects. The Corcovado National Park alone contains at least 13 major ecosystems, including lowland forests, cloud forests, lagoons, mangrove swamps, beaches, coral reefs, and is home to about 5,000 species of plants, including more than 700 species of trees.
However, efforts attempted to minimize illegal activities including poaching, hunting and mining that represent a serious threat against the Park's rich biodiversity have proven insufficient. Besides, projects like the Osa Biological Corridor that would eventually connect Corcovado with larger extensions of forest, so that diversity preservation could be ensured, depend on official and voluntary civil cooperation working together. Half of the land required is in private hands, which demands wiser official policies to ensure both the Corridor geographic isolation limits and viable economic alternatives for landholders and residents.
A few organizations to protect Osa have emerged. The following are the best known:
The Local Commission of the Osa Biological Corridor: composed of representatives of local communities in the Corridor and many of the Osa's grassroots organizations.
The Technical Coalition for the Osa Biological Corridor: an existing coalition of national and local conservation organizations of five well-established Costa Rican conservation groups working in the Osa Peninsula.
Friends of Osa, a group of landowners in the southern part of the Peninsula, created to manage their lands as a private wildlife refuge.