Osa Peninsula

Pacific waves meet tropical rain forest
in the Osa Peninsula.
© David Woodfall

Fact Sheets

Take it with you: Learn more about the Osa Peninsula in these convenient, printable fact sheets.

Osa Peninsula Fact Sheet
(PDF, 206 KB, new window)
Osa Peninsula Map
(PDF, 427 KB, new window)

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Jutting out into the Pacific Ocean in the southwest corner of Costa Rica, the Osa Peninsula encompasses lush primary rain forests and a complex system of freshwater and marine resources. The remote region includes multiple protected areas including Corcovado and Piedras Blancas National Parks.

In 1975, with an assisted land acquisition of 86,485 acres, the Conservancy helped the Costa Rican government create the more than 100,000-acre Corcovado National Park on the western part of the peninsula.

Why the Conservancy Selected this Site
The Osa Peninsula is a geological formation which developed independently from the rest of Costa Rica and then joined the isthmus several million years ago. Its unique formation and naturally wet systems - which differ from the rest of the dry Pacific - have produced high levels of biodiversity.

Animals
The area hosts a rich array of fauna including jaguar, the Central American squirrel monkey, the Baird's tapir and three species of sea turtles (olive ridley, Pacific green, and leatherback). More than 375 bird species are found on the Osa Peninsula including the country's largest population of the threatened scarlet macaw. Osa is also home to the harpy eagle and the yellow-billed cotinga.

Plants
A fourth of Costa Rica's tree species, are found on the Osa Peninsula, including the newly discovered genus, Ruptiliocarpon (Lepidobotryaceae). The Osa Peninsula supports more than 4000-5000 vascular plant species, many of which are found no where else on Earth. The rain forest is made up of 700 tree species— the greatest tree species diversity in all of Central America.

Threats
It is estimated that outside of the National Parks, less than 10 percent of the lands on the Osa Peninsula are under secure title. This has resulted in lands being cleared for logging and agriculture at a higher rate than anywhere else in Costa Rica. Gold mining in the rivers and streams has also led to serious environmental threats including, water pollution and soil erosion.

What the Conservancy Is Doing
Biodiversity Monitoring and Protected Areas Management
In the Osa, which includes Piedras Blancas and Corcovado National Parks and the Osa Biological Corridor, the Conservancy is working to not only setup biodiversity monitoring programs but to improve management, resulting in a measurable reduction in key threats to both areas — logging, hunting, mining and squatting.

Most recently the Conservancy began the developing park management plans for the Parks, their adjacent nature reserves (Golfito Wildlife Refuge and Caño Island Biological Reserve respectively) and the Golfo Dulce Forest Reserve (which makes up most of the Osa Biological Corridor).

When finalized these plans will be implemented by the Osa Conservation Area (ACOSA) staff and community members. The plans will incorporate procedures for measuring their own success as well as methods for adaptation when course correction is necessary. Strategies for the protection and operation of the park, land used planning and zoning and wildlife management programs are also included.

Another important part of the Conservancy's work in the Osa is our efforts to build local capacity to run the protected areas—the upkeep and purchase of key equipment and infrastructure, like ranger stations. Qualified staff are needed to effectively implement management plans and the Conservancy is helping to hire, train and equip them. Additionally, the community-based volunteer Natural Resource Vigilance Committees (COVIRENAS) are being trained in ecology, basic patrolling techniques and relevant legal procedures. Both park staff and the Conservancy are working with the COVIRENAS to put their mission into practice.

Land Purchase and Private Lands Conservation
Land purchase also plays an important part in the Conservancy's work in the Osa. Though the area is made up of national parks and protected areas many people still live and own land inside their borders. The Conservancy is developing strategies to resolve land tenure issues and other legal issues related to consolidating the parks and the connecting Osa Biological Corridor, which is critical to biodiversity conservation.

A large part of the Conservancy's Private Lands Conservation strategy is to implement conservation easements in priority areas throughout the Corridor. Once put in place these easements would be held and monitored by local non-governmental organizations as well as the Conservancy. The conservation easement is a tool that the Conservancy has long maintained as essential to its conservation work around the world. In the Osa we continue to research and expand the scope of private lands conservation tools as well as promote the use of these tools, new and old, among landholders and other interested stakeholders.

The Osa Campaign
The global importance of this unique region, which faces ever-increasing threats, has led The Nature Conservancy to partner with Conservation International, the Costa Rica-USA Foundation, and the Government of Costa Rica in the Osa Campaign - a unique conservation and fundraising effort. Through the Campaign these partners are conserving the biodiversity of the Osa by strengthening national parks, creating biological corridors between them, and involving local communities in conservation efforts.