Costa Rica: Preventing Ecosystem Collapse in the Osa Peninsula and beyond

Conservation Value:

The Osa Peninsula contains the largest mesic rainforest remaining on the Pacific slope of Central America, largely within Corcovado National Park. It has the largest expanse of mangrove wetlands on the Pacific slope of Central America and a unique coastal marine ecosystem—the Golfo Dulce tropical fjord.  The Osa is estimated to house 2.5% of the world’s biodiversity while covering less than 0.001% of its total surface area, and was described by National Geographic in 2016 as “the most biological intense place on earth”.

Threats:

The main threat in the Osa Peninsula is illegal hunting, which is still prevalent in the region.  The concern is greatest with respect to the lowland paca (Cuniculus paca), white-lipped peccary (Tayassu pecari) and collared peccary (Pecari tajacu). Other species are hunted to a lesser degree, including game birds such as: tinamou (Tinamus major and Tinamus major castaneiceps) and great curassow (Crax rubra).  Research has identified key areas of hunting pressure, however no concerted effort had been been made to reduce illegal hunting on the peninsula. A presentation at the 21st Mesoamerican Congress in San Jose in 2017 revealed that bushmeat offtake could be around 28.5 kg per year for each family hunting in the peninsula.

Actions & Results:

Osa Conservation (OC) is leading a conservation effort that mobilizes citizen scientists, community members, ecotourism operators, park administrators and multiple NGOs to preserve the globally significant biodiversity of the Osa Peninsula in the face of climate change.  To accomplish this, OC is restoring forest connectivity and climate resilience from ridge to reef—across an altitudinal gradient from the southern Pacific tropical lowlands of the Osa Peninsula to the high elevation wilderness of La Amistad National Peace Park (Talamanca Mountains).  Thanks to its ‘Ridge to Reef’ initiative, OC is successfully engaging civil society to help protect one of the world’s last wild places.  In 2024, OC planted 240,231 native, rare, and/or threatened trees across 157 ha in their working landscape of the AmistOsa Biological Corridor.  Trees were planted and sites maintained on 117 ha of farmland, with a ‘Restoration Network’ that includes 285 small-and mid-sized farms.  In the Térraba-Sierpe National Wetland, 72 community members were employed to restore 40 ha of mangrove.  All combined, 2024 was the most impactful planting season in OC’s history.  To address barriers to wildlife movement, OC created canopy connectivity with 29 arboreal bridges of various designs.  The data from the first phase of the project was presented to the local government with a plan for additional arboreal bridges in the AmistOsa region.  OC’s efforts to boost civil responsibility focused on biodiversity monitoring and mitigating human wildlife conflicts in the Osa Peninsula and Piedras  Blancas National Park.  Workshops and events such as the first International Jaguar Day and an Environmental Festival emphasized the importance of predators and their habitats.  A cornerstone of these efforts is the AmistOsa Biodiversity Survey, which builds local capacity for biodiversity monitoring using citizen science tools like iNaturalist.  A total of 29 workshops in 14 communities engaged 496 participants.  Observations increased, with 26,674 new entries, involving 797 new species and 458 new observers.  Baseline data from 2022 tripled in 2024.  OC’s Youth Nature Club continued to provide youth with an immersive nature-based learning experience, fostering the next generation of conservation stewards.  Since its formation in 2021, the club has established twelve chapters across six communities and six educational centers in Costa Rica’s south Pacific, reaching over 500 students annually.  OC has built partnerships with elementary, middle, and high schools across the twelve chapters they work with, to enhance nature based education for underprivileged rural youth in Costa Rica.  A big thank you to the Paul W. O’Leary Foundation for making this possible.

Zero in on one community involved in this project in this short video from the Our Planet series.

See more videos below.