Mangrove Restoration Actions in the Térraba Sierpe National Wetland

Blog Post by Luis Carlos Solis, Mangrove Restoration Coordinator

The Térraba Sierpe National Wetland encompasses the largest mangrove forest in Costa Rica with an area greater than 16,000 hectares which, due to its biological importance, was declared of international importance by the International Convention on Ramsar Wetlands. In this protected area, mangrove resources have been used since pre-Columbian times when indigenous communities extracted dye from the bark of the red mangrove (Rhizophora mangle) to dye their clothing.

A section of land cleared of invasive ferns

Currently, the inhabitants of the wetland base their economy on various activities such as the extraction of the “piangua” mollusk (Anadara tuberculosa), artisanal fishing, and the isolated production of various crops and livestock; however, in the past, the local economy was based on the extraction of wood for the production of coal, firewood and construction materials, which decimated the mangrove forest. As a result of this deforestation, the “negraforra” fern (Acrostichum aureum) has dominated the wetland, which is an opportunistic species that is difficult to eradicate. Due to its high density, it acts as a barrier to the natural growth of the mangrove.

A pianguero working on planting mangroves


A pianguero in a Mangrove Nursery

As a result of this barrier in forest regeneration, Osa Conservation is carrying out mangrove restoration actions through the project “Effective strengthening of mangrove ecosystems in Costa Rica and improvement of the quality of life of the local coastal population” with funding from ALDI SÜD and KfW-DEG. Osa Conservation is pursuing this project in conjunction with the Association of Piangueros and Marine Resources of Ajuntaderas (APREMAA) in order to promote the health, integrity and sustainability of a degraded ecosystem.

The Osa Conservation Team out in the field

These restoration actions are based on active management, a technique that uses human intervention to remove the barriers that prevent the natural regeneration of the mangrove. This involves removing the fern in order create a more favorable environment for mangroves at restoration sites. The project is also establishing mangrove tree nurseries in order to accelerate the recovery processes of the ecosystem. All these tasks are carried out in conjunction by different institutions and national and international organizations such as the Osa Conservation Area, the Osa Municipality, the National University through its Applied Tropical Ecology Laboratory, Bluesensus, Shore-Rainbow Export Processing Group, ICE Group-El Diquís Hydroelectric Project, and GIZ Agency, among others.

Cutting the ferns in a restoration plot

These efforts are part of a government policy for the conservation and recovery of wetlands as a fundamental element in the sustainable development of the communities that depend on them as a way of life. For Osa Conservation, it is a privilege to be a part of these efforts and to safeguard the fundamental services the wetlands offer.

The Universidad Nacional team


The Association of Piangueros members working to plant mangroves

To find out more about our work with mangrove conservation, click here.


Building our Marine Program: Connecting in the Osa

Blog post by Mónica Espinoza Miralles, Marine Conservation Scientist

For those passionate about the underwater world it is amazing to see how extraordinarily different the seas are around the world. This was the case for us:  Noelia Hernández, an oceanographer from Spain and Osa Conservation’s new Marine Program Coordinator, and myself, Mónica Espinoza, a marine biologist from Costa Rica and Osa Conservation’s new Marine Conservation Scientist. We had the opportunity to meet for the first time at Saladero Ecolodge, and from that moment, we realized that we both have a great affinity, passion and curiosity towards the sea. For this reason, we are extremely excited to be the new members of the Marine Conservation Program at Osa Conservation, to build on the local partnerships, and to protect this unique and special marine landscape.

The experience at Saladero Ecolodge started by taking a canoe and navigating through the calm waters of Golfo Dulce. Once across this incomparable tropical fjord with a depth of around 200 meters, you can see the Piedras Blancas National Park. Saladero is located right at the foot of this protected area, a site that immediately exhibits that special interaction between the sea and the land.

Saladero EcoLodge view from the sea

When we arrived, we had the opportunity to explore the primary and secondary forests that surround this beautiful hidden corner of the South Pacific, and to suddenly find the flow of the river that crosses and bathes the beautiful lands of the tropical forest and converges in the waters of the blue sea of Golfo Dulce. That is when we decided to venture in kayaks to be one with the river, to flow through its channels and be surrounded by nature. At the mouth of the Esquinas River, we found the complex mangrove ecosystem, a place of great diversity in flora and fauna and a refuge for future generations of hammerheads, also known as the guardians of Isla del Coco.

Mangrove forest perspective from the kayak

After that wonderful experience in this important carbon sink, the desire to enter the underwater world increased. So, we took our snorkeling equipment and dove to find the submerged paradise that many seek. The world below the sea surface is a place that captivates you, takes you out of everyday life and makes you live in the present where the connection with nature is magnified. This is where we had a magical encounter with a curious hawksbill sea turtle, which seemed to stop us in time and show us how magnificent these creatures are in their own way. Sea turtles are not only beautiful animals, but also show incredible perseverance and endurance. After all, they have nested on beaches for millions of years.

Noelia exploring a hard-coral formation

At the end of our little adventure we headed back to Saladero Ecolodge completely unaware of the encounter that awaited us. In a moment of rest on the kayak, we were appreciating the horizon and suddenly we observed a splash of water in the distance. We looked at each other excitedly, and when we looked closely we could distinguish around five dorsal fins that broke the surface tension of the water; they were bottlenose dolphins. Seeing one of the resident species of marine mammals in the Golfo Dulce feeding from our kayak was nothing short of spectacular. At the end of the day, this confirmed what we had read and heard about the Golfo Dulce, a home to many species, both resident and migratory, and a key site of essential ecosystems. Such an experience only reconfirmed our excitement and dedication to helping Osa Conservation expand a Marine Conservation Program to protect these incredible habitats. We look forward to sharing more information with you in the near future about this new program.

Monica kayaking on the way back to Saladero EcoLodge after sighting bottlenose dolphins

Sometimes it is difficult to imagine the amount of life that congregates right on the coast, but after this experience in Saladero, we are extremely enthusiastic about the new opportunities that await us. Even more important is to fulfill our mission to preserve what we are so passionate about and that we now call our new home.

If you too are interested in participating in the marine exploration of the Golfo Dulce and the Osa, check out our travel package offered here—join us for a few days exploring the rainforests, the mangroves, and waters of the Golfo Dulce. We hope to see you soon!


Osa Big Day 2018

Blog Post and Photos by Patrick Newcombe

Osa Conservation’s landscape is a mosaic of terrestrial habitats including grasslands, palm forests, reforested areas, secondary and primary forests, as well as aquatic habitats such as a ponds, rivers, lagoons and ocean. Elevation ranges from sea level to 1,083 feet (330 meters). This habitat and elevation range result in phenomenal bird diversity and illustrate the importance of the habitat conservation and restoration occurring at Osa Conservation.

June 25 was the first Big Day at Osa Conservation! In birding circles, a Big Day is a twenty-four-hour time period from midnight to midnight where a team tries to identify as many species as possible by sight or sound, in compliance with the American Birding Association’s official rules. Adding to the challenge, we planned a carbon-free Big Day without motorized vehicles. We found 135 bird species despite a three-hour downpour in prime birding hours! We would love to do a Big Day again during migration to include migrating species such as warblers and shorebirds, and we feel that we could break a much higher benchmark.

The Big Day Team

Our team consists of Thomas, Zac and Patrick from Osa Conservation, as well as Henry, a local resident, and Nito, a Costa Rican birding expert and owner of Surcos Tours. The excitement mounts the evening before as we discuss strategies and plans over dinner. “What do you think a realistic goal is? …80? …90?” “What time should we look for the crested owl?” “What do you think of walking up the river?”

The alarm goes off at 3:45 a.m. and we quickly pick up Crested Owl and Common Pauraque calls around the clearing around the Biological Station. And we are off!

We walk down to Osa Verde where we bird the farm fields interspersed with hedgerows and trees along with the reforestation arboretum.


Then, we continue along the former air strip reclaimed by marsh and grassland and along the ocean before heading back down the driveway to the entrance of Osa Verde.

Here we stop to enjoy Emilie’s delicious field breakfast of gallo pinto, fried eggs, and plantain (Emilie was awake even earlier than us to prepare our field breakfasts!). It’s still not 9:00 a.m. and we have birded an amazing seventy-four species, far surpassing our expectations! Nito comments that it’s a good thing that Osa Conservation has worked so hard to conserve this land and the wide variety of habitats, allowing us to find such a wide range of species.

Ruddy-Breasted Seedeater

Our plan is to head off to the primary and secondary forest where we anticipate quickly adding many forest species. But, as birders know, the results of a Big Day are often influenced by the weather. Before entering the forest, the torrential downpour begins and we rush along the trail to reach a shelter overlooking the pond known for its “frog explosions” after rainy nights. We hang out on the platform for an hour with only a Purple Gallinule making an appearance. Although realizing that most species will be hiding quietly in the rain, we decide to head out in the downpour and, luckily, spot a Green Heron as we leave the pond area on Discovery Trail. Just before, we had hiked the second half of Discovery Trail in the morning and seen twenty-three species but, disappointingly, now the birds are in hiding.

Reaching Piro River, we find the water level has risen significantly, but we decide to stick to our plan to head up through the river to look for an occupied Band-tailed Barbthroat’s nest, staked out by Patrick and Zac the day before. Piro River raises our spirits as we also spot a Fasciated Tiger-Heron.

The rain continues steadily and we head back along Discovery Trail. When we reach the Biological Station, everyone is gathering for lunch and eagerly questioning us about the Big Day.

After lunch, we head up Tangara Trail in hopes of seeing the Spectacled Owl that Patrick and Eduardo had found on Saturday. Our hopes are also set on finding a flock. Rainforest birding is tough because we often go long distances with few birds until meeting a flock where we have to pick out as many species as possible before it moves off.

The forest is quiet except for the Scarlet Macaws and Orange-chinned Parakeets making a racket. It is not until high up Ajo Trail that we encounter our first flock. What a reward: about fifteen species, including a Gray-headed Kite, fly in.

Nito suggests heading up towards Cerra Osa in hopes of spotting some birds of prey. Cerra Osa is at 1,083 feet (330 meters) above sea-level and consists of a reforested area where the tree cover is not as dense. We are rewarded by a Northern Bentbill and White-necked Puffbird, two very unexpected species, while also finishing out our honeycreeper sweep with a Green Honeycreeper.


White-Necked Puffbird

After checking out Cerro Osa, we head back down to the research station to reassess our list. Since we usually see Amazon Kingfishers and a Ringed Kingfisher lower down Piro River, we head down to explore the river some more, quickly snagging a few more species including kingfishers as well as the Scarlet-rumped Cacique and Golden-naped Woodpecker. Night is approaching, and Nito and Henry have to return to Puerto Jimenez. Osa Conservation’s first Big Day has come to an end.

An endangered Black-Cheeked Ant Tanager

It’s been a fulfilling day. Before coming to the Osa Peninsula I had participated in some Big Days as well as the World Series of Birding and was very curious to see what we could accomplish during a Big Day on Osa Conservation’s property. One hundred and thirty-five species far surpassed my expectations. Our list can be found here. (If you’re interested, here is a description of a Big Day during the World Series of Birding in New Jersey.)

More important than the overall number, the Big Day illustrated to me the engaged and motivated community at Osa Conservation. At lunch and dinner, many people asked questions about the Big Day and the birds, often wishing us luck during our search. We worked as a team in partnership with local guides, Nito and Henry, continuing our friendship. It is the comradeship within the team and at Osa Conservation that I will remember most.

Hopefully, there will be more Big Days at Osa Conservation to illustrate its amazing bird diversity and the importance of the conservation being done.

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