Special topic: International Day for Biological Diversity - Protecting ecosystems and adapting to climate change in Costa Rica's Cahuita National Park

A man in shorts in front of his house

Fisherman Don Saballo in Costa Rica; Picture: Gitti Müller

'When we used to go out in our boats and spread our nets, we would come back after one or two hours and would have caught around 50 kg of fish. I was able to feed my family and buy this house', explains Juan Francisco Saballo.

Although it was once his pride and joy, his house, which has now become dilapidated, is for sale. The roof needs urgent attention, but the 60-year old fisherman does not have any money to fix it. If he had to subsist solely on his catch of fish, his family would have starved long ago. The water has grown too warm for the aquatic species and the surf is too strong. The buffer of coral reefs has succumbed to the pressures of climate change and its impacts. The fish have moved further north, and the money that Don Saballo earns from his small tourist business is not enough to keep up his house, so now he will also be following the fish further north to Puerto Limón.

Cahuita National Park

Don Saballo's son José is remaining behind. He is 38 years old and is an employee of Cahuita National Park on the Caribbean coast. His workplace covers around 1,102 ha of land and 23,290 ha of ocean. With a gleam in his eyes, he remarks that it's the most beautiful workplace in the world. This part of the Caribbean coast includes a variety of ecosystems: coral reefs, sandy beaches, forests, rivers and mangroves. Leatherback and green sea turtles hatch on the sandy beaches and a range of fish and crustaceans find refuge in the maze of mangrove roots. The corals and seagrass beds also offer a habitat and source of food for many species including sea urchins, sponges, fish and sea turtles. The Cahuita area is home to 21 different species of reptile, 17 amphibian species, two species of ape and four wildcat species.

In 1970, Cahuita was placed under special protection as a national monument and was declared a national park in 1978. Three different zones are placed under protection in this area. A buffer zone around the protected area should ensure that additional 'stress factors' like excessive agriculture and application of fertilisers are limited near the protected area and that the people's ecological awareness is promoted. Within the second zone, which is fully protected, around 25,000 ha should preserve the largest possible extent of the natural ecosystems. This zone is only accessible for scientific purposes and for environmental education. There is a prohibition on the construction of breakwaters, electric lines, radio towers and streets as well as leisure activities and tourism.

Loss of coral

Together with eighteen other colleagues, José watches over the national park. When he walks along the visitor's footpath, he frequently comes across dead coral that has washed ashore, which he piles at collection points. Piles of coral reaching up to two metres in height rise up like memorials along the path. 'It's not the tourists,' says José, 'it's climate change. Some corals are only about 80 centimetres beneath the surface of the water now. The ocean temperatures have risen here and it has become too warm for them. The currents have also changed and the tides have become more extreme. That's why the corals break off more easily.'

Over the past 20 years, around 40% of the living corals have been irrecoverably lost, and the rate of coral growth has dropped by half over the past century. It is a huge loss for biodiversity, and the species that have managed to survive on the reefs were apparently better prepared to adapt to the change in conditions. The loss of coral, however, has not only affected aquatic species: the waves are now meeting fewer and fewer impediments upon the coast; the beach is being washed away and trees are being torn free. Erosion and sedimentation is one of the main problems facing Cahuita.

German project on ecosystem protection

Adaptation to climate change is a particular challenge facing us today. This includes both preventing additional stress on flora and fauna as well as planning for climate change within the foreseeable future both within and outside the park's boundaries. The project supported by the International Climate Initiative (ICI) for establishing a national protection system for Cahuita is based on creating synergy between adaptation to the effects of climate change and the concepts of biodiversity conservation. The project is being implemented on the ground by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) and two local partners.

It is a project that started in 2010 and should continue until 2014. Even in 2012 at its halfway point, it has been seen as a success, pointing the way for other regions and projects. The system of protected areas that will be established in Costa Rica should - according to the plan - encompass as many ecosystems as possible, be efficiently managed, and have stable financing at its disposal. A comprehensive management plan was drafted in alignment with local conditions and needs, and provides, among other things, training to the Cahuita staff. Part of the project plan also includes a measure that would lay the Cahuita visitor footpath so that it will not be destroyed every couple years due to rising sea levels and waves.

Ecosystem adaptation and protection

Climate change adaptation also means strengthening the natural protection mechanisms of ecosystems, particularly in places where serious impacts can no longer be stopped. The loss of coral due to ocean acidification is difficult to stop, but the resultant erosion due to increased wave impacts can be halted by reinforcing and conserving coastal vegetation. Mangroves, for example, are the best protection against sedimentation and act as a kind of filter against terrestrial contamination. This in turn gives the coral ecosystems more time to 'adapt' to acidification and increasing ocean temperatures. Greater influence must therefore also be exercised beyond the park's boundaries to reduce threats and stress factors, for example those associated with pesticides used in agricultural areas.

Mangroves are among the most productive ecosystems that exist. While terrestrial species live in the 'upper levels' of the trees and shrubs, truly aquatic species live among their roots. The network of roots and the biogenic sediments that collect among them provide a habitat for fish, crabs and shrimp. Mangroves also play an important role for climate protection, and there is good reason for them to be called the 'blue carbon sinks' of the ocean. They absorb roughly five times as much CO2 as other types of trees, and they protect the coasts from waves, hurricanes and flooding. That's why conserving the mangroves is so important, says the park ranger José, who then returns to his work with a friendly 'Adiós'.

Climate change adaptation is necessary in order to conserve the park and its diversity of plants and animals. And maybe someday the grandchildren of Juan Francisco Saballo, the sixty-year-old fisherman, will find a job in the 'most beautiful workplace in the world', the Cahuita National Park.

(Text based on an article from Gitti Müller)