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A coastal-oak grows next to a beach
Florianópolis, Brazil

Invasion of Pine Trees in the Dunes of Florianópolis, Brazil Aggravates the Effects of Climate Change on the Island

Cutting down trees is generally an action associated with the destruction of the environment, not its preservation. It is no wonder that the professor at the Federal University of Santa Catarina (UFSC), Michele Dechoum, meets curious and sometimes disapproving eyes while removing invasive trees from the dunes of Florianópolis.

“I've already received threats, people taking pictures and filming, saying they're going to report me to the city hall. But, after we explain what we do, most of the time we get support from the residents”, says Dechoum, who coordinates the Laboratory of Ecology of Biological Invasions, Management and Conservation (Leimac) at UFSC.

Since 2010, the professor has organized community gatherings on the beaches and parks of Florianópolis alongside forestry engineer Silvia Ziller, from Instituto Hórus. Each volunteer manages to cut, on average, 200 to 300 trees in each visit. So far, over 420,000 trees with no commercial value have been cut and discarded in joint efforts coordinated by them with hundreds of volunteers.

a beach with no trees
Invasive plant species such as pines and eucalyptus have been removed from the coastal area of Florianápolis to allow the recovery of the dunes / Credit: Patricia Figueiredo.
A man walks on the sand
Eugênio Luiz Gonçalves, a volunteer and president of the resident’s council in the Costa de Dentro neighborhood, shows protected flower beds by the Açores beach created by volunteers and researchers / Credit: Patricia Figueiredo.

Although it seems counterintuitive, the “mutirões”, which are volunteer actions carried out by  citizens of Florianópolis, seek to protect the restinga from a biological invasion caused by pine trees (Pinus Elliottii), eucalyptus (Eucalyptus spp) and casuarinas (Casuarina equisetifolia, commonly known as coastal she-oak). The restinga is a coastal forest that forms on sandy, acidic, and nutrient-poor soils, and consists mostly of small-scale trees and shrub vegetation. The dunes on which they grow are the city's main barrier against storm surges.

Invasive species are organisms that are not native to a specific area. In Florianópolis, they cause erosion in the coastal dunesbecause, under the shade of these invasive trees, the native plants of the restinga cannot survive. The restinga is found in several areas along Brazil's coast, spanning from Northeastern Brazil to Southern Brazil and covering an area of 7,900 square kilometers, according to Brazilian Institute of Geography and Statistics (IBGE). Besides invasive species, it is also heavily threatened by the expansion of cities along the coast of the Atlantic. 

Without the protection of the restinga on the frontal dunes, the city of Florianópolis will be more affected by rising sea levels, according to researcher Marina Hirota, professor of meteorology at UFSC. A projection for the year 2100 estimates that 13,4% of Florianópolis,  that is, 54,63 km2, would be affected by rising sea levels, according to the scenario  estimated by the IPCC for that year. 

Sea waves very closed to a house in a beach
Mozambique Beach, part of the Rio Vermelho State Park, in Florianópolis; vegetation is formed largely by pine, eucalyptus and casuarinas, invasive alien species that hinder the growth of the typical restinga vegetation / Credit: Patricia Figueiredo.

Additionally, in a recent article published by the journal Plant Ecology, Hirota and other researchers explain that the spread of one of the invasive species that is very common in Florianópolis is expected to be favored by climate change, as seed germination rates are likely to benefit from higher temperatures. 

Extreme weather events, such as cyclones and intense storm surges, which have become increasingly common due to climate change, can also cause greater damage due to the proliferation of invasive species in coastal vegetation”, explains Hirota. One example is the strong storm surge that destroyed houses and retaining walls all over the city in 2017. More recently, floods have also affected neighboring areas, such as the one last June that displaced over 70 residents of a small town in the South of Santa Catarina. 

The increasing damage caused by storms and cyclones has already been noticed by some residents of the island, who have observed some changes in their surroundings over the last years.These climate risks increasingly threaten the state capital of Santa Catarina, a city of over 500,000 people and an important touristic destination in the South of Brazil.

In spite of the importance of tourism for the economy of Santa Catarina, coastal resilience is not a priority for the local government. This year, the funding allocated to the environment and climate offices by the state government is only R$ 118 million, which is 0,25% percent of the total annual budget dedicated to its different offices and secretaries. As for the city of Florianópolis, only R$ 39 million will be allocated to the municipal environment secretary this year. According to professor Michele Dechoum, who organizes volunteer actions, a lot of the work that should be done by governments is currently in the hands of citizens. 

She adds that one example is sandboarding - a sport similar to snowboarding, but practiced over sand dunes by instructor Marcelo Osvaldo da Silveira, who has been teaching in the dunes of Lagoa da Conceição for 11 years. With his own car, he picks up seedlings of native species in the city’s conservatory garden and takes them to the volunteer “mutirões”.

“Having worked there for a long time, and having this contact with the sea, I can already see that the waves have been digging deeper and deeper into the dunes, and that the restinga vegetation as we know it has been disappearing,” says Marcelo, who organized a WhatsApp group to encourage other residents to join the mutirões.

Two people on the sand
Biologist Michele Dechoum (in blue shirt) and forest engineer Silvia Ziller (in orange shirt) spread seedlings of native species in the dunes of Praia da Joaquina, part of the Lagoa da Conceição Dunes Municipal Natural Park / Credit: Patricia Figueiredo.

The risks that foreign species bring to the ecosystem are known by the authorities. In 2016, the state government created a program for the management and control of invasive alien species. 

Since 2012, the city of Florianópolis has had a municipal law that determined the replacement of all pine trees, eucalyptus and casuarinas on the island with native bushes from the restinga, such as Eugenia catharinae, within 10 years. 

A decree that succeeded the law also determined that, as of 2020, inspections should notify the owner of properties with the invasive species and impose a fine of R$ 100 per specimen not removed.

The deadline for both laws, however, was not met, and no fines have been registered until now, according to the municipality. So far, inspection actions by the city officials, which are responsible for monitoring the municipal law and enforcing fines, have targeted only public land. The city's environmental authority says it’s been “acting diligently in the process of removing exotic species in accordance with local legislation and, most importantly, for conserving local biodiversity”. However, even publicly owned areas still have a huge presence of invasive species. The greatest example is the Rio Vermelho State Park, which has 40% of its territory of more than 1,500 hectares covered by invasive species, mainly pine trees.

Biological invasions

One of the most harmful invasive species for native vegetation, the pine tree arrived in Florianópolis in the 1960s thanks to misguided public policies. The Rio Vermelho State Park, formerly a degraded restinga area, was the scene of experimental pine plantations from 1963 onwards, in the wake of a state decree. The plan was to use these species to contain the advance of the dunes over the Rio Vermelho, Lagoa da Conceição and Ingleses neighborhoods, and allow urbanization to advance through these regions. 

In addition to that, pine seedlings were distributed free of charge in city hall actions, and many residents planted the species in their backyards to try to keep the dunes away from their properties. Decades later, however, several studies have proven that not only do the trees not hold back the dunes but they’re also detrimental to the native species, as the state authorities admit in the official webpage of the Rio Vermelho State Park. The trees have a great capacity to multiply and dominate, as they thrive in unbalanced environments and have competitive advantages over creeping and climbing herbaceous native species such as beach potato (Ipomoea pes-caprae) and acariçoba (Hydrocotyle bonariensis), which have been affected by the alien species in the park.

As pine seeds can travel up to 60 kilometers with the wind, many trees also appeared in other preservation areas which were not targeted by the original experiment such as the Dunas da Lagoa da Conceição City Park.

Previously invaded by pine trees, the park's landscape has been altered in recent years by volunteer efforts that have removed thousands of trees from the dunes and planted seedlings from the restinga instead. The first voluntary joint efforts took place there and, today, there are few specimens of exotic species left in the region.

In some areas of the dunes, the restinga has already recovered by itself and has taken over the spaces previously occupied by pines and eucalyptus. However, in other parts of the park, seedlings of native species had to be planted to recover the land.

“Since we couldn't find seedlings in any commercial nursery, we had to partner with the municipal nursery to develop them as part of a university research project. Today, some volunteers look for seedlings in the south of the island, with their own cars, and bring them to the planting efforts”, says Dechoum.

little trees in a nursery
Native species nursery / Credit: Patricia Figueiredo.

In an article published by Dechoum in the journal Biological Invasions, the professor estimates that, had the team not started the volunteering efforts in 2010, by 2028 a third of the Dunas da Lagoa da Conceição City Park would be overrun by pine trees.

Community engagement 

Sandboard teacher Marcelo Osvaldo da Silveira, who has been volunteering for 11 years,organizes events with children and teenagers from marginalized communities. In addition to taking part in planting native seedlings and learning about environmental education, the young volunteers also get free sand boarding lessons.

Another partnership was established with the surf school located at Praia da Joaquina, where there were also joint efforts to remove pine trees from the dunes. To encircle and mark the newly restored restinga areas, the Leimac researchers had the help of surf instructors.

A resident of the Costa de Dentro region since the 1980s, Eugênio Luiz Gonçalves, is also a volunteer in the mutirões that take place in his neighborhood. Now the president of the Costa de Dentro Community Council, he says, community actions are important, but the government should make more efforts to lead the conservation of the restinga.

“The tourist who comes to Florianópolis wants to see nature, and where does he go to see that? Where there is a preserved restinga. If there’s nothing left, he will travel elsewhere,” Gonçalves points out. 

Other side

Biological invasions have been a problem for Santa Catarina for decades, and the issue is even more serious in Florianópolis since most of its territory is located on an island. The state does have a List of Invasive Exotic Species, published for the first time in 2010, but the document does not stipulate how these should be controlled - the monitoring and inspections rely on the creation of separate laws for each of the species. In addition to that, the list itself should be revised every two years, according to a resolution by the State Council for the Environment (Consema). Despite this, the most recent edition available is from 2016.

Sought by Folha, the Institute of the Environment (IMA) of Santa Catarina spoke through its manager of biodiversity and forests, Ana Cimardi. The spokesperson stated that “the process of revising the list of invasive alien species is under the coordination of Consema” and that there is no deadline for its publication.

The IMA also declared that “the responsibility for the early detection and control of invasive alien species belongs to all public entities” and that, in the case of the municipality of Florianópolis, “the IMA operates within its conservation units”.

Regarding the delay in removing invasive species from the Rio Vermelho State Park, which is under the responsibility of IMA, the institute claimed that “the delay to remove commercial wood was due to the pandemic.” The IMA also declared that it is “in the process of constructing the bidding notice for the sale of wood with economic value, removal of other exotic species without commercial value and the elaboration and execution of the environmental restoration project” of the park. 

The city of Florianópolis, on the other hand, was questioned about the deadline set in the municipal law, and responded through the Municipal Foundation for the Environment of Florianópolis (Floram). The foundation said, in a note, “that the Municipality of Florianópolis has been working diligently in the process of removing exotic species and replacing them with native ones.”

According to the city hall, the removal of the species was “delayed by the Covid-19 pandemic”, but remains “a priority” of the municipal administration.

This story was produced with support from Internews's Earth Journalism Network. It was first published on November 4, 2023 in Folha de S.Paulo in Portuguese, and has been translated and lightly edited for length and clarity.

Banner image: A coastal-oak grows next to a beach / Credit: Patricia Figueiredo.