Amazon is the biome in Brazil with the fewest records of invasive alien species (IAS), whether animals or plants, making up the forest. The region has 80% remaining natural areas. This reality contrasts with that of the Atlantic Forest, which has only 12% to 28% of its original area. However, the environmental devastation caused by the current levels of deforestation underwent by the Amazon ecosystem has been an issue of concern by researchers.

The data is part of the  Relatório Temático sobre Espécies Exóticas Invasoras, Biodiversidade e Serviços Ecossistêmicos [Thematic Report on Invasive Alien Species, Biodiversity and Ecosystem Services], which highlights the impacts of such organisms over forest and human dynamics. The research was carried out over three years and identified that the invasion process is characterized by four stages: transport (removal of species from their natural habitat); introduction (into a different environment); establishment; and expansion. The study counted more than 500 IAS within the Brazilian ecosystems.

According to the report, invasive alien species are organisms known to be among the most important vectors related to the loss of biodiversity and ecosystem services in Brazilian biomes, along with changes in land and sea use. In addition, these factors  influence climate change, over-exploitation of resources and pollution. Compromising fishing and water quality, essential for communities that depend on these resources for survival, are also consequences. 

The negative effects caused by invasive alien species also affect the country's economy. The report estimates that US$ 2.88 trillion (around R$ 14.4 trillion) will be committed to the loss and management of these organisms on a global scale between 1970 and 2022 – during this period, there was an explosion in cases of IAS due to the increase in navigation and the use of air transport. With these impacts, pandemics, endemics and risk to sociocultural activities are more likely to become a reality.

Forage grasses

One of the biggest concerns in the Amazon is the occupation of invasive exotic grasses in the forests. According to the report, the appearance of these plants can be related to the occurrence of fires, as they accumulate a large amount of biomass. Mário Orsi, one of the project coordinators, explains that these land invasions are increasingly caused by deforestation rates. “We made it crystal clear that invasive alien species are favored by degraded environments".

Invading fishes pose danger

According to the Amazon Institute of Man and Environment (Imazon), every day an area equivalent to 250 soccer fields is deforested in the Amazon. However, devastations are not the only factors attracting the EEIs. Mário Orsi points out that the region's watershed is being affected by the invasion of fish species that are not part of the ecosystem. “The farming of invasive fish, such as tilapia, has led to serious issues already affecting some parts of the Amazon.”

“But not just them. “There are several groups that may be coming, including the golden mussel. No biome, regardless of preservation, is immune to invasive alien species. However, when degraded, territories become more susceptible. The EEIs compete with native species, take over areas and can, among their impacts, affect what we know as the quality of life of Amazon peoples, unbalance the soil and water quality, and mischaracterize habitats in the region", he adds.

Wild boar

Orsi points out that the boar, considered one of the 100 worst species in the world, may be reaching the Amazon – it has already been found in Tocantins. The animal is known to cause substantial damage, not only to the environment. “The activity not only leads to the deterioration of forest ecosystems but also disrupts natural springs. It poses a threat of transmitting diseases to the local wildlife populations. Moreover, it exerts a substantial economic burden on the community, particularly impacting small-scale farmers and producers.” “His aggressive nature may lead to the expulsion of individuals from their communities,” says the researcher.

Peacock bass threatens South Brazilian areas

The invasion of species is a reality not only in the Amazon biome. Animals native to the region are being transported irresponsibly to other locations in Brazil, such as the peacock bass. The fish is already widely seen in rivers in the South and Southeast regions of Brazil, for example, and has been used in sport fishing activities. Even though it may appear to be harmless entertainment, sport fishing can lead to irreversible detrimental effects on the ecosystem. "It's notorious what the peacock bass is causing to our native species in the Southeast and South", says Mário Orsi.

"It leads to extinctions, preys on native species, roots out the native fauna from the area it lives, a situation mainly driven by the practice of sport fishing. The peacock bass is a typical case of intentional release. It has moved from the Amazon to the Southeast and South because of sport fishing," says the report's coordinator. “The report underscores the urgent need for management strategies for the peacock bass, as the situation in this region is critical. It has been conclusively demonstrated that the presence of this species is leading to the extinction of native species,” he further explains.

The climate changes of temperature increase that exist today are conditions that have favored the adaptation of the peacock bass in waters different from those found in the Amazon. Orsi emphasizes that in Rio Grande do Sul and Santa Catarina, where the climate is typically colder, there are already reports of the presence of this fish. “But it still hasn't adjusted due to weather issues. However, as the climate is changing a lot, it is very likely that it will [adapt],” says Mário.

Pirarucu

The pirarucu is also a species native to the Amazon that is already being recorded in other biomes. The type of transport that Mário points out as being responsible for this phenomenon are unintentional and intentional - fishing and aquaculture. "These species of pirarucu arrived in the Upper Paraná basin and are doing very well in reservoirs. We still need to study more to know its degree of impact. It is still an emblematic case that is happening here and that can have even greater dimensions, "he concludes.

There are invaders in the urban area of the Amazon

IAS are introduced to sites in a variety of ways. One of them may have been the cause of the presence of the Asian gecko in the urban areas of the Amazon: cargo ships, in this case, of plants and fruits. Annelise D’Angiolella, PhD in zoology and professor at the Federal Rural University of the Amazon (Ufra) in Capitão Poço, in northeastern Pará, explains that possible risks of the species to native animals of the biome have not yet been identified, but it is a type of organism that spreads very quickly.

“In 2021, our work was published reporting a kind of Asian lizard in Capitão Poço. It had already been registered in 2015, in Belém. We also have records in Castanhal and Manaus (AM). It is a species that is most associated with urban environments or gardens. After they settled in Belém, they may have been transported by car or bus to Capitão Poço. Another species is the wall gecko, which is also exotic and has lived in the country since the time of the discovery, "says the researcher.

Rattlesnaker

Unlike the Asian lizard, which apparently poses no risks, another animal worries researchers in Pará: the rattlesnake. Annelise points out that the species is typical of more open environments, such as the Cerrado and the Caatinga, but deforestation in the Amazon has provided the appearance of this type of snake. "It does not occur here, but we have records in Paragominas. With the destruction of the habitat, these animals are increasing their area of occurrence”.

"When there is deforestation, the vegetation cover changes, the conditions are different. Now that it is deforested, it receives more insolation, with lower plants, with higher temperatures; so, these animals in open environments will be more favored. But the biggest problem of the species we have is that these animals have no natural predators and have not developed within our fauna. When it is not native, they have no predators and have a disorderly growth of these populations that can lead to several problems, "she adds.

Brazilian territory challenges government action

A front developed by the Ministry of the Environment (MMA) has focused on invasive species that threaten or impact the biological diversity of Brazilian biomes. The National Strategy for Invasive Alien Species was established by Resolution 07/2018 of the National Biodiversity Commission (Conabio) and brings together guidelines and decisions to manage, prevent, manage and control the entry and permanence of these organisms in spaces. The integrated vision of the program takes into account several sectors: social, cultural, health and economic.

Ibama

Another institution that has also developed actions to combat the advance of invasive species is the Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis (Ibama) [Brazilian Institute of Environment and Renewable Natural Resources]. Rodrigo Agostinho, president of the institute, pointed out that the theme is already within the strategic planning. "Ibama controls the entry of animals and plants into Brazil, as it is responsible for the emissions of the so-called CITES licenses," he says.

The license refers to the International Trade in Species of Wild Flora and Fauna in Danger of Extinction (Cites). However, Agostinho states that this control within the national territory is an additional difficulty encountered by the agency. “We have greater difficulty controlling the movement of species within the territory, due to the size of the challenge and the structure we have today”, he says. “We are updating the wild boar action plan to prevent it from entering the Amazon. It will be quite a challenge, but essential”, he adds.

Alternatives to control IAS

- In the case of the Amazon, the Thematic Report on Invasive Alien Species, Biodiversity and Ecosystem Services states that controlling the presence of alien species in the biome is possible, since 80% of the current remaining area is still composed of native organisms.

- The researchers list four steps to better reverse the situation in the Brazilian biomes:

STEP 1: Prevention - the best strategy

STEP 2: Eradication - early detection and rapid response to achieve eradication

STEP 3: Control - IAS are present in many locations, so it is important to do a population reduction

STEP 4: Control - IAS are widespread and expanding - immense costs

Source: Brazilian platform for Biodiversity and Ecosystem Services