Dengue-bearing mosquito and other invasive species in Brazil cause annual losses of up to BRL 15 billion

The number may be an underestimate in light of gaps in studies of the problem, according to the authors of a report issued by the Brazilian Platform on Biodiversity and Ecosystem Services.

By Elton Alisson  |  Agência FAPESP – Invasive exotic species in Brazil, such as mosquitoes of the genus Aedes that transmit dengue, yellow fever, chikungunya and zika, causes annual losses amounting to as much as BRL 15 billion, enough to build 15 maximum biosafety laboratories (BSL-4) like the one to be implemented in Campinas, São Paulo state.

The estimate comes from a group of researchers who authored the “Thematic Report on Invasive Exotic Species, Biodiversity and Ecosystem Services” launched on March 1 by the Brazilian Platform on Biodiversity and Ecosystem Services (BPBES), established in 2015 with the support of BIOTA-FAPESP, the FAPESP Research Program on Biodiversity Characterization, Conservation, Restoration and Sustainable Use.

According to data from the report, Brazil has 476 invasive exotic species of plants, animals and microorganisms introduced deliberately or accidentally by human action to places not part of their natural habitats. They reproduce, multiply and spread to new areas, where they typically threaten native species and disturb ecosystem balance.

“They represent one of the top five causes of biodiversity loss on a global scale,” said Michele de Sá Dechoum, a professor at the Federal University of Santa Catarina (UFSC) and one of the coordinators of the report. The other four are habitat destruction, climate change, pollution, and overexploitation of natural resources.

Of the 476 invasive exotic species recorded in Brazil, 268 are animals, while 208 are plants and algae, mostly native to Africa, Europe and Southeast Asia.

The mosquito Aedes aegypti, for example, originated in Egypt and has spread to tropical and subtropical regions of the world since the Great Navigations in the sixteenth century. The insect came to Brazil in the colonial period.

These intruder species are present in all regions and all ecosystems, especially in degraded environments and areas with high levels of human circulation. Urban areas are vulnerable to them owing to intense movement of people, commodities and other goods through ports and airports, the authors note.

“Not all well-conserved areas are immune to invasion. Invasive species are found in 30% of Brazil’s conservation units,” said Andrea Junqueira, a professor at the Federal University of Rio de Janeiro (UFRJ) and also a coordinator of the report.

Invasive species are mainly introduced via trading in animals for sale as pets, and in ornamental and horticultural plants, according to the report.

The Red lionfish (Pterois volitans) inhabits coral reefs in the Indian Ocean and Pacific. It can also be found in the West Atlantic, where it was introduced by humans (photo: Sílvia Ziller)

“Most of the invasive species that have negative impacts in Brazil were intentionally introduced. They include tilapia, peacock bass, feral swine and giant African snails,” said Mário Luis Orsi, a professor at the State University of Londrina (UEL) and another coordinator of the report.

Over a 35-year period from 1984 to 2019, the minimum estimated loss due to the impact of only 16 invasive exotic species ranged from USD 77 billion to USD 105 billion, for an annual average of USD 2 billion-USD 3 billion. Most of these species are agricultural and silvicultural pests, responsible for losses worth USD 28 billion in the period; and disease vectors such as A. aegypti, all of which together caused losses worth USD 11 billion in the period.

The estimates were based on a survey of financial damages in terms of lost revenue and the cost of managing actions to prevent, control and mitigate the negative impacts of invasive exotic species reported by government bodies, state-owned enterprises and business organizations.

The losses may well be underestimated, however, since they take into account only 16 of the 476 species identified, and also because many gaps remain to be filled in knowledge and appraisal of the impact of invasive exotic species, the authors note.

“The impact is far greater than we imagine. More scientific studies of many species with high invasive potential are needed. The marine environment needs more attention in light of the potential damage,” Orsi said.

The damage caused by invasive species relates to production losses, lost work hours, hospitalizations, and interference with tourism.

Species such as the Golden mussel (Limnoperna fortunei) also cause severe economic damage by fouling hydroelectric power developments, wastewater treatment plants and fish farming net tanks.

“Cleaning of mussel incrustations is estimated to cost BRL 40,000 per day for a small hydropower plant and as much as BRL 5 million per day due to turbine downtime in the case of large dams like Itaipu [the world’s second-largest hydroelectric power plant, responsible for around 9% of Brazil’s power consumption],” the report’s authors write.

Domestic cats and dogs

The invasive exotic species recorded in Brazil include animals and plants considered “charismatic”, such as domestic cats and dogs, ornamental bushes and trees, and some turtles and primates. In these cases, it is harder for laypeople to understand their impact. Pets only become a threat if they escape or are abandoned or allowed to roam free, according to the authors.

“This is particularly the case if they enter protected areas where they can transmit disease and prey on native wild animals that inhabit the forest, interfering with the local ecological balance,” they note.

Dissemination of knowledge about the origins of invasive exotic species and their negative implications for society can help reduce popular opposition to management of these species, according to the authors.

Cases of successful public engagement with the management of invasive exotic species cited in the report include a program to control the Slash pine (Pinus elliotti) in Dunas da Lagoa da Conceição Municipal Natural Park in Florianópolis (Santa Catarina state), and Cipó Vivo, a project focusing on control of signalgrass (Urochloa spp.) in Serra do Cipó National Park (Minas Gerais state).

“Some timber companies are eliminating invasive exotic species outside production areas to comply with certification requirements,” Dechoum said.

The power generation sector has also acknowledged the biological invasion problem and is pursuing a positive agenda to minimize its impact.

Brazil does not have an official list, although the national database on invasive exotic species managed by Horus Institute of Environmental Development and Conservation in Florianópolis serves as a reference source, and there are state lists in Bahia, Paraná, Rio Grande do Sul, Santa Catarina, São Paulo and the Federal District.

“Lists are fundamental. Without them, it’s hard and almost ineffectual to plan any kind of management action. The states that have lists are already a step ahead,” Orsi said.

The report (Relatório Temático sobre Espécies Exóticas Invasoras, Biodiversidade e Serviços Ecossistêmicos, available in Portuguese only) can be downloaded by users who register at: www.bpbes.net.br/produto/relatorio-tematico-sobre-especies-exoticas-invasoras-biodiversidade-e-servicos-ecossistemicos/.