Brazil coexists with 272 invasive exotic animals in its various ecosystems, according to the Hórus Institute for Development and Environmental Conservation database. The non-governmental organization has been monitoring, since 2005, species considered exotic because they do not originally belong to that location and invasive because they reproduce and spread in an uncontrolled manner, threatening the area’s biodiversity. There are animals little known to the general public, such as the brown anolis lizard (Anolis sagrei), the crab (Cancer paguros) and the sun coral (Tubastrea sp.), but there are other more famous ones such as the ubiquitous dogs (Canis familiaris), domestic cats (Felis catus) and common pigeons (Columba livia). for sport fishing/hunting or as pets. Sun coral, for example, is native to the Indian and Pacific oceans. It arrived in Brazil through oil platforms manufactured abroad and brought to the Campos Basin. The red crayfish (Procambarus clarkii) arrived in Brazil, coming from the United States, through the aquarium hobby and ended up being released in rivers and lakes. The largemouth bass (Micropterus salmoides), also native to the USA, was initially introduced in the country for aquaculture, but was later released into water bodies in the country for sport fishing. The African tilapia Oreochromis macrochir was also used for fishing. Water tiger turtle (Trachemys sp.), invasive animal, in a lake in Tijuca National Park. Photo: Vitor Abdala/Agência Brasil These animals threaten the local biodiversity by causing an environmental imbalance. After all, they arrive suddenly in an environment that took generations to find a balance between the different beings that inhabit that area. “The problems generated depend on the species. It has predatory species that feed on other animals, such as the lionfish (Pterois volitans), which is quite aggressive and feeds on several species of fish. We have others like wild boars (Sus scrofa), which destroy the natural regeneration of plants in the forest and degrade natural areas. And there are those that occupy the space of native species, such as the water tiger turtle [americana, Trachemys scripta]. They end up occupying reproduction or resting niches of similar native species”, explains the founder of Instituto Hórus, Silvia Ziller. Impacts The National Database of Invasive Exotic Species, maintained by the Horus Institute, also points out other problems, such as the transmission of diseases from exotic animals to native fauna. This is the case of the red crayfish, which is the vector of a fungus that can decimate native species and which had its trade and breeding prohibited by the Brazilian government in 2008. Another example is the panga fish (Pangasianodon hypophthalmus), which comes from Asia and was introduced by the aquarism and aquaculture, which is, according to the database, susceptible to parasitic diseases. There is also the risk of transmitting diseases to humans, as is the case with the giant tiger prawn (Penaeus monodon), vector of viruses and bacteria such as salmonella, native to the Indian and Pacific Oceans and introduced by aquaculture, or the giant African snail (Lissachatina fulica), vector of the worm that causes abdominal angiostrongyliasis, inserted in Paraná as a culinary delicacy. It is worth mentioning that the Aedes aegypti, the mosquito that transmits diseases such as dengue, zika and chikungunya, is also an invasive species. Originally from northeast Africa, it arrived in Brazil accidentally, probably through the slave trade. Another negative impact on biodiversity is the genetic contamination of populations of native species, since exotic animals can mate with natives and generate hybrids. The molly (Poecilia sphenops), which lives from Mexico to the north of South America, for example, hybridizes with the native guaru (Poecilia vivipara). “An invasive animal or plant also when it is in a new environment, in new conditions, sometimes it has potential in the genetic material [para se adaptar], and that explodes into a whole new environment. It’s our mistake [provocar a invasão], but it is up to us to see that this is stopped or at least minimized to reduce the problems”, says Jorge Antonio Lourenço Pontes, PhD in Ecology and Evolution and researcher at the State University of Rio de Janeiro (Uerj). Conservation In 2018, the National Strategy for Invasive Alien Species was created, commanded by the Ministry of the Environment, which consists of instruments such as maintaining a database to monitor the situation and creating specific plans to deal with individual species, groups of species, regions or dispersal routes. One of the main focuses is to protect endangered native species, since, according to the International Union for Conservation of Nature (IUCN), invasive exotics are one of the main causes of extinctions and loss of biodiversity in the world. As the control of invaders is difficult, especially when they have already spread over a large territory, there is a priority to detect invasions early. “Instead of just investing in control programs, which are long term, also investing in a more preventive approach, detecting species when they start to be a problem. Those that are introduced more recently, because they still have smaller populations, are still small foci. Eradication is more feasible than when very large populations are already established. The wild boar is already spread throughout Brazil, as well as the African snail. We will always live with these species. They are no longer amenable to complete deletion. They are subject to control initiatives, in priority areas”, says Ziller. The researcher cites as a successful example of combating invasive species, the eradication of goats from Trindade, an oceanic island located more than a thousand kilometers from the Brazilian coast. The animals, introduced by settlers centuries ago, decimated the native flora. About two decades ago, they were finally eliminated with the aim of trying to restore native vegetation. But just to prove that invasive species are a difficult problem to solve, attempts to restore native flora ended up creating another problem. Among the seedlings produced on the mainland and taken to the island, common lizards (Hemidactylus mabouia) traveled, exotic species even on the American continent that came to populate Trindade. Agência Brasil tried to hear from the Ministry of the Environment and the Brazilian Institute for the Environment and Renewable Natural Resources (Ibama) about strategies for dealing with invasive alien species, but received no response.
Agência Brasil
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