The Amazonian plant that became the most dominant invasive species on the planet – 09/17/2023 – Environment

The Amazonian plant that became the most dominant invasive species on the planet – 09/17/2023 – Environment

The fires in Hawaii left hundreds of dead and desolate images in one of the most idyllic landscapes on the planet. But they also highlighted a factor that would be behind forest fires that, like the one that occurred in Hawaii, are repeated throughout the world: the presence of invasive exotic plants.

According to a recent report supported by the UN, these plants are part of the group of species that are related to 60% of plant and animal extinctions worldwide.

As they are foreign to “invaded” ecosystems, they harm local nature, disrupt food chains and threaten human health at an estimated cost of US$423 billion (around R$2 trillion), points out the report, based on data 2019.

According to experts, invasive plants amplify the effects that climate change has on the planet.

“The action of invasive plants often results in more intense fires, like some of the devastating ones that have recently occurred around the world, releasing even more carbon dioxide into the atmosphere,” the report notes.

And, among these plants, there is one that predominates over the other species: the pontoderia crassipesbetter known as water hyacinth or water hyacinth.

Originally from South America, especially the Amazon region, it is the most widespread exotic invasive terrestrial species.

“As the use of land for agro-industrial production increases, the use of exotic plants that end up becoming invasive also increases, as we are seeing across the planet”, says Professor Helen Roy, specialist in invasive plants and member of the British Center of Ecology and Hydrology.

Roy, who led the report to the UN, points out that this particular plant has had profound effects in different regions, such as Lake Victoria, in Africa.

“The lake, one of the main sources of food for millions of people, is running out of fish, more specifically tilapia, because the water hyacinth absorbs essential nutrients for the animals that live there”, he explains.

And this plant, which is also recognized for the beauty of its flower, has already reached many regions where it has caused serious and diverse damage.

The Amazon jungle

The water hyacinth is a plant native to the Amazon region and the Orinoco River, the main river in Venezuela, where it finds its perfect habitat in the huge waterways.

It is a floating plant that has an incredible ability to reproduce and grow quickly.

Another of its characteristics is that its roots and leaves have the ability to absorb toxic substances from water and filter its contents.

According to experts, what happened is that the explorers who traveled the Orinoco at the end of the 19th century thought that water hyacinth could be a perfect ornamental plant for artificial fountains in their countries of origin.

This is because they are floating plants and have a striking violet flower. In this way, the species reached countries such as the United States and Japan.

“Something that favors water hyacinth for invasion work is that freshwater environments are all very similar around the world, especially those located in the tropical zone”, explained to BBC Mundo (BBC Spanish service) Anibal Pouchard, professor of forestry affairs at the University of Concepción, in Chile.

There is yet another factor: experts have learned about these plants’ ability to filter toxic elements in water, including fertilizers, which has increased their demand around the world.

What they didn’t take into account was the enormous invasive capacity that this plant has.

The case of Lake Victoria – located on the border of Uganda, Tanzania and Kenya – is just a reflection of what has happened in dozens of countries where the invasive plant is present.

Its effects take different forms.

“Due to its exuberance and ability to dominate the aquatic environments where it lives, it does not allow the existence of other native plants, which ends up affecting the balance of the habitat where it invades”, says Pouchard.

This is also why it affects the navigability of these “bodies of water”.

Furthermore, water hyacinth’s ability to absorb and process toxic materials and heavy metals causes it to emit large amounts of carbon dioxide and methane gas when it decomposes, contributing to climate change.

But the problem doesn’t end there. Both Roy and Pouchard point out that, to eliminate water hyacinth, millions of dollars are needed, which are often insufficient.

“Another problem with water hyacinth is that its seed can last for years without germinating. So even if all the water hyacinths can be removed from, say, a pond, there is still the possibility that they will grow again, quickly and luxuriantly, some some time later”, observed Roy.


The expansion of invasive plants is considered critical by scientists and environmentalists.

“It’s a situation that affects the entire society at different levels, regardless of their origin or status: they attack the center of habitats and the supply chains that leave the environment”, explains Roy.

The main solution is prevention in the management of plants destined for export or import.

“It is necessary to take into account that many of these plants that are today invasive were brought in to provide some benefit to people. The problem is that care was not taken with the effects that this could cause”, says Roy.

For this reason, both Roy and Puchard believe that the prevention and control of flora and fauna at borders is one of the most effective measures that can be implemented to prevent the arrival of invasive species.

“Not all plants that are taken from one habitat to another by man are invasive, but we need to know which ones can have a harmful effect on the nature of this new location”, says the researcher.

According to the United Nations report, programs that advance the eradication of invasive species have worked effectively, especially when these plants can be isolated and when their harmful species is quickly detected.

In the specific case of water hyacinth, a series of interventions are being implemented that have managed to control its expansion.

“In the case of water hyacinth, there is a biological element that is an insect (Neochetina bruchi), which looks like a beetle. It does the job of controlling the growth of these species”, concluded Roy.

This text was originally published here.

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