While invasive species spread across Latin America, from water lilies in lagoons to sargassum on beaches, biological control attempts to limit environmental damage without destroying biodiversity.
While invasive species Spreading across lakes, reservoirs, and beaches of Latin America, riverside communities, scientists, and activists are racing against time. From the water lily suffocating 300 lagoons in Mexico to the sargassum covering paradisiacal Caribbean beaches, and toxins in a Chilean lake famous for tourists, the region has become a living laboratory of conflicts between nature, economy, and climate.
Behind every seemingly harmless plant lies a complex story. Hippos in Colombia, goats in the Galapagos Islands, beavers in Patagonia, and water lilies in Mexican lagoons are examples of how exotic species become invasive species. Erasing biodiversity, altering food chains, and generating heavy economic losses. At the same time, creative responses are emerging: biological control with insects, reuse of algae as biogas and in construction, community monitoring, and increasingly organized environmental activism.
What are invasive species and why has Latin America become a target?
When we talk about invasive speciesWe are not talking about just any plant or animal from outside the region, but about organisms that arrive in new territories, usually accidentally or intentionally, and begin to spread aggressively.
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According to the United Nations Development Programme, These species are already the second leading cause of biodiversity loss in the world., second only to direct habitat destruction.
In Latin America, the list is long. Hippos in Colombia, goats eradicated in the Galapagos, and beavers in Patagonia. They show that the problem is not just ecological. Invasive species also cause damage to fishing, agriculture, tourism, and health.
In many cases, governments and communities are forced to spend time and money trying to control pests that started as “ornaments,” economic experiments, or even whims of powerful people.
Within this context, two plants have recently gained prominence: Water lilies, which choke bodies of water in Mexico and other countries, and sargassum, a brown algae that invades beaches in the Caribbean and the Mexican coast..
Meanwhile, in Chile, scientists and activists are monitoring toxins generated by cyanobacteria blooms in a tourist lake, trying to prevent a silent collapse in water quality.
Water lily: an ornamental plant that has become an aggressive invasive species.
The case of the water lily clearly illustrates how Invasive species can originate from something seemingly harmless.Imported at the end of the 19th century as an ornamental plant, the lily went from being a garden and canal decoration to a national problem in Mexico.
Today infests around 300 lakes and lagoons in the countryforming green carpets that impede navigation, block access to crops, and suffocate aquatic fauna.
In the Tecocomulco lagoon, in central Mexico, the situation became critical. A floating “carpet” of lilies blocked boats, isolated crops, and ruined fishing, the main source of income for about 20 people in the surrounding area.
Farmers like Seu Pancho were forced to abandon corn, bean, and broad bean crops to dedicate themselves almost exclusively to the manual extraction of the invasive plant.
Uprooting a lily is not easy. The plant is largely composed of water, which multiplies its weight and complicates its removal. Even so, a brigade of 16 riverside dwellers began carrying out daily cleanups, pushing the infestation back.
What was once just a problem has also become part of the solution: the removed lilies are taken to the growing plots and spread out as if they were fertilizer.
This agricultural use brought an unexpected advantage. Water lilies, used as ground cover and fertilizer, have helped reduce the use of chemical fertilizers., which previously flowed into the lagoon, enriching the water with nutrients and fueling the explosion of the invasive plant.
With the ecological restoration program of the Hidalgo government, coordinated by technicians like Evelyn Terrazas, the community managed to reduce the “plague” to about one-tenth of the water’s surface.
When biological control attempts to turn the tide against the water lily.
The water lily problem is not unique to Mexico. The plant, which has already taken over freshwater systems on five continents, has also invaded reservoirs in northern South Africa.
There, the Hartbeespoort Dam became an extreme example: a green mass where there should only be water, blocking waterways and causing ecological and socioeconomic impacts..
Attempting to control lily using only manual extraction or chemical herbicides has proven to be expensive, slow, and risky for the environment.
It was at this point that the biological control, one of the most sophisticated strategies for dealing with invasive species.
South African researchers have spent years testing “natural enemies” of the water lily in completely controlled environments.
They sought an insect capable of attacking only the invasive plant, without damaging native species or crops. Their bet was on… a small water hyacinth grasshopper, native to South America, described as tiny and voracious.
In ten years, 1 million insects were created in the laboratory, with 300 released in the last year alone.
Each grasshopper is counted and thoroughly tested to ensure that it feeds primarily on lilies. The logic is simple: use a species that reproduces at the same rate as the invasive plant and corrodes it “from the inside,” leaf by leaf.
In the areas where biological control was applied, the signs are visible. The lily leaves show holes and brown spots, curl up, and eventually disintegrate slowly at the bottom.
In about two years, some reservoirs have seen their plant cover reduced from 40% to 5%. Even so, experts admit that the lily will never completely disappear: given its rapid growth rate, the goal is to keep the invasive species under control, not eliminate it entirely.
Sargassum: algae that affects the Caribbean Sea and inspires unexpected solutions
(Thor Tryggvason/Unsplash)
Another critical front of invasive species In this region, it comes from the sea. Sargassum, a brown algae that normally floats in the open ocean, more than a thousand kilometers from the coast, has begun to arrive en masse on beaches in the Caribbean and Mexico.
The result is a scenario that contrasts sharply with the image of a “tropical paradise”: Brown streaks covering the coast, murky water, a strong smell, and millions of tons of biomass accumulating year after year..
Sargassum grows quickly, responding to heat and the presence of nutrients in the water. When it accumulates on beaches, it begins to decompose and releases hydrogen sulfide, which has the same smell as rotten eggs.
This affects not only the marine and coastal ecosystem, but also the economy: Many countries fear the impact on tourism, their main source of income..
To try and contain the spread of the algae, hotels and authorities installed floating “anti-sargassum” barriers which allow fish and turtles to pass through, but block some of the algae masses before they reach the beaches.
Out at sea, specialized boats perform mechanical recovery. Even so, barriers and recovery are temporary solutions that need to be repeated year after year.
At the same time, the excess of sargassum stimulated a creative side. Companies and scientists in Mexico began testing the use of the seaweed as a raw material for… biogas and building materials.
In a laboratory near Mérida, Yucatán, researchers are using fungi that break down fibers and make carbon more accessible, accelerating biogas production by about 30%.
In another project, sargassum was transformed into building blocks, called “saga blocks,” used in a pilot house with about 60% of the structure made of algae.
Transforming an invasive species into an economic resource doesn’t solve the root of the problem, but it can alleviate some of the impact and generate jobs in vulnerable communities.provided there are clear rules to prevent further environmental damage.
Lake Villarrica: toxins, tourism, and environmental activism in Chile
In southern Chile, Lake Villarrica, in the Araucanía region, shows another side of the challenge. There, the problem is not the water lily or the sargassum, but… Intense blooms of algae and cyanobacteria that can produce dangerous toxins..
The lake receives thousands of tourists every summer, but at the same time, it suffers from sewage discharges, waste from fish farms, garbage, and real estate pressure.
The biologist and activist Loreto Lagos, founder of Fundación Raíces de Pucón, decided to react. Their organization monitors biodiversity, visits wetlands, conducts field work, and makes nighttime observations to better understand who lives in these environments and how they are changing.
The diagnosis is clear: excess nutrients in the water, imbalance in the food chain, and intense algal blooms in the summer, many of which produce hepatotoxins and neurotoxins.
In small animals, deaths have been observed. In humans, the most visible cases are skin irritations and gastrointestinal problems.
However, Loreto warns that if nothing changes, The accumulation of toxins can increase the risk of liver cancer and neurological damage in the coming years..
Despite this, authorities often prefer to downplay the problem, fearing it will scare away tourists. A symbolic example was the holding of an Ironman race with the lake green and covered in algae, which activists considered disrespectful to athletes and residents.
The foundation is pushing for clear protocols: measuring toxins regularly, informing the public, and… Close beaches when water levels are dangerous..
In addition to monitoring, Loreto’s team produces biodiversity guides, informational brochures, and gives lectures in schools. The strategy is simple: Without environmental education, the fight against invasive species, pollution, and toxins will always be reactive and belated.
How can the region regain control over invasive species?
The cases of water lily, sargassum, and toxins in Lake Villarrica show that Invasive species and ecological imbalances are not isolated problems, but symptoms of a water and land use model that stresses entire ecosystems.At the same time, they show possible paths.
In Mexico, riverside communities transformed an invasive plant into fertilizer and food for carp, reduced chemical inputs, and recovered fishing, birdlife, and tourism in lagoons that seemed lost.
In South Africa, biological control using specific insects has proven that it is possible to attack an invasive species without resorting solely to poisons.
In the Caribbean, sargassum has become fuel and a building block, opening up a new production chain. In Chile, grassroots activism is pushing for transparency, safety protocols, and respect for the people who live and work on the shores of the lake.
Invasive species won’t disappear overnight.However, the way we deal with them can accelerate destruction or open up space for smarter solutions that combine science, social participation, and the local economy.
And you, do you think Latin America should invest more in biological control, in the economic reuse of invasive species, or in stricter rules to prevent these species from arriving and spreading?