[ad_1]
Dozens of small black calves cling to a fern plant, while thrown at a leafy green carpet, cover the surface of the South Africa’s Crocodile River.
Those weevils are not accidentally thrown into the river: Scientists hope that the insects and their larvae will go through the green carpet, which consists of an unwanted, invasive South American aquatic plant called Salvinia Minima.
The plant gradually takes over freshwater bodies in the northern region of South Africa and suffocates the aquatic life, including the Crocodile River and the Hartbespoort -Dam in which it flows.
The calves, which were used effectively elsewhere in the world to fight water weeds, are now leading South Africa’s charge against the life-sucking plants that threaten ecosystems in at least three northern provinces and crawl to neighboring countries.
After the calves helped control the distribution of Salvinia in parts of the United States, scientists from both countries worked together on a project to collect a starting population in South Africa.
The insects of 1 millimeters Lang (0.03 inches) were brought more than 8,700 miles from Louisiana. Large stations are set up near various dams to grow the lime population.
Once released on an infected site, the beetles make themselves at home on the Salvinia, the only thing they eat, without damaging the local ecosystem, scientists say.
“They lay eggs on this plant, feed on this plant and die on this plant. If this plant dies, they will die too,” said Professor Julie Coetzee, the chief scientist at the South African Institute of Biodiversity in Aquatics. “It damages certain tissues, those tissues are weakened and then the plants sink to the bottom.”
A floating threat
Hartbespoort Dam north of Johannesburg, the location for the pilot project, is an important source of irrigation for nearby farms and a popular recreational site.
“When we bought the property, there was this beautiful little floating plant on the dam and I thought well it was very nice,” said the 53-year-old resident and business industry Max Moller. “Little did I realize that this little floating fern was an absolute threat.”
Moller, the owner of Mogi’s hiking trail, said the Salvinia clogged and damaged the boat cars and also injured the fishing communities over the nine years he lived in the area.
South Africa’s already vulnerable freshwater systems are facing a threat of Salvinia, scientists say. The plants had two important growth track in 2021 and 2022, which survived on the high nitrate content in the water.
Initially, the plant popped up at the dam more than a decade ago, which has long struggled with a water hyacinth invasion, another problematic species.
“If you pull away the hyacinth, peek this plant,” says Coetzee. The invasive plants block the sunlight, which means no oxygen in the water, she said.
“If there is no oxygen, there is no fish, there are no scratches, there are no insects, and you destroy or change the aquatic ecosystem completely,” she said.
Salvinia has a rapid growth rate and its distribution was the most important in the province of Gauteng, where the largest city of Johannesburg and its capital, Pretoria, are located in South Africa. The plant is compiling existing water supply problems by removing the oxygen and struggling the supply in a country that is already struggling with increasing demand and the weakened water infrastructure.
Concerns about the lime’s impact
While the release of the calves will help combat Salvinia, experts warn that there may be unintended side effects.
Anthony Turton, a water expert and researcher at the South Africa’s University of the Free State, warned that their introduction could turn rivers and dams into more suitable homes for bacteria and dangerous organisms.
This includes toxic blue -green algae, known as cyanobacteria, which thrives in nutritious, polluted waterways and already affected almost 60% of the country’s dams.
“With more light and less competition for nutrients, those cyanobacteria will be known in a condition as a flower,” he said. “It is exponential population growth that radically populates the entire water column.”
Turnton said simultaneous action to repair damaged sewage systems and limit the end of agricultural fertilizer is essential for a lasting solution.
“Unless there are efforts to reduce the inflow of nutrients from sewage flow, we only create room for cyanobacteria to grow without competition from floating weeds,” he said.
Threat of spreading to other countries
The calves are not the first insects set to combat an invasive threat in South Africa. The country brought in an error in the 1930s to control the spread of a hardy cactus that is in Mexico that injured ecosystems. The project was considered a success.
The rapid growth of the Salvinia has put the government under pressure to act, especially as researchers warn that neighboring countries are now facing an invasion.
Coetzee said Salvinia arises on the confluence of the Crocodile and Limpopo rivers in the far north of South Africa.
“It now poses a great threat to our neighbors because this plant has been transported by our rivers on our borders,” she said. “It will probably go all the way along the Limpopo, along Botswana and Zimbabwe’s boundaries and to Mozambique.”
“We really have a responsibility to control this plant,” she added.
___
AP Africa News: https://apnews.com/hub/africa
[ad_2]
Source link
