Scientists have presented for the first time a scientific assessment of the impact on the local ecosystem of the rapidly increasing population of hippos brought to South America by the infamous drug lord Pablo Escobar. The results are published in the journal Ecology.
Traditionally, the habitat of hippos is considered to be Africa south of the Sahara. But now another place has appeared on the world map where these animals live.
At one time, Pablo Escobar created a home zoo at his Napoles villa, four hours drive east of Medellin in the northern Colombian municipality of Puerto Triunfo, for which he ordered rhinos, giraffes, zebras and other exotic animals from Africa.
After the death of the drug lord, most of the animals were moved to other zoos. But four hippos fled into the jungle. And it looks like they feel very good there, because, according to ecologists, today their population has reached 80 individuals.
American scientists from the University of California, San Diego, along with their Colombian counterparts, conducted a comprehensive assessment of the impact of these world's largest invasive animals on the local ecosystem.
"This unique species is an important element of the ecosystem in its natural range in Africa, and we found that it exerts no less influence here, on another continent, in a completely different environment with a different set of inhabitants," the head of the university said in a press release. Research by Professor Jonathan Shurin "This effect includes negative effects on water resources, contributing to the development of harmful algae and bacteria."
For two years, scientists carried out a comprehensive assessment of water quality, oxygen levels and stable isotope signatures, and also compared the microbiomes and species composition of insects, crustaceans and other organisms in water bodies with and without hippopotamus populations.
The study showed that hippos, which feed on land at night and spend their days in cool water, have seriously altered the chemical composition and quality of the region's water with their waste products. In the bodies of water where hippos live, the level of organic matter is much higher. The large amount of nutrients introduced by animals from the surrounding landscape promotes the rapid development of bacteria and algae.
“We found that lakes are more productive when they contain hippos. This can change the species composition of algae and bacteria and lead to problems such as eutrophication (saturation of water bodies with nutrients, accompanied by an increase in biological productivity - Ed.) And harmful blooms algae.
According to researchers, the number of hippos will continue to grow in the coming years, and this raises many questions from both scientists and local authorities.
Hippos are usually very difficult to catch, and encountering them poses a serious danger to humans. It is not known how the neighborhood with hippos will end up for local animals - manatees, caimans and giant river turtles that inhabit nearby rivers and lakes.
"The number of hippos tends to grow exponentially," says Shurin. "In the next twenty years, there may be thousands of them. This study shows that it is necessary to decide what to do with them before it is too late. After all, it is much easier to find 80 hippos than thousands. ".