In 1981, infamous drug lord Pablo Escobar imported 4 hippos from Africa to his property close to Medellín, Colombia. After his loss of life in 1993, the herd meandered into the close by Magdalena River. Ecologists estimate there at the moment are 65 to 80 swimming round, and that quantity may attain 800 by 2050.
Introducing new species typically causes environmental mishaps. Toads launched to eat crop-loving beetles took over Australia, and ivy delivered to the New World for adornment has toppled native bushes. However some ecologists assume these hippos might have occurred upon a precious position: 100,000 years in the past, semiaquatic hoofed mammals roamed South America, and Escobar’s pets could also be filling the area of interest they left behind. Listed here are 4 methods they’re shaping their setting.
At a whopping 3,500 kilos every, hippos’ our bodies are in a position to create trails by shallow rivers, altering move. This kinds stream-like waterways the place small fish can disguise from predators. Their survival helps a various ecosystem, which is mostly extra resilient than one with fewer species.
Snacking on shrubs
In Africa, these ungulates’ hefty appetites preserve grass peak in examine, spurring new progress. Contemporary sprouts are decrease in fiber and better in vitamins like nitrogen, making them the right snack for smaller grazers like vicuna. The same, unconfirmed impact could also be at play in Colombia.
Hippopotamuses expel waste whereas wading, and their poop offers a feast for aquatic microorganisms—and in flip a lift for the fish that eat them. However invasive animals by no means come with out issues; waste may immediate algae blooms that drop oxygen ranges, killing swimmers en masse.
The hooves of those chunky beasts dredge up sediment alongside waterbeds, resuspending natural matter that algae dwelling near the floor can feed on. All this stomping additionally kinds small, deep swimming pools the place fish can discover shelter through the dry season when the river degree drops.
This story seems within the Winter 2020, Transformation concern of Fashionable Science.