Scientists discover fate of animals that survived near-extinction – 12/1/2022

Scientists frequently study the consequences of wildlife loss due to hunting, habitat destruction and climate change. But what happens when species on the brink of extinction bounce back?

Research shows that restoring “keystone” species, those that have a major impact on their environment, is vital to the health of ecosystems and can have unexpected benefits for humans.

Here are some examples from North America:

wolves

Few animals evoke the spirit of the American wilderness as much as wolves. Though revered by indigenous communities, European settlers who arrived after 1600 demonized them and tried to exterminate them.

In the mid-twentieth century, there were less than 1,000 gray wolves left in the United States, versus at least 250,000 before colonization.

The Endangered Species Act, passed in 1970, helped in part to revive this predator (at the top of its food chain).

Then, in the 1990s, the federal government brought wolves from Canada to Yellowstone National Park, creating a sort of natural laboratory for scientists.

The new arrivals kept the numbers of moose in balance, preventing them from overusing the vegetation, which in turn provides nesting material for birds and dams for beavers, a phenomenon known as a trophic cascade.

The recovered vegetation helped to contain the erosion of the riverbeds, altering their courses and reducing the meanders.

Other effects have been observed. For one thing, while building their dams, beavers create pools that fish and frogs need to survive. On the other hand, in their hunts, wolves target weak and sick prey, ensuring the survival of the fittest.

A recent article even showed that wolves brought to the state of Wisconsin kept deer off the roads, reducing collisions with cars.

Amaroq Weiss, a biologist at the Arizona-based Center for Biological Diversity, compared ecosystems to tapestries. So “when we remove some threads, we weaken the carpet,” she told AFP.

It is estimated that there are currently over 6,000 gray wolves in the United States. The main threat is legalized hunting in some states.

buffaloes

The history of the American buffalo, also known as the bison, is closely linked to the emergence of the United States.

From 30 million, buffalo numbers plummeted to hundreds in the late 19th century as the government tried to eliminate the native plains tribes whose livelihoods depended on the animal.

“It was an intentional genocide to remove the buffalo, remove the Indians and confine them in reservations,” Cody Considine, of The Nature Conservancy (TNC), told AFP.

These animals are an integral part of TNC’s efforts to restore the Nachusa Grasslands in Illinois.

The buffalo, who were introduced there in 2014 and now number around 100, prefer to eat grass over flowering plants and vegetables, allowing various birds, insects and amphibians to thrive.

“Some of these species without this pasture would simply disappear,” Considine pointed out.

Also, while feeding, bison plow the ground with their hooves, which further helps plant growth and seed dispersal.

TNC currently manages approximately 6,500 buffalo and is creating a pilot program to transfer excess animals to indigenous communities as part of its efforts to recover the United States’ national mammal.

About 20,000 buffalo are believed to roam in “conservation herds,” though none are actually free, according to Considine.

otters

As the dominant predators of marine environments close to shore, sea otters play a very important role in their ecosystem.

Historically, they ranged along the west coast, from Baja California to Alaska, and across Russia and northern Japan, but hunting in the 1700s and 1800s decimated the species, which grew to 300,000.

For a time, they were thought to have been completely wiped out in California, but a small surviving population of around 50 helped them partially recover to around 3,000 in this region today.

Jess Fujii, of the Monterey Bay Aquarium on California’s northern coast, told AFP that research carried out in the 1970s in the Aleutian Islands showed that otters maintained kelp forest balance by controlling populations of sea urchins that feed them.

More complex interactions have been revealed over the past decade, including otters’ downstream benefits to seagrass habitats in California estuaries.

There, sea otters controlled the crab population, which meant more sea slugs could feed on the algae, keeping the sea meadows healthy.

Marine meadows act as “nursery” for young fish and also reduce erosion, which can influence coastal flooding.

“Algae and seagrass are often seen as good ways to sequester carbon, which can help mitigate the ongoing impacts of climate change,” emphasized Fujii, an example of how the destruction of nature can make global warming worse.

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