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These climate hero animals are restoring habitats and reviving ecosystems
A close up of a colorful hornbill.
You might be surprised to learn how much our world is shaped by animals that do mundane things like scratching, digging, eating, and pooping. Especially poo. These activities are the first in a chain of events that result in highly complex ecosystems rich in biodiversity.
Some species, due to their unique skills, food choices, or even size, are pillars of the ecosystem – take them out of the equation and an ecosystem collapses. Without mussels, you might not have drinking water. Without forest elephants, atmospheric carbon dioxide would skyrocket. And if you think an otter’s appetite for sea urchins doesn’t impact your life, think again.
In a world where nature works together to stay in balance, human-caused climate change is like a counterweight that has fallen from the top of a building, threatening more than a million species worldwide. Humans are responsible for altering nearly 100% of Earth’s terrestrial ecosystems, according to a 2021 study published in Frontiers in Forests and Global Change.
These changes are detrimental to the ecosystems on which humanity depends. Now, animals like the beaver, which are all too easy to dismiss as unexceptional or unimportant from our own perspective, may be one of our best hopes for climate salvation.
Stacker has compiled a list of 10 animals from diverse environments, describing how each helps maintain their ecosystem.
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A beaver chewing a branch in a clear river.
Beavers are revered as nature’s civil engineers, a species capable of altering entire ecosystems with the dams they build. Beavers hold back moving water to create a pond where they make their home. Upon encountering the obstruction, running water from the opposite side of the dam is diverted to the surrounding lands, creating wetlands and attracting new flora and fauna to this ecosystem. Although some people, especially farmers, may rightly view this freestanding construction as a nuisance, it can save lives in drought-prone areas.
Dams prevent water sources from becoming too depleted and completely drying up. The wetlands created by the overflow are drying out arid lands that would otherwise be exposed to wildfires. They are so effective at mitigating climate-related drought that the California Department of Fish and Wildlife has earmarked $3 million to restore beaver habitat in North America so they can, in turn, cause more of problems.
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Green mussels growing on a beach rock by the sea.
Freshwater mussels act as tiny water treatment plants that filter pollutants like algae and bacteria from rivers and streams. A bed of mussels the size of two football fields can filter up to 10 million gallons of water a day – and research in Alaska shows they actually get that big. This service keeps their freshwater cohabitants healthy. The mussels themselves can also serve as aquatic ecosystems. When embedded in the bottom of rivers, streams, or lakes, they create a physical structure where good algae can thrive and fish can feed. As water temperatures rise due to climate change, 70% of all mussels in the United States are critically endangered. Without freshwater mussels, humans and animals would face pollution of rivers and significant changes in freshwater ecosystems.
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A sea otter swimming fast underwater.
Sea otters are so much more than cute faces and clownish dispositions. They are essential to the protection of coastal kelp forests. Adult sea otters eat up to 30% of their body weight (or 25 pounds) each day, feasting on abalone, crabs, clams and, most importantly, sea urchins. Without sea otters to control their population, sea urchins can decimate kelp forests, wiping out an underwater ecosystem that is an essential reservoir of carbon dioxide where many other marine species thrive. Coastal ecosystems such as kelp forests remove carbon dioxide from the atmosphere through photosynthesis and store about 20 times more carbon per acre than terrestrial forests. Without sea otters, there would be no kelp; without kelp, carbon sequestration would drop.
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An armadillo walking by the water’s edge.
Armadillos perform a variety of important ecological functions such as pest control, seed dispersal, and even protection of other species. Like the beaver, the South American giant armadillo is an ecosystem engineer. The vast burrows they dig to take refuge and hunt insects are used by dozens of other species for warmth, food and protection from predators. Even the piles of sand and earth moved by armadillos in their burrows are used by other species as resting or sunbathing places. These small ecosystems and the biodiversity they provide are integral to the overall health of the larger one in which they exist.
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A black hornbill eating papaya fruits.
Hornbills are frugivores, a species whose diet consists almost exclusively of raw fruit. Some species of hornbills reach a wingspan of 6 feet. Their size compared to other fruit-eating birds makes them the perfect propagator of plants that bear large fruits. Without the hornbill, the orchards of Canarium and Phoebe would not exist. They spread seeds intact through their droppings over great distances while flying, earning them the nickname “farmer of the forest”. A study published in the Journal of Avian Biology found that hornbill populations can disperse nearly 13,000 seeds per day over an area the size of 184 football fields. Their dispersal promotes ecological prosperity and the diversity of tropical forests.
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African forest elephants
African elephants walking in a row.
These giants of the forest protect their environment by destroying it, to some extent. As these massive creatures move through dense rainforests, they trample and graze small trees and thin vegetation that competes for resources like sunlight and water. Field researchers in the Congo Basin found that where forest elephants existed, the trees were taller and denser. These types of trees are essential to the environment because they store large amounts of carbon. If the forest elephants disappeared tomorrow, 3 billion tons of carbon dioxide would be released, the equivalent of more than 646,000 gasoline-powered vehicles over a year, or more than 7,000 billion kilometers traveled by these vehicles. Forest elephants also help disperse seeds in the forest through their droppings.
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A herd of American bison grazing on a green meadow in front of a mountain.
Bison are essential to maintaining the biodiversity of the American prairies; they do this mainly by eating. Bison create the opportunity for new flora to grow by feeding almost exclusively on grasses that outcompete most other plants for space. Their presence on grasslands doubles plant diversity, according to data from the Konza Prairie Biological Station. The biodiversity of plant species makes ecosystems more resistant to drought. These regions rebound after the species was hunted to near extinction in the late 1800s, culled for profit, sport, and as a way to inflict harm on Native Americans who relied on bison. Bison parts could be crafted into 150 different items, including food, clothing, tools, and weapons, which were essential to Native American survival on the Great Plains.
They also shape their surroundings by scratching. Yes, scratch. The adult male bison can weigh up to 2,000 pounds; adult females can weigh up to 1,200 pounds. When they wallow or roll on the ground to scratch an itch, their powerful bodies create depressions in the earth. These depressions create a buffer – a sort of bunker – from the wide open plain where plant and animal species are further protected from threats.
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A gray wolf walking on a log in the forest.
As climate change shortens the length and intensity of winter, gray wolves are mitigating the impacts on scavenger species like bears, coyotes, and some large birds by increasing their food supply. Milder winters mean an increased survival rate for prey like elk due to lower metabolic effort and fewer winter stressors, according to findings from a University of California, Berkeley study. Less snow means they won’t perish from exhaustion, and earlier melting means easier access to food sources. Wolves provide balance by driving moose away and leaving their remains for scavenger species to feed on.
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A walking pangolin.
The only scaly mammal in the world, pangolins are integral to maintaining healthy forests by feeding on termites. While termites actually help maintain a healthy ecosystem by consuming dead wood and turning it into nutrient-rich organic matter called humus, an unchecked population can take over a forest. A single pangolin can protect about 31 football pitches in the forest from termite damage. Pangolins also keep the soil healthy and airy by digging burrows, which facilitates decomposition and vegetative regrowth.
Pangolins have been hunted almost to extinction due to myths about the medicinal and magical properties of their blood and scales, which are made of material similar to our hair and fingernails and have no benefits for humans. In parts of Asia, pangolin meat is a delicacy; in Africa it is sold as bushmeat. These creatures faced further persecution when they were wrongly named as a possible source of COVID-19.
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A mother and baby tapir in the water with birds in the background.
Like the other heroes on this list, tapirs are frugivores. Seeds from food sources travel through their digestive tract and are eventually thrown along the forest floor in their nutrient-rich waste. Thus, frugivores are essential to restore degraded environments and increase carbon storage. Tapirs prefer to feed in these degraded environments. So, by simply performing daily functions like eating and defecating, the tapir is helping to seed and restore large tracts of its South American rainforest habitats that have been disturbed by fires and deforestation.
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