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Keystone Species

Above Photo by @otterofigram

Have you ever heard of a keystone species? Just like a keystone in an arch, their presence is vital for maintaining the structure of their specific ecosystems. They promote healthy interconnected relationships not just between animals, but also the plants, and the nonliving parts of the environment. Of course, their influence reaches us humans as well. So, who are some of these keystone species and how do they hold their ecosystems together? Let’s get into it!

Probably one of the most famous examples of a keystone species is the gray wolf in Yellowstone National Park. Hunting practices in the 1800s led to the disappearance of this species from the park by the early 1900s. Wolves are natural predators of grazers like elk. So without them, the elk species grew out of control to the point where most of the vegetation was gone. When the wolves were reintroduced in 1995, they began hunting the elk again, which changed their population size and grazing behavior, allowing for the plants to grow back again. This created new habitat for migratory birds to return. Not only that, but the plants also began to stabilize the soil with their roots reducing erosion. Also, wolves don’t finish the food they catch, which means that more were left over carcasses for other predators like mountain lions and bears. Ironically, through killing they were promoting more life.

Those trees that were returning because of the wolves benefited another keystone species as well. Through the creation of their dams, beavers create wetlands and swamps that are the home to many plants, animals, and other organisms. Many species are adapted to these specific environments like the red-winged blackbird and cattails. Wetlands also act a bit as an environmental sponge, absorbing lots of nutrients and toxins from the water before it makes its way back to the ocean. This promotes biodiverse ecosystems and prevents algae from building up at the base of large rivers. Not only that, this storage of water also replenishes underground aquifers humans rely on and helps prepare the environment for drought.

Following the flow of water out to the ocean, sea otters are another large rodent with the responsibility of environmental stewardship in their paws. This keystone species regulates the kelp forests in the Pacific Northwest. These underwater forests are the homes, nurseries, and hunting grounds of many marine species including the sea urchin. But the sea urchins like to eat the kelp, so if their populations get too large, that could mean the destruction of the whole habitat. Luckily, sea urchins are on the menu for sea otters, who keep their population in check, allowing for the kelp forests to continue to thrive.

About 80% of flowering plants rely on pollinators like bees to survive to the next generation. This means that the organisms that depend on these plants for their fruit, seeds, shelter, and oxygen they produce, in turn depend upon the bees. Over 130 different fruits and vegetables depend upon pollinators for reproductive success. Although most of the keystone species effects could cause trophic cascades that eventually impact humans, the importance of pollinators to humans is a bit more direct than the previously mentioned species. This is why many people stress the importance of promoting the health and success of not only the bees who are the poster children of pollination, but also the butterflies, hummingbirds, and even flies who contribute to pollination success as well. I guess you could say they carry the weight of the world on their wings.

As the name suggests, keystone species are the rocks that hold their ecosystems together. Populations ebb and flow through generations but the success of an ecosystem relies upon the interdependent nature of its species. Sometimes we don’t realize how important a species is until it is gone. That is why it's best to promote biodiversity as a whole.


Gray Wolves


Sea Otters:


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