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28 Keystone Species Vital to North America’s Ecology

Whether you’re on land or in the ocean, there is an abundance and variety of life. These species contribute to the unique ecosystems that are found on earth. While all species are an important part of the ecosystem, some are considered the cornerstone. Without these specific organisms, the ecosystem they live in will dramatically change or even fall apart. Known as keystone species, they are irreplaceable and help keep the ecosystem healthy and thriving. In this article we’ll show you 28 examples of keystone species in North America.

First though, let’s learn a little bit more about what a keystone species is…

What is a Keystone Species?

A keystone species is an animal or organism that holds an ecosystem together. The loss of the organism results in the dramatic change or destruction of the ecosystem. A keystone species can be anything from fungi and other plants to herbivores, carnivores, and mutualists. 

Keystone species are not always the most populous in the ecosystem. They are often not the largest either, but their role is crucial for the habitat’s survival. In essence, keystone species are the glue that binds the ecosystem together. If that species is removed, a chain of events is started that dramatically affects the habitat’s structure and biodiversity.

Even though these vital species differ according to their environment, they all have one aspect in common. Keystone animals have widespread influence on the ecosystems they are associated with. Whether it is preventing soil erosion, keeping temperatures cooler, or keeping populations in check, these species are what balance the ecosystem.

Why are Keystone Species Important?

As the cornerstone of their ecosystem, the importance of keystone species cannot be understated. The organisms keep the habitat structure intact, along with the food web. Their importance is based on Robert T. Paine’s research, an American zoology professor.

His research on the removal of the Pisaster ochraceus sea star for the tidal plain on Tatoosh Island, located in Washington State had an enormous impact on the region’s ecosystem. The loss of the starfish allowed invasive mussels to push out other species. Benthic algae that supported limpets, sea snails, and bivalves were almost wiped out. Within 6 months, the biodiversity in the tidal plain was cut to half of its previous numbers.

Yellowstone National Park experienced a similar effect with the removal of the gray wolf. Elk herds rapidly increased destroying the vegetation. Soil erosion and warmer water temperatures were also recorded due to overgrazing. With the reintroduction of the Gray Wolf in the mid-1990s, the park’s ecosystem is slowly recovering.

Herbivores are also keystone species in certain ecosystems. For example, elephants are the cornerstone in a healthy savanna. The elephants graze and knockdown trees that if allowed to mature would eventually turn the savanna into a forest. Lions and hyenas would find it difficult to find prey, and smaller species like mice would not be able to burrow in the warm soil.

Two organisms can also work together to become keystone species. Bees work with flowers to spread pollen and gather nectar. Some plants in Patagonia only with the help from a specific hummingbird species. Without the presence of both, the woody grassland’s ecosystem would cease to exist as we know it.

Keystone species examples in North America

You can find many different keystone species throughout North America, and each one is vital for the survival of their respective habitats.

This list shows 28 examples of keystone species in North America, and tells a little about each species and how they’re important to their respective ecosystem.

1. Sea Otters

Sea otters are coastal marine mammals that inhabit sea-bottoms, rocky shores, and coastal wetlands. They look for areas with a lush kelp forest and plenty of food. Sea otters are crucial to keep sea urchin populations in check which can help promote healthy kelp forests by preventing kelp from being completely devoured by the urchins. 

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2. Mountain Lions

Image: enki0908 | pixabay.com

Mountain lions can live in a variety of ecosystems that include mountains, wetlands, forests, and deserts. Due to the big cat’s territorial nature, they need a large tracts of habitat to thrive. Previously, before human expansion, mountain lions were the top predator in the U.S. Without their presence the populations of elk, deer, and other large grazing animals can grow unchecked altering many ecosystems’ structures.

3. Jaguars

Jaguars are a top predator in habitats in central and south America and southern North America close to running water, including swamps, mangroves, river valleys, tropical and mixed conifer forests. The jaguar’s presence helps to control the populations of other species in the ecosystem. By preventing overpopulation by a species, the jaguar helps to keep the food chain balanced for a healthy environment.

4. Kangaroo Rats

Kangaroo rats have unique adaptations  that allow them to live in desert habitats where they thrive even with little water. These small animals are an integral part of the ecosystem. They encourage and control plant life by feeding on the vegetation and dispersing the seeds in their burrows. Kangaroo rats are also a food source for several predators that include snakes, coyotes, along with barn and burrowing owls that also live in the same systems.

5. Caribou

image: Pixabay.com

The Arctic ecosystems are dependent on the caribou, along with their reindeer cousins. The animals are not only a food source for indigenous peoples in the area but also predators like wolves and bears. The herd animals ensure the ecosystem’s plant structure remains intact by helping to improve soil quality and circulate nutrients that include the seeds necessary for plant regrowth.

6. Snowshoe Hares

Making their homes in northern forests, the snowshoe hare is an important part of their habitat’s ecosystem. The hares are a vital part of the food chain since they are prey for many of the predators that also make their homes in the habitat. Snowshoe hares help keep the predator’s populations steady and encourage new births. As herbivores, they also help to keep plant growth under control and aid in seed dispersal.

7. Grizzly Bears

Grizzly bears

Forest ecosystems depend on grizzly bears. These large omnivores help regulate populations of prey animals like different types of herbivores and prevent overgrazing. The bears also distribute seeds and nutrients through their varied diet. The salmon carcasses they leave behind is an important source of nitrogen for the soil that they help distribute as they move around the area.

8. Gray Wolves

Gray wolves can thrive in a variety of ecosystems that include mountains, forests, deserts, grasslands, and tundra. The predators prey on herd animals like elk and deer that can overgraze an ecosystem if their populations are left unchecked. The carcasses of their prey not only redistribute nutrients back into the soil but also provide food for scavengers and other animals.

9. Beavers

Beavers are an integral part of a wetland’s ecosystem. The dams the beavers build help to establish and maintain a biodiverse habitat, which is essential for other animals. Their dams ensure that the rivers and streams contain water year-round providing a home for fish that are an important food source for other animals in the habitat, earning them both the title of a keystone species as well as ecosystem engineer.

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10. Prairie Dogs

The North American grasslands are home to prairie dogs. The keystone species is more than prey for nearby predators that include hawks, bobcats, foxes, coyotes, badgers, and golden eagles. Their holes and tunnels help aerate the soil allowing seeds to easily germinate. Prairie dog holes also provide shelter for other burrowing animals.

11. Sharks

Sharks are apex predators. With almost no natural enemies, sharks keep their ocean ecosystem balanced by maintaining prey populations. By helping to keep the populations balanced sharks promote species diversity and healthier oceans and marine ecosystems.

12. Starfish

Tidal pools, rocky shores, coral reefs, seagrass meadows, kelp forests, and the seafloor down to 20,000ft are home to starfish. You’ll find a wide variety of starfish species in coastal habitats. They are considered a keystone species due to the prey they consume. They prey on animals that do not have many natural predators in the ecosystem, like mussels, clams, or molluscs, which would quickly overwhelm the ecosystems they are found in if starfish were not there to keep their populations in check.

13. Hummingbirds

The small, quick flying birds have a wide habitat across North America, often due to their migratory patterns. Hummingbirds are crucial for pollination which allows new plant growth and a food source for other animals. Considered mutualists since they work together with the plants, the hummingbird drinks nectar from the flower, and in return, spread the pollen from flower to flower.

14. Fig Tree

While not native to North America, the warm climate trees do grow in California and some southern states. The fruit-bearing trees are considered a keystone species that helps preserve and balance the ecosystem. The fruit is a food source for many animals. Their roots also contribute to the river and stream bank stability preventing erosion and providing homes for birds and animals.

15. Saguaro Cactus

Recognizable by their “arms”, the saguaro cactus is the cornerstone of their habit. Birds build nests inside the plant’s pulpy flesh or with sticks piled in the crooks of its arms. The fruit, flowers, and flesh of the cactus are a food, water, and nectar source for bats, birds, insects, reptiles, and mammals in a climate where food and water sources may be scarce.

16. American Alligators

American alligators are found in swamps and other subtropical marshy ecosystems. Considered an apex predator at full-size, adult alligators have no natural predators and keep other animal populations from overwhelming freshwater ecosystems. American alligators also act as ecosystem engineers as they construct holes in marshy areas that are used by fish and wading birds during the dry season. Young alligators are also prey for turtles, snakes, wading birds, mammals, and larger adult alligators.

17. Honey Bees

Honeybee getting pollen

Honey Bees are a vital part of the ecosystem. The small insects support tree, flower, and plant growth through pollination. The mutualists spread pollen from one plant to another as they hover above the flowers. These plants provide food and shelter for the other animals that exist in the habitat. Honeybees can be found across North America, but are not actually native to North America. Honey bees were brought from Europe and act almost as livestock due to their importance in crop pollination. 

18. Pacific Salmon

Freshwater and terrestrial ecosystems are sustainable with the presence of Pacific salmon. They provide and transport important nutrients as they travel upstream and their lifecycle is completed. The fish are also an important seasonal food source for bears, birds, and other animals.

19. Snow Geese

The tundra ecosystem benefits from the presence of snow geese due to their role in increasing plant diversity through grazing. They also benefit habitats during their southern migration. The birds feed on agricultural waste, along with grass and other plants. By keeping the vegetation controlled, it provides an environment other species can thrive in. The birds are also prey to the wolf and arctic fox.

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20. Spruce Budworm

image by U.S. Forest Service- Pacific Northwest Region via flickr | Public Domain

Canada’s forests are largely altered by this small but mighty species. The herbivore helps to ensure a healthy forest by eating the foliage of coniferous trees, creating gaps in the canopy and therefore creating structural diversity which allows for other species to thrive. The budworm is also an important food source for other insects and birds. The herbivore helps to ensure a healthy forest with diverse plant and animal life.

21. Woodpeckers

Woodpeckers live in forested areas throughout North America. The birds are a cornerstone of the woodland ecosystem. They build their nests inside trees that are often abandoned after the breeding season. The cavities that they nest in also create habitat for other forest dwelling animals. Additionally, woodpeckers control insects that bore into the trunks of trees. 

22. Ivory Bush Coral

image by NOAA public library via flickr | CC BY 2.0

The stony coral lives in deep and shallow reefs, and it is a vital part of its ecosystem. Ivory tree coral erects structures that become homes of other species. Both invertebrates and fish make their homes in the coral. The coral also helps to protect the coastline from wave erosion.

23. Sugar Maples

Found primarily in the eastern U.S., the Sugar Maple provides both food and shelter for a variety of birds and animals. Woodpeckers and other birds nest in the tree’s cavities. Moose, white-tailed deer, snowshoe hares, porcupine, and squirrels eat the tree’s flowers, fruit, bark, and twigs.

24. Red Mangroves

Red Mangroves grow at the water’s edge and provide both shelter and protection to their wetland ecosystem. The tree’s roots sunk into the water provide a home and nursery for crustaceans and fish. The trees also act as a buffer to prevent erosion and minimize floodwaters from storms.

25. Parrotfish

Tropical reef ecosystems are dependent on the parrotfish. The fish help to maintain the coral’s health by eating the macro-algae that grow on it. If the algae are left to grow unchecked, the reef would become overrun with algae, which would harm this dynamic environment.

26. Krill

image by National Marine Sanctuaries via Flickr | Public Domain

Part of the southern ocean ecosystem, krill are essential for the survival of many marine predators. Seals, whales, penguins, and other fish depend on the krill population as a primary food source.

27. Gopher Tortoise

Florida and other southern U.S. states are part of the gopher tortoise’s habitat. The dry-land tortoise encourages plant growth by spreading the seeds in its droppings. The burrows the animal digs also provide shelter for other animals that range from owls and frogs to the endangered indigo snake. In fact, gopher tortoise burrows may host up to over 300 different species of insects and animals.

28. Bats

Bats are found throughout North America, even in densely populated areas. As a keystone species, bats support the health of the ecosystem and biodiversity. Along with dispersing seeds and pollinating plants, bats also help keep insect and arthropod populations under control.