14 Examples of Keystone Species and Their Ecosystem Roles

Robert Paine, a prominent environmentalist, altered a section of the Washington State shoreline in the 1960s and achieved a significant environmental accomplishment. He removed every starfish species in one area in Makaw Bay to comprehend the food chain in tidal ecology.

He came to understand that some species play disproportionately large roles in the overall structure and function of their environment as a result of how quickly the entire ecosystem changed.

Others have the power to upend an entire community of plants and animals with their disappearance, while some creatures have little impact on the ecosystem in which they live.

These important organisms have a name thanks to Paine: keystone species. Here is a closer look at some examples of keystone species found all around the world and at various points in the food chain. But, let’s first get the definition of keystone species.

What is a Keystone Specie?

Keystone species are those whose importance to an ecosystem is such that their impact on other organisms in the system is disproportionate. Ironically, they are the least numerous even yet they have a long-lasting impact on the ecology.

Their presence is therefore very important. Keystone species are typically either dominant or apex predators whose presence maintains the ecosystem’s balance.

In contrast, removing a species promotes the growth of the prey population, which in turn reduces the ecosystem’s biodiversity. They are especially essential in determining the precise numbers of other species in the community.

Even though it might not be the biggest or most numerous species in an ecological community, the removal of a keystone triggers a series of events that drastically alter the habitat’s structure and richness.

These are the living entities that play a crucial role in how their ecosystem functions, although all of an ecosystem’s numerous components are intimately linked.

However, some keystone animals have a significant impact on their group despite not being predators in the slightest. Examples of keystone species and their ecosystem roles will be highlighted in this article.

There is little functional redundancy in keystone species. This means that no other species would be able to fill the species’ ecological niche if it were to vanish from the ecosystem. The environment would be forced to undergo a significant transformation, allowing for the influx of new, potentially invasive species.

A keystone species can be any type of organism, including fungi and plants; they are not usually the biggest or most numerous species in an ecosystem. Animals that have a significant impact on food webs are, nevertheless, virtually universally used as examples of keystone species. The impact these creatures have on food webs varies depending on the habitat.

Examples of Keystone Species

  • Sharks
  • Sea Otter
  • Snowshoe Hare
  • The African Elephant
  • Prairie Dogs
  • Starfish
  • Gray Wolves
  • Grizzly Bears
  • Hummingbirds
  • Saguaro Cactus
  • Figs
  • Beavers
  • Alligators
  • Bees

1. Sharks

One of the biggest fish in the deep seas is this one. It is a voracious predator that consumes all types of fish, making it the keystone species in deep waters. Sharks have been the primary controllers of life in the deep water ecosystem because they prey on weak and diseased fish, keeping the population of fish under control and lowering the risk of disease from sick or dead fish, respectively.

Given the variety of fish species present and the level of fertilization, the marine environment has a very large population. They would become extinct if there were not enough seaweed and food sources in the ocean. Sharks are crucial to marine ecosystems because of this.

2. Sea Otter

A mammal that lives in the North Pacific Ocean consumes sea urchins to preserve the coastal marine ecology. Kelp, a type of seaweed, serves as the food source for these sea urchins. In the environment, kelp serves as the primary food supply for living things including snails, crabs, and geese. The sea otter is a keystone species because of this.

All animals in the environment are managed by kelp due to their presence, which also regulates the presence of sea urchins. They aid in maintaining adequate kelp for other species to eat. The kelp also helps to mitigate climate change by absorbing carbon dioxide and decreasing erosion near the coast by slowing the flow of water.

However, the kelp would diminish and collapse if there were too many sea urchins and no sea otter to control their production. As a result, the sea otter controls the local sea urchin population to safeguard the kelp forests.

3. Snowshoe Hare

Snowshoe hares are food for several predators in the Canadian Boreal woods, in contrast to other keystone species. It is the primary source of food for woodland carnivals. Consequently, if it disappeared, the ecology would suffer. In contrast to other keystone species, the snowshoe hare is abundant in the woodlands.

Because it maintains the equilibrium between the predator and the prey, it becomes a keystone species in its environment. Its presence ensures the ecosystem’s health, but its disappearance would ultimately result in the ecosystem’s demise.

4. The African Elephant

The largest land animal is a keystone species. In Africa, you can find it. It plays a part in the destruction of trees and the consumption of young savannah grassland saplings. Many grass-eating herbivores, including antelopes, buffaloes, and zebras, live in the savannah grasslands.

The elephant’s ingestion of the saplings ensures that the grassland doesn’t change into woods and stays the same. It ensures that there are enough grazing fields for the diverse array of herbivores present in the savannah by decreasing the number of trees and increasing the spaces occupied by grass.

Mice and hares depend on the grass to survive, and their population is likewise kept in check. Over time, the African elephant helps big predators have an abundant supply of prey.

5. Prairie Dogs

These rodents are common in North American grasslands. They are prey to numerous creatures, including wolves and eagles, just like the snowshoe hare.

As a result, they serve as keystone species by maintaining the number of predators and preventing it from declining owing to reproduction, which would upset the equilibrium. Because of their skilled digging, rodents are recognized for creating habitats for some predators, such as ferrets.

Burrowing creates habitat as well as mixes, fertilizes, and aerates the soil, allowing for the growth of additional plants. These rodents, which are herbivores, cut the grass, allowing other plant species to flourish. Additionally, the trimming lessens the amount of water that is lost to the atmosphere through evaporation and transpiration,

6. Starfish

A crucial species in marine life is the starfish. It preserves the environment in the deep waters, just like the shark does. Being a predator, it eats mussels. As a result of the mussel’s growth on the rocky bottom of the water, other species whose establishment is equally dependent on rocky surfaces are less likely to flourish.

Thus, the starfish’s presence helps to regulate the number of mussels in the water and encourages the growth of other species on the rocky surface. In an experiment, the starfish were taken out, which then caused the mussel population to rise.

This was quickly followed by competition for available space with other species, where the dominant and robust species on the rocky terrain outgrew the others. The number of various species has decreased by half in approximately a year. The environment was brought into equilibrium by the starfish’s reintroduction.

7. Gray Wolves

These wolves are the main keystone species that can be found in the Greater Yellow Ecosystem. The habitat is large and includes mountains, meadows, and woods. Many different types of prey live there, but elk, rabbits, and birds are the most common.

There is a possibility of competition for grazing pastures due to the wide variety of herbivores, which is where this wolf enters the picture. It consumes these prey and lessens competition, controlling the amount of grass in the ecosystem as a result. In addition, the wolf eats a variety of birds and so controls their population.

The ecosystem’s different endangered bird species have been preserved thanks to the gray wolf. In the latter half of the 19th century, the US government decided to eradicate the wolf from the ecosystem out of concern for the number of elks and livestock. The results were catastrophic.

Elk were overpopulated, which increased competition for food. Fish and beavers, two other creatures that depend on grass, also risked extinction. The result of overgrazing and overpopulation was that the ground began to erode. The ecosystem’s balance was restored with the return of wolves.

8. Grizzly Bears

For several reasons, these bears are keystone species. To begin with, they manage the salmon population in the water. The present population of seaweed would be burdened by the fish’s rapid growth, which would have an impact on the ecology. The grizzly bear, unlike most carnivores, prefers this prey over herbivores, maintaining life in the aquatic habitat.

The bear is also renowned for its “gardening.” The bear takes its prey far into the forest to consume it, unlike other carnivores. The fish carcasses that are transported from the riverbank decay and fertilize the soil, promoting the establishment of sturdy plants. In addition, they consume the roots of plants. The soil is aerated when the roots are dug up, and the humus produced from the dead animals and fallen leaves is mixed in.

9. Hummingbirds

Due to their mutual role, these are frequently referred to as keystone mutualists. They are important pollination agents and help some plant species thrive and spread by doing so.

A lone hummingbird can spread pollen over a wide region. This means that if the bird vanished, the forest’s vegetation cover would fall, and some plant species that the hummingbird especially pollinated would eventually go extinct. These birds guard the woodlands, which are home to thousands of different animal species.

10. Saguaro Cactus

The desert is where this unique cactus grows. Given that it provides a natural home for a wide variety of species, it serves as both a keystone species and a keystone host. It provides suitable nesting areas for both huge birds like hawks and smaller species like woodpeckers.

Its well-shaped branches, which offer appropriate nesting places, are credited with all these possibilities. The cactus tree’s fruits are also the only source of food the birds have throughout the dry seasons of the year.

11. Figs

The fig tree is a keystone species despite being a plant. It serves as a source of food for both animals and birds. Although animals can eat their leaves, their fruits are the ones that are most in demand.

These year-round fruits give the animals sustenance during the dry season when there isn’t any for them to eat. As a result, the environment would lose many birds and other species if the plant and figs were not present.

12. Beavers

Not only are these creatures persecuted for their fur, but also for the damage they cause to the waterways. The majority of people find it problematic since they frequently reroute or obstruct waterways.

However, some fish species, including salmon, have found suitable habitats thanks to beaver dams. Because they are keystone species, they change the ecology and create wetlands where there were previously none. These dams increase wildlife by putting animals close to drinking water in the woodlands.

13. Alligators

The populations of various species are regulated by alligators. Additionally, they dig burrows to stay warm, and as they move, the burrows fill with water that various animals can use.

14. Bees

Bee pollination and plant reproduction are both aided by bees. These insects find cover in the plants, where they later become food for birds.


As we have seen, keystone species are baseline species that affect and control the population of other species. If these baseline species are destroyed because of anthropogenic activities in that area, we will be most affected but also, the native ecosystem wit be imbalanced or even destroyed.


Editor at EnvironmentGo! | providenceamaechi0@gmail.com | + posts

A passion-driven environmentalist by heart. Lead content writer at EnvironmentGo.
I strive to educate the public about the environment and its problems.
It has always been about nature, we ought to protect not destroy.

Leave a Reply

Your email address will not be published.