Keystone Species

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What is a Keystone Species?

‘Key’ means very important, therefore, keystone species is a type of species in the ecosystem having exceptionally a great importance for other species surrounding the keystone species. The abundance of keystone species will help many other species to thrive and survive. In an ecosystem, every living organism is dependent on other organisms to survive and the species that play a major role in sustenance of other multiple organisms are called keystone species. 

It is not true that the number of key stone species or their biomass is large and therefore they are named so. Rather, their effect in the survival and maintenance of a balanced ecosystem is larger as compared to the other species. Therefore, it can be said that a keystone species is that species having a very large effect on the community through direct and indirect pathways (even though its abundance or biomass in the community is low).

It is also not necessary that only higher animals or carnivores are keystone species; it’s correct that they play their role as keystone species but in certain ecosystems whereas in other ecosystems, any other species can also be a keystone species.

Importance of Keystone Species

After knowing the keystone species definition, we move towards knowing their contribution in maintaining a balanced ecosystem. This species has a large ramifying effect on the structuring of communities. Keystone species can be single species or species guilds which are functional groups of ecologically similar species. It affects the structure of communities in the following ways:

  1. Transforming the physical structure of organisms.

  2. Affecting the prey and host populations that include parasites, pathogens or predators.

  3. Supplying the essential services and resources and acts like mutualists.

  4. Affecting the flow of energy in the environment and becoming material resources as producers and consumers.

Therefore, the loss of a keystone species can lead to the extinctions of other species and population crashes that imbalances the dependency of different organisms on it for ecological services.

Examples of Keystone Species

Some of the keystone species examples are explained below that help us better understand the importance of keystone species.

  1. Sea Otter

Kelp, an algae, produces kelp forest under the ware bodies and this forest can be a habitat for many species like fish, vertebrates and invertebrates. So, multiple populations of species depend upon the kelp forest to survive. There is a threat to this kelp forest known as sea urchin because it destroys and eats the kelp, and ultimately can destroy the kelp forest. So, what are the consequences of this destruction of the kelp forest? The home for many other species will be gone and they won’t be living any longer. 

Here, sea otters play an important role in saving the home of a million species; let’s learn how! Sea Otter eats Sea Urchin and reduces its number in the aquatic ecosystem. This will indirectly help all other species to survive as it will help kelp forest to grow (after less sea urchin in the scene) and since thousands of vertebrates or invertebrates live around the kelp forest, they can survive and reproduce to increase their population. This is how Sea Otters are keystone species as these are exceptionally important for multiple other species to grow in the surroundings. 

Sea Otters

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Sea Urchins

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  1. Top predator keystone species that include wolf, jaguar, leopard, lion, alligator and white shark feed on other species and help in regulating the populations of other species. Since deer, rabbits or other herbivores are the food for these animals and if keystone species are absent, the green vegetation shall be missing with the maximum increase in deer, rabbits or other herbivores.

  2. In the savannas of Southern Africa, Elephants are a keystone species as they consume large quantities of woody vegetation and uproot trees. And if large dark forest is established which is not eaten, there will be no reach of light to other species living in the forest as well as it will be difficult to move for other animals. 

  3. Frog-eating salamanders and sea stars are keystone species in coastal North Carolina.

  4. Pollinators of flowering plants are also key stone species as they play an important role in the reproduction process (pollination) leading to generation of new plantlets. Examples are bees, hummingbirds and bats.

  5. Microorganisms are also keystone species in some ecosystems. For example, in the temperate forest ecosystems, some groups of fungi i.e. mycorrhizae form associations with tree roots (Pine tree) to facilitate the uptake of essential minerals and nutrients. The role of mycorrhizae is to convert insoluble Phosphorus into soluble Phosphorus which is very essential for pine tree survival. If these fungi are absent here, the trees do not grow properly, having a poor development.

FAQ (Frequently Asked Questions)

1. What is the role of keystone species in an ecological community?

Ans. Keystone species meaning is that they are exceptionally important species which help in the survival of other species in an ecosystem, relative to its population. Their role is such that they help in maintaining a balance in an ecosystem where living organisms depend upon each other and help in each other’s survival. If keystone species are absent, the population of a certain species may over dominate the other species and hence create an imbalance in the ecosystem.

2. What are the types of keystone species?

Ans. The three types of keystone species are as follows-

  1. Predators- It is that organism where it kills and eats another organism called prey during the biological interaction. For example- Tiger, leopards and snakes eat other smaller animals such as deer, rats and buffaloes.

  2. Ecosystem Engineers- It is any organism that creates, modifies and maintains or destroys a habitat in a significant manner.

  3. Mutualists- It describes the ecological interaction between multiple species, i.e. two or more species and each species has a mutual or net benefit i.e. mutual benefits on interacting with each other.