Foundation Species

A foundation species provides the foundation of a habitat. Foundation species are also often primary producers.

A primary producer is an organism that creates biomass (living matter) such as plants using photosynthesis to grow. Using energy from sunlight, plants combine water and carbon dioxide to form sugars as an energy source. They use this energy source to live and grow.

As the plants grow, they are producing living matter (biomass). Plants are then eaten by animals. This means that the larger a plant grows, the more food it will provide for animals. So primary producers basically start the food chain.

Since the plants are a food source they attract herbivorous predators (plant eaters). The herbivorous predators are preyed upon by carnivorous predators (meat eaters). So the herbivorous animals come to eat the plants, and then the carnivorous predators come to eat the herbivorous animals that came to eat the plants! The result: a food chain.

Not only do foundation species provide the physical foundation of a habitat, but they may also be the primary producers that begin the food chain in some habitats.

What is a kelp forest?

Kelp forests are marine habitats that occur in cold, nutrient rich water along shallow coastal regions. Kelp forests are some of the most biologically productive habitats in the ocean with some species of kelp capable of growing up to 12 inches per day! That is a very high rate of growth and makes sunlight a critical component of the system as the kelp needs to photosynthesize in the sunlight. Sunlight only penetrates to a certain depth in the ocean which is one reason why kelp forests dominate in shallow coastal regions.

Kelp as a Foundation Species:

Kelp grows very large and can form dense kelp forests which provide a variety of benefits to the animals that live within its boundaries. Fish use kelp forests for cover to hide from predators, and the presence of these animals brings their prey. As a result, a natural food chain and ecosystem develops within a kelp forest. The kelp provides the foundation for the habitat; without the kelp there would be no reason for all of the fish and other organisms to congregate to that area.

Kelp is a primary producer which means it begins the food chain. Kelp turns sunlight and carbon dioxide into sugars, and then it is consumed by a herbivorous predator. The herbivorous predator (plant eater) is then eaten by a carnivorous predator (meat eater). As a result, one animal eats an animal that ate another animal that ate the kelp! The whole food chain within a kelp forest community begins with the foundation species: kelp.

What is a coral?

Corals are actually animals (some people falsely believe that corals are plants) related to jellyfish and anemones. While corals may get their energy from photosynthesis, the photosynthesis itself is performed by algae organisms, called zooxanthellae, that the corals "host in their cells." Some species of coral feed themselves by using tentacles that reach out and grab plankton (tiny organisms in the ocean). Corals also have a limestone skeleton that may be exposed as a coral dies, or bleaches.

Coral as a Foundation Species:

Corals have a limestone (calcium carbonate) skeletal base that forms the foundation of a coral reef. Coralline algae (calcium based encrusting algae) also contributes to the formation of a coral reef. Coral reef communities are often referred to as "rainforests of the seas" due to their high biodiversity and beautiful appearance. Coral reefs only cover an extremely small percentage of the ocean floor yet they are home to a very large percentage of marine animals.

Corals grow into colonies, and colonies combine to form reefs. These reefs provide plenty of shelter to thousands of sea animals including fish, crabs, and shrimps while serving as home to countless species of other organisms. Therefore, corals are the foundation species of coral reef communities.

Unfortunately, endangered coral reefs are rapidly declining due to human activities.

What is Seagrass?

Seagrasses are true flowering plants that have the ability to live completely underwater. These seagrasses form underwater meadows that look similar in appearance to grasslands that you would see on land. These underwater meadows can be formed by just one species of seagrass or be formed by several different species of seagrasses. Since seagrasses get their energy from photosynthesis they are limited to shallow coastal waters in which sunlight easily penetrates. In deeper waters sunlight may not reachdown far enough or be intense enough to support the physiological needs of the plants.

Seagrass as a Foundation Species:
Seagrass is a foundation species due to its formation of these underwater grasslands which are home to many animals. Juvenile fish can seek shelter from predators within the grass beds while other animals may actually feed on the seagrass. The presence of thick beds of seagrass can even slow down waves and create a low turbulence area that provides benefits for various animals and marine processes.

Trees form the foundation of forests all across the world. These forests are home to many species of animals including birds, snakes, lizards, frogs, large cats, bears, primates, and millions of species of insects. Without the trees there would be no forest. That is why trees can be a foundation species; they are the physical features that form the forest. Herbivorous animals use trees as a food source while other animals use trees to create their home (birds and squirrels nest in trees for example). Of course, all of this life attracts the larger predators which results in a food chain and a forest community.

There are many different types of forests and their characteristics may vary depending upon local conditions and natural geographic features.

As previously described, a foundation species is an organism that creates the foundation of a habitat such as kelp creating a kelp forest habitat.

What is a keystone species?

A keystone species is very important for its habitat and can be defined as an animal that has an ecological impact much greater than its abundance would otherwise suggest. This means a keystone species can be small in numbers, but have a huge effect on the habitat or ecosystem.

An example of a keystone species is the sea otter. There may not be a large amount of sea otters in a particular kelp forest, but their presence plays a critical role in maintaining the ecosystem of a kelp forest community. Sea otters eat sea urchins, and sea urchins eat the kelp. Without sea otters eating sea urchins, the sea urchins would eat all of the kelp and there would be no more kelp forest! So sea otters are a vital component of the system even though they may not be present in large numbers.

A trophic cascade refers to the relationship between predators and their prey as well as how it affects the abundance or scarcity of organisms in the ecosystem. Lets go over an example.

Say organism A eats organism B, and organism B eats organism C. If there is a high abundance of organism B then they will eat all of organism C and keep organism C at low abundances. However, if organism A starts to eat a lot of organism B, then organism B will lower in abundance which means there is now less of "B" eating "C." As a result, organism C would be allowed to become more abundant thanks to organism A eating organism B.

Example of a Trophic Cascade:

You should now know that kelp is a foundation species that provides the foundation of a kelp forest. We have also discussed how sea otters are an example of a keystone species in the kelp forest community. So lets examine what happens when we remove the sea otter keystone species from the kelp forest ecosystem.

The sea otters eat sea urchins, and sea urchins eat kelp. Sea otters keep the sea urchin populations in low numbers by eating them which means there isn't enough sea urchins to cause much damage to the kelp forest (since sea urchins eat the kelp). If you remove sea otters from a kelp forest then they will no longer be able to eat the sea urchins, and as a result the sea urchin population would be allowed to increase. This higher abundance in sea urchins means that there are now enough sea urchins to eat all of the kelp. The sea urchin population would be allowed to grow out of control and completely wipe out the beautiful and biologically productive kelp forest habitat. The aftermath would be nothing but a bunch of rocks covered in sea urchins like the picture above.

This is why it is extremely important for us to conserve top level predators that keep the food chain intact. Unfortunately, many important species have become threatened, endangered, or even extinct due to human activities.

Public awareness is extremely critical, see Monterey Bay Aquarium Great White Shark in Captivity to see and learn more about ocean conservation and how to take action.