Chapter 5, Problem 1CR

To determine

The reasons for southern sea otters acting as keystone species in their environment. The occurrence of southern sea otters as keystone species in their environment and to suggest the possible reasons for protecting this species from extinction.

Answer to Problem 1CR

The southern sea otter act as a keystone species by controlling the population of sea urchins and prevents elimination of kelp. They must be protected from extinction as they support many aquatic plants and animals.

Explanation of Solution

Keystone species are organisms that help define an entire ecosystem. The absence of keystone species would affect the ecosystem. If the keystone species disappear from the ecosystem, no other species would be able to fill its ecological niche. The ecosystem would be forced to change and would allow new species to populate the habitat. A keystone species can be a predator and control the distribution and population of prey species.

The southern sea otters are a part of a complex ecosystem made up of bottom-dwelling creatures, whales, underwater kelp forests, and other species. The species are interdependent on one another for survival.  The sea otters feed on sea urchins, and sea urchins rely on kelp plants for nutrition. They act as a keystone species and prevent the elimination of kelp by controlling the population of sea urchins.

Care must be taken to protect otters from becoming extinct due to the following reasons:

• • In the absence of southern sea otters, the Pacific coast kelp forests would be destroyed by sea urchins and other kelp-eating species. The kelp forests are biologically diverse marine ecosystems. They support many marine plants and animals.
• • It is also unethical to allow human activities to cause the extinction of a species. Otters also help to generate millions of dollars a year in tourism revenues as they are appealing and highly intelligent animals.
• • The pollutants such as pesticides and herbicides may kill kelp plants and other species and disturb the food webs in these aquatic forests. Fertilizers can cause excessive growth of algae and other aquatic plants. This blocks the sunlight to support the growth of giant kelp and otters.
• • Southern sea otters consume shellfish. Accumulation of pollutants and toxic chemicals in the shellfish tissues also kills otters.
• • Orcas had started feeding more on southern sea otters when the population of prey such as lions and seals began to decline.
• • The feces of cats containing parasites in coastal waters may infect otters.

Thus, it can be concluded that the southern sea otters act as a keystone species in their environment as they prevent the elimination of kelp and must be protected from extinction.