Keystone species and foundation species are sometimes also ecosystem engineers, which change the environment and provide habitat for a variety of species.In the process, they have a profound effect on community structure.Which of the following would be considered members of keystone or foundation species but not ecosystem engineers?
A) Beavers that cut down trees and dam streams, changing flowing water into ponds
B) Porcupines that, while digging for food, create soil pits that persist and create plant habitats
C) Termites that build mounds, increasing soil fertility and plant density in the area
D) Woodpeckers that excavate holes in dead trees, creating habitats for a variety of species
E) Sea otters that act as top predators and start trophic cascades in kelp ecosystems

Question

Quizplus · Accepted Answer

Sea otters are considered keystone species because of their critical role in maintaining the structure of the kelp ecosystem by preying on sea urchins, which in turn helps to control the sea urchin population and prevent overgrazing of kelp forests. Unlike the other examples, sea otters do not physically modify the environment or create new habitats through engineering activities; they influence the ecosystem through their predatory relationships.

Keystone Species and Foundation Species Are Sometimes Also Ecosystem Engineers