What is a keystone species?

A keystone species is defined as a critical species that plays a fundamental role in maintaining the structure, diversity, and overall functioning of an ecosystem. The concept originates from the idea in architecture where a keystone holds all the other stones in place, ensuring stability. Similarly, in ecological terms, a keystone species exerts a disproportionately large influence compared to its abundance within the ecosystem.

The presence or absence of a keystone species can lead to significant changes in the entire ecosystem, affecting other species and the habitat overall. For example, predators, like sea otters or wolves, can control the populations of herbivores, which in turn influences plant communities and overall biodiversity. Their role is vital, as their interactions help to regulate various ecological processes.

This distinction is crucial, as it highlights the connection and interdependence of species within ecosystems. Other options suggest diminished roles or disruptive characteristics that do not capture the importance or influence keystone species have on ecological balance.