Keystone Species Impact on Ecosystems

A species that exerts a dominating influence on the structure and function of a community or ecosystem is identified as a keystone species. These species have a disproportionately large effect on their environment relative to their abundance.

Why Keystone Species?

• Keystone species significantly shape the ecosystem. Their removal can lead to dramatic changes, potentially causing the collapse of the community. Examples include sea otters controlling sea urchin populations or beaver dams altering habitats.

Other Species Types

• Fundamental species: While sometimes overlapping with keystone species, this term can also refer to species that create or significantly modify habitats (ecosystem engineers).
• Functional species: This is a broad category including any species performing a specific role (like producers or decomposers) but doesn't necessarily imply a dominating influence.
• Indicator species: These species serve as early warnings for environmental problems or health changes in an ecosystem, reflecting conditions rather than dominating structure/function.

Therefore, the definition provided in the question most accurately describes a keystone species.