Final answer:
A climax community is indicated by the stabilization of a community's population and composition, which remains unless a significant disturbance occurs, resulting in the final stage of ecological succession.
Step-by-step explanation:
Scientists recognize that a climax community has been reached when they observe that the population of a community stabilizes and doesn't significantly change in size or scope, indicating the final stage of ecological succession. This means the succession of communities is completed, resulting in a stable balance of all organisms within the ecosystem.
The climax community will remain relatively stable unless a significant disturbance, like a disaster, alters the ecosystem, starting succession anew. It is important to note that what constitutes a climax community can vary greatly depending on the region's climate and geology, such as tropical rainforests in the tropics or coniferous forests in northern areas.