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How does ecological succession change the species composition of a community over time?

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Diagram showing energy flow in a food chain from a tree to a caterpillar, then to a bird, and finally to microbes, with red arrows illustrating energy transfer and heat loss at each stage. — community ecology Energy transfer and heat loss along a food chain.

Ecological succession is the process by which the structure of a biological community evolves over time through a partially predictable sequence of species replacement. This progression is driven by the fact that species modify their environment, creating conditions that favor new arrivals while becoming less hospitable to the current inhabitants.12

The process typically follows these stages:

Colonization: In disturbed or barren environments, pioneer species—such as lichens, mosses, and microorganisms—are the first to arrive. These species are adapted to harsh conditions and reproduce quickly.3
Modification: As pioneer species grow and die, they alter the habitat, such as by building soil fertility or changing mineral composition.13
Succession: These environmental changes allow new, better-suited species to move in. For example, as taller plants like shrubs and trees become established, they cast shade that deprives pioneer species of the sunlight they require, causing the pioneers to die out locally.32
Climax: Succession may eventually reach a climax community, a relatively stable state dominated by a small number of prominent species.13