What is Community Succession?
Community succession is the gradual change in species composition and ecosystem structure over time. Starting from bare substrate or disturbed land, pioneer species colonize first, followed by a progression toward a stable climax community shaped by environmental conditions and species interactions.
Community succession is ecological change driven by pioneer species establishing first, then being replaced by later species over decades or centuries until reaching climax equilibrium. Two main types exist: primary succession (bare rock/lava) and secondary succession (disturbed but not sterilized land).
- 1↓Pioneer Species ColonizationLichens, mosses, grasses establish on bare rock or fresh lava flow; create soil and organic matter.
- 2↓Early Succession (Herbaceous Stage)Herbs and small shrubs increase; soil deepens; species diversity grows; shade gradually increases.
- 3↓Mid-Succession (Shrub/Young Forest)Shrubs and small trees dominate; shade-tolerant species emerge; understory develops; soil enriches.
- 4↓Late Succession (Mature Forest)Large shade-tolerant trees dominate; complex canopy layers; high biodiversity; stable nutrient cycling.
- 5Climax CommunityStable self-replacing community in equilibrium with climate; dominant species shade-tolerant; minimal change without disturbance.
Step-by-step worked examples
A lava flow in Hawaii is colonized by pioneer species. Trace succession for 200 years.
Year 0–10: Lichens and mosses establish, breaking rock into soil. Year 10–50: Grasses, ferns, small shrubs appear; soil thickens. Year 50–150: Native 'ōhi'a trees establish; understory fills with native plants. Year 150+: Mature 'ōhi'a forest with diverse canopy and ground layer.
An abandoned farm in North Carolina stops being plowed. What is the succession pathway?
Year 0–3: Pioneer annuals (crabgrass, ragweed) quickly dominate. Year 3–10: Perennial grasses and small shrubs; pine seedlings establish. Year 10–30: Pine forest dominates; shade increases; oak seedlings germinate. Year 30+: Oaks replace pines; transition to oak-hickory hardwood forest (climax for the region).
A forest fire destroys most vegetation in a temperate woodland. Is this primary or secondary succession?
This is secondary succession — soil remains intact despite fire. Year 1–2: Fast-growing herbaceous plants and grasses dominate (pioneer herbaceous stage). Year 2–15: Shrubs and small trees (often fire-adapted species like aspen) establish. Year 15+: Slower shade-tolerant species gradually replace pioneers; eventual return to original forest type or new climax depending on climate shifts.
Flashcards
Quick quiz
Q1.Which organisms typically colonize bare rock first?
Q2.Primary succession occurs on…
Q3.What defines a climax community?
Q4.A forest fire kills trees but leaves soil intact. What type of succession follows?
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Common mistakes
Primary and secondary succession start the same way. — Correct: Primary begins on bare rock with no soil; secondary begins with existing soil and is faster.
Pioneer species stay in an ecosystem permanently. — Correct: Pioneers are eventually shaded out and replaced by mid- and late-succession species.
Succession stops when the first tall trees appear. — Correct: Succession continues for decades or centuries until climax; species composition keeps changing.
All ecosystems reach the same climax community. — Correct: Climax community is determined by local climate, soil, and latitude — varies by region.
FAQ
What are pioneer species and why are they important?
Pioneer species (lichens, mosses, grasses) colonize bare substrate first. They break down rock, create soil, and shade the ground, enabling later species to establish.
How long does community succession take?
Primary succession: 100–1000+ years (soil formation is slow). Secondary succession: 50–200 years (soil already exists).
What is the difference between primary and secondary succession?
Primary: bare substrate, soil must form from scratch, very slow. Secondary: existing soil remains, faster recovery, often after fire or human disturbance.
Can a climax community be disturbed?
Yes — fire, logging, or climate change can reset succession. The ecosystem then begins secondary succession anew.