An abandoned agricultural field in a temperate region undergoes predictable ecological changes over time. Arrange the stages of secondary ecological succession in the correct chronological order from the initial disturbance to the formation of a stable ecosystem.
- 1Pioneer annual weeds and crabgrass rapidly germinate and colonize the exposed soil.
- 2Perennial grasses and herbaceous flowering plants take root and outcompete annual species.
- 3Sun-loving shrubs and fast-growing pioneer trees such as young pines form a low canopy.
- 4Shade-tolerant hardwood trees, such as oaks and maples, grow into a dense, mature climax forest.
Answer
The correct chronological sequence begins with pioneer annual weeds, followed by perennial grasses, then shrubs and pioneer pines, and concludes with a mature hardwood climax forest.
Secondary succession begins in an area where an existing ecosystem was disturbed but soil remains intact. Fast-growing annual weeds colonize the bare soil first, followed by perennial grasses, which build soil organic matter. Woody shrubs and sun-loving pioneer trees next form a mid-successional canopy. Finally, slow-growing, shade-tolerant hardwood trees establish and form a persistent climax forest.
Step-by-Step Solution
Key Concept
Secondary ecological succession follows an orderly progression of plant communities on previously inhabited, disturbed soil until reaching a stable climax community.