During ecological succession, predictable structural and functional changes occur as an early pioneer stage progresses toward a mature climax ecosystem. Which of the following statements accurately characterizes the trends in community bioenergetics, biomass accumulation, and species interactions during this succession?
- Total ecosystem biomass accumulates while net community productivity approaches zero as gross primary productivity becomes balanced by community respiration.Answer
- BNet community productivity reaches its highest peak at the climax stage because secondary succession continuously accumulates unconsumed organic yield faster than primary succession.
- CEarly pioneer colonizers on bare rock rely on specialized vascular transport tissues (xylem and phloem) to extract mineral nutrients directly from unweathered substrate.
- DPrimary succession proceeds rapidly without pioneer weathering because pre-existing organic soil beds are already established prior to colonization.
Answer
Total ecosystem biomass accumulates while net community productivity approaches zero as gross primary productivity becomes balanced by community respiration.
As an ecosystem matures toward a climax community, species richness and total biomass increase. Energy expenditure for maintenance (community respiration) rises until total gross primary productivity equals total respiration. Consequently, net community productivity drops toward zero while biomass-to-energy-flow ratios reach maximum stability.
Step-by-Step Solution
Key Concept
Bioenergetics and System Dynamics of Ecological Succession