Practice question

A mature or conventionally defined climax community has high standing biomass and relative stability because long-lived organisms and complex trophic interactions dominate after prolonged succession. Plants accumulate woody tissue and extensive roots, while soils store organic matter and nutrients. Gross primary production may remain substantial, but community respiration also becomes large because the accumulated biomass must be maintained. Net ecosystem production therefore approaches a lower value than in rapidly growing earlier stages. Stability here means persistence or recovery around a dynamic range, not an unchanging endpoint; fires, storms, climate shifts, herbivory, and species turnover continue. Diversity is often higher than in pioneer stages, although it does not invariably reach a maximum. High primary productivity alone is not diagnostic, and high productivity combined with instability better describes some early or disturbed systems. Modern ecology recognizes multiple possible late-successional states rather than one universal climax. Within the classic succession framework used by the item, however, accumulated biomass and comparatively stable community organization are the expected defining features.