The balance between the foliage projective covers of overstorey and understorey strata in Australian vegetation

Abstract

Foliage projective cover [FPC] of the overstory (canopy) of a climax community appears to reach an equilibrium value determined largely by the prevailing climate. Overstory FPC decreases in climax communities in a graded series from humid to arid regions. Understory cover (of all strata below the canopy) in climax communities attains a balance with overstory FPC. Disturbance (gaps, microhabitats, fire, overgrazing, invasion of woody weeds, etc.) may reduce the overstory cover which will be compensated by an increase in understory cover. Secondary succession back to the climax structure will follow a path maintaining an inverse linear relationship between understory cover and overstory cover. Species diversity appears to decrease as overstory cover increases.