Ontogenetic states, effective density, and classification of plant populations

Uranov (1975) formulated a theory of the age structure of plant populations and, in particular, defined the index of ageness Delta. On the basis of th is theory, the concepts of the energy efficiency of plants in a certain ont ogenetic state and the average efficiency of a population (omega) are intro duced. A new classification of populations with respect to the types of age structure is proposed which is based on both the Delta and omega values an d, accordingly, is named the delta-omega classification. The notion of effe ctive population density is defined. This parameter takes into account diff erent "loads" of plants in different ontogenetic states on the environment and is quantitatively equal to the product of the population density and om ega. The proposed approaches and methods are illustrated by data on the dis tribution of age states in different plant species.