Lefkovitch matrix models

Although Leslie matrix models have the longer history, an alternative approach introduced in the mid-1960's by Lefkovitch is often more useful. Rather than being based on age-specific survival and fecundity rates, it is based on stage-specific survival rates. Lefkovitch models are often more useful for several reasons:

• It's often difficult or impossible to age animals and plants accurately.

• In some organisms, especially perennial plants, survivorship and fecundity are more closely related to size (or some other variable by which a population might be stage-classified) than to age.

• In some organisms, especially herbaceous perennial plants, individuals may actually revisit stages they already left, e.g., they may get smaller from one season to the next.

• Focusing on life-cycle stages helps to focus attention on identifying the critical transitions that may provide opportunities for management.