Constructing a life-cycle graph

The easiest way to understand Lefkovitch models is to talk about the construction of a life cycle graph.

1. Choose a projection interval, commonly a year.

2. Identify life-cycle stages and define a node for each.

3. Draw a directed line from each node to any other node into which it can move in a single time step.

4. Label each line with a coefficient reflecting either the probability of the transition or reproductive outputs (for lines leading to the initial life stage).

You can see an example of this in the life cycle graph for teasel (Figure 1).

Figure 1: A life cycle graph for teasel (Dipsacus sylvestris, redrawn from Figure 4.4 of [1]).