Figure
10.1. Life graphs and matrices for three linear deterministic matrix models. Circles denote an age or stage,
represented by a row and column in each matrix. Arrows denote transition probabilities and fecundity: P = probability
of surviving and remaining in a stage, G = probability of surviving and
“growing” into another stage, F = number of
same-sex offspring produced per reproductive individual. (a) A Leslie matrix, with each row and column representing
a single time step. Individuals die after year 4; (b) stage-based model for Loggerhead Sea Turtles
(Crowder et al.
1994). Individuals spend 1 year in stage 1 and multiple years in stages 2–5.
This model has a postbreeding census
(Caswell 1989); subadults that become adults in each time step reproduce, and a fecundity term appears in the fourth
column (starred). (c) Male-only stage-based model for Red-cockaded Woodpeckers
(Heppell et al. 1994). Multiple
transitions are possible for fledglings, helpers, and floaters. Nonbreeding helpers increase fledgling survival rates (F 2
).
As in the Loggerhead Sea Turtle model, the postbreeding census requires the matrix to include fecundity terms for
fledglings, floaters, and solitary males that become breeders just before the census (starred).
10.1. Life graphs and matrices for three linear deterministic matrix models. Circles denote an age or stage,
represented by a row and column in each matrix. Arrows denote transition probabilities and fecundity: P = probability
of surviving and remaining in a stage, G = probability of surviving and
“growing” into another stage, F = number of
same-sex offspring produced per reproductive individual. (a) A Leslie matrix, with each row and column representing
a single time step. Individuals die after year 4; (b) stage-based model for Loggerhead Sea Turtles
(Crowder et al.
1994). Individuals spend 1 year in stage 1 and multiple years in stages 2–5.
This model has a postbreeding census
(Caswell 1989); subadults that become adults in each time step reproduce, and a fecundity term appears in the fourth
column (starred). (c) Male-only stage-based model for Red-cockaded Woodpeckers
(Heppell et al. 1994). Multiple
transitions are possible for fledglings, helpers, and floaters. Nonbreeding helpers increase fledgling survival rates (F 2
).
As in the Loggerhead Sea Turtle model, the postbreeding census requires the matrix to include fecundity terms for
fledglings, floaters, and solitary males that become breeders just before the census (starred).