Chapter 12 - Age-grouping, Time-specific Life-tables and Predictive Population Models

This chapter is concerned with techniques for animals whose generations overlap widely; age-grouping is a prerequisite for these methods which have been most widely applied to vertebrate populations. Analysis is easiest with two extreme types of population - the stationary and the exponentially expanding. If the population can be assumed to be stationary, then the fall-off in numbers in successive age groups will reflect the survivorship curve and thus a time specific (or vertical) life-table can be constructed on this basis. If the population is expanding, unconstrained by its environment, the age structure may become stabilized and then mortality can be estimated from the difference between expected and actual growth rates.

Age-grouping may also provide useful information on the fertility or potential fertility of the population.

12.1 Age-grouping 12.1.1 Ageing young by developmental stage 12.1.2 Ageing by using structures 12.2 Time-specific life-tables and survival rates 12.2.1 Physiological time 12.2.2 Life-table parameters 12.2.3 Recruitment in the field 12.2.4 Empirical models 12.2.5 Intrinsic rate models and variable life tables 12.2.6 Lewis-Leslie matrices