PAS P2a, Time Series Analysis uses data from specific interacting populations obtained by regular population sampling; i.e., a set of records for the density of each species per unit area of habitat taken at equal intervals over a particular stretch of time. The analysis is most appropriate for species with discrete generations or breeding cycles; i.e., animals with a single generation a year or which breed at a particular time each year. However, P2a has also been used successfully to model continuously breeding organisms.
Data should be in the form of population density counts of a particular stage of development, or of all stages added together, taken at discrete and equidistant points in time. The data must be entered in the Single-Species Time Series Analysis program P1a. Then each population must be analyzed by P1a and the models created must be saved to disk. These single-species models are then used as the default models when P2a indicates that the two species do not interact with each other. Models must be created by P1a and saved to disk for P2a to run properly.