Time series analyses and Leslie matrix models for the growth rate of habituated groups.

The base case used the actual data for survivorship and fertility throughout the study, without making any adjustments for any types of deaths or veterinary interventions. The additional cases excluded deaths from poaching or respiratory disease, and added deaths when gorillas received veterinary interventions. The rate per gorilla-year equals the number of those deaths or interventions (N), divided by the 5652 gorilla-years observed during this study. The standard errors (SE) for those rates are calculated among the calendar years observed. Numbers in brackets indicate Leslie matrix predictions of the growth rate if 50% of the gorillas treated would have died in the absence of veterinary treatment. See the Methods for estimates of other potential sources of uncertainty in the growth rates.