Table 1. Modelled elephant population growth rate, population doubling time and population size for the contraception period 2006–2026.
| Modelled scenarios for Munyawana elephant population | Parameters | Annual growth rate (%)v | Population doubling time (years)vi | Projected population size | ||||
| Age of sexual maturity (years)i | Implemen-ation age (years)ii | Concep-tion duration (years)iii | Calving interval (years)iv | 2006 (start) | 2026 (end) | |||
| Munyawana- current contraception plan | The combined Phinda & Sutton contacepted, Zuka non-treated plans | 4.20 | 18 | 98 | 230 | |||
| Munyawana- no-contraception plan | 9 | - | - | 3 | 7.58 | 10 | 102vii | 469 |
| Scenario 1 | 9 | 10 | 1 | 8 | 4.16 | 18 | 98 | 217 |
| Scenario 2 | 9 | 10 | 3 | 8 | 4.13 | 18 | 98 | 216 |
| Scenario 3 | 8 | 9 | 2 | 8 | 4.36 | 17 | 98 | 228 |
| Scenario 4 | 9 | 10 | 2 | 8 | 4.15 | 18 | 98 | 216 |
| Scenario 5 | 10 | 11 | 2 | 8 | 4.03 | 19 | 98 | 211 |
| Scenario 6 | 9 | 8 | 2 | 8 | 3.19 | >20 | 98 | 178 |
| Scenario 7 | 9 | 10 | 2 | 6 | 5.06 | 15 | 98 | 259 |
| Scenario 8 | 9 | 10 | 2 | 10 | 3.48 | 20 | 98 | 196 |
| Current contraception plan for the individual elephant populations within the Munyawana Conservancy | ||||||||
| Phinda | 9 | 11 | 3 | 8 | 3.71 | 19 | 87 | 184 |
| Zuka-no-contraception | 9 | - | - | 3 | 8.73 | 6 | 4 | 25 |
| Sutton | 8 | 10 | 3 | 9 | 5.26 | 12 | 7 | 21 |
Parameters for the age of sexual maturity were 8 years, 9 years (baseline) and 10 years.
Parameters for the contraception implementation age were 8 years (prevent the first calf and only allow the first calf at 19 years after allowing an 8 year calving interval) or 10 years (baseline – allows the first natural birth, if the cow conceive at the baseline of 9 years age at sexual maturity).
The length of time that a female was released from contraception to ensure conception, with the parameters of 1 year, 2 years (baseline) and 3 years.
Parameters for the contraception induced calving intervals were 6 years, 8 years (baseline) and 10 years.
The growth rate was calculated for the 20-year time span (2006–2026) from the slope of regression on the natural log of population size against year.
The time it takes for the population to double the starting numbers.
The Munyawana elephant population total at the beginning of 2006, was calculated as if no females were on contraception for the past 3 years and would have conceived, accordingly a calving interval of 3 years was maintained from the age of the youngest calf.
The parameters for the eight individual modelled scenarios and the current implemented immunocontraception plans within the Munyawana population are presented within the table above.