Table 9. Critical threshold of population parameters for female Pipistrellus pygmaeus, below which a population of 100 females is likely to become extinct within an arbitrary 500 years; figures in brackets show the vital rates used in the population models.
| Vital rate | Critical values (vital rates) | |
|---|---|---|
| Annual survival | ||
| Survival in first year | S 1 | 0.46 (0.527) |
| Survival in second year | S 2 | 0.70 (0.799) |
| Survival in third year plus | S 3 | 0.77 (0.799) |
| Productivity | ||
| Mean litter size in second year | L 2 | 0.20 (1.038) |
| Mean litter size in third year plus | L 3 | 0.85 (1.038) |
| Proportion breeding in second year | Alpha 2 | 0.18 (0.930) |
| Proportion breeding in third year plus | Alpha 3 | 0.77 (0.930) |