Population Viability Analysis of the Endangered Roan Antelope in Ruma National Park, Kenya, and Implications for Management
Table 3
Results of the VORTEX PVA model for roan antelopes simulated over 100 years under alternative management options.
Management option
SD ()
PE (%)
SD ()
TE (years)
Baseline (no action)
−0.074
0.186
100
0
0
32
Restocking with 4 groups (option 7a)
−0.07
0.185
100
0
0
36
Restocking with 6 groups (option 7b)
−0.07
0.178
100
0.01
0
42
Restocking with 8 groups (option 7c)
−0.071
0.173
99.9
0.01
0.19
45
Restocking with 10 groups (option 7d)
−0.07
0.171
99.8
0.02
0.22
48
Reduced fire severity (option 4)
−0.055
0.178
99.2
0.12
1.41
43
Reduced drought severity (option 5)
−0.044
0.164
97.2
1.05
2.77
53
Calf mortality 5% (option 2)
−0.061
0.183
99.9
0
0.06
38
Subadult mortality 5% (option 3)
−0.068
0.185
99.9
0
0.06
35
Adult mortality 10% (option 1)
0.001
0.134
13.7
66.37
49.27
>100
Combined interventions (option 6)
0.023
0.099
0.2
248.3
31.58
>100
Protected sanctuary with current population of 3 groups (option 8a)
0.043
0.095
0
582.13
62.76
>100
Protected sanctuary with 4 groups (option 8b)
0.043
0.096
0
586.38
64.12
>100
Protected sanctuary with 6 groups (option 8c)
0.042
0.095
0
586.27
65.38
>100
Protected sanctuary with 8 groups (option 8d)
0.041
0.095
0
588.45
56.91
>100
Protected sanctuary with 10 groups (option 8e)
0.041
0.094
0
590.99
61.08
>100
NB: and SD () = population growth rate and its standard deviation; PE (%) = mean probability of extinction; and SD () = mean population size and its standard deviation; TE = median time to extinction, in years.
