Table 3. Perturbation of invaded area with time for each model.

Model	t = 8	t = 18	t = 28
Model A worst	0.50	0.91	0.36
Model A best	0.46	0.94	0.39
Model B	0.35	0.26	0.12
Model C	1.29	0	0.02
Model D	ND (*)	0.70	0 (¤)

A value of zero means that the scaled area does not change with a combination of parameters +/−10%. (*) ND means that the value is not defined because the invaded area for the baseline value is 0. (¤) Since a change in the parameter values of model D has negligible effects on the invaded area at time t  = 18 yrs (see Table 2), it was not possible to define worst and best cases associated with this variable, and the sensitivity was set to 0.