Fig. 6. Mean-variance portraits are quantified in terms of characteristics of ecological resilience, particularly by amplitude. Amplitude is the magnitude of the response of the landscape’s transformed normalized difference vegetation index (TNDVI) from reference conditions (in 1972) during or after a disturbance (in 1984). The amplitude for each statistic is calculated by subtracting (A) the mean TNDVIs for 1972 and 1984 and (B) the mean of the TNDVI variances for 1972 and 1984.