Fig. 1.

Anthropogenic disturbances could generally strengthen phenotypic selection by increasing maladaptation and/or the opportunity for selection. (A) The disturbance causes maladaptation by shifting fitness peaks away from current trait distributions. The gray histogram illustrates the trait distribution of a fictive population which is well adapted to predisturbance conditions, and the black and red curves show the hypothetical pre- and postdisturbance fitness functions of the same trait, respectively. (B) The disturbance diminishes mean absolute fitness (e.g., number of offspring), thus increasing the variance in relative fitness and the opportunity for selection.