Sensing and site-specific dispersal rates
When the environment fluctuates within a sub-habitat, and environmental variability is sufficiently high, the optimal dispersal strategy is to produce a proportion of dispersing and non-dispersing seeds (Fig 3). If individuals do not have clues about which habitat they are in, then the only way to do this is disperse from all habitats in the same rate (combinations of dispersal rates that are the same in both patches sit on the diagonal in Figs 3a and b). However, when such clues are available and individuals can get a sense as to where they are, they adjust the dispersal rate to each habitat. The optimal dispersal strategy in both examples is then away from the diagonal, providing selection for site-specific dispersal rates, and, in this way, there is selection for sensing and adapting the dispersal rate to the native habitat. Which dispersal rates are selected for depends on the details, such as changes in frequency of environmental variability. Here we show the difference when there is a change in the frequency of the good years.