Mean migration rates with increasing degrees of freedom (DOF) in a <i>t</i>-distribution kernel for long-distance dispersal.

<p>Bars indicate envelope of one standard deviation. When DOF = 1, the dispersal kernel is "heavy tailed." When DOF is >>1 (e.g. DOF = 100), the dispersal kernel has the comparatively limited range of a Gaussian distribution, and resulting mean migration rates represent the rate of spreading by local diffusion.