Separate populations of the same species often exhibit correlated fluctuations in abundance, a phenomenon known as spatial synchrony. Dispersal can generate spatial synchrony and more frequent dispersal increases synchrony. However, dispersal patterns investigated are typically simplistic and ignore occasional long-distance dispersal, which is common in natural systems. I used protist microcosms and theoretical models to investigate the impact of dispersal pattern on spatial synchrony.
I found that occasional long-distance dispersal significantly increased spatial synchrony. This is due to the nonlinear relationship of synchrony to dispersal rate in the microcosm system. Increased long-distance dispersal at the expense of short-distance dispersal increased synchrony of widely separated populations without affecting short-distance synchrony. However, the theoretical models show that occasional long-distance dispersal can reduce short-distance synchrony without increasing long-distance synchrony, decreasing overall synchrony, depending on the shape of the dispersal rate-synchrony relation.