A METHOD TO DETERMINE THE MEAN POLLEN DISPERSAL OF INDIVIDUAL PLANTS GROWING WITHIN A LARGE POLLEN SOURCE

Pollen dispersal has been recently focused on as a major issue in the risk assessment of transgenic crop plants. The shape of the pollen dis persal of individual plants is hard to determine since a very large nu mber of plants must be monitored in order to track rare long-distance dispersal events. Conversely, studies using large plots as a pollen so urce provide a pollen distribution that depends on the shape of the so urce plot. We report here on a method based on the use of Fourier tran sforms by which the pollen dispersal of a single, average individual c an be obtained from data using large plots as pollen sources, thus all owing the estimation of the probability of long-distance dispersal for single plants. This method is subsequently implemented on simulated d ata to test its susceptibility to random noise and edge effects. Its c onditions of application and value for use in ecological studies, in p articular risk assessment of the deliberate release of transgenic plan ts, are discussed.