We try to explain the large differences observed in the proportion of needles colonized by fungal species in coniferous litter by spore dispersal properties. We constructed a population dynamics model, assuming that litter is a resource that is fragmented into ephemeral units, periodically produced. Spore dispersion on needles on a small spatial scale was assumed to follow a Poisson distribution. The model was compared with an experimental system using Thysanophora penicillioides on Abies alba needles and its relevance to field conditions is discussed.