Previous studies show that long distance dispersing has an evolutionarily advantage over short distance (or non-) dispersing under disturbance. Despite the widely seen correlation among dispersal distance, the number of dispersing offspring, and the offspring size; few large offspring move to the neighborhood of their parents site, or numerous small offspring disperse in distance, the tradeoff among them has not been discussed in the previous studies. Here, we consider the tradeoff, and investigate which is advantageous over the others under disturbance, the short distance strategy in which large offspring disperses in the neighborhood of parents or the long distance strategy which disperses many small offspring in distance, especially when mortality is size dependent. We also consider a case which offspring adopt a search strategy.

The mathematical analysis and agent-based simulation outcomes show that short distance dispersing, corresponding to budding, could be advantageous over number of small offspring dispersing long distance when (i) small organisms suffer higher mortality than relatively larger organisms, (ii) offspring search for vacant habitat and returns to the natal habitat if unsuccessful in searching, (iii) disturbance occur frequently but in small spatial scale, while short distance dispersal becomes disadvantageous when mortality is proportional to organism's size.