Hypothesized changes in dispersal distances according to different dispersal causes. Notice that the competition scale varies according to the relationship between the partners engaged in competition. Parent-offspring competition should entail short dispersal distances. Kin competition should generate variable dispersal distances according to the genetic structure of the population, eventually leading to colonization of new habitats by specially designed phenotypes. Conspecific competition should entail emigration out of populations. Modified from [18,26,27].