THE DYNAMICS OF JUVENILE DISPERSAL - WHY FIELD ECOLOGISTS MUST INTEGRATE

The impact of dispersing juveniles on population and community dynamic s is a topic of considerable debate, particularly for marine species w ith broadly dispersing larvae. We argue that sampling problems continu e to pose a serious impediment to progress. The root of the problem is the large variation in dispersal dynamics over space and time. For sh ort-distance dispersal the variance in dispersal has been largely igno red. By contrast, for long-distance dispersal the variance in dispersa l may have been overemphasized due to the inappropriate time scales of sampling. We present data for an intertidal barnacle, Semibalanus bal anoides, to contrast conclusions reached from standard sampling of lon g-distance juvenile dispersal with those reached by techniques that mo re appropriately integrate the dynamics of dispersers over time. The s tandard sampling approach misrepresents the true juvenile dynamics.