The dangers of ignoring metapopulation structure for the conservation of salmonids

Because of their tendency to return to natal streams, salmonid populations have often been viewed in ecological isolation, although the notion of an e volutionarily significant unit (ESU) recognizes dispersal on evolutionary t ime scales. We investigated the consequences of dispersal (straying) on an ecological time scale where straying creates a metapopulation structure for salmonid streams within an ESU. We developed a simple model for salmonid m etapopulations, focusing on source and sink populations, and used the model to highlight the dangers of ignoring this structure in conservation effort s. We show that exactly the wrong conservation efforts may occur if metapop ulation structure exists but is ignored.