Many argue that environmental variability and, increasingly, regional threats, are the major controls on real metapopulations. Because recolonization depends on the successful establishment of new recruits in a habitat patch, the factors influencing recolonization must reflect the life-history traits that effect this. Predictions from Theory Migration can alter population dynamics qualitatively. Patchy population distributions can develop as a result of local migratin, even on a homogeneous physical template. Metapopulations can persist even in cases where many or all of the local populations in patches are extinction-prone.
Extinction thresholds emerge as habitat levels below which the metapopulation fails.
Moreover, these thresholds may not be predictable or detectable until after the threshold has been passed. Isolation effects arise because recolonization probabilities decrease as a function of increasing distance to a propagule source. Asynchrony in location population dynamics can arise a consequence of the balance of local birth and death processes, extinctions, and recolonizations. This is manifest as appreciable population turnover. In general, the predictions of metapopulation theory are intuitive and compelling but have found only weak support in field studies.