FPC is almost the same as a metapopulation. Metapopulation theory assumes that all local populations can eventually become extinct. Beklemishev s approach is closer to island biogeography models where there is at least one stable independent population on the mainland. Some subpopulations are stable, some are not stable. The latter are supported by the immigration flow from stable subpopulations.
Population is a symmorphological and a symphysiological unit.
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