Ecology of coordinated stasis

Coordinated stasis is indicated by recurrent fossil assemblages that have virtually the same species composition, species-abundance distribution, and skeletal morphology (of at least the dominant species), occurring at different geographic localities and stratigraphic levels within a particular region. Assemblages appear to persist for 105 to 106 yr, through multiple transgressive-regressive cycles, and seem to keep pace with shifting depositional environments. This type of paleoecologic stasis appears to record stable, long-lived regional ecosystems, which are larger and more durable than local ecosystems or “communities”. Although study of such large ecologic systems is just beginning, by both paleoecologists and neoecologists, it is not too early to consider the possible processes controlling their distribution and organization. Regional ecologic stasis may result simply from the prevalence of stable local systems, or it could require different explanations that take into account hierarchical properties of spatiotemporally extensive multispecies systems. Possible allogenic models include: coordinated faunal tracking of preferred environments, constancy of habitat structure and recruitment sources, and intervals of extreme environmental uniformity promoting deployment of large, long-lived benthic ecosystems. Promising autogenic models include: persistent metapopulation structure maintaining regional ecosystem composition and function, some form of large-scale connectance stability, and the incorporation of disturbance and turnover occurring in local systems within more persistent regional systems.