BackThe process of ecological locking requires strong species interactions to be a major ordering force on the composition and structure of communities. These strong species interactions should impose a consistent ecological structure (membership and relative abundance) whenever the same species are put together under similar conditions. Therefore, when similar taxa are found together under similar environmental conditions, they should yield a recognizable paleocommunity (in the sense of Bennington and Bambach 1996) which recurs whenever similar paleoenvironmental conditions are recognized. The hypothesis that strong species interactions are a major ordering force of the Yorktown fauna was tested using multivariate and constancy analyses.
The strongest correlations among Yorktown fossil assemblages were between samples from the same basic paleocommunity type collected at the same locality. Samples from the same paleocommunity type collected at different localities were dissimilar enough that the null hypothesis that they were the same could be discarded. Therefore, the strongest ordering force in Yorktown fossil assemblages is clearly local - i.e., local paleoenvironmental conditions.
The strong species interactions required for ecological locking to work are not recognizable in Yorktown faunas. Rather, the structure of the paleocommunities appears to be controlled by local paleoenvironmental conditions, as with Bambach and Bennington (1996), Bennington and Bambach (1996), Holterhoff (1996), and Stanton and Dodd (1997). Ecological locking can most likely be discarded as a major factor in maintaining the morphologic stasis seen in Yorktown lineages.