Time-averaging, taphonomy, and their impact on paleocommunity reconstruction: death assemblages in Texas bays.

The death assemblages in upper Copano Bay and upper Laguna Madre, Texas, were compared with the living communities as sampled over a two-year period in order to determine how taphonomy and time-averaging affect paleocommunity reconstruction. The living and death assemblages were compared using taxonomic composition, numerical abundance, diversity, biomass, and trophic and habitat proportions. Taxonomic composition, particularly adult taxonomic composition, and the biomass of the death assemblage more accurately reflect the characteristics of the living community than do numerical abundance and other community attributes based upon numerical abundance such as diversity. Taxonomic composition and biomass are less modified by taphonomy and time-averaging, because they are temporally more persistent characteristics of the community. Community and paleocommunity attributes are not equivalent, because the paleocommunity is described using time-averaged data. Ecological theory must be supplanted by paleoecological theory that takes into account this temporal component.