Integrating Molluscan Dead-Shell Assemblages with Long-Term Biological Monitoring: Archives of Spatio-Temporal Gradients in Puget Sound, Southern California, and Jamaica

'Live-dead comparison' refers to the measurement of compositional fidelity between living communities and co-occurring accumulations of dead skeletal material (time-averaged 'death assemblages') and has long been used as a means of validating taphonomic and paleoecological interpretations in the fossil record. More recently, live-dead comparisons have been applied as a tool for detecting biological strain resulting from anthropogenic stressors on local to regional scales. However, two important limitations to live-dead comparisons remain underexplored: (1) to what extent are the organisms that readily-preserve in death assemblages (and the fossil record) a sufficient proxy for the broader ecological patterns of living communities that include a plurality of soft-bodied clades, and (2) what temporal context and variation is lost when – as is typically the case – the living community is only sampled once alongside the dead (i.e., a single 'snapshot' of standing diversity)? Examining these questions requires time series of living community compositional data with a broad taxonomic scope; such datasets are the purview of long-term biomonitoring programs, be they government-mandated, contracted, or non-profit. The following chapters represent collaborative efforts between academic paleontologists and agency ecologists to assess the power of bivalve death assemblages as surrogates of the whole-fauna community dynamics using exceptionally-long time series or historical records in three environmentally-distinct locations: (1) the naturally-variable regional benthos of Puget Sound (Chapter 1; 30-year living time series + death assemblage), (2) the historically-polluted Palos Verdes shelf off of Los Angeles County (Chapters 2-3; 50-year living time series + two death assemblages), and (3) the mangrove swamps of Jamaica's Kingston Harbour (Chapter 4; one live-dead sampling + historic surveys of the living).