Benthic marine faunas are currently experiencing rapid shifts in community structure which are already having deleterious effects on marine ecosystems. Since many systematic surveys of marine communities occurred after those communities had been disturbed, our knowledge of “what is natural” is incomplete: a phenomenon that has been termed the “shifting baseline syndrome.” Since ecologic restoration efforts require an understanding of previous community states, alternative methods for delineating pre-disturbance community states are essential. In this study we apply analyses of life vs. death assemblage composition of communities that have undergone different histories of disturbance. Live and dead mollusks obtained from transects constructed in two bays adjacent to San Salvador Island, Bahamas, were identified and community structure was compared. In Snow Bay, where little anthropogenic disturbance has occurred, diversity and relative abundance between life and death assemblages were more similar than the same metrics for life and death assemblages collected from Bonefish Bay, where development has resulted in elevated levels of fecal coliform bacteria. We conclude that the changes to the benthic molluscan communites resulting from development in Bonefish Bay have not yet been recorded by the attendant death assemblage. Thus, molluscan death assemblages may be used as proxies for pre-disturbance community states in environments that have already been degraded.
Kelsey Feser, ’10 Manning, IA
Sponsor: Benjamin Greenstein