TAPHONOMIC LAG ON LAND: SNAIL DEATH ASSEMBLAGES SHOW RAPID INCORPORATION OF SYNANTHROPIC LIVING COMMUNITIES ON SAN SALVADOR ISLAND, THE BAHAMAS

In the emerging field of conservation paleobiology, disparities between life and death assemblages have been utilized to quantify anthropogenic changes in community composition. Taphonomic inertia describes the rate at which these disparities change as the death assemblage incorporates elements of the changing living community. Live/dead comparisons repeated over several years can provide a unique opportunity to assess this rate directly. While pioneered in marine systems, live/dead surveys are of clear value in the terrestrial realm as well, given the intense anthropogenic transitions that many terrestrial sites are experiencing. It is therefore important to quantify taphonomic inertia in these settings.

Yanes (2012) conducted an extensive live/dead survey of the land snail fauna of San Salvador Island, The Bahamas, in 2010. That study revealed a large disparity between life and death assemblages in anthropogenically altered sites. In 2015 the localities of Yanes (2012) were revisited and, following the same methodology, comperable samples were collected. Relative to 2010, similarities of life assemblages to sympatric life assemblages increased significantly. This suggests that the death assemblage is dynamic, with a high rate of taphonomic incorporation – a limited window for taphonomic inertia – in this system, and that community change may only be detectable in this way for a limited time.